Polarizing plate with surface protective film

Abstract

This invention provides a polarizing plate capable of suppressing the effects of ultraviolet light on polarizing elements, display elements, etc., and preventing the generation of foreign matter. The invention relates to a polarizing plate with a surface protective film, comprising: a polarizing plate having, sequentially, a hard coating layer, a protective layer, and a polarizing element; and a surface protective film having a substrate layer and an adhesive layer disposed on one side of the substrate layer, and being adhered to the surface of the hard coating layer of the polarizing plate via the adhesive layer; the hard coating layer contains an ultraviolet absorber, and the adhesive layer contains a base polymer having reactive functional groups and an isocyanate-based crosslinking agent, wherein the content of the isocyanate-based crosslinking agent in the adhesive layer is 2 to 5 parts by weight relative to 100 parts by weight of the base polymer having reactive functional groups.

Description

Technical Field

[0001] This invention relates to a polarizing plate with a surface protective film. Prior Technology

[0002] For liquid crystal display devices, which are representative image display devices, polarizing elements are arranged on both sides of the liquid crystal cell due to their image formation method. Polarizing elements are typically used as polarizing plates with a protective layer on at least one side. From the viewpoint of improving viewing angle, they can also be used as polarizing plates with a retardation layer, which further includes a retardation layer. Furthermore, for organic electroluminescent (EL) display devices, by placing a circular polarizing plate on the viewing side, problems such as reflection of external light or background reflection caused by the high reflectivity of the organic EL element are prevented. As a general circular polarizing plate, there are known circular polarizing plates formed by laminating a polarizing element and a retardation layer (typically a λ / 4 plate) such that the slow axis of the retardation layer is at an angle of approximately 45° relative to the absorption axis of the polarizing element (e.g., Patent Document 1).

[0003] In the aforementioned image display device, for the polarizing plate (viewing-side polarizing plate) disposed on the viewing side of display elements such as liquid crystal cells and organic EL elements, a scratch-resistant hard coating is provided on the protective layer disposed on the viewing side of the polarizing element. Furthermore, for the viewing-side polarizing plate, by adding an ultraviolet absorber to the adhesive layer used to bond the polarizing element to the protective layer disposed on its viewing side, the influence of ultraviolet rays on the polarizing element, display element, etc., is suppressed.

[0004] However, over time, foreign matter (such as crystalline foreign matter) may be generated in the adhesive layer containing ultraviolet absorbers. When observing an image display device using this polarizing plate, it may sometimes be seen as bright spots. [Previous Technical Documents] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2006-171235 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] The objective of this invention is to provide a polarizing plate that can suppress the effects of ultraviolet light on polarizing elements, display elements, etc., and prevent the generation of foreign matter. [Technical means to solve the problem]

[0008] Furthermore, for polarizing plates, the purpose is usually to protect the surface during the manufacturing process, inspection steps, and transportation process. During the period until they are put into use, they are treated as polarizing plates with a protective film temporarily attached. The protective film is peeled off when they are used.

[0009] In order to solve the above problems, the inventors tried adding an ultraviolet absorber to the hard coating layer provided in the protective layer. As a result, it was found that the generation of foreign matter in the adhesive layer was prevented. On the other hand, when the surface protective film was peeled off, contamination was generated on the surface of the polarizing plate.

[0010] The inventors conducted further research and found that by using a specific adhesive layer as the adhesive layer of the surface protective film, it is possible to suppress contamination on the surface of the polarizing plate. As a result, a polarizing plate that can suppress the influence of ultraviolet light on polarizing elements, display elements, etc., and prevent the generation of foreign matter can be obtained.

[0011] According to one aspect of the present invention, a polarizing plate with a surface protective film is provided. The polarizing plate with the surface protective film comprises: a polarizing plate having, sequentially, a hard coating layer, a protective layer, and a polarizing element; and a surface protective film having a substrate layer and an adhesive layer disposed on one side of the substrate layer, and being adhered to the surface of the hard coating layer of the polarizing plate via the adhesive layer; the hard coating layer comprises an ultraviolet absorber, and the adhesive layer comprises a base polymer having reactive functional groups and an isocyanate-based crosslinking agent, wherein the content of the isocyanate-based crosslinking agent in the adhesive layer is 2 to 5 parts by weight relative to 100 parts by weight of the base polymer having reactive functional groups. In one embodiment, the peeling force when peeling the above-mentioned surface protective film at a peeling speed of 0.3 m / min, a peeling temperature of 23°C, and a peeling angle of 180° is 0.2 N / 25 mm or less. In one embodiment, the polarizing plate has a phase difference layer on the side opposite to the side where the polarizing element is disposed. In one embodiment, the hard coating is a hardened body of a hard coating forming composition comprising a curing compound and the ultraviolet absorber, wherein the content of the ultraviolet absorber in the hard coating is 0.1 to 3.0 parts by weight relative to 100 parts by weight of the curing compound. In one embodiment, the base polymer is a (meth)acrylic polymer having hydroxyl and / or carboxyl groups. In one embodiment, the ultraviolet absorber comprises at least one ultraviolet absorber selected from hydroxyphenyltriazole ultraviolet absorbers and benzotriazole ultraviolet absorbers. [Effects of the Invention]

