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

Abstract

The present application provides a thin optical film that inhibits discoloration. The optical film with an adhesive layer of the present application comprises, 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 • 24 hours or more, in a cross-sectional view, the end of the adhesive layer is more 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.

Description

TECHNICAL FIELD

[0001] 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. BACKGROUND

[0002] In recent years, image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices, inorganic EL display devices) have rapidly spread. In an organic EL display device in which an organic EL panel is mounted, since the organic EL panel has a metal layer having high reflectivity, problems such as reflection of external light or background reflection easily occur. Therefore, it is known that these problems are prevented by disposing a circularly polarizing plate including a λ / 4 plate on the visual side (for example, Patent Documents 1 to 3).

[0003] As the above-mentioned circularly polarizing plate, by using a λ / 4 plate having a reverse wavelength dispersion property, excellent antireflection properties can be achieved. On the other hand, from the viewpoint of thinning of image display devices, there is also a demand for thinning of circularly polarizing plates.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-311239

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2002-372622

[0008] Patent Document 3: Japanese Patent No. 3325560 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] In order to achieve thinning of circularly polarizing plates, the present inventors and others have found that, when a circularly polarizing plate is produced using a thin λ / 4 plate, the moisture permeability of the λ / 4 plate increases, and as a result, discoloration easily occurs at the end portion compared to conventional circularly polarizing plates.

[0011] The present application was completed in order to solve the above-mentioned technical problem, and the main object thereof is to provide an optical film which is thin and in which discoloration is suppressed.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] An optical film such as a circular polarizing plate is usually provided with an adhesive layer for sticking to an image display unit. The present inventors have conducted intensive studies in order to achieve the above object, and as a result, have found that when an optical film with an adhesive layer is cut into a desired shape, defects occur at the end of the adhesive layer and a phase difference layer is exposed, which can affect discoloration of a polarizer, and have conceived that the discoloration can be suppressed by controlling the defects at the end of the adhesive layer within a prescribed range, thereby completing the present application.

[0014] According to one aspect of the present application, there is provided an optical film with an adhesive layer, which comprises, in order from a 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 • 24 hours or more, in a cross-sectional view, the end of the adhesive layer is more 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.

[0015] In one embodiment, the above-mentioned polarizing plate includes the above-mentioned polarizer and the protective layer disposed only on the visible side of the above-mentioned polarizer.

[0016] In one embodiment, the thickness of the above-mentioned polarizer is 10 μm or less.

[0017] In one embodiment, the strain amount of the above-mentioned adhesive layer at a stress of 0.4 N when stress-strain measurement is performed at 23°C is 900% or less.

[0018] In one embodiment, the above-mentioned phase difference layer includes an oriented and cured layer of a liquid crystal compound, the oriented and cured layer of the liquid crystal compound has Re(550) and Re(450) that satisfy the relationship 0.8 ≤ Re(450) / Re(550) < 1, the Re(550) of the oriented and cured layer of the liquid crystal compound is 100 nm to 190 nm, and the angle formed between the slow axis of the oriented and cured layer of the liquid crystal compound and the absorption axis of the above-mentioned polarizer is 40° to 50°.

[0019] According to one aspect of the present application, there is provided an image display device including the above-mentioned optical film with an adhesive layer.

[0020] In one embodiment, the above-mentioned image display device is an organic electroluminescence display device.

[0021] Effects of the Invention

[0022] According to the optical film with an adhesive layer of the present application, exposure of a phase difference layer can be suppressed, and as a result, discoloration of a polarizer can be suppressed even when a thin phase difference layer is used. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Schematic cross-sectional view of an optical film with an adhesive layer according to an embodiment of the present application.

[0024] Figure 2 Schematic cross-sectional view of an optical film with an adhesive layer according to another embodiment of the present application. DETAILED DESCRIPTION

[0025] The following describes embodiments of the present application, but the present application is not limited to these embodiments.

[0026] (Definitions of terms and symbols)

[0027] The definitions of terms and symbols in this specification are described below.

[0028] (1) Refractive indices (nx, ny, nz)

[0029] "nx" is the refractive index in the direction in which the in-plane refractive index becomes the largest (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.

[0030] (2) In-plane retardation (Re)

[0031] "Re(λ)" is the in-plane retardation measured at 23°C using light having a wavelength of λ nm. For example, "Re(550)" is the in-plane retardation measured at 23°C using light having a wavelength of 550 nm. Re(λ) is calculated by the formula: Re(λ) = (nx - ny) x d when the thickness of the layer (film) is set to d (nm).

[0032] (3) Thickness-direction retardation (Rth)

[0033] "Rth(λ)" is the thickness-direction retardation measured at 23°C using light having a wavelength of λ nm. For example, "Rth(550)" is the thickness-direction retardation measured at 23°C using light having a wavelength of 550 nm. Rth(λ) is calculated by the formula: Rth(λ) = (nx - nz) x d when the thickness of the layer (film) is set to d (nm).

[0034] (4) Nz coefficient

[0035] The Nz coefficient is calculated by Nz = Rth / Re.

[0036] (5) Angle

[0037] When an angle is mentioned in this specification, the angle includes both clockwise rotation and counterclockwise rotation with respect to a reference direction. Thus, for example, "45°" means ±45°.

[0038] A. Overall configuration of optical film with adhesive layer

[0039] Figure 1 A schematic cross-sectional view of an optical film with adhesive layer according to one embodiment of the present application. The illustrated example of an optical film with adhesive layer 100A has, in order from the visual side, a polarizing plate 10, a retardation layer 20, and an adhesive layer 30. The polarizing plate 10 includes a polarizer 11, a protective layer (outer protective layer) 12 disposed on the visual side of the polarizer 11, and a protective layer (inner protective layer) 13 disposed on the side opposite the visual side of the polarizer 11. The protective layer 13 can also be omitted as desired or the like. For example, when the retardation layer 20 can serve as a protective layer for the polarizer 11, the protective layer 13 can be omitted.

[0040] Figure 2 A schematic cross-sectional view of an optical film with adhesive layer according to another embodiment of the present application. The illustrated example of an optical film with adhesive layer 100B has, in order from the visual side, a polarizing plate 10, a retardation layer 20, and an adhesive layer 30. The polarizing plate 10 includes a polarizer 11 and an outer protective layer 12, and an 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) serves as a protective layer for the polarizer 11. An optical film with adhesive layer in which the inner protective layer is omitted is more likely to cause discoloration of the polarizer when the retardation layer is exposed, compared with an optical film with adhesive layer in which the inner protective layer is provided, and thus the effects of the present application can be more preferably obtained.

