Optical laminate

Abstract

To provide an optical laminate having a surface protective film temporarily bonded onto an optical film, the optical laminate capable of preventing an uneven peeling when the surface protective film is separated and removed.SOLUTION: An optical laminate includes: an optical film having a polarizing plate including a polarizer and an antiglare layer arranged on one side of the polarizing plate; and a surface protective film including a base material film and an adhesive layer, and temporarily adhered in a separable manner on the antiglare layer of the optical film, interposing the adhesive layer. In the optical film, an absolute value is 120 or less with regard to a difference between a surface free energy γSOF at a surface protective film side of the optical film and a surface free energy γSPSA at the adhesive layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical laminate. [Background technology]

[0002] In recent years, image display devices, such as liquid crystal display devices and electroluminescence (EL) display devices (e.g., organic EL display devices and inorganic EL display devices), have rapidly become widespread. Various optical films are used in image display devices depending on the purpose and desired characteristics. In practice, a surface protection film is often temporarily and removably attached to the optical film during the manufacturing process, inspection process, transportation, etc. of the optical film to protect the optical film from scratches, dirt, and the like. However, depending on the type and configuration of the optical film, peeling unevenness (typically, a phenomenon in which adhesive components of the surface protection film remain on the optical film) may occur when the surface protection film is peeled off during actual use of the optical film. This may result in problems with the appearance of the optical film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-38254 Summary of the Invention [Problem to be solved by the invention]

[0004] A primary object of the present invention is to provide an optical laminate in which a surface protective film is temporarily attached to an optical film, in which peeling unevenness is suppressed when the surface protective film is peeled off and removed. [Means for solving the problem]

[0005] [1] According to an embodiment of the present invention, there is provided an optical laminate. The optical laminate comprises an optical film having a polarizing plate including a polarizer and an antiglare layer disposed on one side of the polarizing plate; and a surface protection film including a substrate film and a pressure-sensitive adhesive layer, the surface protection film being temporarily and releasably attached to the antiglare layer side of the optical film via the pressure-sensitive adhesive layer. The surface free energy γS of the optical film on the surface protection film side is OF and the surface free energy γS of the adhesive layer PSA The absolute value of the difference is 120 or less. [2] In the above [1], the low-speed peel strength between the surface protective film and the optical film is 0.001 N / 25 mm or more. [3] In the above [1] or [2], the low-speed peel strength between the surface protective film and the optical film is 0.016 N / 25 mm or less. [4] In any one of the above [1] to [3], the arithmetic mean roughness Ra of the surface of the optical film on the surface protection film side is 0.15 μm to 0.50 μm. [5] In any one of [1] to [4] above, the polarizer includes a non-polarizing portion, the anti-glare layer includes a non-anti-glare portion, and the non-polarizing portion and the non-anti-glare portion are provided at corresponding positions. [6] In any one of [1] to [5] above, the optical laminate further has an anti-reflection layer on the opposite side of the anti-glare layer from the polarizing plate, and the surface protection film is removably temporarily attached to the anti-reflection layer via the pressure-sensitive adhesive layer. [7] In the above [6], the haze of the antireflection layer is less than 1.0%, and the haze of the antiglare layer is 5.0% or more. [8] In any one of [1] to [7] above, the optical laminate further has an antifouling layer on the opposite side of the anti-reflection layer from the anti-glare layer, and the surface protection film is removably temporarily attached to the antifouling layer via the pressure-sensitive adhesive layer. [Effects of the Invention]

[0006] According to an embodiment of the present invention, an optical laminate can be realized in which a surface protective film is temporarily attached to an optical film, and in which peeling unevenness when the surface protective film is peeled off is suppressed. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Representative embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Note that the drawings are drawn schematically for ease of viewing and understanding, and the length, width, thickness, proportions, etc. do not reflect the actual shape.

[0009] A. Overview of optical laminates FIG. 1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. The illustrated optical laminate 300 includes an optical film 200 and a surface protection film 100. The optical film 200 includes a polarizing plate 120 and an anti-glare layer 130 disposed on one side of the polarizing plate 120. If necessary, the optical laminate 300 (substantially, the optical film 200) may further include an anti-reflection layer 140 on the side of the anti-glare layer 130 opposite the polarizing plate 120, as shown in the illustrated example. If necessary, an anti-fouling layer 150 may be provided on the side of the anti-reflection layer 140 opposite the anti-glare layer 130. If the anti-reflection layer 140 is omitted, the anti-fouling layer 150 may be provided on the surface of the anti-glare layer 130. The surface protection film 100 includes a substrate film 10 and a pressure-sensitive adhesive layer 20, and is temporarily and releasably attached to the anti-glare layer side of the optical film 200 via the pressure-sensitive adhesive layer 20. In the illustrated example, the surface protective film 100 is temporarily and releasably attached to the antifouling layer 150. When the antifouling layer is omitted, the surface protective film 100 can be temporarily and releasably attached to the antireflection layer 140. When the antifouling layer and the antireflection layer are omitted, the surface protective film 100 can be temporarily and releasably attached to the antiglare layer 130.

[0010] In the embodiment of the present invention, the surface free energy γS of the optical film 200 on the surface protection film 100 side OF and the surface free energy γS of the adhesive layer 20 of the surface protection film 100 PSA The absolute value of the difference between the surface free energy γS and the surface free energy γS is 120 or less, preferably 80 or less, more preferably 50 or less, even more preferably 20 or less, particularly preferably 15 or less, and especially preferably 10 or less. The smaller the absolute value of the difference in surface free energy, the better, and the lower limit may be, for example, 0.1, or may be, for example, 0.5, or may be, for example, 1.0. According to an embodiment of the present invention, even when a surface protection film is temporarily attached to an optical film that includes an anti-glare layer and therefore has an uneven surface, by controlling the absolute value of the difference between the surface free energy of the surface protection film side of the optical film and the surface free energy of the pressure-sensitive adhesive layer of the surface protection film to 120 or less, uneven peeling can be suppressed when peeling and removing the surface protection film. The surface free energy γS of the surface protection film side of the optical film OF The surface free energy γS of the pressure-sensitive adhesive layer of the surface protection film can be, for example, 5.0 mN / m to 70.0 mN / m, or, for example, 10.0 mN / m to 55.0 mN / m. PSA can be, for example, 20.0 mN / m to 100.0 mN / m, or, for example, 30.0 mN / m to 70.0 mN / m.

[0011] The surface free energy γS is γS=γ d S+γ p S+γ h S, which is calculated by the Kitazaki-Hata theory (Journal of the Japan Adhesion Association, Vol. 8, No. 3, p. 131-141, 1972). d S is the dispersion component of the surface free energy, and γ p S is the polar component of the surface free energy, and γ h S is the hydrogen bond component of the surface free energy. A specific method for determining the surface free energy will be described in the Examples below.

[0012] In one embodiment, the low-speed peel force between the surface protection film 100 (substantially, the pressure-sensitive adhesive layer 20) and the optical film 200 is preferably 0.001 N / 25 mm or more, more preferably 0.003 N / 25 mm or more, even more preferably 0.005 N / 25 mm or more, particularly preferably 0.006 N / 25 mm or more, and particularly preferably 0.007 N / 25 mm or more. The low-speed peel force is preferably 0.016 N / 25 mm or less, more preferably 0.014 N / 25 mm or less, and even more preferably 0.012 N / 25 mm or less. If the low-speed peel force is less than 0.001 N / 25 mm, the surface protection film may lift during processing, transportation, inspection, etc. of the optical laminate (substantially, the optical film). If the low-speed peel force exceeds 0.016 N / 25 mm, poor peeling of the surface protection film may occur. The method for measuring the low-speed peel strength will be explained in the examples below.

