Optical film with adhesive layer and image display device provided with the same

Abstract

The present application relates to an optical film with an adhesive layer and an image display device provided with the optical film with an adhesive layer. The present application provides an optical film which is thin and discoloration is suppressed. The optical film with an adhesive layer of the present application is provided with, in order from the visible side, a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer, a phase difference layer, and an adhesive layer, the phase difference layer having a moisture permeability of 300 g / m 2 • 24h or more, in a cross-sectional view, an end portion of the adhesive layer is more inside than an end portion of the polarizer, and a horizontal distance between the end portion of the adhesive layer and the end portion of the polarizer is 0 μm to 50 μm.

Description

[0001] This application is a divisional application of Chinese application number 202180082032.9, filed on November 26, 2021, entitled "Optical film with adhesive layer and image display device having the optical film with adhesive layer". Technical Field

[0002] The present invention relates to an optical film with an adhesive layer and an image display device having the optical film with the adhesive layer. Background Technology

[0003] In recent years, image display devices, represented by liquid crystal displays and electroluminescent (EL) displays (such as organic EL displays and inorganic EL displays), have rapidly become widespread. In organic EL displays equipped with organic EL panels, problems such as external light reflection or background reflection easily occur because the organic EL panel has a highly reflective metal layer. Therefore, it is known to prevent these problems by placing a circular polarizer containing a λ / 4 plate on the viewing side (for example, Patent Documents 1-3).

[0004] As described above, excellent anti-reflection properties can be achieved by using a λ / 4 plate with inverse wavelength dispersion characteristics. On the other hand, from the viewpoint of making image display devices thinner, there is also a demand for thinner circular polarizers.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2003-311239 Patent Document 2: Japanese Patent Application Publication No. 2002-372622 Patent Document 3: Japanese Patent No. 3325560 Summary of the Invention

[0006] The technical problem that the invention aims to solve With the aim of making the circular polarizer thinner, the inventors discovered that when using a thin λ / 4 plate to make the circular polarizer, the moisture transmittance of the λ / 4 plate increases, resulting in a tendency for discoloration to occur at the ends compared to conventional circular polarizers.

[0007] The present invention was made to solve the above-mentioned technical problems, and its main objective is to provide a thin optical film that suppresses discoloration.

[0008] Means for solving technical problems Optical films such as circular polarizers typically include an adhesive layer for bonding to an image display unit. To achieve the aforementioned objective, the inventors conducted in-depth research and discovered that when an optical film with an adhesive layer is cut into a desired shape, defects occur at the ends of the adhesive layer, exposing the phase retardation layer. This affects the decolorization of the polarizer. Furthermore, they realized that controlling the defects at the ends of the adhesive layer within a specified range could suppress this decolorization, thus completing the present invention.

[0009] According to one aspect of the present invention, an optical film with an adhesive layer is provided, comprising, from the visible side,: a polarizer including a polarizer and a protective layer disposed on at least one side of the polarizer; a retardation layer; and an adhesive layer, wherein the retardation layer has a moisture permeability of 300 g / m². 2 • After 24 hours or more, in a cross-sectional view, the end of the adhesive layer is located further inside than the end of the polarizer, and the horizontal distance between the end of the adhesive layer and the end of the polarizer is 0 μm to 50 μm.

[0010] In one embodiment, the polarizer includes the polarizer and a protective layer disposed only on the visible side of the polarizer.

[0011] In one embodiment, the thickness of the polarizer is less than 10 μm.

[0012] In one embodiment, the strain of the adhesive layer under a stress of 0.4 N during stress-strain measurement at 23°C is less than 900%.

[0013] In one embodiment, the phase difference layer comprises an alignment-cured layer of a liquid crystal compound, wherein Re(550) and Re(450) of the alignment-cured layer of the liquid crystal compound satisfy the relationship 0.8≤Re(450) / Re(550)<1, Re(550) of the alignment-cured layer of the liquid crystal compound is 100nm~190nm, and the angle between the slow axis of the alignment-cured layer of the liquid crystal compound and the absorption axis of the polarizer is 40°~50°.

[0014] According to one aspect of the present invention, an image display device is provided, which includes the above-described optical film with an adhesive layer.

[0015] In one embodiment, the image display device is an organic electroluminescent display device.

[0016] Invention Effects The optical film with an adhesive layer according to the present invention can suppress the exposure of the retardation layer, resulting in the suppression of polarizer decolorization even when a thin retardation layer is used. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of an optical film with an adhesive layer according to one embodiment of the present invention.

[0018] Figure 2 This is a schematic cross-sectional view of an optical film with an adhesive layer according to another embodiment of the present invention. Detailed Implementation

[0019] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.

[0020] (Definitions of terms and symbols) The definitions of terms and symbols used in this specification are as follows.

[0021] (1) Refractive index (nx, ny, nz) “nx” is the refractive index in the direction where the refractive index is greatest in the plane (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and “nz” is the refractive index in the thickness direction.

[0022] (2) In-plane phase difference (Re) “Re(λ)” is the in-plane phase difference measured at 23°C using light with a wavelength of λnm. For example, “Re(550)” is the in-plane phase difference measured at 23°C using light with a wavelength of 550nm. Re(λ) is calculated using the formula: Re(λ) = (nx - ny) × d when the thickness of the layer (film) is set to d (nm).

[0023] (3) Phase difference in the thickness direction (Rth) “Rth(λ)” is the phase difference in the thickness direction measured using light with a wavelength of λnm at 23℃. For example, “Rth(550)” is the phase difference in the thickness direction measured using light with a wavelength of 550nm at 23℃. Rth(λ) is calculated using the formula: Rth(λ) = (nx - nz) × d when the thickness of the layer (film) is set to d (nm).

[0024] (4) Nz coefficient The Nz coefficient is obtained by Nz=Rth / Re.

[0025] (5) Angle When referring to angles in this specification, the angle includes both clockwise and counterclockwise rotations relative to a reference direction. Therefore, for example, "45°" means ±45°.

[0026] A. Overall structure of the optical film with adhesive layer Figure 1This is a schematic cross-sectional view of an optical film with an adhesive layer according to one embodiment of the present invention. The optical film 100A with an adhesive layer shown in the figure includes, from the visible side, a polarizer 10, a phase retardation layer 20, and an adhesive layer 30. The polarizer 10 includes a polarizer 11, a protective layer (outer protective layer) 12 disposed on the visible side of the polarizer 11, and a protective layer (inner protective layer) 13 disposed on the side of the polarizer 11 opposite to the visible side. The protective layer 13 may be omitted depending on the purpose, etc. For example, when the phase retardation layer 20 can also serve as a protective layer for the polarizer 11, the protective layer 13 may be omitted.

