Optical laminate, and polarizing plate, surface plate and image display device provided with the optical laminate

Abstract

Provided is an optical laminate that does not use a specific material for an easy-adhesion layer, has excellent adhesion between a polyester film having a high degree of face orientation ΔP and the easy-adhesion layer, and that suppresses local defects. An optical laminate has an easy-adhesion layer, a concavo-convex layer, and an anti-fouling layer on a polyester film, defines the refractive index in the slow axis direction in the plane of the polyester film as nx, the refractive index in the direction orthogonal to the slow axis in the plane as ny, and the refractive index in the thickness direction of the polyester film as nz, the polyester film satisfies the following formula 1-2, for the concavo-convex layer, defines the three-dimensional skewness of the surface of the concavo-convex layer as Ssk, and the three-dimensional arithmetic mean roughness of the surface of the concavo-convex layer as Sa, Ssk and Sa satisfy the following formula 2-1. 0.140 ≤ ΔP (1-2) 0.80 ≤ A ≤ 1.90 (2-1) [In formula 1-2, "ΔP" represents "((nx+ny) / 2)-nz".] [In formula 2-1, "A" represents "log 10 (Sa[μm]×100 / Ssk)". Wherein, 0 < Ssk].

Description

Technical Field

[0001] The present invention relates to optical laminates, and polarizers, surface plates and image display devices having the optical laminates. Background Technology

[0002] In image display devices such as liquid crystal displays, organic EL displays, micro LED displays, small LED displays, and quantum dot displays, various optical laminates are incorporated to improve image visibility and suppress damage to the device surface. These optical laminates are typically formed by constructing functional layers such as uneven layers on a plastic film. Furthermore, triacetylcellulose films with low optical anisotropy are preferably used as the plastic film in the optical laminate. In this specification, "triacetylcellulose film" is sometimes referred to as "TAC film".

[0003] However, TAC films have problems with dimensional stability and mechanical strength, especially in large-screen image display devices.

[0004] Therefore, polyester films such as polyethylene terephthalate (PET) films have been proposed as alternatives to TAC films. In this specification, "polyethylene terephthalate film" is sometimes referred to as "PET film".

[0005] However, when PET film is applied to image display devices that output polarized light, such as liquid crystal displays and organic EL displays, rainbow-like interference patterns called iris spots are generated due to the in-plane phase difference of the PET film, which reduces visibility.

[0006] As a countermeasure against iris spots, a method has been proposed to make the in-plane phase difference of the PET film extremely large (for example, Patent Document 1).

[0007] The PET film with extremely large in-plane phase difference in Patent Document 1 is obtained by unidirectionally stretching the PET film. However, unidirectionally stretched films have problems such as being prone to breakage in the stretching direction.

[0008] As a countermeasure against iris spots, contrary to Patent Document 1, a means of reducing the in-plane phase difference of the PET film was considered.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2011-107198

[0012] Patent Document 2: Japanese Patent Application Publication No. 2012-32819

[0013] Patent Document 3: Japanese Patent Application Publication No. 2016-6530 Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] PET films with small in-plane phase differences can be obtained, for example, by reducing the stretch ratio. However, PET films with reduced stretch ratios have lower mechanical strength due to inconsistent orientation in the thickness direction, thus lacking practicality.

[0016] Furthermore, PET films with small in-plane phase differences can be cited as examples of PET films. Compared with general biaxially oriented PET films, the PET films of Patent Documents 2 and 3 reduce the in-plane phase difference by reducing the difference in stretch ratio between the MD direction (flow direction) and the TD direction (width direction).

[0017] PET films like those in Patent Documents 2 and 3, which reduce in-plane phase difference without decreasing the stretch ratio, are characterized by high planar orientation degree ΔP. However, due to the poor adhesion of the easy-to-bond layer in these biaxially oriented PET films with high planar orientation degree ΔP, the interface between the PET film and the easy-to-bond layer is prone to peeling when a functional layer is applied to the easy-to-bond layer. This problem can be solved by using an easy-to-bond layer made of a material with excellent adhesion. However, in the above solutions, the range of materials that can be selected for the easy-to-bond layer is limited, restricting product design and thus lacking practicality. Furthermore, in the case of overall optical design of optical laminates, when an easy-to-bond layer of a specific material exists on the PET film, the materials of the functional layers formed on the easy-to-bond layer are also limited.

[0018] In addition, when a functional layer is formed on a biaxially oriented PET film with a high degree of planar orientation ΔP by means of an easy-to-adhere layer, local differences in transmittance and reflectance may sometimes cause local defects in the optical laminate.

[0019] In view of the above-mentioned problems, the object of the present invention is to provide an optical laminate that does not use a specific material for the easy-to-bond layer, has excellent adhesion between the polyester film with high surface orientation degree ΔP and the easy-to-bond layer, and suppresses local defects; and to provide a polarizer, a surface plate and an image display device having the optical laminate.

[0020] Methods for solving problems

[0021] In order to solve the above problems, the present invention provides the following [1] to [4].

[0022] [1] An optical laminate having an easy-to-adhere layer, an uneven layer and an anti-fouling layer on a polyester film.

[0023] When the refractive index of the polyester film in the plane along the slow axis is defined as nx, the refractive index in the plane orthogonal to the slow axis is defined as ny, and the refractive index in the thickness direction of the polyester film is defined as nz, the polyester film satisfies the following equations 1-2.

[0024] For the above-mentioned uneven layer, when the three-dimensional skewness of the surface of the above-mentioned uneven layer is defined as Ssk and the three-dimensional arithmetic mean roughness of the surface of the above-mentioned uneven layer is defined as Sa, Ssk and Sa satisfy the following equation 2-1.

[0025] 0.140≤ΔP (1-2)

[0026] 0.80≤A≤1.90 (2-1)

[0027] [In Equations 1-2, "ΔP" represents "((nx+ny) / 2)-nz".]

[0028] In Equation 2-1, "A" represents "log". 10 (Sa[μm]×100 / Ssk)”. Among them, 0<Ssk.]

[0029] [2] A polarizer having a polarizing element, a first transparent protective plate disposed on one side of the polarizing element and a second transparent protective plate disposed on the other side of the polarizing element, wherein at least one of the first transparent protective plate and the second transparent protective plate is the optical laminate described in [1] above, and the optical laminate is disposed such that the surface of the anti-fouling layer is facing the side opposite to the polarizing element.

[0030] [3] A surface plate for an image display device, wherein an optical laminate is bonded to a resin plate or a glass plate, wherein the optical laminate is the optical laminate described in [1] above, and the optical laminate is arranged such that the surface of the anti-fouling layer faces the opposite side to the resin plate or the glass plate.

[0031] [4] An image display device, wherein the display element is arranged such that the anti-fouling layer side of the optical laminate described in [1] faces the opposite side to the display element, and the optical laminate is disposed on the surface.

[0032] The effects of the invention

[0033] The optical laminate of the present invention, as well as the polarizer, surface plate and image display device having the optical laminate, do not use a specific material easy-to-bond layer, can improve the adhesion between the polyester film with high surface orientation degree ΔP and the easy-to-bond layer, and can suppress local defects of the optical laminate. Attached Figure Description

[0034] Figure 1 This is a cross-sectional view schematically illustrating one embodiment of the optical laminate of the present invention. Detailed Implementation

[0035] The optical laminate of the present invention will now be described in detail.

[0036] It should be noted that the description of the numerical range of "AA~BB" in this instruction manual refers to "above AA and below BB".

[0037] [Optical laminates]

[0038] The optical laminate of the present invention has an easy-to-adhere layer, an uneven layer, and an anti-fouling layer on a polyester film.

[0039] When the refractive index of the polyester film in the plane along the slow axis is defined as nx, the refractive index in the plane orthogonal to the slow axis is defined as ny, and the refractive index in the thickness direction of the polyester film is defined as nz, the polyester film satisfies the following equations 1-2.

[0040] For the above-mentioned uneven layer, when the three-dimensional skewness of the surface of the above-mentioned uneven layer is defined as Ssk and the three-dimensional arithmetic mean roughness of the surface of the above-mentioned uneven layer is defined as Sa, Ssk and Sa satisfy the following equation 2-1.

[0041] 0.140≤ΔP (1-2)

[0042] 0.80≤A≤1.90 (2-1)

[0043] [In Equations 1-2, "ΔP" represents "((nx+ny) / 2)-nz".]

[0044] In Equation 2-1, "A" represents "log". 10 (Sa[μm]×100 / Ssk)”. Among them, 0<Ssk.]

[0045] Figure 1 This is a cross-sectional view schematically illustrating one embodiment of the optical laminate of the present invention. Figure 1 The optical laminate 100 has an easy-to-adhere layer 20, an uneven layer 30 and an anti-fouling layer 40 sequentially on the polyester film 10.

[0046] <Polyester film>

[0047] For polyester films, when the refractive index in the slow axis direction within the plane is defined as nx, the refractive index in the direction orthogonal to the slow axis within the plane is defined as ny, and the refractive index in the thickness direction of the polyester film is defined as nz, the following equations 1-2 must be satisfied.

[0048] 0.140≤ΔP (1-2)

[0049] [In Equations 1-2, "ΔP" represents "((nx+ny) / 2)-nz".]

[0050] In this specification, unless otherwise specified, the refractive indices nx, ny, and nz, in-plane phase difference, and thickness-direction phase difference refer to values ​​at a wavelength of 550 nm. In this specification, "in-plane phase difference" is sometimes denoted as "Re," and "thickness-direction phase difference" is denoted as "Rth."

[0051] Formula 1-2

[0052] Equation 1-2 specifies that ΔP represented by "((nx+ny) / 2)-nz" is greater than or equal to 0.140. ΔP is called the surface orientation degree, which is a parameter representing the orientation intensity of the entire surface of the film.

[0053] When ΔP is less than 0.140, the mechanical strength of the polyester film becomes insufficient, which in turn reduces the physical properties of the optical laminate, such as the pencil hardness.

[0054] ΔP is preferably 0.145 or higher, more preferably 0.150 or higher. It should be noted that recent image display devices have incorporated curved surface designs, therefore, considering both pencil hardness and flexibility, the lower limit of ΔP is preferably 0.160 or higher, more preferably 0.176 or higher.

[0055] When ΔP is too large, it is sometimes difficult to keep nx-ny below 0.0250. Therefore, ΔP is preferably below 0.250, more preferably below 0.220, and even more preferably below 0.200.

[0056] Examples of implementations for the range of ΔP include 0.140 and above, 0.140 and above 0.250 and below, 0.140 and above 0.220 and below, 0.140 and above 0.200 and below, 0.145 and above 0.250 and below, 0.145 and above 0.220 and below, 0.145 and above 0.200 and below, 0.150 and above 0.250 and below, 0.150 and above 0.220 and below, 0.150 and above 0.200 and below, 0.160 and above 0.250 and below, 0.160 and above 0.220 and below, 0.160 and above 0.200 and below, 0.176 and above, 0.176 and above 0.250 and below, 0.176 and above 0.220 and below, and 0.176 and above 0.200 and below.

[0057] The polyester film of the optical laminate of the present invention needs to satisfy the above formulas 1-2. While the polyester film satisfying formulas 1-2 possesses the aforementioned physical properties, it suffers from poor adhesion. The optical laminate of the present invention improves the adhesion between the polyester film and the easy-to-adhere layer by sequentially forming an easy-to-bond layer, a specific uneven layer, and an anti-fouling layer on the specific uneven layer, thereby improving the overall adhesion of the optical laminate. The reasons for improving the adhesion of the optical laminate are explained below.

[0058] The nx, ny, and nz of the polyester film, as well as the in-plane phase difference and the phase difference in the thickness direction (described later), can be measured, for example, using the Otsuka Electronics Corporation's trade name "RETS-100".

[0059] In this specification, unless otherwise stated, nx, ny, nz, ΔP, Re, Rth, Sa, Ssk, and A refer to the average of the 14 measurements excluding the minimum and maximum values. It should be noted that "A" refers to "A" in Equation 2-1.

[0060] In this specification, the 16 measurement sites are preferably defined as follows: a region 0.5 cm from the outer edge of the sample is used as a blank area; for the region further inward than the blank area, when lines are drawn that divide the longitudinal and transverse directions into 5 equal parts, the 16 intersection points are used as the measurement centers. For example, when the sample is quadrilateral, a region 0.5 cm from the outer edge of the quadrilateral is used as a blank area; the region further inward than the blank area is divided into 5 equal parts along the longitudinal and transverse directions, and the 16 intersection points of the resulting dashed lines are used as the centers for measurement. Furthermore, the average value of the 14 points excluding the minimum and maximum values ​​is used as the value of each parameter.

[0061] When the sample being measured is a shape other than a quadrilateral such as a circle, ellipse, triangle, or pentagon, it is preferable to draw a quadrilateral inscribed in these shapes. For the aforementioned quadrilaterals, measurements are taken at 16 locations using the method described above.

[0062] Unless otherwise stated, the atmosphere for measuring various parameters in this instruction manual is a temperature of 23℃±5℃ and a relative humidity of 40% to 65%. Furthermore, unless otherwise stated, the sample should be exposed to the above atmosphere for at least 30 minutes before each measurement.

[0063] Formula 1-1

[0064] The polyester film preferably satisfies the following formula 1-1.

[0065] nx - ny ≤ 0.0250 (1-1)

[0066] Equation 1-1 specifies that the difference between the refractive index nx in the slow axis direction of the polyester film and the refractive index ny in the fast axis direction, which is orthogonal to the slow axis in the same plane, is small.

[0067] If equation 1-1 is not satisfied and nx-ny exceeds 0.0250, the rainbow spot caused by the in-plane phase difference cannot be suppressed.

[0068] Unless otherwise specified, the iris in this instruction manual refers to the iris as seen with the naked eye.

[0069] Furthermore, when nx-ny exceeds 0.0250, the difference in refractive index of the polyester film increases with the viewing direction, thereby increasing the degree to which the reflectivity of the optical laminate varies with direction. When the reflectivity of the optical laminate varies with direction, local defects that occur when Equation 2-1 is not satisfied can sometimes be easily identified. By keeping nx-ny below 0.0250, it is easy to suppress the identification of local defects.

[0070] More preferably, nx-ny is 0.0240 or less, and even more preferably 0.0230 or less.

[0071] When nx-ny is too small, it is difficult to suppress black screen. Therefore, nx-ny is preferably 0.0050 or more, more preferably 0.0080 or more, and even more preferably 0.0100 or more.

[0072] In this manual, "black screen" refers to the following phenomenon: when light passes through the polarizing element and the polyester film in sequence and is observed through polarized sunglasses, the entire surface appears dark.

[0073] In the components shown in this specification, where multiple upper limit options and lower limit options for numerical values ​​are shown respectively, a combination of one selected from the upper limit option and one selected from the lower limit option can be used as an implementation of the numerical range.

[0074] For example, in the case of nx-ny, implementations with numerical ranges of 0.0250 or less, 0.0050 or more and 0.0250 or less, 0.0050 or more and 0.0240 or less, 0.0050 or more and 0.0230 or less, 0.0080 or more and 0.0250 or less, 0.0080 or more and 0.0240 or less, 0.0080 or more and 0.0230 or less, 0.0100 or more and 0.0250 or less, 0.0100 or more and 0.0240 or less, and 0.0100 or more and 0.0230 or less can be given.

[0075] Other physical properties

[0076] The preferred properties of the polyester film, such as in-plane phase difference and phase difference in the thickness direction, are within the following ranges.

[0077] In this specification, the in-plane phase difference and the phase difference in the thickness direction refer to the values ​​calculated by the following formula. In the following formula, "T" refers to the thickness of the polyester film.

[0078] In-plane phase difference (Re) = (nx - ny) × T [nm] (1)

[0079] Phase difference in the thickness direction (Rth) = ((nx+ny) / 2-nz)×T[nm](2)

[0080] -In-plane phase difference (Re-)

[0081] The in-plane phase difference of the polyester film is preferably less than 1200 nm, more preferably less than 1100 nm, more preferably less than 1000 nm, and more preferably less than 950 nm.

[0082] By keeping the in-plane phase difference below 1200 nm, it is easy to suppress the iris spot.

[0083] The in-plane phase difference of the polyester film is preferably 50 nm or more, more preferably 100 nm or more, more preferably 150 nm or more, more preferably 200 nm or more, more preferably 250 nm or more, more preferably 300 nm or more, and more preferably 400 nm or more.

[0084] By achieving an in-plane phase difference of 50 nm or more, black screen issues can be easily suppressed. This is because polyester films with an average in-plane phase difference of less than 50 nm can hardly disrupt linearly polarized light, allowing it to pass through directly. On the other hand, polyester films with an average in-plane phase difference of 50 nm or more will disrupt linearly polarized light. It should be noted that, in order to improve the mechanical strength of the polyester film, such as pencil hardness, an in-plane phase difference of 520 nm or more is preferred, and more preferably 620 nm or more.