[0013] The polarizing plate 120 has a polarizer 121, a protective layer 122 arranged on one side of the polarizer (the anti-glare layer side in the illustrated example), and a protective layer 123 arranged on the other side of the polarizer. At least one of the protective layers 122 and 123 may be omitted depending on the purpose, use, desired properties, etc. of the optical film. Therefore, the polarizing plate may be a so-called double-protected polarizing plate, a so-called single-protected polarizing plate, or may be composed of a polarizer alone.

[0014] In one embodiment, the polarizer 121 includes a non-polarizing portion 125, and the anti-glare layer 130 includes a non-anti-glare portion 135. The non-polarizing portion 125 and the non-anti-glare portion 135 are typically provided in corresponding positions. As used herein, "provided in corresponding positions" means that the non-polarizing portion and the non-anti-glare portion overlap when the optical film is viewed in a plan view. The non-polarizing portion and the non-anti-glare portion may be provided in any appropriate positions depending on the purpose. Typically, the non-polarizing portion and the non-anti-glare portion may be provided in positions corresponding to the camera portion of an image display device when the optical film is applied to the image display device. With this configuration, when the optical film is applied to the image display device, the impact on the camera performance of the image display device can be minimized. The optical film as a final product (the optical film cut to a size and shape corresponding to the image display device to which it is applied) may each have only one non-polarizing portion and two or more (e.g., two, three, four, or five) non-anti-glare portions.

[0015] The arithmetic mean roughness Ra of the surface of the optical film 200 facing the surface protection film 100 may be, for example, 0.15 μm to 0.50 μm, or may be, for example, 0.20 μm to 0.40 μm. This may be due to the fact that the anti-glare layer has an uneven surface, as described above. According to an embodiment of the present invention, even when a surface protection film is temporarily attached to an optical film having an uneven surface, the generation of bubbles can be suppressed by using a surface protection film as described in Section C below. The arithmetic mean roughness Ra can be measured in accordance with JIS B 0601.

[0016] The components of the optical laminate will be described below.

[0017] B. Optical Film B-1.Polarizer A polarizer typically has a polarizing portion and a non-polarizing portion, the polarizing portion being substantially all of the portion other than the non-polarizing portion.

[0018] A polarizer is typically made of a polyvinyl alcohol (PVA) resin film containing a dichroic substance (e.g., iodine). Examples of PVA resins include polyvinyl alcohol, partially formalized polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and partially saponified ethylene-vinyl acetate copolymer.

[0019] The PVA resin preferably contains an acetoacetyl-modified PVA resin. With this configuration, a polarizer having desired mechanical strength can be obtained. The amount of the acetoacetyl-modified PVA resin is preferably 5% by weight to 20% by weight, and more preferably 8% by weight to 12% by weight, based on 100% by weight of the entire PVA resin. If the amount is within this range, a polarizer having better mechanical strength can be obtained.

[0020] The polarizer preferably contains iodide or sodium chloride (sometimes collectively referred to as a halide). Examples of iodides include potassium iodide, sodium iodide, and lithium iodide. The content of the halide in the polarizer is preferably 5 to 20 parts by weight, more preferably 10 to 15 parts by weight, relative to 100 parts by weight of the PVA-based resin. In the manufacturing method described below, the halide is blended into a coating liquid that forms a PVA-based resin layer, which is a precursor of the polarizer, and can be finally introduced into the polarizer. Introducing a halide into the polarizer can improve the orientation of PVA molecules in the polarizer, thereby achieving a polarizer with excellent optical properties (typically, both a high degree of polarization and a high single-unit transmittance).

[0021] The polarizer preferably exhibits absorptive dichroism at any wavelength between 380 nm and 780 nm. The single transmittance of the polarizer is preferably 41.0% to 46.0%, and more preferably 42.0% to 45.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more. According to an embodiment of the present invention, even if the single transmittance is within the above range, the degree of polarization can be maintained within this range.

[0022] The thickness of the polarizer is, for example, 12 μm or less, preferably 10 μm or less, more preferably 1 μm to 8 μm, and even more preferably 3 μm to 7 μm. When the thickness of the polarizer is within the above range, curling during heating can be well suppressed and good appearance durability during heating can be obtained.

[0023] The polarizer can be produced by any appropriate method. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

[0024] Specific examples of polarizers made of a single-layer resin film include hydrophilic polymer films such as PVA films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films that have been dyed with iodine or a dichroic substance such as a dichroic dye and stretched, and polyene-based oriented films such as dehydrated PVA films and dehydrochlorinated polyvinyl chloride films. A polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching it is preferred because of its excellent optical properties.

[0025] The dyeing with iodine is carried out, for example, by immersing the PVA film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be carried out after the dyeing treatment or while dyeing. Alternatively, the PVA film may be stretched and then dyed. If necessary, the PVA film may be subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, or the like. For example, by immersing the PVA film in water and washing it before dyeing, it is possible to wash away dirt and antiblocking agents on the surface of the PVA film, and also to swell the PVA film, thereby preventing uneven dyeing.

[0026] Specific examples of polarizers obtained using laminates include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a polarizer obtained using a laminate of 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 produced, for example, by applying a PVA-based resin solution to the resin substrate and drying the resin substrate 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 then stretching and dyeing the laminate to convert the PVA-based resin layer into a polarizer. In this embodiment, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is preferably formed on one side of the resin substrate. The stretching typically involves immersing the laminate in a boric acid aqueous solution and stretching it. Furthermore, the stretching may further include, if necessary, in-air stretching of the laminate at an elevated temperature (e.g., 95°C or higher) before stretching in the boric acid aqueous solution. Additionally, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment by heating while being transported in the longitudinal direction, thereby shrinking the laminate by 2% or more in the width direction. Typically, the manufacturing method of this embodiment includes subjecting the laminate to an auxiliary in-air stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment, in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of PVA, even when PVA is coated on a thermoplastic resin, thereby achieving high optical properties. Furthermore, by simultaneously increasing the orientation of PVA in advance, problems such as a decrease in orientation or dissolution of PVA when immersed in water in the subsequent dyeing or stretching steps can be prevented, thereby achieving high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disordering of the orientation of polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain a halide. This can improve the optical properties of a polarizer obtained through treatment steps in which the laminate is immersed in a liquid, such as a dyeing treatment and an underwater stretching treatment. Furthermore, the optical properties can be improved by shrinking the laminate in the width direction through the drying shrinkage treatment.The obtained resin substrate / polarizer laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the polarizer), or any suitable protective layer may be laminated on the surface obtained by peeling the resin substrate from the resin substrate / polarizer laminate or on the surface opposite to the peeled surface, depending on the purpose. Details of the method for producing such a polarizer are described in, for example, JP 2012-73580 A and Japanese Patent No. 6470455 A. The entire disclosures of these publications are incorporated herein by reference.

[0027] The non-polarizing portion 125 may be a portion that is not dyed with a dichroic material, or may be a portion that is dyed with a dichroic material and then bleached by any appropriate method (bleached portion). The non-polarizing portion is preferably a bleached portion. Bleaching after dyeing can improve the strength of the non-polarizing portion.