[0027] Figure 2 This is a schematic cross-sectional view of an optical film with an adhesive layer according to another embodiment of the present invention. The optical film 100B with an adhesive layer shown in the figure has, from the visible side, a polarizer 10, a retardation layer 20, and an adhesive layer 30. The polarizer 10 includes a polarizer 11 and an outer protective layer 12; the inner protective layer is omitted. In this embodiment, the retardation layer 20 has a stacked structure including a first retardation layer 20a and a second retardation layer 20b, and the retardation layer 20 (essentially the first retardation layer 20a) also serves as a protective layer for the polarizer 11. Compared to an optical film with an adhesive layer and an inner protective layer, the optical film with an adhesive layer omitting the inner protective layer is more prone to polarizer decolorization when the retardation layer is exposed, thus allowing for a more preferable effect of the present invention.

[0028] In an embodiment of the present invention, the moisture permeability of the phase retardation layer 20 is 300 g / m². 2 For at least 24 hours, in a cross-sectional view, the end of the adhesive layer 30 is positioned further inward than the end of the polarizer 11. Here, "inward" means being in the same position, allowing the end of the adhesive layer 30 and the end of the polarizer 11 to be on the same vertical line in the cross-sectional view. More specifically, in a cross-sectional view, when the end of the polarizer 11 is positioned as P1 and the end of the adhesive layer 30 is positioned as P2, P1 and P2 are on the same vertical line, or P2 is further inward than P1, and the distance (horizontal distance) D between P1 and P2 is 50 μm or less. The distance D between P1 and P2 is preferably short, and can be 0 μm to 40 μm, 0 μm to 35 μm, 0 μm to 30 μm, or 0 μm to 25 μm. By suppressing the exposure of the end of the retardation layer 20 caused by defects in the adhesive layer 30 during shearing, even when using a retardation layer with high moisture permeability, discoloration of the polarizer 11 can be suppressed.

[0029] The phase retardation layer 20 and the polarizer 10 are typically bonded together by an adhesive layer, such as an adhesive layer or a bonding agent layer. In a cross-sectional view, the end of the adhesive layer is preferably located further inward than the end of the polarizer. The horizontal distance between the end of the polarizer and the end of the adhesive layer is preferably short, for example, 0 μm to 50 μm, 0 μm to 40 μm, 0 μm to 35 μm, 0 μm to 30 μm, or 0 μm to 25 μm. By suppressing the exposure of the polarizer due to defects at the end of the adhesive layer, a more preferable effect of suppressing polarizer decolorization can be obtained. Furthermore, the ends of the protective layer and the phase retardation layer are preferably located on the same vertical line as the end of the polarizer in a cross-sectional view.

[0030] Although not illustrated, it is preferable to temporarily attach a release film to the surface of the adhesive layer until the optical film with the adhesive layer is ready for use. Furthermore, the optical film with the adhesive layer may further include other optical functional layers. The types, characteristics, quantity, combination, and placement of the optical functional layers that can be provided in the optical film with the adhesive layer can be appropriately determined according to the purpose.

[0031] The total thickness of the optical film with the adhesive layer is preferably 120 μm or less, more preferably 100 μm or less, and even more preferably 80 μm or less. For example, the lower limit of the total thickness can be 45 μm. Optical films with adhesive layers having this total thickness can contribute to the thinning of image display devices, while also exhibiting excellent flexibility and bending durability, and are therefore preferably used in bent image display devices and / or image display devices capable of bending or folding.

[0032] In one embodiment, the optical film with an adhesive layer is a single sheet cut to a specified size. Because the adhesive layer of the optical film in this embodiment suffers less damage due to shear stress during the cutting process, discoloration at the end of the polarizer after being cut into a single sheet can be suppressed. As the cutting process, any suitable method can be used, such as punching, milling (full-back processing), or FFC machining.

[0033] The following is a more detailed explanation of the constituent elements of an optical film with an adhesive layer.

[0034] B. Polarizing film B-1. Polarizer As the polarizer 11, any suitable polarizer can be used. For example, the polarizer can be made of a single layer of resin film, or it can be obtained by using a laminate of two or more layers.

[0035] Specific examples of polarizers composed of single-layer resin films include those that have undergone dyeing and stretching treatments using dichroic substances such as iodine or dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol (PVA)-based resin films, partially formaldehyde-modified PVA-based resin films, and partially saponified ethylene-vinyl acetate copolymer films; and polyolefin-based oriented films such as dehydrated PVA products or dehydrochlorinated polyvinyl chloride products. Due to their excellent optical properties, polarizers obtained by dyeing PVA-based resin films with iodine and then uniaxially stretching them are preferred.

[0036] The dyeing process using iodine described above is performed, for example, by immersing the PVA-based resin film in an aqueous iodine solution. The stretching ratio for the uniaxial stretching is preferably 3 to 7 times. Stretching can be performed after dyeing or simultaneously with dyeing. Alternatively, dyeing can be performed after stretching. The PVA-based resin film can be subjected to swelling treatment, cross-linking treatment, washing treatment, drying treatment, etc., as needed. For example, immersing the PVA-based resin film in water for washing before dyeing not only removes dirt or anti-blocking agents from the surface of the PVA-based resin film but also causes the PVA-based resin film to swell to prevent uneven dyeing.

[0037] As a specific example of a polarizer obtained using a laminate, examples include polarizers obtained using a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a polarizer obtained using a resin substrate and a PVA-based resin layer coated on the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate can be manufactured, for example, as follows: a PVA-based resin solution is coated onto a resin substrate and dried to form a PVA-based resin layer on the resin substrate, resulting in a laminate of the resin substrate and the PVA-based resin layer; the laminate is then stretched and dyed to form a polarizer from the PVA-based resin layer. In this embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Furthermore, stretching may, as needed, further include air stretching of the laminate at a high temperature (e.g., above 95°C) prior to stretching in the aqueous boric acid solution. The resulting resin substrate / polarizer laminate can be used directly (i.e., the resin substrate can be used as a protective layer for the polarizer), or the resin substrate can be peeled off from the resin substrate / polarizer laminate, and any suitable protective layer for the corresponding purpose can be laminated on the peeled surface for use. Detailed descriptions of this polarizer manufacturing method are available, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0038] The thickness of the polarizer is, for example, 25 μm or less, preferably 10 μm or less, and more preferably 8 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more.