[0085] Examples of embodiments for the range of in-plane phase difference of the polyester film include 50nm to 1200nm, 50nm to 1100nm, 50nm to 1000nm, 50nm to 950nm, 100nm to 1200nm, 100nm to 1100nm, 100nm to 1000nm, 100nm to 950nm, 150nm to 1200nm, 150nm to 1100nm, 150nm to 1000nm, 150nm to 950nm, 200nm to 1200nm, 200nm to 1100nm, 200nm to 1000nm, 200nm to 950nm, 250nm to 1200nm, and 250nm to 950nm. Above 1100nm, below 250nm, below 1000nm, above 250nm, below 950nm, above 300nm, below 1200nm, above 300nm, below 1100nm, above 300nm, below 1000nm, above 300nm, below 950nm, above 400nm, below 1200nm, above 400nm, below 1100nm, above 400nm, below 1000nm, above 400nm, below 950nm, above 520nm, below 1200nm, above 520nm, below 1100nm, above 520nm, below 1000nm, above 520nm, below 950nm, above 620nm, below 1200nm, above 620nm, below 1100nm, above 620nm, below 1000nm, above 620nm, below 950nm.

[0086] -Phase difference in the thickness direction (Rth)-

[0087] The phase difference in the thickness direction of the polyester film is preferably 2000 nm or more, more preferably 3000 nm or more, further preferably 4000 nm or more, and even more preferably 5000 nm or more.

[0088] By making the phase difference in the thickness direction of the polyester film greater than 2000nm, it is possible to easily suppress black screen when viewed from an oblique angle, not only in the front direction.

[0089] In order to make it easy to make Re / Rth within the range described later, the phase difference in the thickness direction of the polyester film is preferably 15000 nm or less, more preferably 12000 nm or less, and even more preferably 9000 nm or less.

[0090] Examples of implementations for the range of phase difference in the thickness direction of the polyester film include 2000nm to 15000nm, 2000nm to 12000nm, 2000nm to 9000nm, 3000nm to 15000nm, 3000nm to 12000nm, 3000nm to 9000nm, 4000nm to 15000nm, 4000nm to 12000nm, 4000nm to 9000nm, 5000nm to 15000nm, 5000nm to 12000nm, and 5000nm to 9000nm.

[0091] -Re / Rth-

[0092] The Re / Rth of the polyester film is preferably 0.20 or less, more preferably 0.17 or less, and even more preferably 0.15 or less.

[0093] A low Re / Rth ratio indicates that the polyester film exhibits near-uniform biaxial stretching. Therefore, by setting this ratio to 0.20 or less, the mechanical strength of the polyester film can be improved, and wrinkles that negatively impact visibility due to environmental changes can be suppressed. To easily achieve these effects, the in-plane phase difference of the polyester film is preferably within the aforementioned range.

[0094] The lower limit of Re / Rth is usually around 0.01.

[0095] Examples of implementations for the range of Re / Rth include 0.01 to 0.20, 0.01 to 0.17, and 0.01 to 0.15.

[0096] -Haze, Total Light Transmittance-

[0097] The haze of the polyester film according to JIS K7136:2000 is preferably 3.0% or less, more preferably 2.0% or less, and even more preferably 1.0% or less.

[0098] In addition, the total light transmittance of the polyester film according to JIS K7361-1:1997 is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more.

[0099] -UV transmittance-

[0100] The transmittance of the polyester film at a wavelength of 380 nm is preferably less than 20%, and more preferably less than 10%.

[0101] -thickness-

[0102] To improve mechanical strength, the thickness of the polyester film is preferably 10 μm or more, more preferably 20 μm or more, further preferably 25 μm or more, and even more preferably 30 μm or more. It should be noted that by making the polyester film thickness 10 μm or more, when other components come into contact with the polyester film side of the optical laminate and stress is generated, the stress is less likely to be transmitted to the interface between the polyester film and the easy-to-adhere layer; this is preferable from this perspective.

[0103] In addition, in order to reduce in-plane phase difference and improve bending resistance, the thickness of the polyester film is preferably 75 μm or less, more preferably 60 μm or less, further preferably 55 μm or less, and even more preferably 50 μm or less.

[0104] Examples of implementations for the range of plastic film thickness include 10μm to 75μm, 10μm to 60μm, 10μm to 55μm, 10μm to 50μm, 20μm to 75μm, 20μm to 60μm, 20μm to 55μm, 20μm to 50μm, 25μm to 75μm, 25μm to 60μm, 25μm to 55μm, 25μm to 50μm, 30μm to 75μm, 30μm to 60μm, 30μm to 55μm, and 30μm to 50μm.

[0105] -Stretch-

[0106] To easily satisfy equations 1-1 and 1-2, it is preferable not to reduce the stretch ratios in the longitudinal and transverse directions, and to make the stretch ratios in the two directions close.

[0107] Therefore, polyester film is preferably a stretch film, and more preferably a biaxially oriented film.

[0108] The specific stretching conditions are described below.

[0109] "raw material"

[0110] Examples of polyesters constituting polyester films include: homopolymers obtained by polycondensation of dicarboxylic acids and diols; copolymers obtained by polycondensation of one or more dicarboxylic acids and two or more diols; copolymers obtained by polycondensation of two or more dicarboxylic acids and one or more diols; and blended resins formed by mixing one or more homopolymers and one or more copolymers.

[0111] The polyester film may contain additives such as ultraviolet absorbers, inorganic particles and other slippery particles, heat-resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, lightfast agents, flame retardants, heat stabilizers, antioxidants, antigelling agents and surfactants, within a range that does not hinder the effects of the present invention.

[0112] Examples of dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, diphenylcarboxylic acid, diphenoxyethane dicarboxylic acid, diphenylsulfone carboxylic acid, anthracene dicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyl adipic acid, trimethyl adipic acid, pimelic acid, azelaic acid, dimer acid, sebacic acid, octanoic acid, and dodecanedicarboxylic acid.

[0113] Examples of diols include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanediethanol, 1,4-cyclohexanediethanol, decanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-bis(4-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)sulfone.

[0114] In polyesters, polyethylene terephthalate is preferred to improve mechanical strength. That is, the polyester film preferably contains polyethylene terephthalate.

[0115] Examples of polymerization methods for polyethylene terephthalate include: direct polymerization, in which terephthalic acid reacts directly with ethylene glycol, and other dicarboxylic acids and glycols as needed; and transesterification, in which dimethyl terephthalate is transesterified with ethylene glycol; etc. In the transesterification method, the dimethyl terephthalate may contain methyl esters of other dicarboxylic acids, as needed. Similarly, the ethylene glycol may contain other glycols, as needed, in the transesterification method.

[0116] The intrinsic viscosity of polyethylene terephthalate is preferably between 0.45 and 0.70. If the intrinsic viscosity is below 0.45, the effect of improving tear resistance is reduced; if the intrinsic viscosity is above 0.70, the filtration pressure rises significantly, thus making high-precision filtration difficult.

[0117] Layer Composition

[0118] Polyester film can be a single-layer structure or a multi-layer structure.

[0119] Single-layer structures are easier to control in terms of stretching. Equations 1-1 and 1-2 are easily satisfied by not reducing the stretching ratios in the longitudinal and transverse directions and by making the stretching ratios in both directions close. Therefore, from the perspective of easily satisfying Equations 1-1 and 1-2, single-layer structures that are easy to control in terms of stretching are preferred.

[0120] On the other hand, for example, from the perspective of being able to impart the effects produced by changing the composition of each layer, multilayer polyester films are preferred. For example, when a laminated polyester film consisting of at least three layers is produced by co-extrusion, if a polyester with a low oligomer content is used in the surface layer, the amount of oligomer precipitation on the film surface after heat treatment can be easily suppressed.

[0121] When a multilayer polyester film is formed, the thickness of the surface layer, measured by the thickness of one side, is preferably 3 μm or more, more preferably 5 μm or more, and is 25% or less, more preferably 20% or less, and particularly preferably 10% or less of the total thickness.

[0122] Examples of polyester film manufacturing

[0123] Taking PET film as an example, the implementation method of the manufacturing method of polyester film will be described.

[0124] First, the PET granules are thoroughly vacuum-dried. The vacuum-dried PET granules are then fed into an extruder and melt-extruded into sheets at a temperature of 260°C to 290°C. After cooling and solidification, the unstretched PET sheets are used to form films. At this point, high-precision filtration is performed to remove foreign matter from the resin in any location where the molten resin is maintained at 260°C to 290°C. The filter media used in the high-precision filtration of the molten resin is not particularly limited, but sintered stainless steel filter media is preferred. Sintered stainless steel filter media exhibits excellent performance in removing aggregates mainly composed of Si, Ti, Sb, Ge, and Cu, as well as high-melting-point organic matter. Furthermore, the filter particle size is preferably 15 μm or less. The above-mentioned filter particle size is a value at an initial filtration efficiency of 95%.

[0125] In the extrusion process, PET is melted and extruded from an extrusion die, then cooled and solidified using cooling rollers to obtain an unstretched sheet. If necessary, two or three extruders, two or three manifolds, or feed blocks can be used to laminate the polyester resin layers. To improve sheet planarity, electrostatic application or liquid coating methods are preferred to enhance the adhesion between the sheet and the rotating cooling drum.

[0126] The unstretched film obtained above is stretched along its length using rollers heated to 70°C to 120°C, thereby obtaining a uniaxially oriented PET film. If it is desired to reduce the deformation of the orientation axis caused by the so-called bowing phenomenon, a method can be adopted that reduces the stretching ratio in the length direction within a range where there is no thickness unevenness, or a method can be used that sets a higher stretching temperature.

[0127] It should be noted that the surface temperature at the start of stretching is preferably between 80°C and 93°C. If it is within this temperature range, orientation and crystallization will not proceed excessively in the initial stage of stretching, thus achieving a preferred ΔP.

[0128] Next, the two ends of the film are held by clamps and introduced into a hot air zone heated to 70°C to 200°C. After drying, it is stretched along the width direction. Then, it is introduced into a heat treatment zone within the range of the heat fixation temperature described later for heat treatment, thereby completing the crystal orientation. In this heat treatment process, a relaxation treatment of 2% to 10% can be performed along the width or length direction as needed.

[0129] It should be noted that PET film can also be manufactured using synchronous biaxial stretching instead of the aforementioned step-by-step biaxial stretching.

[0130] The stretching ratio during membrane stretching is preferably 2 to 6.5 times in both the length and width directions, more preferably 2.5 to 5.5 times, and even more preferably 3 to 4.8 times.

[0131] By making the membrane stretch ratio more than 2, equations 1-2 can be easily satisfied. In addition, by making the membrane stretch ratio less than 6.5, it is easy to suppress ΔP from becoming too large, thereby making it easier to suppress wrinkles and cracks during membrane fabrication.

[0132] The ratio of the stretch ratio in the length direction to the stretch ratio in the width direction, i.e., "stretch ratio in the length direction / stretch ratio in the width direction", is preferably 1.7 or less, more preferably 1.4 or less. Furthermore, the ratio is preferably 0.5 or more, more preferably 0.7 or more, and even more preferably 1.0 or more.

[0133] By making the stretch ratio in the length direction / the stretch ratio in the width direction within the above range, Equation 1-1 can be easily satisfied.

[0134] It should be noted that, when using progressive stretching, the orientation of the film tends to be strongly influenced by the stretching direction of the final segment. Therefore, in progressive stretching, it is preferable to make the stretching ratio in the length direction higher than the stretching ratio in the width direction.

[0135] Furthermore, when using a step-by-step stretching method, the stretching in the width direction is preferably performed in at least two stages. It is particularly preferable to perform the width stretching in two or more sections with different stretching temperatures. In this case, it is desirable that the stretching temperature of the later stage is preferably 5°C or more, more preferably 10°C or more higher than the stretching temperature of the earlier stage. The high-temperature later stage stretching process can mitigate the deformation of optical properties caused by the bending in the width direction generated in the earlier stage, thus suppressing variations in in-plane phase difference in the width direction. Additionally, when performing width stretching in two stages, it is preferable that the stretching ratio of the later stage is lower than that of the earlier stage. By reducing the stretching ratio of the later stage, the deterioration of film thickness unevenness can be suppressed. Specifically, when performing width stretching in two stages, it is preferable to perform the first stage stretching at a ratio of 1.5 to 4.5 times at a temperature between 120°C and 200°C, followed by a further stretching at a ratio of 1.01 to 2.0 times at a temperature between 150°C and 230°C. The following explanation will focus on a scenario where the first stage of tensioning is performed at a temperature between 120°C and 200°C, and the second stage of tensioning is performed at a temperature between 150°C and 230°C. Sometimes, the first stage of tensioning is referred to as TD1, and the second stage of tensioning is referred to as TD2.

[0136] When performing two-stage stretching within the above-mentioned range, the stretching temperature of TD1 is preferably 120°C to 200°C, more preferably 130°C to 150°C. If the temperature is below 120°C, the film will rupture; if the temperature is above 200°C, the deformation of the film properties in the width direction will increase. The stretching ratio is preferably 1.5 to 4.5 times. Furthermore, the stretching temperature of TD2 is preferably 150°C to 230°C, more preferably 180°C to 220°C. The stretching ratio is preferably 1.01 to 2.0 times.

[0137] In this way, by performing two-stage stretching within a temperature range of 120°C to 230°C, and thus achieving a total stretching ratio of 3.0 to 4.8 times, it is possible to reduce the variation of in-plane phase difference in the width direction while maintaining the planar orientation that preserves mechanical strength.

[0138] From the perspective of improving the thermal dimensional stability of the film, heat curing at a high temperature is preferred. Specifically, the upper limit of the heat curing temperature is preferably above 130°C, and more preferably above 160°C. However, if heat curing is performed at a high temperature, optical distortion caused by bending can easily occur, and sometimes the variation in in-plane phase difference increases. Therefore, the upper limit of the heat curing temperature is preferably below 220°C.

[0139] <Easy-to-adhere layer>

[0140] The optical laminate of the present invention needs to have an easy-to-adhere layer between the polyester film and the uneven layer.

[0141] Even with the textured and antifouling layers described later, the overall adhesion of the optical laminate cannot be improved without an easy-to-adhere layer.

[0142] The resin constituting the easy-bonding layer is not particularly limited, and examples include thermoplastic resins and thermosetting resins such as polyester resins, polyurethane resins, and acrylic resins, with thermoplastic resins being preferred. Furthermore, among thermoplastic resins, polyester resins and polyurethane resins that readily reduce the refractive index difference between the polyester film and the easy-bonding layer, as well as the refractive index difference between the easy-bonding layer and the uneven layer, are preferred, with polyester urethane resins being even more preferred.

[0143] The number average molecular weight of the resin constituting the easy-to-bond layer is preferably 10,000 or more, more preferably 20,000 or more. The number average molecular weight of the resin is preferably 100,000 or less, more preferably 60,000 or less. By ensuring that the number average molecular weight of the resin constituting the easy-to-bond layer is within the above range, it is possible to easily suppress the aggregation and breakdown of the easy-to-bond layer.

[0144] Preferred ranges for the number-average molecular weight of the resin constituting the easy-to-adhere layer include 10,000 to 100,000, 10,000 to 60,000, 20,000 to 100,000, and 20,000 to 60,000.

[0145] The glass transition temperature of the resin constituting the easy-to-bond layer is preferably 30°C or higher, more preferably 50°C or higher, and even more preferably 70°C or higher. The glass transition temperature of this resin is preferably 120°C or lower, more preferably 110°C or lower, and even more preferably 90°C or lower. By setting the glass transition temperature of the resin constituting the easy-to-bond layer to the above range, it is easy to suppress the embrittlement of the easy-to-bond layer due to heat during the process. Examples of heat during the process include the heat generated during the drying process of the anti-fouling coating liquid and the anti-fouling coating liquid, and the heat generated when the optical laminate is bonded to the polarizing element.

[0146] Preferred ranges for the glass transition temperature of the resin constituting the easy-to-adhere layer include 30°C to 120°C, 30°C to 110°C, 30°C to 90°C, 50°C to 120°C, 50°C to 110°C, 50°C to 90°C, 70°C to 120°C, 70°C to 110°C, and 70°C to 90°C.

[0147] The easy-to-bond layer may contain additives such as refractive index modifiers, dyes, pigments, leveling agents, ultraviolet absorbers, antioxidants, and light stabilizers, within a range that does not impair the effects of the present invention; and various crosslinking agents for adjusting hardness or viscosity. Examples of such crosslinking agents include non-yellowing XDI-based, IPDI-based, and HDI-based isocyanates, and ionization-curable multifunctional monomers.

[0148] The easy-to-adhesive layer can be formed by online coating during the polyester film preparation process, or by offline coating after the polyester film preparation process.