[0041] In the embodiment of the present application, the moisture permeability of the retardation layer 20 is 300 g / m 2 • 24 h or more, and in a cross-sectional view, the end portion of the adhesive layer 30 is more on the inner side than the end portion of the polarizer 11. Here, "on the inner side" includes being located at the same position, and in a cross-sectional view, the end portion of the adhesive layer 30 is allowed to be located on the same vertical line as the end portion of the polarizer 11. More specifically, in a cross-sectional view, when the position of the end portion of the polarizer 11 is PI and the position of the end portion of the adhesive layer 30 is P2, PI and P2 are located on the same vertical line, or P2 is more on the inner side than PI, and the distance (horizontal distance) D between PI and P2 is 50 μm or less. The distance D between PI 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 exposure of the end portion of the retardation layer 20 due to defects or the like of the adhesive layer 30 at the time of shearing processing, discoloration of the polarizer 11 can be suppressed even when a retardation layer with a large moisture permeability is used.

[0042] The phase difference layer 20 and the polarizing plate 10 are typically bonded together via an adhesive layer, an adhesive layer, or the like. In a cross-sectional view, the end portion of the adhesive layer is preferably more inside than the end portion of the polarizer. The distance (horizontal distance) between the end portion of the polarizer and the end portion of the adhesive layer is preferably short, for example, can be 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 polarizing plate due to the defect of the end portion of the adhesive layer or the like, the discoloration suppression effect of the polarizer can be more preferably obtained. Further, the end portions of the protective layer and the phase difference layer are preferably on the same vertical line as the end portion of the polarizer in a cross-sectional view.

[0043] Although not illustrated, a release film is preferably temporarily bonded to the surface of the adhesive layer until the optical film with the adhesive layer is supplied to use. In addition, the optical film with the adhesive layer can further include other optical functional layers. The kind, property, number, combination, arrangement position, and the like of the optical functional layer that can be provided in the optical film with the adhesive layer can be appropriately set according to the purpose.

[0044] The total thickness of the optical film with the adhesive layer is preferably 120 μm or less, more preferably 100 μm or less, and further preferably 80 μm or less. The lower limit of the total thickness can be, for example, 45 μm. The optical film with the adhesive layer having such a total thickness can contribute to the thinness of the image display device, and at the same time, can have excellent flexibility and bending durability, and thus can be preferably applied to a curved image display device and / or an image display device capable of being bent or folded.

[0045] In one embodiment, the optical film with the adhesive layer is a single piece of film that is cut to a prescribed size. The optical film with the adhesive layer of the embodiment of the present application can suppress the discoloration of the end portion of the polarizer after being cut to a single piece, because the adhesive layer has less defects due to the shear stress at the time of the cutting process. As the cutting process, any appropriate method such as punch processing, full-back processing, and FFC processing can be used.

[0046] Hereinafter, the constituent elements of the optical film with the adhesive layer are described in more detail.

[0047] B. Polarizing plate

[0048] B-1. Polarizer

[0049] As the polarizer 11, any appropriate polarizer can be used. For example, the polarizer can be composed of a single layer of a resin film, and a laminate of two or more layers can also be used.

[0050] As a specific example of the polarizer composed of a single layer of a resin film, there are a hydrophilic polymer film on which dyeing treatment with a dichroic substance such as iodine or a dichroic dye and stretching treatment are performed, such as a polyvinyl alcohol (PVA)-based resin film, a partially formaldehyde-treated PVA-based resin film, an ethylene-vinyl acetate copolymer partially saponified film, and the like. Since the optical characteristics are excellent, a polarizer obtained by dyeing a PVA-based resin film with iodine and uniaxially stretching the same is preferably used.

[0051] The dyeing with iodine is performed, for example, by immersing a PVA-based resin film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching can be performed after the dyeing treatment or can be performed while dyeing. Alternatively, the dyeing can be performed after the stretching. The PVA-based resin film can be subjected to swelling treatment, cross-linking treatment, washing treatment, drying treatment, and the like as needed. For example, the PVA-based resin film is immersed in water and washed with water before dyeing, which not only washes dirt or an anti-blocking agent from the surface of the PVA-based resin film but also swells the PVA-based resin film to prevent uneven dyeing.

[0052] As a specific example of the polarizer obtained using the laminate, there are a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate. The polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate is produced, for example, by coating a PVA-based resin solution on a resin substrate and drying to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer, and stretching and dyeing the laminate to produce a polarizer from the PVA-based resin layer. In the present embodiment, the stretching typically includes stretching the laminate by immersing it in an aqueous boric acid solution. Further, the stretching can further include, as needed, aerial stretching of the laminate at a high temperature (e.g., 95°C or higher) before the stretching in the aqueous boric acid solution. The obtained laminate of the resin substrate / polarizer can be used as it is (i.e., the resin substrate can be used as a protective layer for the polarizer), or the resin substrate can be peeled from the laminate of the resin substrate / polarizer, and the obtained laminate can be used by laminating an arbitrary appropriate protective layer for the corresponding purpose on the peeled surface. Details of the production method of such a polarizer are described in, for example, Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0053] The thickness of the polarizer is, for example, 25 μm or less, preferably 10 μm or less, 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, further preferably 3 μm or more.

[0054] The polarizer preferably exhibits absorption dichroism at any one of wavelengths of 380 nm to 780 nm. The monomer transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, further preferably 99.9% or more.

[0055] B-2. Protective Layer

[0056] The outer protective layer 12 and the inner protective layer 13 (when present) are each composed of any appropriate film that can be used as a protective layer for a polarizer. As a material constituting the inner protective layer 13, representative examples include a cyclic olefin resin such as polynorbornene, a (meth)acrylic resin, a polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), a polyolefin resin such as polyethylene, and a polycarbonate resin. As a representative example of the (meth)acrylic resin, a (meth)acrylic resin having a lactone ring structure can be given. (Meth)acrylic resins having a lactone ring structure are described, for example, in Japanese Patent Application Publication No. 2000-230016, Japanese Patent Application Publication No. 2001-151814, Japanese Patent Application Publication No. 2002-120326, Japanese Patent Application Publication No. 2002-254544, and Japanese Patent Application Publication No. 2005-146084. These publications are incorporated herein by reference. The inner protective layer 13 is preferably composed of a cyclic olefin resin. As a material constituting the outer protective layer 12, representative examples include a cellulose resin such as triacetyl cellulose (TAC), and a resin that can form a microporous film (for example, a polyurethane resin).