[0039] The polarizer preferably exhibits absorption dichroism at any wavelength from 380 nm to 780 nm. The transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, and more preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0040] B-2. Protective layer The outer protective layer 12 and the inner protective layer 13 (when present) are each composed of any suitable film that can be used as a protective layer for a polarizer. Representative materials constituting the inner protective layer 13 include cyclic olefin resins such as polynorbornene, (meth)acrylic resins, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin resins such as polyethylene, and polycarbonate resins. Representative examples of (meth)acrylic resins include (meth)acrylic resins having a lactone ring structure. (Meth)acrylic resins having a lactone ring structure are described, for example, in Japanese Patent Application Publication Nos. 2000-230016, 2001-151814, 2002-120326, 2002-254544, and 2005-146084. These publications are referenced in this specification. The inner protective layer 13 is preferably made of a cyclic olefin resin. Representative materials constituting the outer protective layer 12 include cellulose resins such as cellulose triacetate (TAC) and resins capable of forming microporous membranes (e.g., polyurethane resins).

[0041] As described below, the optical film with an adhesive layer can be disposed on the visible side of an image display device (representatively an organic EL display device) with the outer protective layer as the visible side. Therefore, the outer protective layer can be subjected to surface treatments such as hard coating, anti-reflective treatment, anti-sticking treatment, and anti-glare treatment as needed. Furthermore / or, the outer protective layer can be further treated to improve visibility when viewed through polarized sunglasses (representatively, imparting (ellipsoidal) polarization or ultra-high phase difference). By implementing such treatment, excellent visibility can be achieved even when viewing the displayed image through polarized lenses such as polarized sunglasses. Therefore, the optical film with an adhesive layer can also be preferably applied to image display devices that can be used outdoors.

[0042] The thickness of the outer protective layer is preferably 10 μm to 80 μm, more preferably 15 μm to 70 μm, and even more preferably 20 μm to 50 μm. Furthermore, when a surface treatment is applied, the thickness of the outer protective layer includes the thickness of the surface treatment layer.

[0043] In one embodiment, the inner protective layer is preferably optically isotropic. In this specification, "optically isotropic" means an in-plane phase difference Re(550) of 0 nm to 10 nm and a thickness-direction phase difference Rth(550) of -10 nm to +10 nm. The thickness of the inner protective layer is preferably 10 μm to 80 μm, more preferably 20 μm to 70 μm, and even more preferably 30 μm to 50 μm.

[0044] C. Phase difference layer Phase difference layer 20 Figure 1 The layer shown can be a single layer. The phase difference layer 20 can also be as follows: Figure 2 The stacked structure shown has a first phase difference layer 20a and a second phase difference layer 20b, and can have more than three layers.

[0045] The moisture permeability of the phase difference layer (or, in the case of a laminated structure, the moisture permeability as a whole of the laminate) is, for example, 300 g / m³. 2 • 24 hours or more, for example, 350g / m 2 •24h~700g / m 2 • 24h. When using a phase retardation layer with this humidity, the effects of the present invention can preferably be obtained.

[0046] The thickness of the retardation layer (or the total thickness in a stacked structure) can be appropriately set according to the purpose. The thickness of the retardation layer is preferably 1 μm to 15 μm, more preferably 1 μm to 10 μm, and even more preferably 2 μm to 8 μm. Even when using such a thin and highly moisture-permeable retardation layer, decolorization at the polarizer tip can be suppressed, which is one of the features of this invention.

[0047] When the retardation layer 20 is a single layer, it can function as a λ / 4 plate. The refractive index characteristics of the retardation layer typically show a relationship of nx > ny = nz. The in-plane phase difference Re(550) of the retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and even more preferably 120 nm to 160 nm. Furthermore, "ny = nz" here not only means that ny and nz are exactly equal, but also includes cases where they are substantially equal. Therefore, without impairing the effects of the present invention, it is permissible for ny to be greater than nz or less than nz.

[0048] The Nz coefficient of the phase décor layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. By satisfying this relationship, an organic EL display device with excellent reflective hue can be obtained.

[0049] The phase retardation layer preferably exhibits an inverse dispersion wavelength characteristic where the phase difference value increases corresponding to the wavelength of the measured light. In this case, the Re(450) / Re(550) ratio of the phase retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and less than 0.95. With this configuration, very excellent anti-reflection properties can be achieved.

[0050] The angle between the slow axis of the retardation layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably about 45°. If the angle is within this range, by fabricating the retardation layer into a λ / 4 plate as described above, an organic EL display device with excellent anti-reflective properties can be obtained.

[0051] The phase retardation layer can be made of any suitable material as long as it meets the above characteristics. Specifically, the phase retardation layer can be an alignment-cured layer of a liquid crystal compound (hereinafter referred to as a liquid crystal alignment-cured layer), or it can be a stretched film of a resin film.

[0052] When the retardation layer is a liquid crystal alignment-cured layer, by using a liquid crystal compound, the difference between nx and ny in the resulting retardation layer can be significantly greater than that of a non-liquid crystal material, thus significantly reducing the thickness of the retardation layer used to obtain the desired in-plane retardation. As a result, further thinning of the optical film with an adhesive layer (resulting in an image display device) can be achieved. In this specification, "alignment-cured layer" refers to a layer in which a liquid crystal compound is aligned in a predetermined direction within the layer, and its alignment state is fixed. Furthermore, "alignment-cured layer" includes the concept of an alignment-cured layer obtained by curing liquid crystal monomers. In this embodiment, rod-shaped liquid crystal compounds are typically aligned in a state where they are arranged in the slow axis direction of the retardation layer (uniform alignment). Specific examples of liquid crystal compounds and details of methods for forming liquid crystal alignment-cured layers are described, for example, in Japanese Patent Application Publication Nos. 2006-163343 and 2006-178389. The descriptions in these publications are incorporated herein by reference.

[0053] The thickness of the phase retardation layer, which is composed of a single layer of liquid crystal alignment curing layer, can be, for example, 1 μm to 5 μm.

[0054] When the phase retardation layer 20 has a stacked structure of a first phase retardation layer 20a and a second phase retardation layer 20b, the first phase retardation layer is preferably a single layer as described above that can function as a λ / 4 plate. The angle between the slow axis of the first phase retardation layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably about 45°.

[0055] The second phase retardation layer can be a so-called positive C-plate whose refractive index characteristics show a relationship of nz > nx = ny. By using a positive C-plate as the second phase retardation layer, oblique reflections can be effectively prevented, and a wide field of view for anti-reflection becomes possible. In this case, the phase difference Rth (550) in the thickness direction of the second phase retardation layer is preferably -50nm to -300nm, more preferably -70nm to -250nm, even more preferably -90nm to -200nm, and particularly preferably -100nm to -180nm. Here, "nx = ny" not only means that nx and ny are strictly equal, but also includes the case that nx and ny are substantially equal. That is, the in-plane phase difference Re (550) of the second phase retardation layer can be less than 10nm.