[0149] The preferred dry coating amount of the easy-to-adhere layer is 0.05 g / m². 2 Above 0.75g / m 2 The thickness of the easy-to-adhesive layer is not particularly limited, but is preferably 10 nm to 600 nm. In the case of laminated polyester film, easy-to-adhesive layer, textured layer, and anti-fouling layer, in order to prevent poor visibility at each interface due to the difference in refractive index, the thickness of the easy-to-adhesive layer is preferably 10 nm to 40 nm or 70 nm to 270 nm.

[0150] <Undulated Layer>

[0151] The optical laminate of the present invention has an uneven layer on the easy-to-adhere layer.

[0152] Formula 2-1

[0153] When the three-dimensional skewness of the surface of the uneven layer is defined as Ssk and the three-dimensional arithmetic mean roughness of the surface of the uneven layer is defined as Sa, the uneven layer needs Ssk and Sa to satisfy the following equation 2-1.

[0154] 0.80≤A≤1.90 (2-1)

[0155] In Equation 2-1, "A" represents "log". 10 (Sa[μm]×100 / Ssk)”. Where, 0 <Ssk。]

[0156] In this specification, Ssk is the skewness Rsk of the roughness curve of the two-dimensional roughness parameter described in JIS B0601:1994, extended to a three-dimensional value. It is calculated using the following formula a, with orthogonal coordinate axes X and Y placed on the reference surface, the measured surface shape curve set as z = f(x,y), and the size of the reference surface set as Lx and Ly. Ssk is specified in ISO 25178:2012.

[0157] Ssk is an index that represents the degree of skewness in the positive and negative directions of the elevation distribution, based on the average elevation of the entire measured surface. If the elevation distribution follows a normal distribution, Ssk represents 0. If the elevation distribution is skewed in the negative direction, Ssk shows a positive value; the greater the skewness in the negative direction, the larger the positive value of Ssk. Conversely, if the elevation distribution is skewed in the positive direction, Ssk shows a negative value; the greater the skewness in the positive direction, the larger the negative value of Ssk.

[0158] [Number 1]

[0159]

[0160] In equation a, “Sq” is the root mean square deviation of the surface height distribution as defined in equation b below.

[0161] [Number 2]

[0162]

[0163] In this specification, Sa is the arithmetic mean roughness Ra of the two-dimensional roughness parameter described in JIS B0601:1994, extended to a three-dimensional value. With orthogonal coordinate axes X and Y placed on the reference surface, and the roughness surface defined as Z(x,y), it is calculated using the following formula c. Sa is specified in ISO 25178:2012.

[0164] [Number 3]

[0165]

[0166] In equation c, Ar = Lx × Ly.

[0167] In Equation 2-1, “A” is derived from “log”. 10 (Sa[μm]×100 / Ssk)” represents this.

[0168] Therefore, it can be said that “A” in Equation 2-1 shows a minimum value in any of the following cases from x-1 to x3.

[0169] x-1: The case where Sa is too small.

[0170] x-2: When Ssk is too large.

[0171] x-3: The case where Sa is moderately small and Ssk is moderately large.

[0172] When the Sa value of the uneven layer, as in x-1, is too small, the unevenness of the layer is hardly reflected on the surface of the antifouling layer, which is essentially a smooth surface of the optical laminate. If other components come into contact with the optical laminate, whose surface shape is generally smooth, the stress applied while these other components are attached to the surface of the optical laminate will hardly be relieved and will be transmitted to the interface between the polyester film and the easy-to-adhere layer. Therefore, if the Sa value of the uneven layer, as in x-1, is too small, it may sometimes be impossible to improve the adhesion between the polyester film and the easy-to-adhere layer.

[0173] Furthermore, when the surface area (Ssk) of the uneven layer, as in x-2, is too large, the proportion of the uneven layer with a lower elevation than the average sea area becomes extremely high. As a result, the surface of the antifouling layer, i.e., the surface of the optical laminate, becomes a shape with a very high proportion of sea areas. If other components come into contact with the optical laminate with such a large surface area, stress is applied while these other components are attached to the sea area of ​​the optical laminate. Therefore, this stress is hardly relieved and is transmitted to the interface between the polyester film and the easy-to-adhere layer. Thus, if the surface area (Ssk) of the uneven layer, as in x-2, is too large, it is sometimes impossible to improve the adhesion between the polyester film and the easy-to-adhere layer. In addition, when an antifouling layer is formed on an uneven layer with an excessively large Ssk, the antifouling layer is sufficiently formed at the location corresponding to the sea area of ​​the uneven layer, but it is difficult to form an antifouling layer at the location corresponding to the island area, resulting in uneven thickness of the antifouling layer. Therefore, due to the difference in transmittance or reflectance between the location corresponding to the sea area and the location corresponding to the island area, bright spots and other defects may sometimes occur in the optical laminate.

[0174] Furthermore, when Sa is moderately small and Ssk is moderately large, as in x-3, the surface shape exhibits a small degree of unevenness, and the proportion of the sea area is moderately high compared to the island area. When other components come into contact with the optical laminate with this surface shape, stress is applied while the other components are attached to the sea area of ​​the optical laminate, so the stress is hardly relieved and is transmitted to the interface between the polyester film and the easy-to-adhere layer. Therefore, if Sa is moderately small and Ssk is moderately large, as in x-3, it is sometimes impossible to improve the adhesion of the interface between the polyester film and the easy-to-adhere layer.

[0175] Furthermore, it can be said that “A” in Equation 2-1 exhibits a maximum value in any of the following cases from y-1 to y3.

[0176] y-1: The case where Sa is too large.

[0177] y-2: The case where Ssk is too small.

[0178] y-3: When Sa is moderately large and Ssk is moderately small.

[0179] When the Sa value of the uneven layer, as in y-1, is too large, the antifouling layer is sufficiently formed at the location corresponding to the sea portion of the uneven layer. On the other hand, it is difficult to form an antifouling layer at the location corresponding to the island portion of the uneven layer, resulting in uneven thickness of the antifouling layer. Therefore, due to the differences in transmittance or reflectance between the locations corresponding to the sea portion and the locations corresponding to the island portion, bright spots and other defects may sometimes occur in the optical laminate.

[0180] Furthermore, when the surface area (Ssk) of the uneven layer, as in y-2, is too small, the ratio of the island portion to the sea portion of the uneven layer is close to 1:1, and consequently, the ratio of the island portion to the sea portion on the surface of the optical laminate is also close to 1:1. The island portion is easier to contact with other components than the sea portion, thus facilitating adhesion. Therefore, when other components come into contact with the surface shape of the optical laminate with an uneven layer like y-2, stress is applied while these other components are attached to the island portion of the optical laminate. Consequently, this stress is hardly relieved and is transmitted to the interface between the polyester film and the easy-to-adhere layer. Thus, when the surface area (Ssk) of the uneven layer, as in y-2, is too small, it is sometimes impossible to improve the adhesion between the polyester film and the easy-to-adhere layer.

[0181] Furthermore, in cases like y-3 where Sa is moderately large and Ssk is moderately small, the surface shape exhibits a moderately large unevenness, with the proportion of the sea portion not being excessively high compared to the island portion. While optical laminates with this surface shape are less prone to adhesion problems, an antifouling layer is sufficiently formed at the sea portion of the uneven layer. On the other hand, it is difficult to form an antifouling layer at the island portion of the uneven layer, resulting in uneven thickness of the antifouling layer. Therefore, due to bright spots caused by differences in transmittance or reflectance between the sea portion and the island portion, local defects may sometimes occur in the optical laminate.

[0182] In summary, without satisfying Equation 2-1, the interfacial adhesion between the polyester film and the easy-to-adhere layer cannot be improved. Furthermore, without satisfying Equation 2-1, uneven thickness in the antifouling layer can lead to problems such as localized bright spots due to differences in transmittance or reflectance. In other words, without satisfying Equation 2-1, the problem of localized defects in the optical laminate cannot be suppressed.

[0183] In Formula 2-1, A is preferably 0.90 or more, more preferably 0.95 or more, and even more preferably 1.00 or more. Furthermore, in Formula 2-1, A is preferably 1.75 or less, more preferably 1.65 or less, and even more preferably 1.60 or less.

[0184] Examples of implementations of the range of A in Formula 2-1 include 0.80 to 1.90 and 0.80 to 1.75 and 0.80 to 1.65 and 0.80 to 1.60 and 0.90 to 1.90 and 0.90 to 1.75 and 0.90 to 1.65 and 0.90 to 1.60 and 0.95 to 1.90 and 0.95 to 1.75 and 0.95 to 1.65 and 0.95 to 1.60 and 1.00 to 1.90 and 1.00 to 1.75 and 1.00 to 1.65 and 1.00 to 1.60 and 1.00 to 1.60 and 0 ...90 to 1.90 and 0.80 to 1.75 and 0.80 to 1.75 and 0.80 to 1.65 respectively.

[0185] In this specification, Ssk and Sa are measured in a 0.26 mm square area (Lx and Ly in formulas a to c above are 0.26 mm). The longitudinal and transverse lengths of the area for measuring Ssk and Sa may not be exactly the same, and there may be slight differences. The measurement area in this example is 258 μm × 259 μm. Furthermore, in this specification, Ssk and Sa refer to the values ​​measured without setting a sampling length.

[0186] Ssk and Sa can be measured, for example, using a laser microscope-type surface shape measuring instrument. An example of a laser microscope-type surface shape measuring instrument is the Olympus product "LEXT OLS4000".

[0187] Formula 2-2

[0188] The preferred uneven layer Ssk satisfies the following equation 2-2.

[0189] 0.10≤Ssk≤1.50 (2-2)

[0190] By setting Ssk to between 0.10 and 1.50, Equation 2-1 can be easily satisfied.

[0191] Ssk is more preferably 0.12 or more, more preferably 0.15 or more. In addition, Ssk is more preferably 1.00 or less, more preferably 0.90 or less, more preferably 0.70 or less, and more preferably 0.55 or less.

[0192] Examples of implementations of the SSK range include 0.10 to 1.50 and below, 0.10 to 1.00 and below, 0.10 to 0.90 and below, 0.10 to 0.70 and below, 0.10 to 0.55 and below, 0.12 to 1.50 and below, 0.12 to 1.00 and below, 0.12 to 0.90 and below, 0.12 to 0.70 and below, 0.12 to 0.55 and below, 0.15 to 1.50 and below, 0.15 to 1.00 and below, 0.15 to 0.90 and below, 0.15 to 0.70 and below, and 0.15 to 0.55 and below.

[0193] Formula 2-3

[0194] The preferred texture layer Sa satisfies the following formula 2-3.

[0195] 0.020μm≤Sa≤0.200μm (2-3)

[0196] By making Sa between 0.020 μm and 0.200 μm, Equation 2-1 can be easily satisfied.

[0197] Sa is more preferably 0.030 μm or more, more preferably 0.040 μm or more. Furthermore, Sa is more preferably 0.150 μm or less, more preferably 0.100 μm or less, and even more preferably 0.085 μm or less.

[0198] Examples of implementations within the range of Sa include 0.020 μm and 0.200 μm, 0.020 μm and 0.150 μm, 0.020 μm and 0.100 μm, 0.020 μm and 0.085 μm, 0.030 μm and 0.200 μm, 0.030 μm and 0.150 μm, 0.030 μm and 0.100 μm, 0.030 μm and 0.085 μm, 0.040 μm and 0.200 μm, 0.040 μm and 0.150 μm, 0.040 μm and 0.100 μm, and 0.040 μm and 0.085 μm.

[0199] The uneven layer preferably comprises an adhesive resin and particles.

[0200] Adhesive Resins

[0201] The adhesive resin preferably comprises a cured product of a curable resin composition. Examples of cured products of curable resin compositions include cured products of thermosetting resin compositions and cured products of ionizing radiation-curable resin compositions; cured products of ionizing radiation-curable resin compositions are preferred for further improvement of mechanical strength.

[0202] The proportion of cured product of the curable resin composition relative to all the adhesive resin in the uneven layer is preferably 60% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and even more preferably 100% by mass.

[0203] Thermosetting resin composition is a composition containing at least a thermosetting resin, and is a resin composition that is cured by heating.

[0204] Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. In thermosetting resin compositions, curing agents can be added to these curing resins as needed.

[0205] Ionizing radiation-curable resin compositions are compositions comprising compounds having ionizing radiation-curable functional groups. In this specification, "compounds having ionizing radiation-curable functional groups" are sometimes referred to as "ionizing radiation-curable compounds".

[0206] Ionizing rays are electromagnetic waves or charged particle beams that contain energy quanta capable of polymerizing or cross-linking molecules. They are usually ultraviolet rays or electron rays. In addition, electromagnetic waves such as X-rays and gamma rays, as well as charged particle beams such as alpha rays and ion beams can also be used.

[0207] Examples of functional groups that can be cured by ionizing radiation include (meth)acryloyl, vinyl, allyl, and other olefinic unsaturated groups, as well as epoxy and oxetyl groups. Compounds having olefinic unsaturated groups are preferred as ionizing radiation-curable compounds; compounds having two or more olefinic unsaturated groups are more preferred; and polyfunctional (meth)acrylate compounds having two or more olefinic unsaturated groups are even more preferred.

[0208] As a multifunctional (meth)acrylate compound, either monomers or oligomers can be used, with oligomers being preferred. Specifically, the uneven layer preferably contains a cured product of a multifunctional (meth)acrylate oligomer as the binder resin. The cured product of the multifunctional (meth)acrylate oligomer can improve the surface hardness of the optical laminate while suppressing excessive curing shrinkage of the uneven layer, thus preventing excessive elevation differences in the uneven layer containing particles. Therefore, by using a cured product of a multifunctional (meth)acrylate oligomer in the uneven layer, excessive increases in Ssk and Sa can be easily suppressed.

[0209] On the other hand, since oligomers have a higher viscosity than monomers, the leveling properties of the coating liquid for the embossed layer sometimes decrease, and the surface area (Ssk) increases. Therefore, it is more preferable for the embossed layer to contain both oligomers and monomers as a multifunctional (meth)acrylate compound. That is, the embossed layer preferably contains a cured product of multifunctional (meth)acrylate oligomers and a cured product of multifunctional (meth)acrylate monomers as a binder resin.

[0210] When using oligomers and monomers as multifunctional (meth)acrylate compounds, the mass ratio of oligomers to monomers is preferably 20:80 to 80:20, more preferably 20:80 to 60:40 or 40:60 to 80:20, and even more preferably 40:60 to 60:40.

[0211] Examples of multifunctional (meth)acrylate oligomers include urethane (meth)acrylates, epoxy (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, and other (meth)acrylate polymers.

[0212] Carbamate (meth)acrylates are obtained, for example, by reacting polyols and organic diisocyanates with hydroxy (meth)acrylates.

[0213] The lower limit of the weight-average molecular weight of the multifunctional (meth)acrylate oligomer is preferably 500 or more, more preferably 1000 or more, and the upper limit is preferably 5000 or less, more preferably 3000 or less.

[0214] By making the weight-average molecular weight of the oligomer 500 or higher, excessive curing shrinkage of the uneven layer can be easily suppressed. In addition, by making the weight-average molecular weight of the oligomer 5000 or lower, the decrease in leveling properties and excessive increase in SSK of the coating liquid for the uneven layer can be easily suppressed.

[0215] Examples of embodiments for the weight-average molecular weight range of multifunctional (meth)acrylate oligomers include 500 to 5000 and 5000 to 3000, 1000 to 5000 and 1000 to 3000.

[0216] In this specification, weight-average molecular weight and number-average molecular weight refer to the converted values ​​of polystyrene determined by gel permeation chromatography.

[0217] Among multifunctional (meth)acrylate compounds, examples of difunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexanediol diacrylate.

[0218] Examples of (meth)acrylate monomers with three or more functions 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.

[0219] The aforementioned (meth)acrylate monomers can modify a portion of the molecular backbone. For example, (meth)acrylate monomers modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl groups, cyclic alkyl groups, aromatic groups, bisphenols, etc., can also be used.

[0220] In addition, monofunctional (meth)acrylates may be added as ionizing radiation curing compounds for purposes such as adjusting the viscosity of the coating liquid for uneven coating.

[0221] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and isobornyl (meth)acrylate.

[0222] The aforementioned ionizing radiation curable compounds can be used alone or in combination of two or more.

[0223] In addition to ionizing radiation-curable compounds, polymers can also be added to the coating liquid for uneven coatings to adjust the viscosity. Examples of polymers include substances with a weight-average molecular weight exceeding 5,000 and below 200,000.

[0224] When the ionizing radiation curable compound is an ultraviolet curable compound, the ionizing radiation curable composition preferably contains additives such as photopolymerization initiators and photopolymerization accelerators.