[0028] The planar shape of the non-polarizing portion may be any appropriate shape as long as it does not adversely affect the camera performance of the image display device to which the optical film is applied. Specific examples of the planar shape of the non-polarizing portion include a circle, an ellipse, a square, a rectangle, a diamond, a polygon, and an irregular shape.

[0029] The transmittance of the non-polarizing portion (for example, the transmittance measured with light of 550 nm wavelength at 23°C) is preferably 50% or more, more preferably 60% or more, even more preferably 75% or more, and particularly preferably 90% or more. Such a transmittance ensures the desired transparency of the non-polarizing portion. As a result, when a polarizer is arranged so that the non-polarizing portion corresponds to the camera portion of an image display device, adverse effects on the camera's imaging performance can be suppressed.

[0030] Preferably, the non-polarizing portion is a low-density portion having a relatively low content of dichroic material. Specifically, the low-density portion has a lower content of dichroic material than the polarizing portion. This configuration avoids quality problems such as cracks, delamination, and glue extrusion, compared to when the non-polarizing portion is formed mechanically (for example, by mechanical punching using an engraving blade, a plotter, a water jet, or the like). Furthermore, because the low-density portion has a low content of dichroic material itself, the transparency of the non-polarizing portion is maintained better than when the non-polarizing portion is formed by decomposing the dichroic material using laser light or the like.

[0031] The low-concentration portion is a portion having a lower dichroic substance content than the polarizing portion. The dichroic substance content of the low-concentration portion is preferably 1.0 wt % or less, more preferably 0.5 wt % or less, and even more preferably 0.2 wt % or less. When the dichroic substance content of the low-concentration portion is within this range, the desired transparency can be sufficiently imparted to the low-concentration portion. For example, when the low-concentration portion is used as the camera unit of an image display device, excellent imaging performance can be achieved in terms of both brightness and color. Meanwhile, the lower limit of the dichroic substance content of the low-concentration portion is usually below the detection limit. When iodine is used as the dichroic substance, the iodine content can be determined, for example, from the X-ray intensity measured by fluorescent X-ray analysis using a calibration curve prepared in advance using a standard sample.

[0032] The difference between the content of the dichroic material in the polarizing portion and the content of the dichroic material in the low-density portion is preferably 0.5% by weight or more, more preferably 1% by weight or more. If the difference in content is within this range, a low-density portion having the desired transparency can be formed.

[0033] B-2.Protective layer The protective layers 122 and 123 are each made of any suitable resin film. Typical materials for the resin film include cellulose-based resins such as triacetyl cellulose (TAC), cycloolefin-based resins such as polynorbornene, (meth)acrylic resins, polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin-based resins such as polyethylene, and polycarbonate-based resins. A typical example of a (meth)acrylic resin is a (meth)acrylic resin having a lactone ring structure. Examples of (meth)acrylic resins having a lactone ring structure are described in, for example, JP 2000-230016 A, JP 2001-151814 A, JP 2002-120326 A, JP 2002-254544 A, and JP 2005-146084 A. These publications are incorporated herein by reference. From the viewpoint of ease of processing into modified shapes, etc., cellulose-based resins are preferred, and TAC is more preferred. From the viewpoint of obtaining a polarizing plate with low moisture permeability and excellent durability, cycloolefin-based resins and (meth)acrylic resins are preferred.

[0034] In one embodiment, the protective layer 123 is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane retardation Re(550) is 0 nm to 10 nm and the retardation Rth(550) in the thickness direction is -10 nm to +10 nm.

[0035] The thickness of each of the protective layers 122 and 123 is preferably 10 μm to 80 μm, more preferably 12 μm to 40 μm, and even more preferably 15 μm to 35 μm.

[0036] B-3. ​​Anti-glare layer The anti-glare layer 130 typically has an anti-glare portion and a non-anti-glare portion, the anti-glare portion being substantially all of the portion other than the non-anti-glare portion.

[0037] The anti-glare layer may have any suitable configuration as long as it has the desired anti-glare function (anti-glare function). Specifically, the anti-glare layer may be formed from a curable resin composition containing a binder resin and particles. The binder resin typically contains a curable compound. Examples of the curable compound include a polyfunctional monomer, and an oligomer or prepolymer derived from the polyfunctional monomer. The curable resin composition may contain a photopolymerization initiator as needed.

[0038] Examples of particles include inorganic particles and organic particles. Specific examples of inorganic particles include silicon oxide particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, and calcium sulfate particles. Specific examples of organic particles include polymethyl methacrylate resin particles (PMMA particles), silicone resin particles, polystyrene resin particles, polycarbonate resin particles, acrylic styrene resin particles, benzoguanamine resin particles, melamine resin particles, polyolefin resin particles, polyester resin particles, polyamide resin particles, polyimide resin particles, and polyethylene fluoride resin particles. The particles may be used alone or in combination.

[0039] The weight average particle diameter of the particles is preferably 1 μm to 10 μm, and more preferably 2 μm to 7 μm. The weight average particle diameter of the particles can be measured, for example, by the Coulter count method.

[0040] The refractive index of the particles is preferably 1.1 to 1.9, and more preferably 1.2 to 1.7. Examples of particles having such a refractive index include silicone particles, polystyrene particles, polymethyl methacrylate, and copolymers of styrene and methacrylic acid. The difference (n1-n2) between the refractive index n1 of the particles and the refractive index n2 of the binder resin is preferably -0.01 or less, more preferably -0.03 or less, and even more preferably -0.05 or less. With this configuration, an anti-glare layer with excellent transparency can be obtained.

[0041] The amount of the particles to be added is preferably 0.2 to 12 parts by weight, and more preferably 0.5 to 12 parts by weight, relative to 100 parts by weight of the binder resin.

[0042] The thickness of the anti-glare layer is preferably 1 μm to 20 μm, more preferably 3 μm to 15 μm, and even more preferably 4 μm to 10 μm.

[0043] The anti-glare layer (effectively, the anti-glare portion) typically has an irregular surface. The arithmetic mean roughness Ra of the irregular surface is preferably 0.01 μm to 1 μm, more preferably 0.05 μm to 0.5 μm. The maximum height Ry of the irregular surface is preferably 0.5 μm to 5 μm, more preferably 1 μm to 3 μm. The average inclination angle θa of the irregular surface is preferably 0.3° to 5°, more preferably 0.5° to 4°. This configuration makes it possible to obtain an anti-glare layer that has sufficient anti-glare function while suppressing adverse effects on the visibility of image display devices. The definitions of the arithmetic mean roughness Ra, the maximum height Ry, and the average inclination angle θa are based on JIS B 0601 (1994 edition). Furthermore, these characteristic values ​​can be measured using a stylus-type surface roughness tester (for example, a high-precision microprofile tester manufactured by Kosaka Laboratory, product name "Surfcorder ET4000"). The average tilt angle θa is θa=tan -1 The value is defined by the formula Δa. Δa is the value obtained by dividing the reference length L of the roughness curve from the sum (h1+h2+h3+·······+hn) of the differences (heights h) between the apexes of adjacent convex portions and the lowest points of adjacent concave portions on the roughness curve defined in JIS B 0601 (1994 edition), that is, Δa=(h1+h2+h3+······+hn) / L. Note that the non-anti-glare portion may have a flat surface.

[0044] Since the anti-glare layer can have the above-described specific uneven surface, the outermost surface of the optical film can also have an uneven surface corresponding to the above-described uneven surface. According to an embodiment of the present invention, even when a surface protection film is temporarily attached to an optical film having such a specific uneven surface, peeling unevenness can be suppressed when the surface protection film is peeled off.