[0056] The second retardation layer, having a refractive index characteristic of nz > nx = ny, can be formed from any suitable material. The second retardation layer is preferably formed from a film containing a liquid crystal material fixed in a vertical orientation. The liquid crystal material (liquid crystal compound) capable of vertical orientation can be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the retardation layer can be the liquid crystal compound and the method for forming the retardation layer described in Japanese Patent Application Publication Nos. 2002-333642

[0020] to

[0028] . In this case, the thickness of the second retardation layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and even more preferably 0.5 μm to 5 μm.

[0057] D. Adhesive layer As the adhesive layer, it is preferable to use an adhesive layer with high elasticity and less adhesive loss due to shearing.

[0058] When the adhesive layer is subjected to stress-strain measurement at 23°C, the strain at a stress of 0.4N is, for example, 900% or less, preferably 800% or less, more preferably 200% to 600%, and even more preferably 200% to 400%.

[0059] The creep value of the adhesive layer at 85°C is preferably below 80 μm, more preferably 1 μm to 60 μm, and even more preferably 1 μm to 50 μm. The creep value can be measured using the method described in the examples.

[0060] The storage elastic modulus G' of the adhesive layer at 25°C is preferably 1.00 × 10⁻⁶. 5 Pa or higher, more preferably 1.10 × 10 Pa 5 Pa or higher, and preferably 2.00 × 10 Pa. 6 Below Pa.

[0061] The storage elastic modulus G' of the adhesive layer at 85°C is preferably 7.00 × 10⁻⁶. 4 (Pa) or more, more preferably 1.00 × 10 5 Pa or higher, more preferably 1.50 × 10 Pa 5 Pa or higher, and preferably 5.50 × 10 Pa. 6 Below Pa.

[0062] The moisture permeability of the adhesive layer can be, for example, 2500 g / m². 2 • Less than 24 hours, preferably 100g / m 2 •24h~2000g / m 2 •24h.

[0063] The thickness of the adhesive layer is, for example, 5 μm to 50 μm, preferably 5 μm to 35 μm, and more preferably 5 μm to 25 μm.

[0064] Examples of adhesives used to form the adhesive layer include rubber-based adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinylpyrrolidone adhesives, polyacrylamide adhesives, and cellulose adhesives. The base polymer for adhesion is selected based on the type of adhesive. Among adhesives, acrylic adhesives are preferred due to their excellent optical transparency and bonding properties.

[0065] Acrylic adhesives use (meth)acrylic polymers as their base polymers. These (meth)acrylic polymers typically contain alkyl (meth)acrylates as the main monomer unit. Furthermore, (meth)acrylates refer to acrylates and / or methacrylates, and have the same meaning as (meth) in this specification.

[0066] Alkyl methacrylates, which form the main backbone of (meth)acrylate polymers, can be exemplified by linear or branched alkyl groups having 1 to 18 carbon atoms. These substances can be used alone or in combination. The average number of carbon atoms in these alkyl groups is preferably 3 to 9.

[0067] In addition, considering aspects such as adhesion properties, durability, phase difference adjustment, and refractive index adjustment, alkyl methacrylates containing aromatic rings, such as phenoxyethyl methacrylate and benzyl methacrylate, can be used as comonomers.

[0068] To improve adhesion or heat resistance, one or more comonomers having polymerizable functional groups containing unsaturated double bonds such as (meth)acryloyl or vinyl groups can be introduced into (meth)acrylic polymers via copolymerization. Specific examples of such comonomers include hydroxyl-containing monomers such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylaurate (meth)acrylate, or (4-hydroxymethylcyclohexyl)-methacrylate; carboxyl-containing monomers such as (meth)acrylate, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; anhydride-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; styrene sulfonic acid or allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamide propanesulfonic acid, (meth)acrylate sulfonylpropane, and (meth)acryloyloxynaphthalene sulfonic acid; and phosphate-containing monomers such as 2-hydroxyethylacryloyl phosphate.

[0069] In addition, as comonomers, examples include (meta)acrylamide, N,N-dimethyl (meta)acrylamide, N-butyl (meta)acrylamide, or N-hydroxymethyl (meta)acrylamide, N-hydroxymethylpropane (meta)acrylamide, and other (N-substituted) amide monomers; (meth)acrylate aminoethyl ester, (meth)acrylate N,N-dimethylaminoethyl ester, (meth)acrylate tert-butylaminoethyl ester, and other (meth)acrylate alkylaminoalkyl ester monomers; (meth)acrylate methoxyethyl ester, (meth)acrylate ethoxyethyl ester, and other (meth)acrylate alkoxyalkyl ester monomers; N-(meth)acryloyloxyalkylene Succinimide monomers such as methylsuccinimide or N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyoctamethylenesuccinimide, and N-acryloylmorpholine; maleimide monomers such as N-cyclohexylmaleimide or N-isopropylmaleimide, N-laurylmaleimide or N-phenylmaleimide; and itaconimid monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide.

[0070] Furthermore, other comonomers that can be used include vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazolium, vinyloxazole, vinylmorpholine, N-vinylcarboxylic amides, styrene, α-methylstyrene, N-vinylcaprolactam, and other vinyl monomers; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy-containing acrylic monomers such as glycidyl methacrylate; diol acrylate monomers such as polyethylene glycol methacrylate, polypropylene glycol methacrylate, methoxyethylene glycol methacrylate, and polypropylene glycol methacrylate; and acrylate monomers such as tetrahydrofurfuryl methacrylate, fluoro(meth)acrylate, organosilicon (meth)acrylate, or 2-methoxyethyl acrylate. Furthermore, isoprene, butadiene, isobutylene, and vinyl ethers can also be used.

[0071] Furthermore, as comonomers other than those mentioned above, examples include silane monomers containing silicon atoms. Examples of silane monomers include 3-acryloyloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, and 10-acryloyloxydecyltriethoxysilane.

[0072] Furthermore, as comonomers, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can also be used. Esters, caprolactone-modified dipentaerythritol hexa(meth)acrylates, and other esters of (meth)acrylic acid and polyols, etc., are multifunctional monomers with two or more unsaturated double bonds such as (meth)acryloyl groups and vinyl groups; polyester (meth)acrylates, epoxy (meth)acrylates, and urethane (meth)acrylates, etc., in which two or more unsaturated double bonds such as (meth)acryloyl groups and vinyl groups, which are the same as the monomer components, are added to the backbone of polyesters, epoxy resins, urethanes, etc.

[0073] The (meth)acrylic polymer is mainly composed of alkyl (meth)acrylate. The proportion of alkyl (meth)acrylate in the total weight ratio of the monomers is preferably 70% to 99.9% by weight, more preferably 75% to 99% by weight, and even more preferably 80% to 98% by weight. By using alkyl (meth)acrylate as the main component, adhesives with excellent adhesive properties can be obtained.