[0225] Examples of photopolymerization initiators include one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenyl ketone, michleilone, benzoin, benzoyl dimethyl ether, benzoylbenzoate, α-acyl oxime ester, anthraquinone, haloketone, and thioxanthone derivatives. Among these, α-hydroxyalkylphenyl ketone, which is less prone to yellowing, is preferred.

[0226] Photopolymerization accelerators can reduce polymerization inhibition caused by air during curing and increase the curing speed. For example, one or more of the following can be selected: isoamyl p-dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, etc.

[0227] Granules

[0228] Particles can include organic particles, inorganic particles, and metal-based particles. Among these, organic particles and inorganic particles are preferred.

[0229] Examples of organic particles include those composed of polymethyl methacrylate, polyacrylic acid-styrene copolymer, melamine resin, polycarbonate, polystyrene, polyvinyl chloride, benzoguanamine-melamine-formaldehyde condensate, silicone, fluorinated resins, and polyester resins. Organic particles exhibit good dispersibility and are therefore preferred from the perspective of easy control of Sa and Ssk.

[0230] The lower limit of the average particle size of the organic particles is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 2.0 μm or more, and the upper limit is preferably 5.0 μm or less, more preferably 4.0 μm or less, and even more preferably 3.0 μm or less.

[0231] By ensuring the average particle size of the organic particles is 0.5 μm or larger, excessive reduction in Sa can be easily suppressed. Furthermore, given the same content of organic particles based on mass standards, a larger average particle size results in a smaller number of organic particles. Therefore, if the average particle size of the organic particles is too large, it is easy to form independent, steep protrusions, thus tending to increase Ssk (Satrical Scale). Therefore, by ensuring the average particle size of the organic particles is 5.0 μm or less, excessive increase in Ssk can be easily suppressed.

[0232] Examples of implementations for the range of average particle size of organic particles include 0.5 μm to 5.0 μm, 0.5 μm to 4.0 μm, 0.5 μm to 3.0 μm, 1.0 μm to 5.0 μm, 1.0 μm to 4.0 μm, 1.0 μm to 3.0 μm, 2.0 μm to 5.0 μm, 2.0 μm to 4.0 μm, and 2.0 μm to 3.0 μm.

[0233] The average particle size of organic particles can be calculated, for example, by the following operations (A1) to (A3).

[0234] (A1) Take a transmission observation image of the optical laminate using an optical microscope. The magnification is preferably 500x or higher and 2000x or lower.

[0235] (A2) After extracting any 10 organic particles from the observed image, calculate the particle size of each organic particle. The particle size is determined as the distance between the two lines in the combination of lines that maximize the distance between the two lines when the particle is held between two arbitrary parallel lines.

[0236] (A3) After performing the same operation 5 times in another image of the same sample, the average value obtained by the numerical mean of the total 50 particle sizes is taken as the average particle size of the organic particles.

[0237] The coefficient of variation of the particle size of the organic particles is preferably 13% or less, more preferably 12% or less, and even more preferably 11% or less.

[0238] By keeping the coefficient of variation of the organic particle size below 13%, Sa and Ssk can be easily controlled.

[0239] The coefficient of variation of the particle size of organic particles can be obtained, for example, from the standard deviation and average particle size calculated using 50 particles used in the calculation of the average particle size in (A1) to (A3) above, according to the following formula.

[0240] Coefficient of variation (%) = (Standard deviation / Average particle size) × 100

[0241] Examples of inorganic particles include those composed of silica, alumina, zirconium oxide, and titanium dioxide. Among these, silica is preferred for improving transparency. Furthermore, fumed silica is preferred among silica particles.

[0242] Fumed silica refers to amorphous silica with a particle size of less than 200 nm produced by a dry process. It can be obtained by reacting silicon-containing volatile compounds in the gas phase. Specifically, examples include substances produced by hydrolyzing silicon compounds such as silicon tetrachloride in a flame of oxygen and hydrogen. Fumed silica is suitable from the perspective of easily hydrophobicating the surface.

[0243] When inorganic particles are used alone, it is preferable to form an aggregate of multiple inorganic particles, and to use the aggregate to impart unevenness to the uneven layer.

[0244] Furthermore, by hydrophobizing inorganic particles, aggregates can be formed by inorganic particles wrapping around organic particles. Therefore, when comparing a system consisting solely of organic particles with a system combining both organic and inorganic particles, the system using both tends to have a larger Sa (Sa value). On the other hand, since inorganic particles form smooth, uneven surfaces, when comparing a system consisting solely of organic particles with a system combining both organic and inorganic particles, the system using both tends to have a smaller Ssk (Score).

[0245] It should be noted that when inorganic particles are used alone, the height of the protrusions is lower than that when organic particles are used alone, and there is a tendency to form an overall gently sloping shape.

[0246] The inorganic particles preferably have undergone a hydrophobic surface treatment. This hydrophobic treatment suppresses excessive aggregation of the inorganic particles. Furthermore, by combining hydrophobically treated inorganic particles with organic particles, as described above, it is easier to increase Sa and Ssk.

[0247] Examples of inorganic particles that have undergone hydrophobic treatment include inorganic particles with surface functional groups of the inorganic particles reacting with the surface treatment agent. Examples of surface functional groups of inorganic particles include, for instance, silanol groups in silica particles.

[0248] As a surface treatment agent, one or more can be selected from the following: trimethylsilyl chloride, dimethyldichlorosilane, trimethylsilyltrifluoromethane sulfonate, chloromethyltrimethylsilane, hexamethyldisilazane, triethylsilane, triethylsilyl chloride, triisopropylsilyl chloride, tert-butyldimethylsilane, tert-butyldimethylsilyl chloride, octylsilane, hexadecylsilane, allyltrimethylsilane, trimethylvinylsilane, aminosilane, methacryloxysilane, and polydimethylsiloxane.

[0249] To enhance hydrophobicity, the surface treatment agent preferably has an alkyl group with a high number of carbon atoms within its molecule. Specifically, the surface treatment agent preferably has an alkyl group with 5 or more carbon atoms within its molecule, and more preferably has an alkyl group with 6 or more carbon atoms within its molecule. The aforementioned alkyl group can be straight-chain or branched, but is preferably straight-chain.

[0250] It should be noted that when the number of carbon atoms in the alkyl group of the molecule is too high, the proportion of functional groups on the surface of the inorganic particles that can react with the surface treatment agent decreases due to the large molecular size of the surface treatment agent. Therefore, the number of carbon atoms in the alkyl group of the surface treatment agent is preferably 20 or less, more preferably 16 or less, and even more preferably 12 or less.

[0251] When using inorganic particles alone, it is preferable to combine inorganic particles that have undergone hydrophobication treatment with different surface treatment agents. This is because, when only inorganic particles that have undergone hydrophobication treatment with the same surface treatment agent are used, aggregation may sometimes be excessive due to the commonalities in their properties.

[0252] When using inorganic particles that have undergone hydrophobic treatment with different surface treatment agents, the lower limit of the number of carbon atoms in the alkyl group of the surface treatment agent for the inorganic particles is preferably 4 or more, more preferably 6 or more, and the upper limit is preferably 20 or less, more preferably 16 or less, and even more preferably 12 or less. Examples of embodiments for the range of the number of carbon atoms in the alkyl group of the surface treatment agent for the inorganic particles include 4 or more and 20 or less, 4 or more and 16 or less, 4 or more and 12 or less, 6 or more and 20 or less, 6 or more and 16 or less, and 6 or more and 12 or less. Alternatively, the number of carbon atoms in the alkyl group of the surface treatment agent for the inorganic particles is preferably 3 or less, more preferably 2 or less, and even more preferably 1.

[0253] The lower limit of the average particle size of the inorganic particles is preferably 3 nm or more, more preferably 5 nm or more, and even more preferably 8 nm or more, and the upper limit is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less.

[0254] Examples of implementations for the range of average particle size of inorganic particles include 3 nm to 100 nm, 3 nm to 50 nm, 3 nm to 30 nm, 5 nm to 100 nm, 5 nm to 50 nm, 5 nm to 30 nm, 8 nm to 100 nm, 8 nm to 50 nm, and 8 nm to 30 nm.

[0255] By ensuring the average particle size of the inorganic particles falls within the aforementioned range, the uneven shape resulting from the aggregates of inorganic particles can be easily controlled. It should be noted that, unless otherwise stated, the average particle size of the inorganic particles in this specification refers to the average primary particle size. The average particle size of the inorganic particles can be determined, for example, using laser scattering.

[0256] Examples of metallic particles include particles composed of metals such as gold and silver, and metallic-coated particles that coat the surface of organic particles with metal. Due to their high density, metallic particles are difficult to float on the surface of an uneven layer, thus limiting their ability to increase sa (Sa). Furthermore, because metallic particles have low affinity for the binder resin, the protruding portions of these particles are not coated with resin, resulting in steep protrusions. Therefore, metallic particles tend to have a low sa level and cause sk (Ssk) to become excessively large.

[0257] In summary, it is preferable that the uneven layer does not contain metallic particles.

[0258] The particle shape can be spherical, elliptical, amorphous, etc., with spherical particles being preferred. Spherical particles can easily prevent the unevenness of the layer from becoming too steep, thus easily preventing excessive growth of Ssk.

[0259] Regarding the content of particles, relative to 100 parts by weight of the binder resin, the lower limit is preferably 0.3 parts by weight or more, more preferably 0.4 parts by weight or more, and even more preferably 0.5 parts by weight or more, and the upper limit is preferably 12.0 parts by weight or less, more preferably 11.0 parts by weight or less, and even more preferably 10.0 parts by weight or less.

[0260] By making the particle content 0.3 parts by mass or more, it is easy to suppress the Sa from becoming too small and the Ssk from becoming too large in the uneven layer. Furthermore, by making the particle content 12.0 parts by mass or less, it is easy to suppress the Sa from becoming too large in the uneven layer. Additionally, when the particles are organic particles, by making the particle content 12.0 parts by mass or less, it is also easy to suppress the Ssk from becoming too small.

[0261] Examples of embodiments where the particle content is within the range of 100 parts by weight of the binder resin include 0.3 parts by weight to 12.0 parts by weight, 0.3 parts by weight to 11.0 parts by weight, 0.3 parts by weight to 10.0 parts by weight, 0.4 parts by weight to 12.0 parts by weight, 0.4 parts by weight to 11.0 parts by weight, 0.4 parts by weight to 10.0 parts by weight, 0.5 parts by weight to 12.0 parts by weight, 0.5 parts by weight to 11.0 parts by weight, and 0.5 parts by weight to 10.0 parts by weight.

[0262] The lower limit of the average film thickness of the uneven layer is preferably 0.5 μm or more, more preferably 0.7 μm or more, and even more preferably 1.0 μm or more, and the upper limit is preferably 7.0 μm or less, more preferably 5.0 μm or less, and even more preferably 3.0 μm or less.

[0263] By making the average film thickness of the uneven layer 0.5 μm or more, it is easy to suppress the excessive increase of Sa and Ssk in the uneven layer. Furthermore, by making the average film thickness of the uneven layer 7.0 μm or less, it is easy to suppress the excessive decrease of Sa and Ssk in the uneven layer.

[0264] Examples of implementations that define the range of average film thickness for the uneven layer include 0.5 μm to 7.0 μm, 0.5 μm to 5.0 μm, 0.5 μm to 3.0 μm, 0.7 μm to 7.0 μm, 0.7 μm to 5.0 μm, 0.7 μm to 3.0 μm, 1.0 μm to 7.0 μm, 1.0 μm to 5.0 μm, and 1.0 μm to 3.0 μm.

[0265] The average film thickness of each layer constituting the optical laminate, such as the uneven layer and the antifouling layer, can be calculated, for example, by selecting any 20 locations from cross-sectional photographs of the optical laminate obtained by scanning transmission electron microscopy (STEM) and calculating the average thickness. These 20 locations are selected in a non-concentrated manner.

[0266] The accelerating voltage and magnification of STEM can be set according to the layer of the object being measured. For example, in the case of an uneven layer, the accelerating voltage of STEM is preferably 10kV to 30kV and the magnification of STEM is preferably 1000 to 7000 times.

[0267] The uneven layer may also contain other additives to a extent that does not impair the effects of the present invention. Examples of additives include leveling agents, ultraviolet absorbers, antioxidants, and light stabilizers.

[0268] The lower limit of the refractive index of the uneven layer is preferably 1.48 or higher, more preferably 1.50 or higher, and even more preferably 1.52 or higher, while the upper limit is preferably 1.58 or lower, more preferably 1.54 or lower, and even more preferably 1.53 or lower. By making the refractive index of the uneven layer within the above range and the refractive index of the antifouling layer within the range described later, the light reflectance Y value can be easily reduced.

[0269] Examples of implementations for the range of refractive index of the uneven layer include 1.48 or more and 1.58 or less, 1.48 or more and 1.54 or less, 1.48 or more and 1.53 or less, 1.50 or more and 1.58 or less, 1.50 or more and 1.54 or less, 1.50 or more and 1.53 or less, 1.52 or more and 1.58 or less, 1.52 or more and 1.54 or less, and 1.52 or more and 1.53 or less.

[0270] Solvent

[0271] Solvents are typically used in coating solutions for uneven coatings to adjust viscosity or to dissolve or disperse the components.

[0272] Solvents can include, for example: ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as dioxane and tetrahydrofuran; aliphatic hydrocarbons such as hexane; alicyclic hydrocarbons such as cyclohexane; aromatic hydrocarbons such as toluene and xylene; carbon halogens such as dichloromethane and dichloroethane; esters such as methyl acetate, ethyl acetate, and butyl acetate; alcohols such as isopropanol, butanol, and cyclohexanol; cellosolves such as methyl cellosolve and ethyl cellosolve; glycol ethers such as propylene glycol monomethyl ether acetate; acetic acid cellosolves; sulfoxides such as dimethyl sulfoxide; amides such as dimethylformamide and dimethylacetamide; etc., or mixtures thereof.

[0273] If the drying time of the solvent in the coating solution for the uneven coating is too long, the particle size (Ssk) may become too large due to excessive particle aggregation. Conversely, if the drying time of the solvent in the coating solution for the uneven coating is too short, the particle size (Sa) may become too small due to insufficient particle aggregation. Therefore, it is preferable to use a mixture of solvents with fast evaporation rates and solvents with slow evaporation rates in the coating solution for the uneven coating.

[0274] In this specification, a solvent with a fast evaporation rate refers to a solvent whose evaporation rate is 100 or higher when the evaporation rate of butyl acetate is set to 100. Conversely, a solvent with a slow evaporation rate refers to a solvent whose evaporation rate is less than 100 when the evaporation rate of butyl acetate is set to 100.

[0275] In the solvent of the coating liquid for the uneven coating, the lower limit of the evaporation rate of the solvent with a fast evaporation rate is preferably 120 or more, more preferably 130 or more, and even more preferably 140 or more, and the upper limit of the evaporation rate is preferably 400 or less, more preferably 300 or less, and even more preferably 220 or less. Examples of solvents with fast evaporation rates include methyl isobutyl ketone (160 evaporation rate), methyl ethyl ketone (370 evaporation rate), toluene (200 evaporation rate), and 2-propanol (150 evaporation rate).

[0276] Examples of implementations for the range of evaporation rates of solvents with fast evaporation rates include 120 to 400 rpm, 120 to 300 rpm, 120 to 220 rpm, 130 to 400 rpm, 130 to 300 rpm, 130 to 220 rpm, 140 to 400 rpm, 140 to 300 rpm, and 140 to 220 rpm.

[0277] In the solvent of the coating liquid for the uneven coating, the lower limit of the evaporation rate of the solvent with a slow evaporation rate is preferably 15 or more, more preferably 20 or more, and even more preferably 25 or more, and the upper limit of the evaporation rate is preferably 90 or less, more preferably 50 or less, and even more preferably 35 or less. Examples of solvents with a slow evaporation rate include cyclohexanone with an evaporation rate of 32 and propylene glycol monomethyl ether acetate with an evaporation rate of 44.

[0278] Examples of implementations for the range of evaporation rates of solvents with slow evaporation rates include 15 to 90 ohms, 15 to 50 ohms, 15 to 35 ohms, 20 to 90 ohms, 20 to 50 ohms, 20 to 35 ohms, 25 to 90 ohms, 25 to 50 ohms, and 25 to 35 ohms.

[0279] In the solvent of the coating liquid for the uneven layer, the mass ratio of the solvent with a fast evaporation rate to the solvent with a slow evaporation rate is preferably 50:50 to 90:10, more preferably 50:50 to 80:20 or 60:40 to 90:10, and even more preferably 60:40 to 80:20.

[0280] Furthermore, regarding the solvent content in the coating liquid for the uneven coating, the lower limit of the solid component concentration is preferably 30% by mass or more, and more preferably 35% by mass or more. Furthermore, regarding the solvent content in the coating liquid for the uneven coating, the upper limit of the solid component concentration is preferably 70% by mass or less, and more preferably 45% by mass or less.