[0012] According to the present invention, a polarizing plate is provided that can suppress the influence of ultraviolet light on polarizing elements, display elements, etc., and prevent the generation of foreign matter. Simple Explanation of the Diagram

[0013] Figure 1 is a schematic cross-sectional view of a polarizing plate with a surface protective film according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view of a polarizing plate with a surface protective film according to one embodiment of the present invention. Figure 3 is a schematic cross-sectional view of a polarizing plate with a surface protective film according to one embodiment of the present invention. Implementation

[0014] (Definitions of terms and symbols) The definitions of terms and symbols used in this specification are as follows. (1) Refractive index (nx, ny, nz) "nx" refers to the refractive index in the direction where the in-plane refractive index is maximized (i.e., the slow axis direction), "ny" refers to the refractive index in the direction orthogonal to the slow axis (i.e., the fast axis direction), and "nz" refers to the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane phase difference measured with light at a wavelength of λnm at 23°C. For example, "Re(550)" is the in-plane phase difference measured with light at a wavelength of 550 nm at 23°C. Re(λ) is calculated using the formula: Re(λ) = (nx - ny) × d when the thickness of the layer (film) is set to d (nm). (3) Phase difference (Rth) in the thickness direction "Rth(λ)" is the phase difference in the thickness direction measured with light at a wavelength of λnm at 23°C. For example, "Rth(550)" is the phase difference in the thickness direction measured with light at a wavelength of 550 nm at 23°C. Rth(λ) is calculated using the formula: Rth(λ) = (nx - nz) × d when the thickness of the layer (film) is set to d (nm). (4) Nz coefficient The Nz coefficient is obtained by Nz=Rth / Re. (5) Angle In this specification, when referring to an angle, the angle includes both clockwise and counterclockwise directions relative to a reference direction. Therefore, for example, "45°" means 45° relative to a reference direction in either a clockwise or counterclockwise direction.

[0015] An embodiment of the present invention provides a polarizing plate with a surface protective film, comprising: a polarizing plate having, sequentially, a hard coating layer, a protective layer, and a polarizing element; and a surface protective film having a substrate layer and an adhesive layer disposed on one side of the substrate layer, and being adhered to the surface of the hard coating layer of the polarizing plate via the adhesive layer. In the polarizing plate with a surface protective film of this embodiment, the hard coating layer comprises an ultraviolet absorber, and the adhesive layer comprises a base polymer having reactive functional groups and an isocyanate-based crosslinking agent. The content of the isocyanate-based crosslinking agent in the adhesive layer is 2 to 5 parts by weight relative to 100 parts by weight of the base polymer having reactive functional groups.

[0016] A. The overall structure of the polarizing plate with a protective film. Figure 1 is a schematic cross-sectional view of a polarizing plate with a surface protective film according to one embodiment of the present invention. The polarizing plate 100A with the surface protective film includes: a polarizing plate 10 having a hard coating layer 11, a protective layer 12, and a polarizing element 13 in sequence; and a surface protective film 20 having a substrate layer 21 and an adhesive layer 22 disposed on one side of the substrate layer 21. The surface protective film 20 is adhered to the hard coating layer 11 of the polarizing plate 10 via the adhesive layer 22.

[0017] Figure 2 is a schematic cross-sectional view of a polarizing plate with a surface protective film according to another embodiment of the present invention. The polarizing plate 100B with the surface protective film includes: a polarizing plate 10 having, in sequence, a hard coating layer 11, a protective layer 12, a polarizing element 13, and a first retardation layer 15; and a surface protective film 20 having a substrate layer 21 and an adhesive layer 22 disposed on one side of the substrate layer 21. The surface protective film 20 is adhered to the hard coating layer 11 of the polarizing plate 10 via the adhesive layer 22.