[0074] The weight ratio of the comonomer in the total structural monomer is preferably 0.1% to 30% by weight, more preferably 1% to 25% by weight, and even more preferably 2% to 30% by weight.

[0075] From the viewpoint of adhesion and durability, hydroxyl-containing monomers and carboxyl-containing monomers are preferred among these comonomers. Hydroxyl-containing monomers and carboxyl-containing monomers can be used in combination. These comonomers become reaction sites with crosslinking agents when the adhesive contains such agents. Hydroxyl-containing monomers and carboxyl-containing monomers, due to their high reactivity with intermolecular crosslinking agents, are preferred for improving the cohesiveness or heat resistance of the resulting adhesive layer.

[0076] When a hydroxyl-containing monomer is used as a comonomer, its proportion is preferably 0.01% to 15% by weight, more preferably 0.05% to 10% by weight, and even more preferably 0.1% to 5% by weight. Furthermore, when a carboxyl-containing monomer is used as a comonomer, its proportion is preferably 0.01% to 15% by weight, more preferably 0.05% to 10% by weight, and even more preferably 0.1% to 5% by weight.

[0077] The weight-average molecular weight of the aforementioned (meth)acrylic acid polymers is, for example, 1 million to 2.5 million, preferably 1.2 million to 2.3 million. A weight-average molecular weight of 1 million or higher is preferred in terms of heat resistance. However, when the weight-average molecular weight is greater than 2.5 million, the adhesive may harden. Furthermore, the weight-average molecular weight is determined by measuring using GPC (gel permeation chromatography) and calculating using polystyrene.

[0078] This (meth)acrylic acid polymer can be manufactured using well-known methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various free radical polymerizations. Furthermore, the resulting (meth)acrylic acid polymer can be any of the following: random copolymer, block copolymer, graft copolymer, etc.

[0079] Furthermore, the adhesive forming the adhesive layer may contain a crosslinking agent corresponding to the base polymer. For example, when using a (meth)acrylic acid polymer as the base polymer, an organic crosslinking agent or a polyfunctional metal chelate can be used as the crosslinking agent. Examples of organic crosslinking agents include isocyanate-based crosslinking agents, peroxide-based crosslinking agents, epoxy-based crosslinking agents, and imine-based crosslinking agents. Polyfunctional metal chelates are formed by covalent or coordination bonding of a multivalent metal with an organic compound. Examples of multivalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. Examples of atoms in the organic compound undergoing covalent or coordination bonding include oxygen atoms, and examples of organic compounds include alkyl esters, alcohols, carboxylic acids, ethers, and ketones.

[0080] The amount of crosslinking agent used relative to 100 parts by weight of the (meth)acrylic polymer is preferably 0.5 parts to 6 parts by weight, more preferably 1 part to 6 parts by weight, further preferably 2 parts to 5.5 parts by weight, and even more preferably 3 parts to 5 parts by weight.

[0081] The adhesive forming the adhesive layer may contain silane coupling agents and other additives. For example, depending on the application, polyether compounds of polyalkylene glycols such as polypropylene glycol, colorants, pigments and other powders, dyes, surfactants, plasticizers, adhesion promoters, surface lubricants, leveling agents, softeners, antioxidants, reducing agents, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, granular or foil-like materials, etc., may be added. These additives are preferably used in the range of 5 parts by weight or less, more preferably 3 parts by weight or less, and even more preferably 1 part by weight or less relative to 100 parts by weight of the (meth)acrylic polymer.

[0082] E. Image display device The aforementioned optical film with an adhesive layer can be applied to image display devices such as organic EL display devices and liquid crystal display devices. Therefore, embodiments of the present invention include an image display device having the aforementioned optical film with an adhesive layer. When the image display device is an organic EL display device, the aforementioned optical film with an adhesive layer is stacked on the visible side of the organic EL cell with the phase retardation layer on the organic EL cell side.

[0083] Example The present invention will now be specifically described through examples, but the invention is not limited to these examples. The methods for measuring each characteristic are described below. Furthermore, unless otherwise specified, "parts" and "%" in the examples and comparative examples refer to weight.

[0084] (1) Thickness Thicknesses below 10 μm were measured using an interferometric film thickness gauge (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000"). Thicknesses exceeding 10 μm were measured using a digital micrometer (manufactured by Anritsu Co., Ltd., product name "KC-351C").

[0085] (2) Stress-strain measurement The adhesive solution was cast onto the release-treated surface of a polyethylene terephthalate film (thickness: 38 μm) with a dried thickness of approximately 4 μm. After drying at 130°C for 3 minutes, the film was then aged at 50°C for 24 hours to form a cross-sectional area of ​​1 mm². 2 The cylindrical specimen was used as the test sample. The specimen was placed in a tensile testing machine (Shimadzu Autograph AG-IS MS type), and the maximum stress (N / mm²) generated under the conditions of a clamp spacing of 10 mm, a tensile speed of 300 mm / min, and a temperature of 25°C was measured. 2 ) and maximum elongation (%).

[0086] (3) Moisture permeability The sample with a phase retardation layer (a laminate of the first phase retardation layer and the second phase retardation layer) bonded to a 25 μm thick TAC film by an adhesive was used as the test sample and measured according to JIS Z 0208 (cup method).

[0087] (4) Creep value An optical film with an adhesive layer was cut into 10mm × 30mm pieces as test samples. The upper 10mm × 10mm portion of each test sample was adhered to an SUS plate via the adhesive layer and autoclaved at 50°C and 5 atmospheres for 15 minutes. A precision hot plate, positioned with its heating surface perpendicular to the plate, was heated to 85°C. The SUS plate with the adhesive-coated optical film was positioned so that the side without the adhesive layer was in contact with the heated surface of the hot plate. After heating the SUS plate at 85°C for 5 minutes, a 500gf load was applied vertically directly below the lower end of the adhesive-coated polarizing film. The offset of the adhesive-coated optical film from the SUS plate was measured after 1 second and 3600 seconds of the applied load, and these offsets were recorded as Cr1 and Cr2, respectively. 3600 It will be composed of Cr1 and Cr 3600 The creep value is obtained by using the following formula.

[0088] ΔCr=Cr 3600 -Cr1 (5) Stored elastic modulus The release film was peeled off from the adhesive layer prepared in the manufacturing example, and multiple adhesive layers were stacked to prepare a test sample with a thickness of approximately 1.5 mm. The test sample was punched into a disc shape with a diameter of 7.9 mm, clamped between parallel plates, and the dynamic viscoelasticity was measured using the "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific under the following conditions. The stored elastic modulus G' was read from the measurement results.