[0281] Examples of embodiments for the range of solvent content in the coating liquid for uneven coating include 30% by mass or more and 70% by mass or less, 30% by mass or more and 45% by mass or less, 35% by mass or more and 70% by mass or less, and 35% by mass or more and 45% by mass or less.

[0282] Antifouling layer

[0283] The antifouling layer is a layer located on the surface of the uneven layer opposite to the easy-to-adhere layer. The antifouling layer is preferably formed in contact with the uneven layer. That is, it is preferable that there are no other layers between the uneven layer and the antifouling layer.

[0284] In addition, the antifouling layer is preferably configured as the surface of an optical laminate.

[0285] Typically, large stresses are generated when other components come into contact with the surface of the laminate. Therefore, when other components come into contact with the surface of a laminate containing functional layers such as easy-to-adhere layers and textured layers on a polyester film with a high planar orientation ΔP, stress can cause delamination between the polyester film and the easy-to-adhere layers. Among these stresses, transverse stress has the greatest impact.

[0286] However, when other components are in surface contact with the antifouling layer side of the optical laminate of the present invention, the other components slide due to the antifouling function of the antifouling layer, thus making it difficult to generate stress in the lateral direction. Furthermore, since the surface of the optical laminate of the present invention has an unevenness caused by the unevenness layer satisfying Formula 2-1, other components are difficult to adhere to the surface of the optical laminate due to the aforementioned unevenness, making it difficult to generate stress. Therefore, in the optical laminate of the present invention, the interlayer adhesion of the optical laminate as a whole is good, and peeling of functional layers such as easy-to-adhere layers and unevenness layers formed on polyester films with high surface orientation ΔP can be suppressed.

[0287] Furthermore, since the optical laminate of the present invention has an anti-fouling layer formed on the uneven layer satisfying Formula 2-1, it is able to suppress uneven thickness of the anti-fouling layer, thereby suppressing the generation of local defects in the optical laminate.

[0288] The antifouling layer can be formed, for example, by a coating liquid for forming an antifouling layer comprising an adhesive resin composition and an antifouling agent. That is, as an embodiment of the antifouling layer, embodiments comprising an adhesive resin and an antifouling agent can be cited.

[0289] The adhesive resin of the antifouling layer preferably comprises a cured product of a curable resin composition. Examples of cured products of curable resin compositions include cured products of thermosetting resin compositions and cured products of ionizing radiation-curable resin compositions. Among the cured products of curable resin compositions, cured products of ionizing radiation-curable resin compositions are preferred for further improvement of mechanical strength.

[0290] Curable resin compositions for antifouling layers can be exemplified by, for example, curable resin compositions in embossed layers.

[0291] To improve antifouling properties, the resin composition forming the antifouling layer preferably includes a resin composition containing fluorine atoms in its structural units or a resin composition containing siloxane bonds in its structural units. These resin compositions are more preferably curable.

[0292] When using a resin composition containing fluorine atoms in its structural units, or a resin composition containing siloxane bonds in its structural units, it is preferable to use it in combination with other resin compositions. Among resin compositions other than those containing fluorine atoms in their structural units and those containing siloxane bonds in their structural units, a curable resin composition is preferred.

[0293] The cured product of the curable resin composition is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to all the adhesive resin in the antifouling layer.

[0294] As antifouling agents, examples include fluorinated leveling agents and silicone leveling agents.

[0295] To suppress seepage from the antifouling layer, the antifouling agent preferably has reactive groups capable of reacting with the adhesive resin composition. In other words, in the antifouling layer, the antifouling agent is preferably fixed to the adhesive resin composition.

[0296] In addition, antifouling agents that are capable of self-crosslinking are preferred in order to suppress seepage from the antifouling layer.

[0297] The content of the antifouling agent in the antifouling layer is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and the upper limit is preferably 30 parts by weight or less, more preferably 25 parts by weight or less, relative to 100 parts by weight of the adhesive resin of the antifouling layer.

[0298] Examples of embodiments for the range of antifouling agent content in the antifouling layer include 5 to 30 parts by mass, 5 to 25 parts by mass, 10 to 30 parts by mass, and 10 to 25 parts by mass relative to 100 parts by mass of the adhesive resin in the antifouling layer.

[0299] The thickness of the antifouling layer is preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 110 nm or less. By making the thickness of the antifouling layer 200 nm or less, the uneven shape of the textured layer can be easily reflected on the surface of the antifouling layer, which can easily improve the adhesion of the optical laminate.

[0300] If the antifouling layer is too thin, the in-plane uniformity of the antifouling effect will be compromised, and the adhesion of the optical laminate may sometimes decrease. Furthermore, if the antifouling layer is too thin, localized defects such as bright spots may easily occur in the optical laminate. Therefore, the thickness of the antifouling layer is preferably 50 nm or more, more preferably 70 nm or more, and even more preferably 90 nm or more.

[0301] Examples of implementations for the thickness range of the antifouling layer include: below 200nm, above 50nm and below 200nm, above 50nm and below 150nm, above 50nm and below 110nm, above 70nm and below 200nm, above 70nm and below 150nm, above 70nm and below 110nm, above 90nm and below 200nm, above 90nm and below 150nm, and above 90nm and below 110nm.

[0302] As described below, when the antifouling layer has a low refractive index, in order to reduce the light reflectance Y value, the lower limit of the thickness of the antifouling layer is preferably 80 nm or more, more preferably 85 nm or more, and even more preferably 90 nm, and the upper limit is preferably 120 nm or less, more preferably 110 nm or less, and even more preferably 105 nm or less. In this case, it is preferable that the thickness of the antifouling layer is greater than the average particle size of the particles contained in the antifouling layer, such as hollow particles and non-hollow particles.

[0303] Examples of implementations for reducing the refractive index of the antifouling layer include thicknesses ranging from 80 nm to 120 nm, 80 nm to 110 nm, 80 nm to 105 nm, 85 nm to 120 nm, 85 nm to 110 nm, 85 nm to 105 nm, 90 nm to 120 nm, 90 nm to 110 nm, and 90 nm to 105 nm.

[0304] The contact angle of the antifouling layer surface with pure water is preferably 80 degrees or more, more preferably 85 degrees or more, and even more preferably 90 degrees or more. By making the contact angle 80 degrees or more, the sliding properties of other components when in contact with the surface of the optical laminate become good, and the sealing performance of the optical laminate can be easily improved.

[0305] If the contact angle of the antifouling layer with pure water is too large, the hardness and other physical properties of the antifouling layer may decrease due to the increased proportion of the antifouling agent relative to the total solids content of the antifouling layer. Therefore, the contact angle is preferably 130 degrees or less, and more preferably 120 degrees or less.

[0306] Examples of implementation methods for the contact angle range of the antifouling layer with pure water include 80 degrees to 130 degrees, 80 degrees to 120 degrees, 85 degrees to 130 degrees, 85 degrees to 120 degrees, 90 degrees to 130 degrees, and 90 degrees to 120 degrees.

[0307] In this specification, the contact angle refers to the static contact angle measured using the θ / 2 method.

[0308] Pure water can be any type of purified water. The resistivity of pure water is typically between 0.1 MΩ·cm and 15 MΩ·cm.

[0309] The antifouling layer can be made with a low refractive index.

[0310] Specifically, the lower limit of the refractive index of the antifouling layer is preferably 1.10 or higher, more preferably 1.20 or higher, more preferably 1.26 or higher, more preferably 1.28 or higher, and more preferably 1.30 or higher, and the upper limit is preferably 1.48 or lower, more preferably 1.45 or lower, more preferably 1.40 or lower, more preferably 1.38 or lower, and more preferably 1.32 or lower. By making the refractive index of the antifouling layer within the above range, the light reflectance Y value can be easily reduced.

[0311] Examples of implementations for the refractive index range of the antifouling layer include 1.10 to 1.48, 1.10 to 1.45, 1.10 to 1.40, 1.10 to 1.38, 1.10 to 1.32, 1.20 to 1.48, 1.20 to 1.45, 1.20 to 1.40, 1.20 to 1.38, 1.20 to 1.32, 1.26 to 1.48, and 1.26 to 1.48. Below 45, 1.26 to 1.40, 1.26 to 1.38, 1.26 to 1.32, 1.28 to 1.48, 1.28 to 1.45, 1.28 to 1.40, 1.28 to 1.38, 1.28 to 1.32, 1.30 to 1.48, 1.30 to 1.45, 1.30 to 1.40, 1.30 to 1.38, 1.30 to 1.32.

[0312] When the antifouling layer is made to have a low refractive index, the antifouling layer preferably contains particles.

[0313] The particles in the antifouling layer preferably comprise hollow particles and non-hollow particles. That is, the low-refractive-index antifouling layer preferably comprises adhesive resin, hollow particles, and non-hollow particles.

[0314] Hollow particles and non-hollow particles

[0315] The hollow particles and non-hollow particles can be made of any of the inorganic or organic compounds, such as silicon dioxide and magnesium fluoride. Silicon dioxide is preferred due to its low refractive index and strength. The following explanation will focus on hollow silicon dioxide particles and non-hollow silicon dioxide particles.

[0316] Hollow silica particles refer to particles that have an outer shell made of silica, and the interior of the particle surrounded by the outer shell is hollow, containing air within the hollow space. Hollow silica particles are particles in which the refractive index is reduced proportionally to the gas occupancy compared to the original refractive index of silica by including air. Non-hollow silica particles refer to particles that are not hollow inside, unlike hollow silica particles. Non-hollow silica particles are, for example, solid silica particles.

[0317] The shape of hollow silica particles and non-hollow silica particles is not particularly limited, and can be spherical, ellipsoidal, or polyhedral, or similar to a sphere. However, if scratch resistance is considered, spherical, ellipsoidal, or similar shapes are preferred.

[0318] Hollow silica particles, by containing air within them, reduce the overall refractive index of the antifouling layer. Using larger-sized hollow silica particles with a higher air content further reduces the refractive index of the antifouling layer. However, hollow silica particles tend to have poor mechanical strength. In particular, using larger-sized hollow silica particles with a higher air content can easily reduce the scratch resistance of the antifouling layer.

[0319] Non-hollow silica particles, dispersed in the binder resin, enhance the scratch resistance of the antifouling layer.

[0320] For both hollow silica particles and non-hollow silica particles, it is preferable to set the average particle size of the hollow silica particles and the average particle size of the non-hollow silica particles in such a way that the hollow silica particles are close to each other, while the non-hollow particles can enter between the hollow silica particles.

[0321] Specifically, the ratio of the average particle size of non-hollow silica particles to the average particle size of hollow silica particles, i.e., "average particle size of non-hollow silica particles / average particle size of hollow silica particles," is preferably 0.29 or less, more preferably 0.27 or less. By setting the average particle size ratio within the above range, hollow silica particles and non-hollow silica particles are easily and uniformly dispersed in the film thickness direction of the antifouling layer, which can easily improve scratch resistance. It should be noted that the above-mentioned average particle size ratio is preferably 0.05 or more, more preferably 0.15 or more.

[0322] Examples of implementations for the range of the above-mentioned average particle size ratio include 0.05 or more and 0.29 or less, 0.05 or more and 0.27 or less, 0.15 or more and 0.29 or less, and 0.15 or more and 0.27 or less.

[0323] Regarding the average particle size of the hollow silica particles, considering optical properties and mechanical strength, the lower limit is preferably 50 nm or more, more preferably 60 nm or more, and the upper limit is preferably 100 nm or less, more preferably 80 nm or less. Examples of implementations for the range of the average particle size of the hollow silica particles include 50 nm or more but less than 100 nm, 50 nm or more but less than 80 nm, 60 nm or more but less than 100 nm, and 60 nm or more but less than 80 nm.

[0324] If dispersibility is considered while preventing the aggregation of non-hollow silica particles, the lower limit of the average particle size of the non-hollow silica particles is preferably 5 nm or more, more preferably 10 nm or more, and the upper limit is preferably 20 nm or less, more preferably 15 nm or less. Examples of implementations for the range of average particle size of non-hollow silica particles include 5 nm or more and 20 nm or less, 5 nm or more and 15 nm or less, 10 nm or more and 20 nm or less, and 10 nm or more and 15 nm or less.

[0325] Hollow silica particles and non-hollow silica particles are preferably coated with a silane coupling agent. As a silane coupling agent, a silane coupling agent having (meth)acryloyl or epoxy groups is preferred.

[0326] By surface-treating silica particles with a silane coupling agent, the affinity between the silica particles and the binder resin is improved, making it difficult for silica particles to aggregate. Therefore, the silica particles are easily and uniformly dispersed. Furthermore, by using a silane coupling agent to enhance the affinity between the silica particles and the binder resin, the resistance to the flow of the wetted antifouling layer formed on the raised portion of the uneven layer to the flat portion is increased, thus easily suppressing excessive reduction in the thickness of the antifouling layer on the raised portion of the uneven layer. Therefore, local defects in the optical laminate can be easily suppressed.

[0327] The higher the content of hollow silica particles, the higher the filling rate of hollow silica particles in the binder resin, and the lower the refractive index of the antifouling layer. Furthermore, the higher the content of hollow silica particles, the higher the viscosity of the coating liquid for the antifouling layer. This increases the resistance when the wet antifouling layer formed on the convex portion of the uneven layer flows down to the flat portion side of the uneven layer, thus easily suppressing excessive reduction in the film thickness of the antifouling layer on the convex portion of the uneven layer. Therefore, it is easier to suppress local defects in the optical laminate. Therefore, the content of hollow silica particles relative to 100 parts by weight of binder resin is preferably 100 parts by weight or more, more preferably 130 parts by weight or more.

[0328] On the other hand, if the content of hollow silica particles is too high, the mechanical strength of the antifouling layer, such as its scratch resistance, tends to decrease. Furthermore, if the content of hollow silica particles is too high, the content of the antifouling agent decreases relatively, thus tending to reduce the antifouling performance. Therefore, the content of hollow silica particles is preferably 300 parts by weight or less, more preferably 200 parts by weight or less, relative to 100 parts by weight of the binder resin.

[0329] Examples of embodiments for the range of hollow silica particles content relative to 100 parts by weight of the adhesive resin include 100 parts by weight or more and 400 parts by weight or less, 100 parts by weight or more and 300 parts by weight or less, 130 parts by weight or more and 400 parts by weight or less, and 130 parts by weight or more and 300 parts by weight or less.

[0330] If the content of non-hollow silica particles is low, even if non-hollow silica particles are present on the surface of the antifouling layer, it may not affect the increase in hardness. Furthermore, the higher the content of non-hollow silica particles, the higher the viscosity of the coating liquid for the antifouling layer. This increases the resistance when the wet antifouling layer formed on the convex portion of the uneven layer flows down to the flat portion, thus easily suppressing excessive reduction in the film thickness of the antifouling layer on the convex portion. Therefore, it is easier to suppress local defects in the optical laminate. Additionally, the higher the content of non-hollow silica particles, the easier it is to reduce the effect of uneven shrinkage caused by the polymerization of the binder resin. Therefore, the content of non-hollow silica particles is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, relative to 100 parts by mass of the binder resin.

[0331] On the other hand, if the content of non-hollow silica particles is too high, the content of antifouling agent is relatively reduced, thus tending to reduce antifouling properties. Therefore, the content of non-hollow silica particles is preferably 150 parts by weight or less, more preferably 100 parts by weight or less, and even more preferably 50 parts by weight or less, relative to 100 parts by weight of binder resin.

[0332] Examples of embodiments for the range of non-hollow silica particles content relative to 100 parts by weight of the adhesive resin include 10 to 150 parts by weight, 10 to 100 parts by weight, 10 to 50 parts by weight, 20 to 150 parts by weight, 20 to 100 parts by weight, and 20 to 50 parts by weight.

[0333] The antifouling layer may also contain other additives within a range that does not impair the effects of the present invention. Examples of additives include ultraviolet absorbers, antioxidants, and light stabilizers.

[0334] Solvent

[0335] Solvents are typically used in coating solutions for antifouling layers to adjust viscosity or to dissolve or disperse the components.

[0336] The solvent for the antifouling coating liquid can be the same substance as the solvent exemplified as the solvent for the anti-contamination layer coating liquid.

[0337] If the drying time of the solvent in the antifouling coating solution is too long, the wet antifouling layer formed on the raised portion of the uneven layer will excessively flow down to the flat portion side of the uneven layer, thus sometimes resulting in an excessively reduced film thickness of the antifouling layer on the raised portion of the uneven layer. Conversely, if the drying time of the solvent in the antifouling coating solution is too short, the leveling properties of the antifouling layer may be insufficient. Therefore, it is preferable to use a mixture of solvents with fast evaporation rates and solvents with slow evaporation rates in the antifouling coating solution.