[0057] As described later, the optical film with an adhesive layer can be arranged on the viewable side of an image display device (representatively, an organic EL display device) in such a manner that the outer protective layer becomes the viewable side. Therefore, the outer protective layer can also be subjected to surface treatment such as hard coat treatment, anti-reflection treatment, anti-sticking treatment, anti-glare treatment, and the like as needed. The outer protective layer can also be further subjected to treatment for improving viewability when viewed through polarized sunglasses (representatively, imparting (elliptical) circularly polarizing function, imparting ultra-high phase difference) as needed. By carrying out such treatment, excellent viewability can be achieved even when the display screen is viewed through a polarizing lens such as polarized sunglasses. Therefore, the optical film with an adhesive layer can also be preferably applied to an image display device that can be used outdoors.

[0058] The thickness of the outer protective layer is preferably 10 μm to 80 μm, more preferably 15 μm to 70 μm, and further preferably 20 μm to 50 μm. In addition, when surface treatment is performed, the thickness of the outer protective layer is the thickness including the thickness of the surface treatment layer.

[0059] The inner protective layer is preferably optically isotropic in one embodiment. "Optically isotropic" in this specification means that the in-plane retardation Re(550) is 0 nm to 10 nm, and the thickness direction retardation Rth(550) is -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 further preferably 30 μm to 50 μm.

[0060] C. Phase Difference Layer

[0061] The phase difference layer 20 can be a single layer as shown in Figure 1 The phase difference layer 20 can also have a stacked structure of a first phase difference layer 20a and a second phase difference layer 20b as shown in Figure 2

[0062] The moisture permeability of the phase difference layer (when stacked, the moisture permeability of the entire stack) is, for example, 300 g / m 2 • 24 h or more, and can be, for example, 350 g / m 2 • 24 h to 700 g / m 2 • 24 h. When a phase difference layer having such moisture permeability is used, the effects of the present application can be preferably obtained.

[0063] The thickness of the phase difference layer (when stacked, the total thickness) can be appropriately set according to the purpose. The thickness of the phase difference layer is preferably 1 μm to 15 μm, more preferably 1 μm to 10 μm, and further preferably 2 μm to 8 μm. Even when such a thin phase difference layer having a large moisture permeability is used, the discoloration of the end portion of the polarizer can be suppressed, which is one of the features of the present application.

[0064] When the phase difference layer 20 is a single layer, the phase difference layer can function as a λ / 4 plate. The phase difference layer typically has a refractive index characteristic showing a relationship of nx>ny=nz. The in-plane retardation Re(550) of the phase difference layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and further preferably 120 nm to 160 nm. In addition, "ny=nz" here includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, there can be cases where ny>nz or ny

[0065] ​The Nz coefficient of the phase difference layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. By satisfying this relationship, an organic EL display device having a very excellent reflection color tone can be obtained.

[0066] The phase difference layer preferably exhibits a reverse dispersion wavelength characteristic in which the phase difference value increases as the wavelength of the measuring light increases. In this case, the Re(450) / Re(550) of the phase difference layer is preferably 0.8 or greater and less than 1, more preferably 0.8 or greater and 0.95 or less. If configured in this manner, a very excellent antireflection characteristic can be achieved.

[0067] The angle formed by the slow axis of the phase difference layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, and further preferably about 45°. If the angle is in this range, by making the phase difference layer a λ / 4 plate as described above, an organic EL display device having a very excellent antireflection characteristic can be obtained.

[0068] The phase difference layer can be configured from any appropriate material as long as the above-described characteristics can be satisfied. Specifically, the phase difference layer can be an oriented and cured layer of a liquid crystal compound (hereinafter referred to as a liquid crystal oriented and cured layer), and can also be a stretched film of a resin film.

[0069] When the phase difference layer is a liquid crystal oriented and cured layer, by using a liquid crystal compound, the difference between nx and ny of the resulting phase difference layer can be made significantly larger than that of a non-liquid crystal material, and thus the thickness of the phase difference layer for obtaining a desired in-plane phase difference can be significantly reduced. As a result, further thinning of the optical film with an adhesive layer (resulting in an image display device) can be achieved. The "oriented and cured layer" in the present specification refers to a layer in which a liquid crystal compound is oriented in a prescribed direction within the layer, and the oriented state thereof is fixed. Furthermore, the "oriented and cured layer" is a concept that includes an oriented and cured layer obtained by curing a liquid crystal monomer. In the present embodiment, a rod-shaped liquid crystal compound is typically oriented in a state in which it is aligned in the slow axis direction of the phase difference layer (uniform orientation). Specific examples of liquid crystal compounds and details of the formation method of a liquid crystal oriented and cured layer are described in, for example, Japanese Patent Application Publication No. 2006-163343 and Japanese Patent Application Publication No. 2006-178389. The descriptions of these publications are incorporated herein by reference.

[0070] The thickness of the phase difference layer configured from a single layer of a liquid crystal oriented and cured layer can be, for example, 1 μm to 5 μm.

[0071] When the phase difference layer 20 has a stacked structure of the first phase difference layer 20a and the second phase difference layer 20b, as the first phase difference layer, it is preferable to use a phase difference layer that is a single layer as described above and that functions as a λ / 4 plate. The angle formed between the slow axis of the first phase difference layer and the absorption axis of the polarizer is preferably 40° to 50°, more preferably 42° to 48°, and further preferably about 45°.

[0072] The second phase difference layer can be a so-called positive C plate that has a refractive index characteristic showing a relationship of nz> nx= ny. By using a positive C plate as the second phase difference layer, it is possible to prevent reflection in the diagonal direction and to widen the viewing angle of the anti-reflection function. In this case, the thickness-direction phase difference Rth(550) of the second phase difference layer is preferably -50 nm to -300 nm, more preferably -70 nm to -250 nm, further preferably -90 nm to -200 nm, and particularly preferably -100 nm to -180 nm. Here, "nx= ny" includes not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. That is, the in-plane phase difference Re(550) of the second phase difference layer can be less than 10 nm.