[0089] (Measurement conditions) Deformation mode: Torsion Measurement temperature: -40℃~150℃ Heating rate: 5℃ / minute Measurement frequency: 1Hz (6) Monomer transmittance The polarizer with a polarizer / protective layer was measured using a UV-Vis-NIR spectrophotometer (V-7100, manufactured by Nippon Spectrophotometer Co., Ltd.). The transmittance Ts at wavelengths of 380 nm to 780 nm was taken as the unit transmittance Ts of the polarizer. This Ts was a Y value measured using a two-dimensional field of view (C-light source) of JIS Z8701 and corrected for visual sensitivity.

[0090] [Manufacturing Example 1: Fabrication of Adhesive Layer A] 1. Preparation of adhesives In a reaction vessel equipped with a cooling pipe, a nitrogen inlet pipe, a thermometer, and a stirring device, 94.9 parts of butyl acrylate, 5 parts of acrylic acid, 0.1 parts of 2-hydroxyethyl acrylate, and 0.3 parts of 2,2'-azobisisobutyronitrile were added along with ethyl acetate to prepare a solution. Then, while blowing nitrogen gas into the solution and stirring, the mixture was reacted at 55°C for 8 hours to obtain a solution containing an acrylic polymer with a weight-average molecular weight of 2.1 million. Subsequently, ethyl acetate was added to this acrylic polymer-containing solution to obtain an acrylic polymer solution with a solids concentration adjusted to 30%.

[0091] An adhesive solution was prepared by sequentially adding 4 parts of a crosslinking agent (manufactured by Polyurethane Corporation of Japan, trade name "Coronate L"), which is mainly composed of a compound with isocyanate groups, and 0.2 parts of an epoxy-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403"), which are 100 parts of the solid components of the above acrylic polymer solution.

[0092] 2. Preparation of the adhesive layer The adhesive solution described above was applied to the surface of a release film formed from a polyethylene terephthalate film (38 μm thick) that had undergone a release treatment, with the dried thickness reaching 20 μm, and then dried to produce adhesive layer A.

[0093] [Manufacturing Example 2: Fabrication of Adhesive Layer B] Except that the amount of crosslinking agent (manufactured by Polyurethane Co., Ltd. of Japan, trade name "Coronate L") added is 0.6 parts and the adhesive solution is coated in such a way that the thickness after drying reaches 15 μm, the adhesive layer B is prepared in the same manner as in manufacturing example 1.

[0094] [Manufacturing Example 3: Fabrication of Adhesive Layer C] In addition to using 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate as monomer components to obtain a solution containing an acrylic polymer with a weight average molecular weight of 1.8 million, using 0.1 parts of trimethylolpropane / phenylenediamine diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Takenate D110N") and 0.3 parts of peroxide crosslinking agent (manufactured by Nippon Yushi Co., Ltd., trade name "Nyper BMT") as crosslinking agents, and coating the adhesive solution to achieve a thickness of 15 μm after drying, the adhesive layer C was prepared in the same manner as in Manufacturing Example 1.

[0095] [Manufacturing Example 4: Fabrication of Adhesive Layer D] In addition to using 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate as monomer components to obtain a solution containing an acrylic polymer with a weight average molecular weight of 1.8 million, using 0.02 parts of trimethylolpropane / phenylenediamine diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Takenate D110N") and 0.3 parts of peroxide crosslinking agent (manufactured by Nippon Yushi Co., Ltd., trade name "Nyper BMT") as crosslinking agents, and coating the adhesive solution to achieve a thickness of 21 μm after drying, the adhesive layer D was prepared in the same manner as in Manufacturing Example 1.

[0096] [Manufacturing Example 5: Fabrication of Adhesive Layer E] Except that the adhesive solution is applied in such a way that the thickness of the resulting adhesive layer reaches 30 μm, the adhesive layer E (thickness of 30 μm) is made in the same manner as in Manufacturing Example 3.

[0097] The viscoelasticity of adhesive layers A to D, prepared in Examples 1 to 4, was measured. Furthermore, the creep value of the adhesive layer was evaluated using optical films with adhesive layers A to D (the optical films with adhesive layers obtained in Examples 1 to 4 below). The results are shown in Table 1.

[0098] [Example 1] 1. Fabrication of the polarizer As the thermoplastic resin substrate, a strip-shaped, amorphous polyethylene terephthalate (PET) copolymer film with a water absorption rate of 0.75% and a Tg of approximately 75°C (thickness: 100 μm) was used. One side of the resin substrate was subjected to corona treatment.

[0099] 13 parts by weight of potassium iodide were added to 100 parts by weight of a PVA-based resin containing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetyl-modified PVA (manufactured by Japan Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z410") in a 9:1 ratio. The resulting product was dissolved in water to prepare a PVA aqueous solution (coating solution).

[0100] The above-mentioned PVA aqueous solution is coated on the corona-treated surface of the resin substrate and dried at 60°C to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate.

[0101] The resulting laminate is stretched uniaxially at its free end to 2.4 times its original length in the longitudinal direction (length direction) between rolls with different circumferential speeds in an oven at 130°C (air-assisted stretching treatment).

[0102] Next, the laminate was immersed in an insoluble bath (an aqueous solution of boric acid prepared by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insoluble treatment).

[0103] Next, the polarizer is immersed in a staining bath at 30°C (an iodine aqueous solution containing iodine and potassium iodide with an iodine concentration of 0.03% by weight and a potassium concentration of 0.2% by weight) for 60 seconds while adjusting the concentration to achieve a final polarizer monomer transmittance (Ts) of 42.0% (staining treatment).

[0104] Next, immerse the sample in a crosslinking bath at a liquid temperature of 40°C (an aqueous solution of boric acid prepared by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (crosslinking treatment).

[0105] Then, while immersing the laminate in a boric acid aqueous solution at a temperature of 70°C (boric acid concentration of 4.0 wt% and potassium iodide concentration of 5.0 wt%), it is uniaxially stretched in the longitudinal direction (length direction) between rolls with different circumferential speeds until the total stretch ratio reaches 5.5 times (water stretching treatment).

[0106] The laminate was then immersed in a washing bath at a temperature of 20°C (an aqueous solution of 4 parts by weight of potassium iodide relative to 100 parts by weight of water) (washing treatment).

[0107] Subsequently, while drying in an oven maintained at 90°C, it is brought into contact with SUS heated rollers with a surface temperature maintained at 75°C for approximately 2 seconds (drying shrinkage treatment). The shrinkage rate in the width direction of the laminate resulting from the drying shrinkage treatment is 5.2%.

[0108] In this way, a polarizer with a thickness of 5μm is formed on the resin substrate.