[0338] In the solvent of the coating liquid for the antifouling layer, the lower limit of the evaporation rate of the solvent with a fast evaporation rate is preferably 125 or more, more preferably 130 or more, and even more preferably 150 or more, and the upper limit of the evaporation rate is preferably 450 or less, more preferably 430 or less, and even more preferably 400 or less.

[0339] Examples of implementations for the range of evaporation rates of solvents with fast evaporation rates include 125 to 450 rpm, 125 to 430 rpm, 125 to 400 rpm, 130 to 450 rpm, 130 to 430 rpm, 130 to 400 rpm, 150 to 450 rpm, 150 to 430 rpm, and 150 to 400 rpm.

[0340] In the solvent of the coating liquid for the antifouling layer, the lower limit of the evaporation rate of the solvent with a slow evaporation rate is preferably 20 or more, more preferably 30 or more, and even more preferably 40 or more, and the upper limit of the evaporation rate is preferably 90 or less, more preferably 60 or less, and even more preferably 50 or less.

[0341] Examples of implementations for the range of evaporation rates of solvents with slow evaporation rates include 20 to 90 oz, 20 to 60 oz, 20 to 50 oz, 30 to 90 oz, 30 to 60 oz, 30 to 50 oz, 40 to 90 oz, 40 to 60 oz, and 40 to 50 oz.

[0342] In the solvent of the antifouling coating liquid, the mass ratio of the solvent with a fast evaporation rate to the solvent with a slow evaporation rate is preferably 50:50 to 90:10, more preferably 50:50 to 80:20 or 60:40 to 90:10, and even more preferably 60:40 to 80:20.

[0343] Furthermore, regarding the solvent content in the coating liquid for the antifouling layer, the lower limit of the solid component concentration is preferably 1% by mass or more, and more preferably 2% by mass or more. Furthermore, regarding the solvent content in the coating liquid for the antifouling layer, the upper limit of the solid component concentration is preferably 10% by mass or less, and more preferably 5% by mass or less.

[0344] Examples of embodiments for the range of solvent content in the coating liquid for antifouling layer include 1% to 10% by mass, 1% to 5% by mass, 2% to 10% by mass, and 2% to 5% by mass.

[0345] <Physical properties>

[0346] The optical laminate preferably has a light reflectance Y value of 3.0% or less, more preferably 2.0% or less, measured from the side with the anti-fouling layer at a light incident angle of 5 degrees.

[0347] It should be noted that there is no specific lower limit for the light reflectance Y value, which is usually around 0.5%.

[0348] In this specification, the light reflectance Y value refers to the light reflectance Y value of the CIE 1931 standard colorimetric system. The light reflectance Y value can be calculated using spectrophotometry. When measuring light reflectance, it is preferable to attach a black plate to the back of the substrate. As a spectrophotometer, an example is the Shimadzu Corporation's product name "UV-3600plus".

[0349] The light reflectance Y value, total light transmittance, and haze are the average values ​​of the 10 measurements taken.

[0350] The total light transmittance of the optical laminate according to JIS K7361-1:1997 is preferably 50% or more, more preferably 80% or more, and even more preferably 90% or more.

[0351] Total light transmittance and haze (described later) are measured with the light incident surface set to the polyester film side. Total light transmittance and haze (described later) can be measured, for example, using a haze meter (part number: HM-150) manufactured by Murakami Color Technology Research Institute.

[0352] In optical laminates, the lower limit of haze according to JIS K7136:2000 is preferably 0.3% or more, more preferably 0.4% or more, and even more preferably 0.5% or more, and the upper limit is preferably 10% or less, more preferably 7% or less, and even more preferably 5% or less.

[0353] Examples of implementations for the haze range of optical laminates include 0.3% to 10% and 0.3% to 7% and 0.3% to 5% and 0.4% to 10% and 0.4% to 7% and 0.4% to 5% and 0.5% to 10% and 0.5% to 7% and 0.5% to 5% and 0.5% to 5%.

[0354] <Size, shape, etc.>

[0355] Optical laminates can be in the form of single-leaf shapes cut to a specified size, or in the form of rolls formed by rolling long sheets into a roll. There is no particular limitation on the size of a single leaf, with a maximum diameter of approximately 2 inches to 500 inches. "Maximum diameter" refers to the maximum length when connecting any two points of the optical laminate. For example, in the case of a rectangular optical laminate, the diagonal of the rectangle is the maximum diameter. In the case of a circular optical laminate, the diameter of the circle is the maximum diameter.

[0356] There are no particular limitations on the width and length of the roll; typically, the width is between 500 mm and 8000 mm, and the length is between 100 m and 10000 m. The roll-shaped optical laminate can be cut into single-leaf shapes according to the size of image display devices, etc. When cutting, it is preferable to avoid cutting the roll ends, which have unstable physical properties.

[0357] The shape of a single leaf is not particularly limited. For example, it can be a polygon such as a triangle, quadrilateral, or pentagon, or it can be a circle or a random amorphous shape. More specifically, when the optical laminate is quadrilateral, the aspect ratio is not particularly limited as long as it does not pose a problem for the display screen. For example, aspect ratios such as 1:1, 4:3, 16:10, 16:9, 2:1, 5:4, and 11:8 can be given.

[0358] [Polarizing filter]

[0359] The polarizer of the present invention is a polarizer having a polarizing element, a first transparent protective plate disposed on one side of the polarizing element, and a second transparent protective plate disposed on the other side of the polarizing element, wherein at least one of the first transparent protective plate and the second transparent protective plate is an optical laminate of the present invention, and the optical laminate is disposed such that the surface of the anti-fouling layer faces the side opposite to the polarizing element.

[0360] <Polarization element>

[0361] Examples of polarizing elements include sheet-type polarizing elements such as polyvinyl alcohol films dyed and stretched with iodine, polyvinyl alcohol formal films, polyvinyl alcohol acetal films, and ethylene-vinyl acetate copolymer saponified films; wire grid-type polarizing elements composed of a large number of parallel metal lines; coated polarizing elements coated with lyotropic liquid crystals or dichroic host-guest materials; and multilayer thin film polarizing elements. These polarizing elements can also be reflective polarizing elements that have the function of reflecting polarizing components while not transmitting them.

[0362] <Transparent Protective Panel>

[0363] A first transparent protective plate is disposed on one side of the polarizing element, and a second transparent protective plate is disposed on the other side. At least one of the first and second transparent protective plates is the optical laminate of the present invention described above.

[0364] Examples of first and second transparent protective plates, other than the optical laminate, include plastic films and glass. Examples of plastic films include polyester films, polycarbonate films, cyclic olefin polymer films, and acrylic films; stretched films of these are preferred to improve mechanical strength. Examples of glass include alkaline glass, nitride glass, soda-lime glass, borosilicate glass, and lead glass. Furthermore, the glass used as the transparent protective plate for protecting polarizing elements is preferably compatible with other components of the image display device. For example, it is preferable to use both the glass substrate for the liquid crystal display element and the transparent protective plate for protecting the polarizing element.

[0365] It should be noted that the polarizing element and the transparent protective plate are preferably bonded together using an adhesive. A general-purpose adhesive can be used, but a PVA-based adhesive is preferred.

[0366] The polarizer of the present invention may be either a first transparent protective plate or a second transparent protective plate, both of which are optical laminates of the present invention as described above. However, it is preferable that one of the first transparent protective plate and the second transparent protective plate is an optical laminate of the present invention as described above. Furthermore, when the polarizer of the present invention is used as a polarizer disposed on the light emitting surface side of a display element, it is preferable that the transparent protective plate on the light emitting surface side of the polarizing element is an optical laminate of the present invention as described above. On the other hand, when the polarizer of the present invention is used as a polarizer disposed on the side of a display element opposite to the light emitting surface, it is preferable that the transparent protective plate on the side of the polarizing element opposite to the light emitting surface is an optical laminate of the present invention as described above.

[0367] [Surface plate for image display device]

[0368] The surface plate for the image display device of the present invention is a surface plate for an image display device on which an optical laminate is bonded to a resin plate or a glass plate, wherein the optical laminate is the optical laminate of the present invention, and the optical laminate is arranged such that the surface of the antifouling layer faces the opposite side to the resin plate or the glass plate.

[0369] The surface plate for an image display device is preferably arranged with the side on which the optical laminate is attached facing the surface side. In other words, the surface plate for an image display device is preferably arranged with the side on which the optical laminate is attached facing the side opposite to the display element.

[0370] As a resin plate or glass plate, a resin plate or glass plate commonly used as a surface plate for image display devices can be used.

[0371] To improve strength, the thickness of the resin plate or glass plate is preferably 10 μm or more. The upper limit of the thickness of the resin plate or glass plate is usually 5000 μm or less. In recent years, due to the popularity of thinner image display devices, it is preferred to be 1000 μm or less, more preferably 500 μm or less, and even more preferably 100 μm or less.

[0372] Examples of embodiments for the range of thickness of the resin plate or glass plate include 10 μm or more and 5000 μm or less, 10 μm or more and 1000 μm or less, 10 μm or more and 500 μm or less, and 10 μm or more and 100 μm or less.

[0373] [Image display device]

[0374] The image display device of the present invention has a display element in which the surface of the anti-fouling layer side of the optical laminate of the present invention faces the opposite side to the display element, and the optical laminate is disposed on the surface.

[0375] Examples of display elements include liquid crystal display elements, organic EL display elements, inorganic EL display elements, plasma display elements, and LED display elements such as small LED display elements and micro LED display elements. These display elements may also have touch panel functionality inside the display element.

[0376] Examples of liquid crystal display (LCD) display methods include IPS, VA, multi-domain, OCB, STN, and TSTN. When the display element is an LCD, a backlight is required. The backlight is positioned on the side of the LCD element opposite to the side containing the optical layers. Examples of backlights include those using quantum dots and those using white light-emitting diodes (LEDs).

[0377] The image display device can be a foldable image display device or a rollable image display device. Additionally, the image display device can be an image display device with a touch panel.

[0378] Example

[0379] The present invention will now be described in detail with examples and comparative examples. It should be noted that the present invention is not limited to the methods described in the examples.

[0380] 1. Evaluation and measurement

[0381] The optical laminates obtained in Examples 1-20 and Comparative Examples 1-21 were subjected to the following measurements and evaluations (1-1 to 1-6). The results are shown in Tables 1-4. It should be noted that, unless otherwise specified, the atmosphere used for each measurement and evaluation was a temperature of 23±5°C and a relative humidity of 40% to 65%. Before each measurement and evaluation, the sample was exposed to the above atmosphere for at least 30 minutes.

[0382] 1-1. Determination of Sa and Ssk

[0383] In the examples and comparative examples, the surface shape of the uneven layer was measured after the formation of the easy-to-adhere layer and the uneven layer on the polyester film (PET film) and before the formation of the antifouling layer. Sa, Ssk, and “A” of Formula 2-1 were calculated from the measured surface shape. The surface shape was measured using a laser microscope (Olympus's trade name “LEXT OLS4000”) under the following conditions. Sa and Ssk measured by the laser microscope were in accordance with ISO 25178:2012. The results are shown in Tables 1-4.

[0384] <Measurement Conditions>

[0385] Objective lens: MPLAPONLEXT50 (50x lens)

[0386] Zoom lens: ×1

[0387] Image size (pixels): 1024×1024

[0388] Image size: 258μm × 259μm

[0389] Sampling length value: Not set

[0390] <Analysis Conditions>

[0391] Analysis Mode: Face

[0392] Calculation type: roughness

[0393] 1-2. Fit

[0394] The blade of the cutter was inserted into the antifouling layer side of the optical laminate of the embodiments and comparative examples, thereby forming a 100-square checkerboard pattern (number of cuts: 11 cut lines in the longitudinal and transverse directions, cut interval: 1 mm). The blade of the cutter used was NT Corporation's product number "BA-52P". Next, adhesive tape (Mickey & Co., Ltd., product name "Cellotape (registered trademark)") was applied to the checkerboard surface of the optical laminate, and then the tape was peeled off, thereby performing a peel test according to the cross-cutting method specified in JIS K5600-5-6:1999. The adhesion of the optical laminates of the embodiments and comparative examples was evaluated according to the following evaluation criteria.

[0395] <Evaluation Criteria>

[0396] A: The number of cells stripped is 0, and there are no cases where part of a cell is missing.

[0397] B: The number of stripped cells is 0, but there are parts of the cells that are missing along the cut, etc.

[0398] C: The number of cells stripped is 1 or more.

[0399] 1-3. Highlights

[0400] The optical laminates of the embodiments and comparative examples were placed on a horizontal platform with the antifouling layer side facing upwards. In a bright room environment, the presence of bright spots was visually evaluated from various angles by observing the reflected light from the fluorescent lamp used as illumination. The evaluation was conducted from approximately 50 cm above the sample in a straight line. The conditions of the bright room environment were set to an illuminance of 500 lux to 1000 lux on the sample. An Hf32 type straight-tube three-wavelength neutral white fluorescent lamp was used for illumination. The illumination position was 2 m above the horizontal platform in the vertical direction.

[0401] A score of 3 is given for not caring about the highlights, 1 point for caring about the highlights, and 2 points for neither. The evaluation was conducted by 20 participants, consisting of 5 participants from each of the 20-59 age groups. The average score of the 20 participants was calculated, and the participants were ranked according to the following criteria.

[0402] <Evaluation Criteria>

[0403] A: Average score above 2.5

[0404] B: Average score above 2.0 and below 2.5

[0405] C: Average score less than 2.0

[0406] 1-4. Contact Angle

[0407] Using a contact angle meter (manufactured by Kyowa Interface Science, part number: DM-300), 1.0 μL of pure water was dropped onto the surface of the antifouling layer side of the optical laminates of the examples and comparative examples, and the static contact angle after 10 seconds of droplet adhesion was measured according to the θ / 2 method. The measurement was performed three times, and the average value was taken as the contact angle of each example and comparative example.

[0408] 1-5. Light reflectance Y value (reflectance)

[0409] A 5cm × 5cm sample was produced by bonding a black board (KURARAY, COMOGLAS DFA2CG 502K (black) series, 2mm thick) to the substrate side of the optical laminate of the examples and comparative examples using a 25μm thick transparent adhesive layer (Panac, trade name: Panaclean PD-S1).

[0410] When the direction perpendicular to the surface of the antifouling layer of the optical laminate is set to 0 degrees, light is incident on the sample from a direction of 5 degrees, and the light reflectance Y value, which is the reflectance of the sample, is measured based on the positive reflection of the incident light.

[0411] Regarding reflectance, a spectrophotometer (Japan Spectrophotometer Co., Ltd., trade name: V-7100) was used to measure 5 degrees of orthogonal reflected light under conditions of a 2-degree field of view, a C-source light source, and a wavelength range of 380 nm to 780 nm. The reflectance value, calculated by software (JASCO Spectrum Manager version 2.0) converting the reflected light to human-perceived brightness, was then used as the reflectance. Ten measurements were taken within the sample, and the average value of these ten measurements was used as the reflectance for each example and comparative example. A 5 mm × 10 mm mask was used for the measurements. Therefore, the size of the measurement spot for reflectance at an incident angle of 5 degrees was 50.2 mm. 2 .

[0412] 1-6. Total light transmittance (Tt) and haze (Hz)

[0413] The total light transmittance (JIS K7361-1:1997) and haze (JIS K7136:2000) of the optical laminates of the Examples and Comparative Examples were measured using a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute). The light incident surface was the polyester film side.

[0414] 2. Synthesis of Compound A (Carbamate Acrylate Oligomer)

[0415] After introducing air into a reaction vessel equipped with a stirrer, thermometer, cooling pipe, and nitrogen inlet pipe, 10.0 parts by mass of 1,3-butanediol, 10.0 parts by mass of 1,4-butanediol, 0.1 parts by mass of p-methoxyphenol, 0.1 parts by mass of dibutyltin dilaurate, and 100.0 parts by mass of methyl ethyl ketone were added. The mixture was heated to 50°C under nitrogen flow with stirring. Meanwhile, 50.3 parts by mass of isophorone diisocyanate were added to a dropping container and uniformly added to the reaction vessel over 1 hour. The temperature of the reaction vessel was maintained at 50±3°C. After maintaining the temperature for 1 hour with stirring, 0.1 parts by mass of p-methoxyphenol and 0.1 parts by mass of dibutyltin dilaurate were further added, and the mixture was heated to 60°C under nitrogen flow with stirring. Subsequently, 176.0 parts by mass of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate in a mass ratio of 80:20, which was added to the dropping container, were uniformly added to the reaction vessel over a period of 1 hour with stirring.