[0073] The second phase difference layer having a refractive index characteristic of nz> nx= ny can be formed of any appropriate material. The second phase difference layer is preferably formed of a film containing a liquid crystal material fixed in a vertical alignment. The liquid crystal material (liquid crystal compound) that can be vertically aligned can be a liquid crystal monomer or a liquid crystal polymer. As specific examples of the liquid crystal compound and the method of forming the phase difference layer, the liquid crystal compound and the method of forming the phase difference layer described in Japanese Patent Application Publication No. 2002-333642,

[0020] to

[0028] can be given. In this case, the thickness of the second phase difference layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and further preferably 0.5 μm to 5 μm.

[0074] D. Adhesive Layer

[0075] As the adhesive layer, it is preferable to use an adhesive layer that has relatively high elasticity and that has little missing adhesive due to shear processing.

[0076] The strain amount of the adhesive layer at a stress of 0.4 N when stress-strain measurement is performed at 23°C is, for example, 900% or less, preferably 800% or less, more preferably 200% to 600%, and further preferably 200% to 400%.

[0077] The creep value of the adhesive layer at 85°C can be preferably 80 μm or less, more preferably 1 μm to 60 μm, and further preferably 1 μm to 50 μm. The creep value can be measured by the method described in the Examples.

[0078] The storage elastic modulus G' of the adhesive layer at 25°C is preferably 1.00 x 10 5 Pa or more, more preferably 1.10 x 10 5 Pa or more, and can also be preferably 2.00 x 10 6 Pa or less.

[0079] The storage elastic modulus G' of the adhesive layer at 85°C is preferably 7.00 x 10 4 Pa or more, more preferably 1.00 x 10 5 Pa or more, further preferably 1.50 x 10 5 Pa or more, and can also be preferably 5.50 x 10 6 Pa or less.

[0080] The moisture permeability of the adhesive layer can be, for example, 2500 g / m 2 24 h or less, preferably 100 g / m 2 24 h to 2000 g / m 2 24 h.

[0081] 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.

[0082] As the adhesive forming the adhesive layer, for example, a rubber-based adhesive, an acrylic-based adhesive, a silicone-based adhesive, a urethane-based adhesive, a vinyl alkyl ether-based adhesive, a polyvinylpyrrolidone-based adhesive, a polyacrylamide-based adhesive, a cellulose-based adhesive, and the like can be given. The base polymer of the adhesive is selected depending on the type of the adhesive. Among the adhesives, an acrylic-based adhesive is preferably used because of excellent optical transparency and adhesive properties.

[0083] The acrylic-based adhesive contains a (meth)acrylic-based polymer as a base polymer. The (meth)acrylic-based polymer generally contains an alkyl (meth)acrylate as a main component as a monomer unit. Further, the (meth)acrylate refers to an acrylate and / or a methacrylate, and has the same meaning as (meth) in the present specification.

[0084] As the alkyl (meth)acrylate constituting the main skeleton of the (meth)acrylic-based polymer, an alkyl group having a carbon number of 1 to 18 in a linear or branched shape can be given. These substances can be used alone or in combination. The average carbon number of these alkyl groups is preferably 3 to 9.

[0085] In addition, from the viewpoints of adhesive properties, durability, adjustment of phase difference, adjustment of refractive index, and the like, an alkyl (meth)acrylate containing an aromatic ring such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate can be used as a comonomer.

[0086] To improve the adhesion or heat resistance, one or more kinds of comonomers having a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group can be introduced into the (meth)acrylic polymer by copolymerization. As specific examples of such comonomers, for example, a hydroxyl group-containing monomer 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-hydroxylauryl (meth)acrylate, or (4-hydroxymethylcyclohexyl)-methyl acrylate; a carboxyl group-containing monomer such as (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid; an anhydride group-containing monomer such as maleic anhydride, itaconic anhydride; a caprolactone adduct of acrylic acid; a sulfonic acid group-containing monomer such as styrene sulfonic acid or allyl sulfonic acid, 2-(meth)acrylamido 2-methylpropane sulfonic acid, (meth)acrylamidopropyl sulfonic acid, (meth)acryloyloxy sulfopropyl (meth)acrylate, (meth)acryloyloxy naphthalene sulfonic acid; a phosphoric acid group-containing monomer such as 2-hydroxyethyl acryloyl phosphate; and the like can be mentioned.

[0087] In addition, as the comonomer, a (N-substituted) amide-based monomer such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, or N-hydroxymethyl (meth)acrylamide, N-hydroxymethylpropane (meth)acrylamide; an alkylaminoalkyl (meth)acrylate-based monomer such as (meth)acrylic acid aminoethyl ester, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate; an alkoxyalkyl (meth)acrylate-based monomer such as methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate; a succinimide-based monomer such as N-(meth)acryloyloxy methylene succinimide, N-(meth)acryloyl-6-oxohexamethylene succinimide, N-(meth)acryloyl-8-oxooctamethylene succinimide, N-acryloylmorpholine; a maleimide-based monomer such as N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, or N-phenyl maleimide; an itaconimide-based monomer such as N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, N-lauryl itaconimide; and the like can be mentioned.

[0088] Further, as the other comonomer, vinyl acetate, vinyl propionate, N-vinyl pyrrolidone, methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, N-vinyl carboxylic acid amides, styrene, α-methyl styrene, N-vinyl caprolactam, and the like vinyl-based monomers; acrylonitrile, methacrylonitrile, and the like cyano acrylate-based monomers; glycidyl (meth)acrylate and the like epoxy group-containing acrylic-based monomers; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxy ethylene glycol (meth)acrylate, methoxy polypropylene glycol (meth)acrylate, and the like diol-based acrylate monomers; tetrahydrofurfuryl (meth)acrylate, fluoro (meth)acrylate, silicone (meth)acrylate, 2-methoxy ethyl acrylate, and the like acrylate-based monomers, and the like can be used. Further, isoprene, butadiene, isobutylene, vinyl ether, and the like can be mentioned.