[0109] 2. Fabrication of Polarizing Films An HC-TAC film is bonded to the polarizer surface of the aforementioned [resin substrate / polarizer] laminate using a PVA-based resin aqueous solution. Specifically, a PVA-based resin aqueous solution (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER (registered trademark) Z-200", resin concentration: 3% by weight) is applied, and the HC-TAC film is bonded by heating in an oven at 60°C for 5 minutes. Furthermore, the HC-TAC film is a cellulose triacetate (TAC) film (25 μm thick) with a hard coating (HC) layer (7 μm thick) formed on it, and is bonded with the TAC film on the polarizer side. Next, the resin substrate is peeled off to obtain a polarizer having an outer protective layer (HC-TAC film) / polarizer.

[0110] 3. Fabrication of the first phase difference layer 55 parts of the compound shown in formula (I), 25 parts of the compound shown in formula (II), and 20 parts of the compound shown in formula (III) were added to 400 parts of cyclopentanone (CPN), and the mixture was heated to 60°C and stirred until dissolved. After confirming dissolution, the mixture was returned to room temperature, and 3 parts of Irgacure 907 (manufactured by BASF Japan Co., Ltd.), 0.2 parts of MEGAFAC F-554 (manufactured by DIC Co., Ltd.), and 0.1 parts of p-methoxyphenol (MEHQ) were added. The mixture was stirred further to obtain a solution. The solution was transparent and homogeneous. The obtained solution was filtered through a 0.20 μm filter membrane to obtain a polymerizable composition. On the other hand, an alignment film was coated with a polyimide solution onto a glass substrate with a thickness of 0.7 mm using a spin coating method. After drying at 100°C for 10 minutes, the film was fired at 200°C for 60 minutes to obtain a coating film. The obtained coating film was subjected to a rubbing treatment to form an alignment film. The rubbing treatment was performed using a commercially available rubbing device. The obtained polymeric composition was spin-coated onto a substrate (essentially an oriented film) and dried at 100°C for 2 minutes. After cooling the resulting coated film to room temperature, it was then subjected to a high-pressure mercury lamp at 30 mW / cm². 2A liquid crystal alignment-cured layer (2.8 μm thick) was obtained by irradiating the liquid crystal alignment-cured layer with ultraviolet light at an intensity of 180 ppm for 30 seconds. The in-plane phase difference Re(550) of the liquid crystal alignment-cured layer was 130 nm. In addition, the Re(450) / Re(550) ratio of the liquid crystal alignment-cured layer was 0.851, exhibiting inverse dispersion wavelength characteristics.

[0111] [Chemical structural formula 1] [Chemical structural formula 2] 4. Fabrication of the second phase difference layer A liquid crystal coating solution was prepared by dissolving 20 parts by weight of a side-chain liquid crystal polymer represented by the following chemical formula (IV) (where the numbers 65 and 35 represent the molar percentage of monomer units; for convenience, a block polymer is used, with a weight-average molecular weight of 5000), 80 parts by weight of a polymerizable liquid crystal displaying a nematic liquid crystal phase (BASF: Paliocolor LC242), and 5 parts by weight of a photopolymerization initiator (CIBA SPECIALTY CHEMICALS: Irgacure 907) in 200 parts by weight of cyclopentanone. The coating solution was then applied to a substrate film (norbornene resin film: Zeon Corporation, Japan, trade name "Zeonex") using a bar coater and dried at 80°C for 4 minutes to align the liquid crystal. The liquid crystal layer was then irradiated with ultraviolet light to cure it, thereby forming an oriented cured layer (liquid crystal orientation cured layer, thickness 0.58 μm) of the liquid crystal compound, which serves as the second phase reversal layer, on the substrate. The layer has a Re (590) of 0 nm, a Rth (590) of -100 nm, and exhibits refractive index characteristics of nz > nx = ny.

[0112] [Chemical structural formula 3] 5. Fabrication of optical films with adhesive layers In step 2, a first retardation layer is adhered to the polarizer surface of the polarizer obtained in step 3 using an adhesive (5 μm thick), and the glass substrate is peeled off. Here, the adhesion is performed such that the angle between the absorption axis of the polarizer and the slow axis of the first retardation layer reaches +45°. Next, a second retardation layer is adhered to the surface of the first retardation layer using a UV-curable adhesive (1 μm thick), and the substrate film is peeled off. Then, adhesive layer A prepared in Manufacturing Example 1 is adhered to the surface of the second retardation layer. Thus, an optical film with an adhesive layer (essentially a circular polarizer with an adhesive layer) is obtained having a structure of [protective layer / polarizer / first retardation layer / second retardation layer / adhesive layer A ( / release film)].

[0113] [Example 2] Except that adhesive layer B is used instead of adhesive layer A, an optical film with an adhesive layer is obtained in the same manner as in Example 1, having a structure of [protective layer / polarizer / first phase difference layer / second phase difference layer / adhesive layer B ( / release film)].

[0114] [Comparative Example 1] Except that adhesive layer C is used instead of adhesive layer A, an optical film with an adhesive layer is obtained in the same manner as in Example 1, having a structure of [protective layer / polarizer / first phase difference layer / second phase difference layer / adhesive layer C ( / release film)].

[0115] [Comparative Example 2] Except that adhesive layer D is used instead of adhesive layer A, an optical film with an adhesive layer is obtained in the same manner as in Example 1, having a structure of [protective layer / polarizer / first phase difference layer / second phase difference layer / adhesive layer D ( / release film)].

[0116] [Comparative Example 3] Except that adhesive layer E is used instead of adhesive layer A, an optical film with an adhesive layer is obtained in the same manner as in Example 1, having a structure of [protective layer / polarizer / first phase difference layer / second phase difference layer / adhesive layer E ( / release film)].

[0117] [Reference Example 1] 1. Fabrication of the polarizer Except that the iodine concentration in the dyeing bath is 0.025% by weight and the potassium concentration is 0.18% by weight, a polarizer with a thickness of 5 μm is formed on the resin substrate in the same manner as in Example 1.

[0118] 2. Fabrication of Polarizing Films In addition to using the laminate of [resin substrate / polarizer] obtained above, a polarizer with a [outer protective layer (HC-TAC film) / polarizer] structure is obtained in the same manner as in Example 1.