[0416] After the addition was complete, the dropping container was cleaned with 120.0 parts by weight of methyl ethyl ketone, and the cleaned solution was directly added to the reaction vessel. The mixture was then kept at a stable temperature for 2 hours with stirring, followed by a temperature increase to 75°C. The temperature was then maintained at 75±3°C with stirring until the peak from isocyanate in the infrared absorption spectrum disappeared. The peak from isocyanate disappeared after approximately 4 to 6 hours. Once the peak was confirmed to have disappeared, the temperature was lowered to 60°C, and 7.0 parts by weight of methanol were added. The mixture was kept at 60±3°C for 30 minutes. Then, 120.8 parts by weight of methyl ethyl ketone were added to obtain a transparent resin solution. Finally, the solvent was removed using an evaporator to obtain the urethane acrylate oligomer, compound A. The weight-average molecular weight of compound A was 2000.

[0417] 3. Preparation of coating solution

[0418] (1) Coating liquid 1 for uneven layer

[0419] The following material was diluted with a mixed solvent of methyl isobutyl ketone and methyl ethyl ketone in a mass ratio of 35:65, according to a solid component concentration of 40% by mass, to prepare coating liquid 1 for uneven coating.

[0420] <Materials for Coating Liquid 1 for Undulated Layers>

[0421] Pentaerythritol triacrylate: 56 parts by weight

[0422] (Nippon Kayaku Co., Ltd., trade name "PET-30", solid content 100% by mass)

[0423] • Composition containing UV-curable acrylate: 44 parts by weight

[0424] (Daiichi Kogyo Pharmaceutical Co., Ltd., trade name "New Frontier R-1403MB", solid content 80% by mass)

[0425] Photopolymerization initiator: 3 parts by weight

[0426] (IGM Resins BV, product name "Omnirad184")

[0427] Leveling agent: 3 parts by weight

[0428] (DIC Company, trade name "MEGAFAC F-568", solid content 5% by mass)

[0429] (2) Coating liquid 2 for uneven layers

[0430] The following material was diluted with a mixed solvent of toluene, 2-propanol and cyclohexanone in a mass ratio of 60:10:30, according to a solid component concentration of 40% by mass, to prepare coating liquid 2 for uneven coating.

[0431] <Materials for Coating Liquid 2 for Undulated Layers>

[0432] Pentaerythritol tetraacrylate: 45 parts by weight

[0433] (Product Name: PETA, Daicel SciTech)

[0434] • Carbamate acrylate oligomers: 55 parts by weight

[0435] (Mitsubishi Chemical Corporation, trade name "UV-1700B", solid content 100% by mass)

[0436] Photopolymerization initiator: 3 parts by weight

[0437] (IGM Resins BV, product name "Esacure 1")

[0438] • Organic granules: 0.5 parts by weight

[0439] (Acrylic beads, average particle size 2.2μm, refractive index 1.559, coefficient of variation: 10.4%)

[0440] Leveling agent: 0.5 parts by weight

[0441] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0442] (3) Coating liquid 3 for uneven layers

[0443] The following material was diluted with a mixed solvent of toluene, 2-propanol and cyclohexanone in a mass ratio of 60:10:30 to prepare a coating solution 3 for uneven coating, with a solid component concentration of 40% by mass.

[0444] <Materials for coating liquid 3 for uneven coating>

[0445] Pentaerythritol tetraacrylate: 45 parts by weight

[0446] (Product Name: PETA, Daicel SciTech)

[0447] • Carbamate acrylate oligomers: 55 parts by weight

[0448] (Mitsubishi Chemical Corporation, trade name "UV-1700B", solid content 100% by mass)

[0449] Photopolymerization initiator: 3 parts by weight

[0450] (IGM Resins BV, product name "Esacure 1")

[0451] • Organic granules: 0.6 parts by weight

[0452] (Acrylic beads, average particle size 2.2μm, refractive index 1.559, coefficient of variation: 10.4%)

[0453] • Fumed silica: 1 part by weight

[0454] (Octylsilane treatment, average particle size 12nm, NIPPON AEROSIL)

[0455] Leveling agent: 0.5 parts by weight

[0456] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0457] (4) Coating liquid 4 for uneven layers

[0458] The following material was diluted with a mixed solvent of toluene, 2-propanol and cyclohexanone in a mass ratio of 60:10:30 to prepare a coating solution 4 for an uneven layer, with a solid component concentration of 40% by mass.

[0459] <Materials for coating liquid 4 for uneven coating>

[0460] Pentaerythritol tetraacrylate: 45 parts by weight

[0461] (Product Name: PETA, Daicel SciTech)

[0462] • Carbamate acrylate oligomers: 55 parts by weight

[0463] (Mitsubishi Chemical Corporation, trade name "UV-1700B", solid content 100% by mass)

[0464] Photopolymerization initiator: 3 parts by weight

[0465] (IGM Resins BV, product name "Esacure 1")

[0466] • Fumed silica: 0.5 parts by weight

[0467] (Octylsilane treatment, average particle size 12nm, NIPPON AEROSIL)

[0468] • Fumed silica: 0.2 parts by weight

[0469] (Methylsilane treatment, average particle size 12nm, NIPPON AEROSIL)

[0470] Leveling agent: 0.5 parts by weight

[0471] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0472] (5) Coating liquid 5 for uneven layers

[0473] The following material was diluted with a mixed solvent of toluene, 2-propanol and cyclohexanone in a mass ratio of 60:10:30 to prepare a coating solution 5 for an uneven coating, with a solid component concentration of 40% by mass.

[0474] <Materials for coating liquid 5 for uneven coating>

[0475] Pentaerythritol tetraacrylate: 45 parts by weight

[0476] (Product Name: PETA, Daicel SciTech)

[0477] • Carbamate acrylate oligomers: 55 parts by weight

[0478] (Mitsubishi Chemical Corporation, trade name "UV-1700B", solid content 100% by mass)

[0479] Photopolymerization initiator: 3 parts by weight

[0480] (IGM Resins BV, product name "Esacure 1")

[0481] • Organic granules: 3 parts by weight

[0482] (Acrylic beads, average particle size 2.3μm, refractive index 1.559, coefficient of variation: 10.2%)

[0483] • Fumed silica: 1 part by weight

[0484] (Octylsilane treatment, average particle size 12nm, NIPPON AEROSIL)

[0485] Leveling agent: 0.5 parts by weight

[0486] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0487] (6) Coating liquid 6 for uneven layers

[0488] The following material was diluted with a mixed solvent of toluene, 2-propanol and cyclohexanone in a mass ratio of 60:10:30 to prepare a coating solution 6 for an uneven coating, with a solid component concentration of 40% by mass.

[0489] <Materials for coating liquid 6 for uneven coating>

[0490] Pentaerythritol tetraacrylate: 45 parts by weight

[0491] (Product Name: PETA, Daicel SciTech)

[0492] • Carbamate acrylate oligomers: 55 parts by weight

[0493] (Mitsubishi Chemical Corporation, trade name "UV-1700B", solid content 100% by mass)

[0494] Photopolymerization initiator: 3 parts by weight

[0495] (IGM Resins BV, product name "Esacure 1")

[0496] • Organic granules: 10 parts by weight

[0497] (Acrylic beads, average particle size 3.0 μm, refractive index 1.559, coefficient of variation: 9.8%)

[0498] Leveling agent: 0.5 parts by weight

[0499] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0500] (7) Coating liquid 7 for uneven layers

[0501] The following material was diluted with a mixed solvent of toluene, 2-propanol and cyclohexanone in a mass ratio of 60:10:30 to prepare a coating solution 7 for an uneven coating, with a solid component concentration of 40% by mass.

[0502] <Materials for coating liquid 7 for uneven coating>

[0503] Pentaerythritol tetraacrylate: 45 parts by weight

[0504] (Product Name: PETA, Daicel SciTech)

[0505] • Carbamate acrylate oligomers: 55 parts by weight

[0506] (Mitsubishi Chemical Corporation, trade name "UV-1700B", solid content 100% by mass)

[0507] Photopolymerization initiator: 3 parts by weight

[0508] (IGM Resins BV, product name "Esacure 1")

[0509] Organic granules: 15 parts by weight

[0510] (Acrylic beads, average particle size 3.6μm, refractive index 1.559, coefficient of variation: 10.5%)

[0511] • Metal-coated particles: 0.5 parts by weight

[0512] (Nickel-coated acrylic beads, average particle size 4.5μm)

[0513] Leveling agent: 0.5 parts by weight

[0514] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0515] (8) Coating liquid for uneven layers 8

[0516] The following material was diluted with a mixed solvent of 4-methyl-2-pentanone and 2-propanol in a mass ratio of 70:30 to prepare a coating solution 8 for an uneven coating, with a solid component concentration of 40% by mass.

[0517] <Materials for coating liquid 8 for uneven coating>

[0518] Pentaerythritol triacrylate: 100 parts by weight

[0519] (Product Name: PET-30, Nippon Kayaku Co., Ltd.)

[0520] Photopolymerization initiator: 3 parts by weight

[0521] (IGM Resins BV, product name "Esacure 1")

[0522] • Metal-coated particles: 0.6 parts by weight

[0523] (Nickel-coated acrylic beads, average particle size 4.5μm)

[0524] Leveling agent: 0.5 parts by weight

[0525] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0526] (9) Coating liquid for uneven layers 9

[0527] The following material was diluted with a mixed solvent of 4-methyl-2-pentanone and 2-propanol in a mass ratio of 70:30 to prepare a coating solution 9 for an uneven layer, with a solid component concentration of 40% by mass.

[0528] <Materials for Coating Liquid 9 for Undulated Layers>

[0529] Pentaerythritol triacrylate: 100 parts by weight

[0530] (Product Name: PET-30, Nippon Kayaku Co., Ltd.)

[0531] Photopolymerization initiator: 3 parts by weight

[0532] (IGM Resins BV, product name "Esacure 1")

[0533] Leveling agent: 0.5 parts by weight

[0534] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0535] (10) Coating liquid for uneven coating 10

[0536] The following material was diluted with a mixed solvent of toluene and cyclohexanone in a mass ratio of 70:30 to prepare a coating liquid 10 for an uneven coating, with a solid component concentration of 40% by mass.

[0537] <Materials for coating liquid 10 for uneven coating>

[0538] Pentaerythritol tetraacrylate: 45 parts by weight

[0539] (Product Name: PETA, Daicel SciTech)

[0540] • Carbamate acrylate oligomers: 55 parts by weight

[0541] (Mitsubishi Chemical Corporation, trade name "UV-1700B", solid content 100% by mass)

[0542] Photopolymerization initiator: 3 parts by weight

[0543] (IGM Resins BV, product name "Esacure 1")

[0544] Organic granules: 15 parts by weight

[0545] (Acrylic beads, average particle size 3.6μm, refractive index 1.559, coefficient of variation: 10.5%)

[0546] Leveling agent: 0.5 parts by weight

[0547] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0548] (11) Coating liquid for uneven coating 11

[0549] The following material was diluted with a mixed solvent of toluene and cyclohexanone in a mass ratio of 70:30 to prepare a coating solution 11 for an uneven coating, with a solid component concentration of 40% by mass.

[0550] <Materials for coating liquid 11 for uneven coating>

[0551] Pentaerythritol tetraacrylate: 45 parts by weight

[0552] (Product Name: PETA, Daicel SciTech)

[0553] • Carbamate acrylate oligomers: 55 parts by weight

[0554] (Mitsubishi Chemical Corporation, trade name "UV-1700B", solid content 100% by mass)

[0555] Photopolymerization initiator: 3 parts by weight

[0556] (IGM Resins BV, product name "Esacure 1")

[0557] • Organic granules: 0.5 parts by weight

[0558] (Acrylic beads, average particle size 3.6μm, refractive index 1.559, coefficient of variation: 10.5%)

[0559] Leveling agent: 0.5 parts by weight

[0560] (Dai Nippon Seika Kogyo Co., Ltd., trade name "SEIKA-BEAM 10-28(TL)", solid content 10% by mass)

[0561] (12) Antifouling coating liquid

[0562] The following materials were diluted with a mixed solvent of methyl isobutyl ketone, methyl ethyl ketone and propylene glycol monomethyl ether acetate in a mass ratio of 40:30:30, according to a solid component concentration of 2.5% by mass, to prepare a coating liquid for antifouling layer.

[0563] Materials for antifouling coating liquid

[0564] • Compound (A) above: 15 parts by weight

[0565] (Carbamate acrylate oligomer, solids content 100% by mass)

[0566] Fluoropolymer composition: 850 parts by weight

[0567] (Arakawa Chemical Industry Co., Ltd., trade name "TU-2362", solid content 10% by mass)

[0568] Photopolymerization initiator: 5 parts by weight

[0569] (IGM Resins BV, product name "Omnirad127")

[0570] Hollow silica particles: 100 parts by weight

[0571] (Average particle size 60 nm, refractive index 1.212)

[0572] Solid silica granules: 25 parts by weight

[0573] (Average particle size 15nm)

[0574] Fluorine-based leveling agent: 100 parts by weight

[0575] (Shin-Etsu Silicone Manufacturing Co., Ltd., trade name "X-71-1203M", solid content 20% by mass)

[0576] 4. Fabrication and preparation of PET film, and measurement of in-plane phase difference, etc., of PET film.

[0577] As examples and comparative examples, the following PET films 1 to 4 were prepared, and the following PET film 5 was also prepared.

[0578] In addition, nx, ny, nz, and in-plane retardation (Re) of each PET film were measured using the trade name "RETS-100" of Otsuka Electronics Co., Ltd. Δn (nx - ny), ΔP, and in-plane retardation (Re) of each PET film are shown in Table 5.

[0579] 4-1. PET Film 1

[0580] <Production of Raw Material (PET(A))>

[0581] The esterification reaction tank was heated. When it reached 200 °C, 86.5 parts by mass of terephthalic acid and 64.5 parts by mass of ethylene glycol were charged. Under stirring, 0.020 parts by mass of antimony trioxide, 0.061 parts by mass of magnesium acetate tetrahydrate, and 0.16 parts by mass of triethylamine as catalysts were charged. Subsequently, pressure was increased and the temperature was raised. After carrying out a pressure esterification reaction under the conditions of a gauge pressure of 0.34 MPa and 240 °C, the esterification reaction tank was restored to atmospheric pressure, and 0.014 parts by mass of phosphoric acid was added. In addition, the temperature was raised to 260 °C over 15 minutes, and 0.012 parts by mass of trimethyl phosphate was added. Then, after 15 minutes, a dispersion treatment was carried out using a high-pressure disperser. Furthermore, an aqueous sodium tripolyphosphate solution containing 0.1% by mass of sodium atoms relative to the silica particles was used. The coarse particle portion was cut off at 35% by centrifugal separation treatment, and filtration treatment was carried out using a metal filter with a mesh size of 5 μm. The ethylene glycol slurry of silica particles with an average particle size of 2.5 μm thus obtained was added at 0.2 parts by mass based on the particle content. After 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction tank, and a polycondensation reaction was carried out under reduced pressure at 280 °C.

[0582] After the polycondensation reaction ended, filtration treatment was carried out using a NASLON filter with a 95% cut-off diameter of 5 μm. Thereafter, it was extruded in a strand shape from a nozzle and cooled using cooling water that had been previously filtered through a filter with a pore size of 1 μm or less to be solidified, and cut into pellets. The intrinsic viscosity of the obtained polyethylene terephthalate resin (A) was 0.64 dl / g, the oligomer content was 0.96% by mass, and it substantially did not contain inert particles and internally precipitated particles. It should be noted that "polyethylene terephthalate resin (A)" is sometimes abbreviated as "PET(A)".

[0583] <Production of Raw Material (PET(B))>

[0584] In the production of the above PET(A), polyethylene terephthalate resin (B) with an intrinsic viscosity of 0.62 dl / g without adding silica particles was obtained. It should be noted that "polyethylene terephthalate resin (B)" is sometimes abbreviated as "PET(B)".

[0585] <Production of PET Film 1>

[0586] 100 parts by weight of PET(B) resin granules with an intrinsic viscosity of 0.62 dl / g were dried at 135°C under reduced pressure of 1 Torr for 6 hours and then fed to extruder 2 for the intermediate layer II. Meanwhile, PET(A) and PET(B) were mixed and adjusted to a silica particle content of 0.10% by weight, dried using conventional methods, and then fed to extruder 1 for the outer layers I and III. The silica particles were those contained in PET(A). The PET supplied to extruders 1 and 2 was dissolved at 288°C. The dissolved polymer was filtered separately using stainless steel sintered filter media, laminated with two types of three-layer confluence blocks, extruded into sheets through a die, and then wound onto a casting drum with a surface temperature of 30°C using an electrostatic casting method. After cooling and curing, an unstretched film was produced. At this time, the discharge rate of each extruder was adjusted so that the thickness ratio of layer I, layer II, and layer III was 5:90:5. The above-mentioned stainless steel sintered filter media is a filter media with "nominal filtration accuracy: 95% cutoff of 10μm particles".