[0089] Further, as the comonomer other than the above, silane-based monomers and the like containing a silicon atom can be mentioned. As the silane-based monomers, for example, 3-acryloyloxypropyl triethoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane, 4-vinylbutyl trimethoxysilane, 4-vinylbutyl triethoxysilane, 8-vinyl octyl trimethoxysilane, 8-vinyl octyl triethoxysilane, 10-methacryloyloxydecyl trimethoxysilane, 10-acryloyloxydecyl trimethoxysilane, 10-methacryloyloxydecyl triethoxysilane, 10-acryloyloxydecyl triethoxysilane, and the like can be mentioned.

[0090] Further, as the comonomer, 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, dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and the like esters of (meth)acrylic acid and polyols having two or more (meth)acryloyl groups, vinyl groups, and the like unsaturated double bonds; polyester (meth)acrylates, epoxy (meth)acrylates, urethane (meth)acrylates, and the like in which two or more unsaturated double bonds of (meth)acryloyl groups, vinyl groups, and the like as the same functional groups as the monomer component are added to the skeletons of polyester, epoxy, urethane, and the like can be used.

[0091] The (meth)acrylic polymer has an alkyl (meth)acrylate as a main component, and the proportion of the alkyl (meth)acrylate in the entire structural monomers is preferably 70 to 99.9% by weight, more preferably 75 to 99% by weight, and further preferably 80 to 98% by weight. By using the alkyl (meth)acrylate as the main component, an adhesive having excellent adhesion properties can be obtained.

[0092] The proportion of the comonomer in the entire structural monomers is preferably 0.1 to 30% by weight, more preferably 1 to 25% by weight, and further preferably 2 to 30% by weight, based on the weight proportion in the entire structural monomers.

[0093] Among these comonomers, from the viewpoints of adhesion and durability, a monomer containing a hydroxyl group and a monomer containing a carboxyl group are preferably used. The monomer containing a hydroxyl group and the monomer containing a carboxyl group can be used in combination. These comonomers become reaction points with the crosslinking agent when the adhesive contains the crosslinking agent. The monomer containing a hydroxyl group, the monomer containing a carboxyl group, and the like are preferably used to improve the cohesiveness or heat resistance of the obtained adhesive layer because they are rich in reactivity with the intermolecular crosslinking agent.

[0094] When the monomer containing a hydroxyl group is contained as the comonomer, the proportion thereof is preferably 0.01 to 15% by weight, more preferably 0.05 to 10% by weight, and further preferably 0.1 to 5% by weight. Also, when the monomer containing a carboxyl group is contained as the comonomer, the proportion thereof is preferably 0.01 to 15% by weight, more preferably 0.05 to 10% by weight, and further preferably 0.1 to 5% by weight.

[0095] The weight average molecular weight of the above (meth)acrylic polymer is, for example, 1 to 25 million, and preferably 1.2 to 2.3 million. When the weight average molecular weight is 1 million or more, it is preferable in terms of heat resistance. Also, when the weight average molecular weight is more than 25 million, there is a case where the adhesive becomes hard. Furthermore, the weight average molecular weight is a value calculated from a value measured by GPC (gel permeation chromatography) and converted using polystyrene.

[0096] Such a (meth)acrylic polymer can be produced by appropriately selecting a publicly known production method such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerization methods. Also, the obtained (meth)acrylic polymer can be any one of a random copolymer, a block copolymer, a graft copolymer, and the like.

[0097] In addition, a cross-linking agent corresponding to the base polymer can be contained in the adhesive forming the adhesive layer. For example, when a (meth)acrylic polymer is used as the base polymer, an organic cross-linking agent or a polyfunctional metal chelate can be used as the cross-linking agent. As the organic cross-linking agent, an isocyanate cross-linking agent, a peroxide cross-linking agent, an epoxy cross-linking agent, an imine cross-linking agent, and the like can be given. The polyfunctional metal chelate is formed by covalent bonding or coordination bonding of a polyvalent metal and an organic compound. As the polyvalent metal atom, Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like can be given. As the atom in the organic compound that covalently or coordinately bonds, an oxygen atom can be given, and as the organic compound, an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, a ketone compound, and the like can be given.

[0098] The amount of the cross-linking agent used is preferably 0.5 parts by weight to 6 parts by weight, more preferably 1 part by weight to 6 parts by weight, further preferably 2 parts by weight to 5.5 parts by weight, and more further preferably 3 parts by weight to 5 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer.

[0099] A silane coupling agent, other additives can be contained in the adhesive forming the adhesive layer. For example, a polyether compound of a polyalkylene glycol such as polypropylene glycol, a powder such as a colorant, a pigment, a dye, a surfactant, a plasticizer, an adhesion-imparting agent, a surface lubricant, a leveling agent, a softening agent, an antioxidant, a reducing agent, an anti-aging agent, a light stabilizer, an ultraviolet absorber, a polymerization inhibitor, an inorganic or organic filler, a metal powder, a particle, a foil, and the like can be appropriately added depending on the use. These additives are preferably used in the range of 5 parts by weight or less, further preferably 3 parts by weight or less, and more further preferably 1 part by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer.

[0100] E. Image display device

[0101] The optical film with an adhesive layer described above can be applied to an image display device such as an organic EL display device, a liquid crystal display device, and the like. Therefore, an embodiment of the present application includes an image display device provided with the optical film with an adhesive layer described above. When the image display device is an organic EL display device, the optical film with an adhesive layer described above is laminated on the viewable side of the organic EL cell in such a manner that the phase difference layer is on the organic EL cell side.

[0102] Example

[0103] Hereinafter, the present application will be specifically described by examples, but the present application is not limited by these examples. The measuring method of each property is described below. Furthermore, unless otherwise specified, "parts" and "%" in the examples and comparative examples are weight standards.

[0104] (1) Thickness

[0105] 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").

[0106] (2) Stress-strain measurement

[0107] 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 (%).

[0108] (3) Moisture permeability

[0109] 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).

[0110] (4) Creep value

[0111] 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.

[0112] ΔCr = Cr 3600 - Cr1

[0113] (5) Storage elastic modulus

[0114] The release film was peeled off from the adhesive layer produced in the production example, a plurality of adhesive layers were laminated, and a test sample having a thickness of about 1.5 mm was produced. The test sample was punched into a disc shape having a diameter of 7.9 mm, was sandwiched between parallel plates, and dynamic viscoelasticity measurement was performed using "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific, Inc. under the following conditions, and the storage elastic modulus G' was read from the measurement results.