[0045] The haze of the anti-glare layer is 5.0% or more, preferably 15% to 55%, more preferably 25% to 45%, and even more preferably 30% to 40%. When the haze of the anti-glare layer is within this range, good anti-glare functionality (anti-glare functionality) can be imparted when the optical film image is applied to a display device. The haze of the non-anti-glare portion can typically be equivalent to that of the anti-reflection layer described below. The haze of the non-anti-glare portion is, for example, less than 1.0%, preferably 0.8% or less, more preferably 0.5% or less, and even more preferably 0.3% or less. The lower the haze, the better, and the lower limit of the haze can be, for example, 0.1%.

[0046] B-4.Anti-reflection layer The antireflection layer may have any suitable structure as long as it has the desired antireflection properties. Specifically, the antireflection layer may be a cured layer of a curable resin composition or a layer formed by a dry process.

[0047] Typical configurations of antireflection layers formed by a dry process include: (1) a single layer of a low refractive index layer having an optical film thickness of 120 nm to 140 nm and a refractive index of about 1.35 to 1.55; (2) a laminate having, from the polarizing plate side, a medium refractive index layer, a high refractive index layer, and a low refractive index layer; and (3) an alternating multilayer laminate of high refractive index layers and low refractive index layers.

[0048] Examples of materials that can form a low refractive index layer include silicon oxide (SiO2) and magnesium fluoride (MgF2). The refractive index of a low refractive index layer is typically about 1.35 to 1.55. Examples of materials that can form a high refractive index layer include titanium oxide (TiO2), niobium oxide (Nb2O3 or Nb2O5), tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), and ZrO2-TiO2. The refractive index of a high refractive index layer is typically about 1.60 to 2.20. Examples of materials that can form a medium refractive index layer include titanium oxide (TiO2) and a mixture of a material that can form a low refractive index layer and a material that can form a high refractive index layer (for example, a mixture of titanium oxide and silicon oxide). The refractive index of a medium refractive index layer is typically about 1.50 to 1.85. The thicknesses of the low refractive index layer, the medium refractive index layer and the high refractive index layer can be set so as to achieve an appropriate optical film thickness depending on the layer structure of the antireflection layer, the desired antireflection performance and the like.

[0049] Specific examples of dry processes include PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition). PVD methods include vacuum deposition, reactive vapor deposition, ion beam assisted deposition, sputtering, and ion plating. CVD methods include plasma CVD. Sputtering is preferred because it allows for more uniform film formation with less unevenness in film thickness.

[0050] The thickness of the antireflection layer formed by the dry process is, for example, about 20 nm to 300 nm.

[0051] As described above, the antireflection layer may be a cured layer of a curable resin composition. The curable resin composition contains a curable resin. Typical examples of the curable resin include thermosetting resins, ultraviolet curable resins, light (visible light) curable resins, and electron beam curable resins. Examples of the curable resin include silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, and polythiolpolyene resins. The curable resin may be a curable compound having an acrylate group and / or a methacrylate group that is cured by heat, light (e.g., ultraviolet light), or an electron beam. Specific examples include oligomers or prepolymers such as acrylates and / or methacrylates of polyfunctional compounds such as polyhydric alcohols. The curable resins may be used alone or in combination of two or more. The curable resin composition may further contain a reactive diluent, a fluorine-containing additive, hollow particles, and / or solid particles depending on the purpose. Commercially available products may be used as such an antireflection layer. A specific example of a commercially available product is the AR film manufactured by Dexerials Corporation.

[0052] The thickness of the antireflection layer, which is a cured layer of the curable resin composition, may be, for example, 0.1 μm to 50 μm, or may be, for example, 0.3 μm to 40 μm, or may be, for example, 0.5 μm to 30 μm, or may be, for example, 1.0 μm to 20 μm, or may be, for example, 2.0 μm to 10 μm.

[0053] The reflectance of the antireflection layer is preferably 1.5% or less, more preferably 1.3% or less, and even more preferably 1.0% or less. The lower the reflectance, the better, and the lower limit may be, for example, 0.2%. If the reflectance is within this range, it is possible to prevent reflection of external light, etc.

[0054] The haze of the antireflection layer is less than 1.0%, preferably 0.8% or less, more preferably 0.5% or less, and even more preferably 0.3% or less. The lower the haze, the better, and the lower limit of the haze may be, for example, 0.1%. If the haze of the antireflection layer is within this range, when the optical film is used in an image display device, it can provide an antireflection function without adversely affecting the display performance.

[0055] B-5. Anti-fouling layer The antifouling layer may have any suitable structure as long as it can provide an antifouling effect. The antifouling layer may contain, for example, a fluorine group-containing silane compound (e.g., an alkoxysilane compound having a perfluoropolyether group) or a fluorine group-containing organic compound.

[0056] The thickness of the antifouling layer is preferably 5 nm to 13 nm, more preferably 5 nm to 10 nm. The refractive index of the antifouling layer may be, for example, 1.0 to 2.0. The antifouling layer preferably exhibits water repellency with a water contact angle of 110 degrees or more.

[0057] C. Surface protection film C-1. Overview of Surface Protection Films As described above, the surface protection film 100 includes the base film 10 and the pressure-sensitive adhesive layer 20 .

[0058] The sagging amount of the surface protection film is, for example, 52 mm or less, preferably 50 mm or less, more preferably 48 mm or less, even more preferably 46 mm or less, particularly preferably 44 mm or less, and especially preferably 42 mm or less. If the sagging amount of the surface protection film is within this range, sufficient strength as a surface protection film can be ensured. On the other hand, the sagging amount can be, for example, 5 mm or more, or, for example, 10 mm or more. The sagging amount can be measured, for example, as follows. The surface protection film is cut into a size of 50 mm x 100 mm, and the adhesive layer is exposed to prepare a test sample. The test sample is attached to a base so that 20 mm of the total length of 100 mm rests on the base and 80 mm protrudes from the base, and a weight is placed on top to secure it in place. The amount by which the protruding portion sags from the base is measured and used as the sagging amount.

[0059] In one embodiment, the low-speed peel strength between the base film 10 and the pressure-sensitive adhesive layer 20 is greater than the low-speed peel strength between the pressure-sensitive adhesive layer 20 and the optical film 200. This configuration can prevent poor peeling when peeling and removing the surface protective film. More specifically, the difference between the low-speed peel strength between the base film 10 and the pressure-sensitive adhesive layer 20 and the low-speed peel strength between the pressure-sensitive adhesive layer 20 and the optical film 200 is preferably 1.0 N / 25 mm or more, more preferably 2.0 N / 25 mm or more, and even more preferably 3.0 N / 25 mm or more. The difference can be, for example, 30 N / 25 mm or less. The low-speed peel strength between the base film 10 and the pressure-sensitive adhesive layer 20 can be, for example, 3.0 N / 25 mm to 30 N / 25 mm. The low-speed peel strength between the pressure-sensitive adhesive layer 20 and the optical film 200 is as described in Section A above.

[0060] In one embodiment, the initial peel force when peeling the surface protection film is, for example, 10.0 N or less, for example, 5.0 N or less, for example, 3.0 N or less, for example, 2.0 N or less, for example, 1.0 N or less, for example, 0.8 N or less, for example, 0.6 N or less, or for example, 0.5 N or less. The lower limit of the initial peel force may be, for example, 0.01 N. When the initial peel force is within this range, the surface protection film can be easily peeled, and peeling defects can be significantly suppressed. The initial peel force may be measured, for example, in accordance with JIS Z 0237. Specifically, a pickup tape is applied to the surface of the surface protection film of the optical laminate along the peeling direction, and the peel force when the pickup tape is used to peel at a 90° tensile direction can be measured as the initial peel force. The width of the pickup tape may be, for example, 10 mm, and the pulling speed may be, for example, 300 mm / min.