[0587] The unstretched film was heated to 100°C using a heated roller assembly and an infrared heater, and then stretched 3.0 times along its length using a roller assembly with a circumferential speed difference to obtain a uniaxially oriented PET film.

[0588] Next, the uniaxially stretched film is guided to the tenter frame, and while holding the ends of the film with clamps, it is guided to a hot air zone at 140°C and stretched 3.2 times in the width direction. Then, while maintaining the width stretch, it is guided to a hot air zone at 210°C, where it is stretched 1.1 times in the width direction. After heat treatment in the hot air zone at 210°C for approximately 5 seconds, a 3% relaxation treatment is performed in the width direction to obtain a biaxially stretched PET film (PET film 1) with a thickness of approximately 40 μm.

[0589] 4-2. PET film 2

[0590] By changing the stretch ratio in the length direction to 3.5 times, the stretch ratio in the first stage in the width direction to 3.6 times, and the stretch ratio in the second stage in the width direction to 1.2 times, biaxially oriented PET film 2 is obtained in the same manner as PET film 1.

[0591] 4-3. PET film 3

[0592] The stretch ratio in the length direction was changed to 3.9 times, the stretch ratio in the first stage in the width direction was changed to 3.7 times, the temperature during the stretching in the second stage in the width direction was changed to 220°C, the stretch ratio in the second stage in the width direction was changed to 1.2 times, and the temperature during the relaxation treatment was changed to 220°C. Otherwise, the same as PET film 1 was obtained, resulting in biaxially oriented PET film 3.

[0593] 4-4. PET film 4

[0594] Referring to Japanese Patent Application Publication No. 2018-112635, a biaxially oriented PET film with a thickness of 25 μm as described in Example 9 of that publication was prepared. This PET film was designated as PET film 4.

[0595] 4-5. PET film 5

[0596] As PET film 5, a biaxially oriented PET film (manufactured by Toyobo Co., Ltd. under the trade name "Cosmoshine A4100", 38μm thick, with an easy-to-adhere layer on one side) is prepared for commercial sale.

[0597] 4-6. PET film 6

[0598] The stretching ratio of the first stage in the width direction is changed to 3.5 times, otherwise the same as PET film 1 is obtained to obtain biaxially oriented PET film 6.

[0599] 4-7. PET film 7

[0600] The stretching ratio of the first stage in the width direction was changed to 3.4 times, otherwise the same as PET film 1 was obtained to obtain biaxially oriented PET film 7.

[0601] 4-8. PET film 8

[0602] By changing the stretch ratio in the length direction to 3.1 times and the stretch ratio in the second stage in the width direction to 1.2 times, biaxially oriented PET film 8 is obtained in the same manner as PET film 1.

[0603] 4-9. PET film 9

[0604] The stretch ratio in the length direction was changed to 4.0 times, the stretch ratio in the first stage in the width direction was changed to 3.7 times, the temperature during the stretching in the second stage in the width direction was changed to 220°C, the stretch ratio in the second stage in the width direction was changed to 1.2 times, and the temperature during the relaxation treatment was changed to 220°C. Otherwise, the same as PET film 1 was obtained, resulting in biaxially oriented PET film 9.

[0605] 5. Fabrication of optical laminates

[0606] 5-1. Optical laminate using PET film 1

[0607] [Example 1]

[0608] Based on a wet mass of 5g / m 2The following easy-to-adhesion coating solution 1 was applied to PET film 1 (refer to "4" above; ΔP: 0.150, nx-ny: 0.125, Re: 500nm) and dried at 70°C for 30 seconds to form a film with a dry mass of 0.5 g / m³. 2 An easily bondable layer.

[0609] Next, based on a wet mass of 12.5 g / m 2 (dry weight 5g / m) 2 Apply the uneven coating liquid 2 to the easily bondable layer in the manner described above, and dry at 70°C for 30 seconds at a concentration of 100 mJ / cm². 2 Irradiation with ultraviolet light creates a dry, uneven layer with a thickness of 5 μm.

[0610] Next, according to a wet mass of 4g / m 2 (Dry weight 0.1g / m) 2 Apply an antifouling coating liquid to the uneven surface using the following method, and dry at 60°C for 30 seconds at a concentration of 200 mJ / cm². 2 Irradiation with ultraviolet light forms a dry, 100 nm thick antifouling layer, resulting in the optical laminate of Example 1.

[0611] <Coating liquid for easy-to-adhesive layers 1>

[0612] A coating liquid with a solid content of 10% by mass was prepared by mixing 33 parts by mass of a polyester resin (Toyobo Co., Ltd.’s trade name “Vylon UR-1400”) and 1 part by mass of a crosslinking agent (Mitsui Chemicals Co., Ltd.’s trade name “Takenate D110N”).

[0613] The wet mass of the embossed layer and the antifouling layer in the optical laminate of Example 1; the drying conditions of the embossed layer and the antifouling layer; the ultraviolet irradiation conditions of the embossed layer and the antifouling layer; the drying thickness of the embossed layer and the antifouling layer; and other manufacturing conditions are Manufacturing Method 1. In Tables 1-4, an item marked "1" in "Manufacturing Method" means that the above manufacturing conditions are the same as those for the optical laminate of Example 1.

[0614] [Examples 2-5]

[0615] By changing the coating liquid 2 for the uneven layer to the substance listed in Table 1, the optical laminates of Examples 2 to 5 were obtained in the same manner as in Example 1.

[0616] [Example 6]

[0617] Based on a wet mass of 5g / m 2 The above-mentioned easy-to-adhesion coating liquid 1 is applied to PET film 1 (refer to "4" above) and dried at 70°C for 30 seconds to form a dried mass of 0.5 g / m³.2 An easily bondable layer.

[0618] Next, according to a wet mass of 2.5 g / m 2 (dry weight 1g / m) 2 Apply the uneven coating liquid 3 to the easily bondable layer in the manner described above, dry at 70°C for 30 seconds, and apply at 100 mJ / cm. 2 Irradiation with ultraviolet light creates a dry, uneven layer with a thickness of 1 μm.

[0619] Next, according to a wet mass of 4g / m 2 (Dry weight 0.1g / m) 2 Apply an antifouling coating liquid to the uneven surface using the following method, and dry at 60°C for 30 seconds at a concentration of 200 mJ / cm². 2 Irradiation with ultraviolet light forms a dry, 100 nm thick antifouling layer, resulting in the optical laminate of Example 6.

[0620] The manufacturing conditions for the wet mass of the textured layer and the antifouling layer in the optical laminate of Example 6; the drying conditions of the textured layer and the antifouling layer; the ultraviolet irradiation conditions of the textured layer and the antifouling layer; the drying thickness of the textured layer and the antifouling layer; etc., are the same as those for Manufacturing Method 2.

[0621] [Compare Examples 1-2, 4-7]

[0622] By changing the coating liquid 2 for the uneven layer to the material listed in Table 1, optical laminates of Comparative Examples 1-2 and 4-7 were obtained in the same manner as in Example 1.

[0623] [Comparative Example 3]

[0624] Based on a wet mass of 5g / m 2 The above-mentioned easy-to-adhesion coating liquid 1 is applied to PET film 1 (refer to "4" above) and dried at 70°C for 30 seconds to form a dried mass of 0.5 g / m³. 2 An easily bondable layer.

[0625] Next, based on a wet mass of 12.5 g / m 2 (dry weight 5g / m) 2 Apply the uneven coating solution 1 to the easily bondable layer in the manner described above, dry at 50°C for 30 seconds, and apply at 100 mJ / cm². 2 Irradiation with ultraviolet light creates a dry, uneven layer with a thickness of 5 μm.

[0626] Next, according to a wet mass of 4g / m 2 (Dry weight 0.1g / m) 2 Apply an antifouling coating liquid to the uneven surface using the following method: dry at 60°C for 30 seconds, using 200 mJ / cm². 2Irradiation with ultraviolet light forms a dry, 100 nm thick antifouling layer, resulting in the optical laminate of Comparative Example 3.

[0627] It should be noted that the manufacturing conditions for the wet mass of the textured layer and the antifouling layer in the optical laminate of Comparative Example 3, the drying conditions of the textured layer and the antifouling layer, the ultraviolet irradiation conditions of the textured layer and the antifouling layer, and the drying thickness of the textured layer and the antifouling layer are manufacturing method 3. The item "3" in "Manufacturing method" in Tables 1 to 4 means that the above manufacturing conditions are the same as those for the optical laminate of Comparative Example 3.

[0628] 5-2. Optical laminate using PET film 2

[0629] [Examples 7-12]

[0630] By replacing PET film 1 with PET film 2 of “4” above, the optical laminates of Examples 7 to 12 are obtained in the same manner as Examples 1 to 6.

[0631] [Comparative Examples 8-14]

[0632] By replacing PET film 1 with PET film 2 of “4” above, optical laminates of Comparative Examples 8 to 14 were obtained in the same manner as Comparative Examples 1 to 7.

[0633] 5-3. Optical laminates using PET film 3

[0634] [Examples 13-18]

[0635] By replacing PET film 1 with PET film 3 of “4” above, the optical laminates of Examples 13 to 18 are obtained in the same manner as Examples 1 to 6.

[0636] [Comparative Examples 15-21]

[0637] By replacing PET film 1 with PET film 3 of “4” above, optical laminates of Comparative Examples 15 to 21 were obtained in the same manner as Comparative Examples 1 to 7.

[0638] 5-4. Optical laminates with altered antifouling layer thickness

[0639] [Example 19]

[0640] The thickness of the antifouling layer was changed to 90 nm, and otherwise the optical laminate of Example 19 was obtained in the same manner as in Example 1.

[0641] [Example 20]

[0642] The thickness of the antifouling layer was changed to 110 nm, and otherwise the optical laminate of Example 20 was obtained in the same manner as in Example 1.

[0643] [Table 1]

[0644]

[0645] [Table 2]

[0646]

[0647] [Table 3]

[0648]

[0649] [Table 4]

[0650]

[0651] As can be confirmed from Tables 1 to 4, in the optical laminates of the embodiments, the polyester film with a high degree of planar orientation ΔP has excellent adhesion to the easy-to-bond layer, and thus the overall optical laminate has excellent adhesion and can suppress local defects.

[0652] 6. Verification of pencil hardness and iris pattern

[0653] 6-1. Fabrication of Optical Laminates

[0654] [Examples 21-24]

[0655] By replacing PET film 1 with PET films 6 to 9 of “4” above, optical laminates of Examples 21 to 24 are obtained in the same manner as in Example 1.

[0656] [Comparative Example 8]

[0657] By replacing PET film 1 with PET film 4 as described above, the optical laminate of Comparative Example 8 was obtained in the same manner as in Example 1.

[0658] [Comparative Example 9]

[0659] By replacing PET film 1 with PET film 5 (as described in "4" above), the optical laminate of Comparative Example 9 was obtained in the same manner as in Example 1. It should be noted that the optical laminate of Comparative Example 9 has an easy-to-adhere layer, an uneven layer, and an anti-fouling layer formed on the side of PET film 5 that does not have an easy-to-adhere layer.

[0660] 6-2. Evaluation

[0661] The optical laminates obtained in Examples 1, 7, 13, 21-24 and Comparative Examples 8-9 were measured and evaluated as described in (1) and (2) below. The results are shown in Table 5.

[0662] (1) Pencil hardness

[0663] The optical laminates obtained in Examples 1, 7, 13, 21-24 and Comparative Examples 8-9 were heated at 100°C for 10 minutes. The heated optical laminates were then subjected to a pencil hardness test according to the scratch hardness (pencil method) of JIS K 5600-5-4:1999. Specifically, a pencil with a specified hardness was brought into contact with the surface of the optical laminate at a 45° angle relative to the sample surface, and moved at a speed of 1.4 mm / s under a 500g load to measure the pencil hardness. After applying the load to the optical laminate as a sample, the sample was heated again at 100°C for 10 minutes before visual evaluation of the scratch.

[0664] For each sample, the above operation was performed three times using pencils of varying hardness. The hardest pencil among those that left no scratches was then taken as the pencil hardness of that sample.

[0665] (2) Iris

[0666] The PET film side of the optical laminate according to the embodiments and comparative examples is arranged on the observation-side polarizer of the image display device 1 configured as described below, with the polarizer side facing it. Next, the image display device is illuminated in a dark room environment, and observations are made with the naked eye from various angles to evaluate the presence or absence of an iris spot according to the following criteria. The evaluators were 20 healthy individuals, 5 from each age group (20-59 years old) with corrected visual acuity of 1.0 or higher.

[0667] The evaluation atmosphere was set at a temperature of 23±5℃ and a relative humidity of 40% to 65%. Furthermore, the sample was exposed to this atmosphere for at least 30 minutes before the evaluation began.

[0668] A: More than 16 people answered that they could not observe the iris.

[0669] B: The number of people who answered that they could not observe the iris was between 11 and 15.

[0670] C: Fewer than 10 people answered that they could not observe the iris.

[0671] <Composition of Image Display Device 1>

[0672] (1) Display element: Organic EL display element with microcavity structure and three independent color mode (coverage based on CIE-xy chromaticity diagram BT.2020-2: 77%).

[0673] (2) Polarizer on the light source side: None

[0674] (3) Observation side polarizer: The polarizer uses a TAC film as a protective film for the polarizing element, which is composed of PVA and iodine. The absorption axis of the polarizing element is configured to be parallel to the horizontal direction of the image.

[0675] (4) Size: 10 inches diagonally

[0676] [Table 5]

[0677] Table 5

[0678]

[0679] As can be confirmed from Table 4, the optical laminates of the embodiments using polyester films satisfying Formulas 1-1 and 1-2 can suppress iris spots caused by in-plane phase differences and can improve the pencil hardness of the optical laminates.

[0680] Symbol Explanation

[0681] 10 Polyester film

[0682] 20 Easy-to-Adhere Layers

[0683] 30 uneven layers

[0684] 40 anti-fouling layer

[0685] 100 optical laminates

Claims

1. An optical laminate having an easy-to-adhere layer, an uneven layer, and an anti-fouling layer on a polyester film, When the refractive index of the polyester film in the slow axis direction within the plane is defined as nx, the refractive index in the direction orthogonal to the slow axis within the plane is defined as ny, and the refractive index in the thickness direction of the polyester film is defined as nz, the polyester film satisfies the following equations 1-2. For the uneven layer, when the three-dimensional skewness of the surface of the uneven layer is defined as Ssk and the three-dimensional arithmetic mean roughness of the surface of the uneven layer is defined as Sa, Ssk and Sa satisfy the following equation 2-1. The haze level is between 0.3% and 7%. 0.140≤ΔP (1-2) 1.00≤A≤1.90 (2-1) In Equation 1-2, "ΔP" represents "((nx+ny) / 2)-nz"; In Equation 2-1, "A" represents "log 10 (Sa×100 / Ssk)”, where Sa is in μm; where, 0 < Ssk.

2. The optical laminate as claimed in claim 1, wherein, The polyester film also satisfies the following formula 1-1, nx-ny≤0.0250 (1-1).

3. The optical laminate as described in claim 1 or 2, wherein, The Ssk of the uneven layer satisfies the following equation 2-2. 0.10≤Ssk≤1.50 (2-2).

4. The optical laminate as described in claim 1 or 2, wherein, The Sa of the uneven layer satisfies the following equations 2-3. 0.020μm≤Sa≤0.200μm (2-3).

5. The optical laminate as described in claim 1 or 2, wherein, The thickness of the antifouling layer is between 1 nm and 200 nm.

6. The optical laminate as claimed in claim 1 or 2, wherein, The contact angle between the surface of the antifouling layer and pure water is greater than 80 degrees.

7. The optical laminate as claimed in claim 1 or 2, wherein, The light reflectance Y value measured at a light incident angle of 5 degrees from the side having the antifouling layer is less than 3.0%.

8. The optical laminate as claimed in claim 1 or 2, wherein, The thickness of the polyester film is between 10 μm and 75 μm.

9. The optical laminate as claimed in claim 1 or 2, wherein, ΔP is above 0.

176.

10. A polarizer comprising a polarizing element, a first transparent protective plate disposed on one side of the polarizing element, and a second transparent protective plate disposed on the other side of the polarizing element, wherein, At least one of the first transparent protective plate and the second transparent protective plate is an optical laminate according to any one of claims 1 to 9, and the optical laminate is configured such that the surface of the anti-fouling layer faces the side opposite to the polarizing element.

11. A surface panel for an image display device, wherein an optical laminate is bonded to a resin plate or glass plate, wherein... The optical laminate is the optical laminate according to any one of claims 1 to 9, and the optical laminate is arranged such that the surface of the antifouling layer faces the opposite side to the resin plate or the glass plate.

12. An image display device, wherein the surface of the optical laminate according to any one of claims 1 to 9 is arranged on a display element such that the antifouling layer side faces the side opposite to the display element, and the optical laminate is disposed on a surface.

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