[0115] (Measurement conditions)

[0116] Deformation mode: torsion

[0117] Measurement temperature: -40°C to 150°C

[0118] Temperature increase rate: 5°C / min

[0119] Measurement frequency: 1 Hz

[0120] (6) Monomer transmittance

[0121] The polarizing plate having the constitution of [polarizer / protective layer] was measured using an ultraviolet-visible near-infrared spectrophotometer (V-7100 manufactured by Shimadzu Corporation), and the transmittance Ts of the wavelength of 380 nm to 780 nm at this time was taken as the monomer transmittance Ts of the polarizer. This Ts is the Y value measured using the two-degree field (C light source) of JIS Z8701 and subjected to visual sensitivity correction.

[0122] [Production Example 1: Production of Adhesive Layer A]

[0123] 1. Preparation of adhesive

[0124] A solution was prepared by adding, to a reaction vessel equipped with a cooling tube, a nitrogen gas introduction tube, a thermometer, and a stirring device, butyl acrylate 94.9 parts, acrylic acid 5 parts, 2-hydroxyethyl acrylate 0.1 part, and 2,2'-azobisisobutyronitrile 0.3 parts together with ethyl acetate. Subsequently, while blowing nitrogen gas into the solution, stirring was performed, and the solution was allowed to react at 55°C for 8 hours, and a solution containing an acrylic polymer having a weight average molecular weight of 2.1 million was obtained. Further, ethyl acetate was added to the solution containing the acrylic polymer, and an acrylic polymer solution having a solid content concentration of 30% was obtained.

[0125] A cross-linking agent (manufactured by Japan Polyurethane Co., Ltd., trade name "Coronate L") having isocyanate groups as a main component and a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") having an epoxy group were sequentially mixed in an amount of 4 parts and 0.2 parts, respectively, relative to 100 parts of the solid content of the above-described acrylic polymer solution, to prepare an adhesive solution.

[0126] 2. Preparation of the adhesive layer

[0127] The above-described adhesive solution was applied to the surface of a release film formed of a polyethylene terephthalate film (thickness: 38 μm) subjected to a release treatment in a manner such that the thickness after drying was 20 μm, and dried to prepare an adhesive layer A.

[0128] [Preparation Example 2: Preparation of the adhesive layer B]

[0129] The adhesive layer B was prepared in the same manner as in Preparation Example 1, except that the amount of the cross-linking agent (manufactured by Japan Polyurethane Co., Ltd., trade name "Coronate L") was 0.6 parts and the adhesive solution was applied in a manner such that the thickness after drying was 15 μm.

[0130] [Preparation Example 3: Preparation of the adhesive layer C]

[0131] The adhesive layer C was prepared in the same manner as in Preparation Example 1, except that a solution containing an acrylic polymer having a weight average molecular weight of 1.8 million was obtained using butyl acrylate 99 parts and 4-hydroxybutyl acrylate 1 part as monomer components, 0.1 parts of trimethylolpropane / xylylenediisocyanate adduct (manufactured by Tosoh Co., Ltd., trade name "Takenate D110N") and 0.3 parts of a peroxide cross-linking agent (manufactured by Japan Oils and Fats Co., Ltd., trade name "Nyper BMT") were used as cross-linking agents, and the adhesive solution was applied in a manner such that the thickness after drying was 15 μm.

[0132] [Preparation Example 4: Preparation of the adhesive layer D]

[0133] The adhesive layer D was prepared in the same manner as in Preparation Example 1, except that a solution containing an acrylic polymer having a weight average molecular weight of 1.8 million was obtained using butyl acrylate 99 parts and 4-hydroxybutyl acrylate 1 part as monomer components, 0.02 parts of trimethylolpropane / xylylenediisocyanate adduct (manufactured by Tosoh Co., Ltd., trade name "Takenate D110N") and 0.3 parts of a peroxide cross-linking agent (manufactured by Japan Oils and Fats Co., Ltd., trade name "Nyper BMT") were used as cross-linking agents, and the adhesive solution was applied in a manner such that the thickness after drying was 21 μm.

[0134] [Production Example 5: Production of Adhesive Layer E]

[0135] Adhesive layer E (thickness: 30 μm) was produced in the same manner as Production Example 3, except that the adhesive solution was applied in such a manner that the thickness of the resulting adhesive layer reached 30 μm.

[0136] The adhesive layers A to D produced in Production Examples 1 to 4 were subjected to viscoelasticity measurement. In addition, the adhesive layers were evaluated for creep value using the optical film with adhesive layer (optical film with adhesive layer obtained in Examples 1 to 4 below) provided with the adhesive layers A to D. The results are shown in Table 1.

[0137] Table 1

[0138]

[0139] [Example 1]

[0140] 1. Production of Polarizer

[0141] As the thermoplastic resin substrate, a long strip-shaped, amorphous copolymerized polyethylene terephthalate film of isophthalic acid (thickness: 100 μm) having a water absorption of 0.75% and a Tg of about 75°C was used. The resin substrate was subjected to corona treatment on one side.

[0142] To 100 parts by weight of a PVA-based resin obtained by mixing polyvinyl alcohol (degree of polymerization: 4200, degree of saponification: 99.2 mol%) and acetyl acetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z410") at a ratio of 9:1, 13 parts by weight of potassium iodide was added, and the resulting mixture was dissolved in water to prepare a PVA aqueous solution (coating solution).

[0143] The above PVA aqueous solution was applied to the corona-treated surface of the resin substrate, and drying was performed at 60°C to form a PVA-based resin layer having a thickness of 13 μm, thereby producing a laminate.

[0144] The resulting laminate was subjected to free-end uniaxial stretching in the longitudinal direction (lengthwise direction) to 2.4 times between rolls having different circumferential speeds in an oven at 130°C (overhead assisted stretching treatment).

[0145] Subsequently, the laminate was immersed in a solubilization bath (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (solubilization treatment).

[0146] Next, the obtained laminate was immersed in an iodine aqueous solution (iodine concentration: 0.03% by weight, potassium concentration: 0.2% by weight) at 30°C for 60 seconds (dyeing treatment) while adjusting the concentration so that the final obtained polarizer had a monomer transmittance (Ts) of 42.0%.