[0061] The components of the surface protection film will be specifically described below.

[0062] C-2. Base film The substrate film may be made of any suitable material as long as the effects of the present invention can be achieved. Specific examples of such materials include polyester-based polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate-based polymers; (meth)acrylic polymers such as polymethyl methacrylate; and cycloolefin-based polymers such as polynorbornene. These may be used alone or in combination of two or more. Polyester-based polymers are preferred, and those with excellent optical properties (e.g., transparency), mechanical strength, thermal stability, moisture barrier properties, isotropy, flexibility, and dimensional stability are particularly preferred. In particular, polyester films with moderate stiffness can easily achieve the desired properties. PET is a typical example of such polyester-based polymers. The properties of the polyester film can be controlled by adjusting the type and combination of the polycarboxylic acid component and polyol component. For example, PET and PEN may be used in combination as the substrate film's constituent materials.

[0063] Other examples of materials constituting the base film include styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers; vinyl chloride-based polymers; amide-based polymers such as nylon 6, nylon 6,6, and aromatic polyamides; imide-based polymers; sulfone-based polymers; polyethersulfone-based polymers; polyetheretherketone-based polymers; polyphenylene sulfide-based polymers; vinyl alcohol-based polymers; vinylidene chloride-based polymers; vinyl butyral-based polymers; arylate-based polymers; polyoxymethylene-based polymers; and epoxy-based polymers. These may be used alone or in combination of two or more.

[0064] The tensile modulus of the substrate film is, for example, 2300 MPa or less, preferably 1500 MPa or less, more preferably 1300 MPa or less, even more preferably 10 MPa to 1300 MPa, and particularly preferably 100 MPa to 1300 MPa. If the tensile modulus of the substrate film is within this range, it can be easy to achieve the above-mentioned desired properties. The tensile modulus is measured in accordance with JIS K 7161.

[0065] The thickness of the substrate film is, for example, 20 μm to 100 μm, for example, 25 μm to 80 μm, or for example, 30 μm to 50 μm. If the thickness of the substrate film is within this range, peeling failure when peeling off the surface protection film can be extremely effectively prevented.

[0066] C-3. Adhesive layer The adhesive layer 20 may have any suitable structure as long as it can achieve the desired surface free energy. The adhesive constituting the adhesive layer typically contains a base polymer, a crosslinking agent, and, if necessary, a silane coupling agent and / or additives. Specific examples of adhesives based on a base polymer include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. The base polymer may be used alone or in combination of two or more. The base polymer is preferably a (meth)acrylic polymer (i.e., the adhesive layer is preferably composed of an acrylic adhesive). Note that (meth)acrylic refers to acrylic and / or methacrylic.

[0067] The (meth)acrylic polymer contains alkyl(meth)acrylate as a main monomer component, and the alkyl(meth)acrylate may be contained in a proportion of preferably 50% by weight or more, more preferably 60% by weight or more, even more preferably 70% by weight or more, particularly preferably 80% by weight or more, and particularly preferably 90% by weight or more of all the monomer components forming the (meth)acrylic polymer.

[0068] The alkyl (meth)acrylate preferably includes a linear or branched alkyl group having 1 to 18 carbon atoms. The alkyl group more preferably has 2 to 10 carbon atoms, and even more preferably has 3 to 8 carbon atoms. Examples of the alkyl (meth)acrylate include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate. The alkyl (meth)acrylates can be used alone or in combination.

[0069] The (meth)acrylic polymer may contain, as a monomer component, a copolymerizable monomer copolymerizable with alkyl (meth)acrylate. Examples of the copolymerizable monomer include a carboxyl group-containing monomer and a hydroxyl group-containing monomer. The carboxyl group-containing monomer is a compound containing a carboxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Acrylic acid is preferred. The hydroxyl group-containing monomer is a compound containing a hydroxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. Copolymerizable monomers other than those mentioned above may be used to adjust the properties of the pressure-sensitive adhesive layer. Examples of such copolymerizable monomers include amino group-containing monomers, amide group-containing monomers, polyfunctional monomers, cyclopolymerizable monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, (meth)acrylic acid esters having an alicyclic hydrocarbon group, (meth)acrylic acid esters having an aromatic hydrocarbon group, vinyl esters, aromatic vinyl compounds, olefins, dienes, and vinyl ethers. The copolymerizable monomers can be used alone or in combination.

[0070] Examples of crosslinking agents that can be used include organic crosslinking agents and polyfunctional metal chelates. Examples of organic crosslinking agents include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, and imine crosslinking agents. Polyfunctional metal chelates are compounds in which a polyvalent metal is covalently or coordinately bonded to an organic compound.

[0071] The amount of the crosslinking agent to be added may be, for example, 0.01 to 5 parts by weight relative to 100 parts by weight of the base polymer.

[0072] The silane coupling agent preferably contains a reactive functional group. The reactive functional group of the reactive functional group-containing silane coupling agent is typically a functional group other than an acid anhydride group. Examples of functional groups other than an acid anhydride group include epoxy groups, mercapto groups, amino groups, isocyanate groups, isocyanurate groups, vinyl groups, styryl groups, acetoacetyl groups, ureido groups, thiourea groups, (meth)acrylic groups, heterocyclic groups, and combinations thereof. The reactive functional group-containing silane coupling agents can be used alone or in combination.

[0073] The amount of the reactive functional group-containing silane coupling agent to be added may be, for example, 0.001 to 2 parts by weight relative to 100 parts by weight of the base polymer.

[0074] Specific examples of additives include colorants, pigments, and other powders, dyes, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, light stabilizers, UV absorbers, antistatic agents (conductive agents), surfactants, polymerization inhibitors, inorganic or organic fillers, metal powders, particles, and foil-like materials. Redox systems may also be used by adding a reducing agent within controllable limits. The type, number, combination, and content of additives may be appropriately determined depending on the purpose.

[0075] By adjusting the type, number, combination and compounding ratio of the monomers that form the base polymer of the adhesive, the type and compounding amount of the crosslinking agent, the type, number, combination and compounding amount of the additives, as well as the reaction temperature, reaction time, etc., it is possible to prepare an adhesive having the desired properties according to the purpose.

[0076] The thickness of the pressure-sensitive adhesive layer is, for example, 5 μm to 50 μm, for example, 10 μm to 40 μm, or for example, 10 μm to 30 μm. If the thickness of the pressure-sensitive adhesive layer is within this range, the above-mentioned desired properties of the surface protection film can be easily achieved.

[0077] The indentation hardness of the pressure-sensitive adhesive layer is, for example, 0.10 MPa or more, preferably 0.25 MPa or more, more preferably 0.35 MPa or more, even more preferably 0.50 MPa or more, particularly preferably 0.70 MPa or more, and especially preferably 1.00 MPa or more. The indentation hardness of the pressure-sensitive adhesive layer can be, for example, 1.50 MPa or less, or, for example, 1.30 MPa or less. The indentation hardness can be measured, for example, by a nanoindenter test.