[0119] 3. Fabrication of the retardation film constituting the retardation layer 3-1. Polymerization of polyester carbonate resins Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with agitators and reflux coolers controlled at 100°C. The apparatus was charged with 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluorene-9-yl]methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), 42.28 parts by mass (0.139 mol) of spirodiol (SPG), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10⁻⁶ mol of calcium acetate monohydrate as a catalyst. -2 Parts by weight (6.78 × 10) -5 (mol). After nitrogen purging under reduced pressure in the reactor, heating is performed using a heat transfer medium. Stirring begins when the internal temperature reaches 100°C. Forty minutes after the start of heating, the internal temperature reaches 220°C and is maintained at this temperature. Simultaneously, depressurization begins, reaching 13.3 kPa 90 minutes after reaching 220°C. Phenol vapor, a byproduct of the polymerization reaction, is introduced into a 100°C reflux cooler to return a certain amount of monomer components contained in the phenol vapor to the reactor. Uncondensed phenol vapor is introduced into a 45°C condenser for recovery. Nitrogen is introduced into the first reactor to temporarily restore its pressure to atmospheric pressure. The oligomerized reaction liquid in the first reactor is then transferred to the second reactor. Next, heating and depressurization are initiated in the second reactor, reaching an internal temperature of 240°C and a pressure of 0.2 kPa after 50 minutes. Polymerization then continues until the specified stirring power is achieved. When the specified power is reached, nitrogen is introduced into the reactor for repressurization, and the generated polyester carbonate resin is extruded into the water. The strands are then sheared to obtain granules.

[0120] 3-2. Fabrication of the retardation film 0.7 parts by mass of PMMA were melt-blended in the obtained polyester carbonate resin (granules). After vacuum drying at 80°C for 5 hours, a strip resin film with a thickness of 130 μm was produced using a film forming apparatus equipped with a single-shaft extruder (manufactured by Toshiba Machinery Co., Ltd., cylinder set temperature: 250°C), a T-die (width: 200 mm, set temperature: 250°C), a cooling roller (set temperature: 120~130°C), and a winding machine. The obtained strip resin film was stretched while being adjusted to obtain a specified phase difference to obtain a phase difference film with a thickness of 38 μm. The stretching conditions were: stretching in the width direction, stretching temperature: 143°C, and stretching ratio: 2.8 times. The obtained phase difference film had a Re(550) of 141 nm, a Re(450) / Re(550) of 0.86, and an Nz coefficient of 1.12.

[0121] 4. Fabrication of optical films with adhesive layers A retardation film is adhered to the polarizer surface of the polarizer obtained in step 2 using an adhesive (5 μm thick). Here, the adhesion is performed such that the angle between the absorption axis of the polarizer and the slow axis of the retardation film reaches +45°. Next, the adhesive layer E prepared in Manufacturing Example 5 is transferred to the surface of the retardation film. Thus, an optical film with an adhesive layer is obtained, consisting of [protective layer / polarizer / retardation layer / adhesive layer E ( / release film)].

[0122] <Cuting and Processing> Using the optical film with adhesive layer obtained in the Examples, Comparative Examples and Reference Examples, a laminate of a surface protective film (manufactured by Nitto Denko, trade name "PPF-100T") with an HC-coated TAC film side laminated on the side is used as the workpiece. Under the following conditions, the end faces of the four sides of the rectangle are cut and ground to 2.5 mm using an end face cutting tool, and then cut into a rectangle with a size of 25 mm × 50 mm.

[0123] [Processing Conditions] Rotational speed / transmission speed: 4500 rpm / 900 mm / min The resulting rectangular optical film with adhesive layer was cut along its thickness. The cross-section was observed using an optical microscope (Olympus MX61L) at 10x magnification. The horizontal distance (adhesive loss) between position P2 at the end of the adhesive layer and position P1 at the end of the polarizer was measured. The results are shown in Table 2.

[0124] <Warm Water Test> The release film was peeled off from the rectangular optical film with an adhesive layer obtained through shearing, exposing the adhesive layer. The optical film with the adhesive layer was then adhered to a glass plate via the adhesive layer and immersed in warm water at 60°C for 30 minutes. The immersed optical film with the adhesive layer was observed under a microscope, and the depth of the discolored area (discoloration amount) was measured using the end of the polarizer as a reference. Furthermore, considering the practically permissible range of discoloration amount, cases with a discoloration amount below 250 μm were evaluated as "good," and cases exceeding 250 μm were evaluated as "poor." The results are shown in Table 2.

[0125] *Strain at a stress of 0.4 N in the stress-strain curve As shown in Table 2, in the reference example with low moisture permeability of the phase retardation layer, even with a large amount of adhesive deficiency, the polarizer's discoloration is within practically permissible limits. However, in the comparative example with both high moisture permeability of the phase retardation layer and a large amount of adhesive deficiency, the polarizer's discoloration is significant. In the embodiment with a small amount of adhesive deficiency, even with high moisture permeability of the phase retardation layer, the polarizer's discoloration is suppressed within practically permissible limits.

[0126] Industrial availability The optical film with adhesive layer of the present invention is preferably used as a circular polarizer for image display devices such as liquid crystal display devices, organic EL display devices, and inorganic EL display devices.

[0127] Symbol Explanation 10 Polarizing filters 11. Polarizer 12 Outer protective layer 13 Inner protective layer 20 phase difference layers 30 Adhesive layer 100 Optical films with adhesive layers

Claims

1. An optical film with an adhesive layer, comprising, starting from the visible side: A polarizer comprising a polarizer and a protective layer disposed only on the visible side of the polarizer; Phase difference layer; and Adhesive layer, The moisture permeability of the phase difference layer is 300 g / m³. 2 ·More than 24h, The thickness of the phase retardation layer is 1 μm to 10 μm. The adhesive used to form the adhesive layer is an acrylic adhesive containing a (meth)acrylic polymer and a crosslinking agent. The amount of the crosslinking agent used is 0.6 to 6 parts by weight relative to 100 parts by weight of the (meth)acrylic polymer. In the cross-sectional view, the end of the adhesive layer is located further inward than the end of the polarizer, and the horizontal distance between the end of the adhesive layer and the end of the polarizer is 0 μm to 50 μm. The decolorization amount of the polarizer in the warm water test is below 250 μm.

2. The optical film with an adhesive layer according to claim 1, wherein, The thickness of the polarizer is less than 10 μm.

3. The optical film with an adhesive layer according to claim 1, wherein, The strain of the adhesive layer under a stress of 0.4 N was less than 900% when the stress-strain measurement was performed at 23°C.

4. The optical film with an adhesive layer according to claim 1, wherein, The phase retardation layer comprises an alignment-cured layer of a liquid crystal compound. The Re(550) and Re(450) of the orientation-cured layer of the liquid crystal compound satisfy the relationship 0.8 ≤ Re(450) / Re(550) < 1. The Re(550) of the orientation-cured layer of the liquid crystal compound is 100nm~190nm. The angle between the slow axis of the orientation-cured layer of the liquid crystal compound and the absorption axis of the polarizer is 40°~50°.

5. An image display device comprising an optical film with an adhesive layer as described in any one of claims 1 to 4.

6. The image display device according to claim 5, wherein it is an organic electroluminescent display device.

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