[0147] Next, the obtained laminate was immersed in a crosslinking bath (aqueous boric acid solution obtained by adding 3 parts by weight of potassium iodide and 5 parts by weight of boric acid to 100 parts by weight of water) at 40°C for 30 seconds (crosslinking treatment).

[0148] After that, the laminate was immersed in an aqueous boric acid solution (boric acid concentration: 4.0% by weight, potassium iodide: 5.0% by weight) at 70°C while being uniaxially stretched in the longitudinal direction (lengthwise direction) between rolls having different circumferential speeds so that the total stretch ratio reached 5.5 times (in-water stretching treatment).

[0149] After that, the laminate was immersed in a washing bath (aqueous solution obtained by adding 4 parts by weight of potassium iodide to 100 parts by weight of water) at 20°C (washing treatment).

[0150] After that, the laminate was dried in an oven maintained at 90°C while being brought into contact with a SUS-made heating roll having a surface temperature maintained at 75°C for about 2 seconds (drying shrinkage treatment). The shrinkage ratio of the laminate in the widthwise direction due to the drying shrinkage treatment was 5.2%.

[0151] Thus, a polarizer having a thickness of 5 μm was formed on the resin substrate.

[0152] 2. Production of Polarizing Plate

[0153] An HC-TAC film was attached to the polarizer surface of the obtained [resin substrate / polarizer] laminate via a PVA-based aqueous resin solution. Specifically, a PVA-based aqueous resin solution (manufactured by Nippon Shokubai Co., Ltd., trade name "GOHSEFIMER (registered trademark) Z-200", resin concentration: 3% by weight) was applied, an HC-TAC film was attached, and the attachment was performed by heating in an oven maintained at 60°C for 5 minutes. Further, the HC-TAC film was a film in which a hard coat (HC) layer (thickness: 7 μm) was formed on a triacetyl cellulose (TAC) film (thickness: 25 μm), and the attachment was performed so that the TAC film was on the polarizer side. Next, the resin substrate was peeled off, and a polarizing plate having a configuration of [outer protective layer (HC-TAC film) / polarizer] was obtained.

[0154] 3. Production of First Phase Difference Layer

[0155] 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 polymeric composition obtained above 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. 2 A 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.

[0156] [Chemical structural formula 1]

[0157]

[0158] [Chemical structural formula 2]

[0159]

[0160] 4. Fabrication of the second phase difference layer

[0161] A liquid crystal coating liquid was prepared by dissolving 20 parts by weight of a side-chain type liquid crystal polymer 20 represented by the following formula (IV) (the numbers 65 and 35 in the formula represent mole% of monomer units, and are expressed by a block polymer for convenience, and the weight average molecular weight is 5000), 80 parts by weight of a polymerizable liquid crystal (BASF Corporation; trade name: Paliocolor LC242) that exhibits a nematic liquid crystal phase, and 5 parts by weight of a photopolymerization initiator (CIBA SPECIALTY CHEMICALS Corporation; trade name: Irgacure 907) in 200 parts by weight of cyclopentanone. Further, after the coating liquid was coated on a base film (norbornene-based resin film: manufactured by Japan Zeon Co., Ltd., trade name "Zeonex") using a bar coater, the liquid crystal was oriented by heating and drying at 80°C for 4 minutes. The liquid crystal layer was irradiated with ultraviolet rays to cure the liquid crystal layer, thereby forming an oriented and cured layer of the liquid crystal compound (liquid crystal oriented and cured layer, thickness: 0.58 μm) that becomes a second phase difference layer on the base material. The layer had an Re (590) of 0 nm, an Rth (590) of -100 nm, and exhibited a refractive index characteristic of nz > nx = ny.

[0162] [Chemical Structure 3]

[0163]

[0164] 5. Production of an optical film with an adhesive layer

[0165] The first phase difference layer was attached to the polarizer surface of the polarizing plate obtained in 2 via an adhesive (thickness: 5 μm), and the glass substrate was peeled off. Here, the attachment was performed in such a manner that the angle between the absorption axis of the polarizer and the slow axis of the first phase difference layer reached +45°. Subsequently, the second phase difference layer was attached to the surface of the first phase difference layer via a UV-curable adhesive (thickness: 1 μm), and the base film was peeled off. Further, the adhesive layer A produced in Production Example 1 was attached to the surface of the second phase difference layer. Thus, an optical film with an adhesive layer (essentially a circularly polarizing plate with an adhesive layer) having the constitution of [protective layer / polarizer / first phase difference layer / second phase difference layer / adhesive layer A ( / peeling film)] was obtained.

[0166] [Example 2]

[0167] An optical film with an adhesive layer having the constitution of [protective layer / polarizer / first phase difference layer / second phase difference layer / adhesive layer B ( / peeling film)] was obtained in the same manner as in Example 1, except that the adhesive layer B was used instead of the adhesive layer A.

[0168] [Comparative Example 1]

[0169] An optical film with the constitution of [protective layer / polarizer / first phase difference layer / second phase difference layer / adhesive layer C ( / release film)] was obtained in the same manner as in Example 1, except that the adhesive layer C was used instead of the adhesive layer A.

[0170] [Comparative Example 2]

[0171] An optical film with the constitution of [protective layer / polarizer / first phase difference layer / second phase difference layer / adhesive layer D ( / release film)] was obtained in the same manner as in Example 1, except that the adhesive layer D was used instead of the adhesive layer A.

[0172] [Comparative Example 3]

[0173] An optical film with the constitution of [protective layer / polarizer / first phase difference layer / second phase difference layer / adhesive layer E ( / release film)] was obtained in the same manner as in Example 1, except that the adhesive layer E was used instead of the adhesive layer A.

[0174] [Reference Example 1]

[0175] 1. Production of polarizer

[0176] A polarizer with a thickness of 5 μm was formed on a resin substrate in the same manner as in Example 1, except that the iodine concentration of the dyeing bath was made to be 0.025% by weight and the potassium concentration was made to be 0.18% by weight.

[0177] 2. Production of polarizing plate

[0178] A polarizing plate with the constitution of [outer protective layer (HC-TAC film) / polarizer] was obtained in the same manner as in Example 1, except that the obtained [resin substrate / polarizer] laminate was used.