[0078] C-4. Modified surface protection film The surface protection film may have, for example, two base films and two pressure-sensitive adhesive layers. Specifically, the surface protection film may have a first base film, a second base film bonded to the first base film via the first pressure-sensitive adhesive layer, and a second pressure-sensitive adhesive layer provided on the second base film on the side opposite to the first pressure-sensitive adhesive layer. In this case, the second pressure-sensitive adhesive layer serves as a pressure-sensitive adhesive layer for temporarily attaching the surface protection film to the optical film. The first pressure-sensitive adhesive layer may have any appropriate configuration. The first base film and the second base film may have the same configuration or different configurations. [Example]

[0079] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The methods for measuring each property are as follows. Unless otherwise specified, "%" and "parts" in the examples are by weight.

[0080] (1) Indentation hardness of adhesive layer The indentation hardness of the pressure-sensitive adhesive layer was measured using a nanoindenter test. Specifically, the test was carried out as follows. The surface protection films obtained in the examples and comparative examples were cut into pieces of approximately 1 cm x 1 cm and fixed to a predetermined support. The release liner was then peeled off to expose the pressure-sensitive adhesive layer, and used as test samples. A "Triboindenter" (manufactured by Hysitron Inc.) was used as the device, and a conical indenter (spherical: radius of curvature 10 μm) was used as the indenter, and single indentation measurements were carried out at a measurement temperature of 25°C. The indentation depth was set to 1300 nm. The indentation hardness (MPa) of the pressure-sensitive adhesive was calculated based on the following formula. Indentation hardness = Load at deepest indentation (maximum load Pmax) / Contact area between indenter and sample (projected contact area A)

[0081] (2) Surface free energy For the surface protection film and the optical film used in the examples and comparative examples, the surface free energy of the pressure-sensitive adhesive layer of the surface protection film and the surface free energy of the surface protection film side of the optical film were determined. Specifically, the results were as follows. For the pressure-sensitive adhesive layer surface and the optical film surface, the surface free energy of water (γ d L=29.1, γ p L=1.3, γ h L = 42.4), bromonaphthalene (γ d L=44.4, γ p L=0.2, γ h L=0), hexadecane (γ d L=27.6, γ p L=0, γ h The contact angle was evaluated using three types of solvents (L = 0). By solving the simultaneous equations for the Young-Dupre equation of the Kitazaki-Hata theory, the γ d S, γ p S, γ h S was calculated to determine the surface free energy γ S. The contact angle was measured as follows. 2 μL of solvent was dropped onto the surface of the pressure-sensitive adhesive layer or optical film, and the contact angle (°) was measured 1 second after the drop. The contact angle was measured using a commercially available contact angle measuring device in accordance with JIS R 3257:1999 (sessile drop method). Specifically, the measurement was performed under the following conditions. The measurement was performed five times, and the average value was used (n=5). [Contact angle measurement conditions] Measurement device: Contact angle measuring device DropMaster DM700 (Kyowa Interface Science Co., Ltd.) Measurement atmosphere: 23°C, 50% RH Measurement liquid: distilled water, bromonaphthalene, hexadecane Measurement time: 1 second after droplet deposition

[0082] (3) Arithmetic mean roughness The optical film was set in a white light interferometer (manufactured by Zygo, product name "Zygo NewView 7300") with the optical film surface facing the objective lens, and interference data of the optical film surface was measured under the following conditions to obtain a two-dimensional image. The arithmetic mean roughness was calculated from the two-dimensional image. The arithmetic mean roughness was calculated by averaging the data from three randomly selected points. [Measurement conditions for white light interferometer] Objective lens: ×10 Internal lens: ×1.0 Resolution; 1.09μm Measurement field of view area: 0.3641mm 2 Removed;Cylinder

[0083] (4) Low-speed peeling force The optical laminates obtained in the examples and comparative examples were allowed to stand for 30 minutes in an environment at a temperature of 23°C and a relative humidity of 50%, and then a peel test was conducted in the same environment at a peel angle of 180° and a pulling speed of 300 mm / min to measure the 180° peel force, which was taken as the low-speed peel force.

[0084] (5) Uneven peeling The optical laminates obtained in the examples and comparative examples were left to stand for 30 minutes in an environment at a temperature of 23°C and a relative humidity of 50%, and then the surface protective film was repeatedly peeled off and the peeling was stopped under the same environment. In a dark room with a black background, unevenness was visually observed in the peeled and peel-stopped areas of the surface protective film, and the result was rated as "occurrence," while unevenness was not visually observed in the peeled and peel-stopped areas of the surface protective film, and the result was rated as "no occurrence."

[0085] [Production Example 1: Preparation of adhesive constituting adhesive layer] A flask equipped with a reflux condenser, stirrer, nitrogen gas inlet tube, and thermometer was charged with 95 parts of n-butyl acrylate (BA) and 5 parts of acrylic acid (AA) as monomer components, and ethyl acetate (polymerization solvent) to a solids concentration of 30%. 0.2 parts of azobisisobutyronitrile (AIBN) was then added as a polymerization initiator. Nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 63°C. The polymerization reaction was carried out for 7 hours, yielding a solution of acrylic polymer 1. The weight-average molecular weight (Mw) of the resulting acrylic polymer 1 was 630,000. The Tg calculated from the Fox equation was -49.3°C. The solution (40%) of acrylic polymer 1 obtained above was diluted to 20% with ethyl acetate, and 500 parts of this solution (100 parts solids) was added with 6 parts (6 parts solids) of a multifunctional epoxy resin (TETRAD-C, manufactured by Mitsui Chemicals, Inc.) as a crosslinking agent, followed by mixing and stirring to prepare a pressure-sensitive adhesive composition (solution) (pressure-sensitive adhesive 1).

[0086] [Production Example 2: Preparation of adhesive constituting adhesive layer] A flask equipped with a reflux condenser, stirrer, nitrogen gas inlet tube, and thermometer was charged with 96 parts of 2-ethylhexyl acrylate (2EHA) and 4 parts of hydroxyethyl acrylate (HEA) as monomer components, and ethyl acetate (polymerization solvent) to a solids concentration of 40%. 0.2 parts of azobisisobutyronitrile (AIBN) was then added as a polymerization initiator. Nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 65°C for 6 hours to carry out the polymerization reaction. The mixture was then aged at 70°C for 4 hours to obtain a solution of acrylic polymer 2. The weight-average molecular weight (Mw) of the resulting acrylic polymer 2 was 540,000. The Tg calculated by the Fox equation was -68.3°C. The solution (40%) of acrylic polymer 2 obtained above was diluted to 20% with ethyl acetate. To 500 parts of this solution (100 parts solids), 1.5 parts (0.15 parts solids) of a solution prepared by diluting a surfactant (KH-10, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) to 10% with ethyl acetate, 4 parts (4 parts solids) of hexamethylene diisocyanate (Tosoh Corporation, Coronate HX) as a crosslinking agent, and 3 parts (0.03 parts solids) of dioctyltin dilaurate (1% ethyl acetate solution) as a crosslinking catalyst were added, and the mixture was mixed and stirred to prepare a pressure-sensitive adhesive composition (solution) (pressure-sensitive adhesive 2).

[0087] [Production Example 3: Preparation of adhesive constituting adhesive layer] The solution (40%) of acrylic polymer 2 obtained in Production Example 2 was diluted to 20% with ethyl acetate, and to 500 parts of this solution (solid content 100 parts), 4 parts (solid content 4 parts) of tolylene diisocyanate (Takenate D-101E, manufactured by Mitsui Chemicals, Inc.) as a crosslinking agent and 3 parts (solid content 0.03 parts) of dioctyltin dilaurate (1% ethyl acetate solution) as a crosslinking catalyst were added, and the mixture was stirred to prepare a pressure-sensitive adhesive composition (solution) (pressure-sensitive adhesive 3).