[0179] 3. Production of phase difference film constituting phase difference layer

[0180] 3-1. Polymerization of polyester carbonate-based resin

[0181] Polymerization was performed using a batch polymerization device formed of 2 vertical reactors equipped with stirring wings and reflux coolers controlled to 100°C. Bis[9-(2-phenoxy carbonyl ethyl) fluorene-9-yl]methane 29.60 parts by mass (0.046 mol), isosorbide (ISB) 29.21 parts by mass (0.200 mol), spiroglycol (SPG) 42.28 parts by mass (0.139 mol), diphenyl carbonate (DPC) 63.77 parts by mass (0.298 mol), and calcium acetate monohydrate 1.19 x 10 -2 parts by mass (6.78 x 10 -5mol) was added. After the inside of the reactor was replaced with nitrogen under reduced pressure, the reactor was warmed using a heat medium, and stirring was started when the inside temperature reached 100°C. Forty minutes after the start of the temperature increase, the inside temperature reached 220°C, and the temperature was controlled so as to maintain this temperature, and at the same time, the pressure was reduced. Ninety minutes after reaching 220°C, the pressure reached 13.3 kPa. The phenol vapor generated along with the polymerization was introduced into a reflux cooler at 100°C, and the monomer components contained in the phenol vapor were returned to the reactor, and the uncondensed phenol vapor was introduced into a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor, and the pressure was temporarily returned to atmospheric pressure, and the oligomerized reaction solution in the first reactor was transferred to the second reactor. Next, the temperature increase and pressure reduction in the second reactor were started, and at 50 minutes, the inside temperature reached 240°C and the pressure reached 0.2 kPa. Thereafter, the polymerization was performed until the prescribed stirring power was reached. When the prescribed power was reached, nitrogen was introduced into the reactor to return the pressure to atmospheric pressure, and the polyester carbonate-based resin produced was extruded into water, and the strands were cut to obtain pellets.

[0182] 3-2. Production of phase difference film

[0183] In the obtained polyester carbonate-based resin (pellets), 0.7 parts by mass of PMMA was melt-kneaded, and after vacuum drying at 80°C for 5 hours, a film-forming apparatus equipped with a uniaxial extruder (Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (width: 200 mm, set temperature: 250°C), a cooling roll (set temperature: 120 to 130°C), and a winding machine was used to produce a long resin film having a thickness of 130 μm. The obtained long resin film was stretched while being adjusted so as to obtain a prescribed phase difference, and a phase difference film having a thickness of 38 μm was obtained. The stretching conditions were stretching in the width direction, a stretching temperature of 143°C, and a stretching ratio of 2.8 times. The obtained phase difference film had an Re(550) of 141 nm, an Re(450) / Re(550) of 0.86, and an Nz coefficient of 1.12.

[0184] 4. Production of optical film with adhesive layer

[0185] The phase difference film was attached to the polarizer surface of the polarizing plate obtained in 2 via an adhesive (thickness: 5 μm). Here, the phase difference film was attached so that the angle of the absorption axis of the polarizer and the slow axis of the phase difference film reached +45°. Next, the adhesive layer E produced in Production Example 5 was transferred to the surface of the phase difference film. In this way, an optical film with an adhesive layer having a [protective layer / polarizer / phase difference layer / adhesive layer E ( / release film)] structure was obtained.

[0186] <Shearing processing>

[0187] A laminate in which a TAC film side of a HC-equipped optical film obtained in the examples, comparative examples, and reference examples with an adhesive layer was laminated with a surface protective film (Nitto Electric Industrial Co., Ltd., trade name "PPF-100T") was used as a workpiece, and the end surface of each of the four sides of the rectangle was cut and polished by 2.5 mm using an end surface cutting tool under the following conditions, and cut into a rectangle of 25 mm x 50 mm in size.

[0188] [Processing conditions]

[0189] Rotational speed / transmission speed: 4500 rpm / 900 mm / min

[0190] The obtained rectangular optical film with an adhesive layer was cut in the thickness direction, and the cross section thereof was observed at a magnification of 10 times using an optical microscope (Olympus Corporation, MX61L), and the horizontal distance (amount of missing adhesive) between the position P2 of the end of the adhesive layer and the position PI of the end of the polarizer was measured. The results are shown in Table 2.

[0191] <Warm water test>

[0192] The release film was peeled from the rectangular optical film with an adhesive layer obtained by cutting processing, and the adhesive layer was exposed. The optical film with an adhesive layer was attached to a glass plate via the adhesive layer, and immersed in warm water at 60°C for 30 minutes. The optical film with an adhesive layer after the immersion was observed using a microscope, and the depth of the region where discoloration occurred (amount of discoloration) was measured with the end of the polarizer as a reference. In addition, considering the allowable range of the amount of discoloration in practical use, the case where the amount of discoloration was 250 μm or less was evaluated as "good", and the case where the amount of discoloration exceeded 250 μm was evaluated as "poor". The results are shown in Table 2.

[0193] Table 2

[0194]

[0195] Strain amount at stress 0.4 N in stress-strain curve

[0196] As shown in Table 2, in the reference example in which the moisture permeability of the phase difference layer was small, the discoloration of the polarizer was within the allowable range in practical use even if the amount of missing adhesive was large, but in the comparative example in which the moisture permeability of the phase difference layer was large and the amount of missing adhesive was also large, the amount of discoloration of the polarizer was large. In the example in which the amount of missing adhesive was small, the discoloration of the polarizer was suppressed within the allowable range in practical use even if the moisture permeability of the phase difference layer was large.

[0197] Industrial applicability

[0198] The optical film with an adhesive layer of the present application is preferably used as a circularly polarizing plate for an image display device such as a liquid crystal display device, an organic EL display device, and an inorganic EL display device.

[0199] Symbol Explanation

[0200] 10 Polarizing plate

[0201] 11 Polarizer

[0202] 12 Outer protective layer

[0203] 13 Inner protective layer

[0204] 20 Retardation layer

[0205] 30 Adhesive layer

[0206] 100 Optical film with adhesive layer

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 strain of the adhesive layer under a stress of 0.4 N in a stress-strain measurement at 23°C was 200%–400%. 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.

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 or 2, 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 alignment-cured layer of the liquid crystal compound is 100 nm to 190 nm. 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° to 50°.

4. An image display device comprising an optical film with an adhesive layer as described in any one of claims 1 to 3.

5. The image display device according to claim 4, wherein it is an organic electroluminescent display device.

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