[0088] [Production Example 4: Preparation of adhesive constituting adhesive layer] A solution (40%) of acrylic polymer 2 obtained in Production Example 2 was diluted to 20% with ethyl acetate. To 500 parts of this solution (100 parts solids), 3 parts (0.3 parts solids) of a solution prepared by diluting an ionic compound (1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, manufactured by Kanto Chemical Co., Ltd., CIL-312) to 10% with ethyl acetate, 0.3 parts (0.3 parts solids) of polyether-modified silicone oil (KF-6004, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone component, 2.5 parts (2.5 parts solids) of tolylene diisocyanate (Takenate D-101E, manufactured by Mitsui Chemicals, Inc.) as a crosslinking agent, and 3 parts (0.03 parts solids) of dioctyltin dilaurate (1% ethyl acetate solution) as a crosslinking catalyst were added, and the mixture was mixed and stirred to prepare a pressure-sensitive adhesive composition (solution) (pressure-sensitive adhesive 4).

[0089] [Production Example 5: Preparation of surface protection film] The adhesive 1 obtained in Production Example 1 was applied to one surface of a PET film (thickness 38 μm), and the solvent was removed by drying at 130° C. for 1 minute to form an adhesive layer (thickness 20 μm). The surface of the adhesive layer was then covered with a release liner and aged for 2 days in a temperature environment of 50° C. to obtain a surface protection film SPV1 having a PET film / adhesive layer configuration.

[0090] [Production Example 6: Preparation of surface protection film] The adhesive 2 obtained in Production Example 2 was applied to one surface of a PET film (thickness 38 μm), and the solvent was removed by drying at 130° C. for 1 minute to form an adhesive layer (thickness 20 μm). The surface of the adhesive layer was then covered with a release liner and aged for 2 days in a temperature environment of 50° C. to obtain a surface protection film SPV2 having a PET film / adhesive layer configuration.

[0091] [Production Example 7: Preparation of surface protection film] The PSA 3 obtained in Production Example 3 was applied to one surface of a PET film (thickness 38 μm), and the solvent was removed by drying at 130° C. for 1 minute to form a PSA layer (thickness 21 μm). The surface of the PSA layer was then covered with a release liner and aged for 2 days in a temperature environment of 50° C. to obtain a surface protection film SPV3 having a PET film / adhesive layer configuration.

[0092] [Production Example 8: Preparation of surface protection film] The PSA 4 obtained in Production Example 4 was applied to one surface of a PET film (thickness 38 μm), and the solvent was removed by drying at 130° C. for 1 minute to form a PSA layer (thickness 15 μm). The surface of the PSA layer was then covered with a release liner and aged for 2 days in a temperature environment of 50° C. to obtain a surface protection film SPV4 having a PET film / adhesive layer configuration.

[0093] [Production Example 9: Preparation of optical film] 1. Polarizer Fabrication A long, amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a Tg of about 75° C. was used as the thermoplastic resin substrate, and one side of the resin substrate was subjected to a corona treatment. A PVA aqueous solution (coating solution) was prepared by dissolving 100 parts by weight of a PVA-based resin made by mixing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFFIMER") in a 9:1 ratio, to which 13 parts by weight of potassium iodide was added, in water. The above PVA aqueous solution was applied to the corona treated surface of the resin substrate and dried at 60° C. to form a PVA resin layer with a thickness of 13 μm, thereby producing a laminate. The resulting laminate was uniaxially stretched 2.4 times in the machine direction (longitudinal direction) in an oven at 130°C (auxiliary in-air stretching treatment). Next, the laminate was immersed in an insolubilizing bath (a boric acid aqueous solution obtained 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 (insolubilizing treatment). Next, the film was immersed in a dye bath (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) at a liquid temperature of 30°C for 60 seconds while adjusting the concentration so that the single transmittance (Ts) of the finally obtained polarizer would be a desired value (dyeing treatment). Next, the sample was immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment). The laminate was then immersed in a boric acid aqueous solution (boric acid concentration 4 wt %, potassium iodide concentration 5 wt %) at a liquid temperature of 70°C and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to a total stretch ratio of 5.5 times (underwater stretching treatment). Thereafter, the laminate was immersed in a cleaning bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20° C. (cleaning treatment). Thereafter, the film was dried in an oven maintained at about 90°C, and brought into contact with a heated roll made of SUS whose surface temperature was maintained at about 75°C (drying shrinkage treatment). In this way, a polarizer with a thickness of approximately 5 μm was formed on the resin substrate, and a long polarizing plate having a resin substrate / polarizer configuration was obtained. The polarizer had a single transmittance Ts of 43.3%. The polarizer had an absorption axis in the longitudinal direction. Hereinafter, the absorption axis direction (longitudinal direction) will be referred to as the "0° direction," and the transmission axis direction (width direction) will be referred to as the "90° direction."

[0094] 2. Preparation of Polarizing Plates An HC-COP film was attached to the surface of the obtained polarizer (the surface opposite to the resin substrate) via a UV-curable adhesive. The HC-COP film was a film in which an HC layer (4 μm thick) was formed on a cycloolefin resin (COP) film (25 μm thick), and the COP film was attached so that it faced the polarizer. Next, the resin substrate was peeled off, and a triacetyl cellulose (TAC) film (25 μm thick) was attached to the peeled surface via a UV-curable adhesive. In this way, a polarizing plate having a configuration of HC layer / COP film (protective layer) / polarizer / TAC film (protective layer) was obtained.

[0095] 3. Fabrication of Optical Film 50 parts of a UV-curable urethane acrylate resin (Shin-Nakamura Chemical Co., Ltd., product name "UA53H-80MB," 80% solids) and 50 parts of a multifunctional acrylate based on pentaerythritol triacrylate (Osaka Organic Chemical Industry Co., Ltd., product name "Viscoat #300," 100% solids) were prepared. Per 100 parts of the total resin solids, these resins were mixed with 0.5 parts of acrylic-styrene copolymer particles (Sekisui Plastics Co., Ltd., product name "Techpolymer SSX1055QXE"), 1.5 parts of synthetic smectite (Kunimine Industries Co., Ltd., product name "Sumecton SAN"), an organoclay thickener, 5 parts of a photopolymerization initiator (BASF, product name "OMNIRAD907"), and 0.1 parts of a leveling agent (Shin-Etsu Chemical Co., Ltd., product name "KY-1203," 20% solids). This mixture was diluted with a toluene / cyclopentanone mixed solvent (70 / 30) so that the solid content concentration was 40%, thereby producing a coating liquid A.

[0096] A triacetyl cellulose film (manufactured by Konica Minolta, Inc., product name "KC4UA") was prepared as a transparent substrate. The above-mentioned coating solution A was applied to the corona-treated surface of the substrate using a wire bar to form a coating film. Next, the substrate on which the coating film was formed was heated at 100°C for 1 minute to dry the coating film. Next, a high-pressure mercury lamp was used to irradiate the film with an integrated light intensity of 300 mJ / cm. 2 The coating was cured by irradiating it with ultraviolet light of 1000 kJ / cm² to produce an anti-glare layer with a thickness of 4 μm. The substrate of the substrate / anti-glare layer laminate was attached to the HC layer of the polarizing plate obtained above, yielding a laminate having a structure of anti-glare layer ( / substrate) / HC layer / COP film (protective layer) / polarizer / TAC film (protective layer). A layer made of a fluorine-based resin was formed as an anti-fouling layer to a thickness of 9 nm on the surface of the anti-reflection layer of the obtained laminate, yielding optical film 1 having a structure of anti-fouling layer / anti-glare layer ( / substrate) / HC layer / COP film (protective layer) / polarizer / TAC film (protective layer).

[0097] [Production Example 10: Preparation of optical film] In the same manner as in Production Example 9, a polarizing plate having a structure of HC layer / COP film (protective layer) / polarizer / TAC film (protective layer) was obtained. The binder resin used was 60 parts by weight of pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300"), 40 parts by weight of urethane acrylate prepolymer (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "UA-53H-80BK"), 20 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 4.0 parts by weight of silicone particles (manufactured by Momentive Performance Materials Japan, LLC, trade name "Tospearl 130", weight average particle size: 3 μm, |D90-D50|: 2.5 μm, refractive index: 1.42), 2.5 parts by weight of synthetic smectite (manufactured by Katakura Co-op Agri Co., Ltd., trade name "Lucentite SAN") as an organoclay, and a photopolymerization initiator (manufactured by IGM Resins, trade name "Omnirad 5.0 parts by weight of "907") and 1.0 part by weight of a leveling agent (manufactured by DIC Corporation, trade name "PC4100", solid content 10%) were mixed and diluted with a toluene / cyclopentanone (CPN) mixed solvent (weight ratio 70 / 30) to prepare coating solution B with a solid content concentration of 33% by weight. The organoclay was diluted with toluene to a solid content of 6% by weight before use. A triacetyl cellulose film (Konica Minolta, product name "KC4UA") was prepared as a transparent substrate. The above-mentioned coating solution B was applied to the corona-treated surface of the substrate using a Comma Coater (registered trademark), heated at 95°C for 1 minute, and then exposed to a high-pressure mercury lamp with an integrated light intensity of 300 mJ / cm. 2 The anti-glare layer was formed to a thickness of 7 μm by irradiating the film with ultraviolet light. Optical film 2 having a structure of antiglare layer ( / substrate) / HC layer / COP film (protective layer) / polarizer / TAC film (protective layer) was obtained in the same manner as in Production Example 9, except that the above antiglare layer was used and no antifouling layer was formed.

[0098] [Example 1] The surface protection film SPV1 obtained in Production Example 5 was temporarily attached to the antifouling layer surface of the optical film 1 obtained in Production Example 9 via a pressure-sensitive adhesive layer to produce an optical laminate 1. The obtained optical laminate 1 was subjected to the above evaluations (1) to (5). The results are shown in Table 1.

[0099] [Example 2] The surface protection film SPV1 obtained in Production Example 5 was temporarily attached to the surface of the antiglare layer of the optical film 2 obtained in Production Example 10 via a pressure-sensitive adhesive layer to produce an optical laminate 2. The obtained optical laminate 2 was subjected to the same evaluations as in Example 1. The results are shown in Table 1.

[0100] [Example 3] The surface protection film SPV2 obtained in Production Example 6 was temporarily attached to the surface of the antiglare layer of the optical film 2 obtained in Production Example 10 via a pressure-sensitive adhesive layer to produce an optical laminate 3. The obtained optical laminate 3 was subjected to the same evaluations as in Example 1. The results are shown in Table 1.

[0101] [Example 4] The surface protection film SPV3 obtained in Production Example 7 was temporarily attached to the surface of the antiglare layer of the optical film 2 obtained in Production Example 10 via a pressure-sensitive adhesive layer to produce an optical laminate 4. The obtained optical laminate 4 was subjected to the same evaluations as in Example 1. The results are shown in Table 1.

[0102] [Example 5] A pressure-sensitive adhesive was prepared in the same manner as in Production Example 3, except that 3 parts (0.3 parts solids content) of a solution prepared by diluting an ionic compound (1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, manufactured by Kanto Chemical Co., Inc., CIL-312) to 10% with ethyl acetate was added. SPV5 was produced in the same manner as in Production Example 7, except that this pressure-sensitive adhesive was used. The obtained SPV5 was temporarily attached to the antifouling layer surface of the optical film 1 obtained in Production Example 9 via the pressure-sensitive adhesive layer, thereby producing optical laminate 5. The obtained optical laminate 5 was subjected to the same evaluations as in Example 1. The results are shown in Table 1.

[0103] [Comparative Example 1] The surface protection film SPV4 obtained in Production Example 8 was temporarily attached to the antifouling layer surface of the optical film 1 obtained in Production Example 9 via a pressure-sensitive adhesive layer to produce an optical laminate 5. The obtained optical laminate 5 was subjected to the same evaluations as in Example 1. The results are shown in Table 1.

[0104] [Table 1]

[0105] In Table 1, "crosslinker A" represents tolylene diisocyanate (Takenate D-101E, manufactured by Mitsui Chemicals), "crosslinker B" represents hexamethylene diisocyanate (Coronate HX, manufactured by Tosoh Corporation), and "crosslinker C" represents a multifunctional epoxy resin (TETRAD-C, manufactured by Mitsui Chemicals). [Industrial Applicability]

[0106] The optical laminate according to the embodiment of the present invention can be suitably used as an intermediate for protecting an optical film during the manufacturing process, inspection process, transportation, etc. of the optical film, and can be suitably used in particular as an intermediate for an optical film having an uneven surface. [Explanation of symbols]

[0107] 10 Base film 20 adhesive layer 100 Surface Protection Film 120 Polarizing Plate 121 Polarizer 122 Protective layer 123 Protective layer 125 Non-polarized part 130 Anti-glare layer 135 Non-anti-glare part 140 Anti-reflection layer 150 Antifouling layer 200 Optical Film 300 Optical laminate

Claims

1. an optical film having a polarizing plate including a polarizer and an antiglare layer disposed on one side of the polarizing plate; and a surface protective film having a base film and a pressure-sensitive adhesive layer, the surface protective film being temporarily and releasably attached to the antiglare layer side of the optical film via the pressure-sensitive adhesive layer; The surface free energy γS of the surface protective film side of the optical film ＯＦ and the surface free energy γS of the pressure-sensitive adhesive layer ＰＳＡ The absolute value of the difference between Optical laminate.

2. The optical laminate according to claim 1 , wherein the low-speed peel strength between the surface protective film and the optical film is 0.001 N / 25 mm or more.

3. The optical laminate according to claim 2 , wherein the low-speed peel strength between the surface protective film and the optical film is 0.016 N / 25 mm or less.

4. 2. The optical laminate according to claim 1, wherein the arithmetic mean roughness Ra of the surface of the optical film on the surface protection film side is 0.15 μm to 0.50 μm.

5. The optical laminate according to claim 1 , wherein the polarizer includes a non-polarizing portion, the anti-glare layer includes a non-anti-glare portion, and the non-polarizing portion and the non-anti-glare portion are provided at corresponding positions.

6. 6. The optical laminate according to claim 1, further comprising an antireflection layer on the opposite side of the antiglare layer from the polarizing plate, and the surface protective film is removably temporarily attached to the antireflection layer via the pressure-sensitive adhesive layer.

7. The optical laminate according to claim 6 , wherein the antireflection layer has a haze of less than 1.0% and the antiglare layer has a haze of 5.0% or more.

8. The optical laminate according to claim 7, further comprising an antifouling layer on the opposite side of the antireflection layer from the antiglare layer, and the surface protective film is releasably temporarily attached to the antifouling layer via the pressure-sensitive adhesive layer.

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