[0018] Figure 3 is a schematic cross-sectional view of a polarizing plate with a surface protective film according to another embodiment of the present invention. The polarizing plate 100C with the surface protective film includes: a polarizing plate 10 having, in sequence, a hard coating layer 11, a protective layer 12, a polarizing element 13, a first retardation layer 15, and a second retardation layer 16; and a surface protective film 20 having a substrate layer 21 and an adhesive layer 22 disposed on one side of the substrate layer 21. The surface protective film 20 is adhered to the hard coating layer 11 of the polarizing plate 10 via the adhesive layer 22.

[0019] In the example shown, the lamination of the protective layer 12 and the polarizing element 13, the lamination of the polarizing element 13 and the first retardation layer 15, and the lamination of the first retardation layer 15 and the second retardation layer 16 are performed via bonding layers 14a, 14b, and 14c, respectively. However, these laminations can also be performed directly without bonding layers, depending on the purpose. Furthermore, in the example shown, the protective layer is provided only on one side (the viewing side) of the polarizing element 13, but protective layers can also be provided on both sides of the polarizing element as needed.

[0020] Although not illustrated, an adhesive layer for attaching the polarizing plate to adjacent optical components may be provided on the outermost layer of the polarizing plate side of the polarizing plate with a surface protective film. In this case, the adhesive layer can be protected by a peel-off pad until it is ready for use.

[0021] When the protective film on the polarizing plate of the present invention is peeled at a peeling speed of 0.3 m / min, a peeling temperature of 23°C, and a peeling angle of 180°, the peeling force is preferably 0.2 N / 25 mm or less, more preferably 0.02 N / 25 mm to 0.18 N / 25 mm, and even more preferably 0.1 N / 25 mm to 0.15 N / 25 mm. If the peeling force is within this range, the surface of the polarizing plate can be properly protected while the protective film is temporarily adhered to it, and it can be easily peeled off during peeling.

[0022] B.Polarizing plate The polarizing plate has a hard coating, a protective layer, and a polarizing element in sequence. The polarizing plate may further have a phase retardation layer as needed.

[0023] B-1. Polarizing element Polarizing elements typically comprise a polyvinyl alcohol-based resin film containing a dichroic substance (such as iodine). Polarizing elements can be made of a single layer of resin film or fabricated using two or more layers in a laminate.

[0024] Specific examples of polarizing elements composed of a single-layer resin film include polarizing elements obtained by dyeing and stretching hydrophilic polymer films such as polyvinyl alcohol (PVA)-based resin films, partially formalized PVA-based resin films, and partially saponified ethylene-vinyl acetate copolymer films using dichroic substances such as iodine or dichroic dyes; and polyene-based alignment films such as dehydrated PVA products or dehydrochlorinated polyvinyl chloride products. Due to their superior optical properties, polarizing elements obtained by dyeing PVA-based resin films with iodine and then uniaxially stretching them are preferred.

[0025] The aforementioned dyeing using iodine can be performed, for example, by immersing the PVA-based resin film in an aqueous iodine solution. The preferred uniaxial stretching ratio is 3 to 7 times. Stretching can be performed after dyeing, or simultaneously with dyeing. Alternatively, dyeing can be performed after stretching. Depending on the requirements, the PVA-based resin film can undergo swelling, crosslinking, cleaning, and drying treatments. For example, by immersing the PVA-based film in water for washing before dyeing, not only can dirt or anti-blocking agents on the surface of the PVA-based resin film be cleaned, but the PVA-based resin film can also swell to prevent uneven dyeing.

[0026] As a specific example of a polarizing element obtained using a laminate, examples include a laminate consisting of a resin substrate and a PVA-based resin layer (PVA-based resin film) deposited on the resin substrate, or a laminate consisting of a resin substrate and a PVA-based resin layer coated on the resin substrate. A polarizing element obtained using a laminate consisting of a resin substrate and a PVA-based resin layer coated on the resin substrate can be manufactured, for example, by: coating a PVA-based resin solution onto a resin substrate and drying it to form a PVA-based resin layer on the resin substrate, thus obtaining a laminate of the resin substrate and the PVA-based resin layer; stretching and dyeing the laminate to form a polarizing element from the PVA-based resin layer. In this embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Furthermore, stretching may, as needed, include air stretching of the laminate at a high temperature (e.g., above 95°C) prior to stretching in the aqueous boric acid solution. The obtained resin substrate / polarizing element laminate can be used directly (i.e., the resin substrate can be used to form a protective layer for the polarizing element), or the resin substrate can be peeled off from the resin substrate / polarizing element laminate, and any suitable protective layer corresponding to the purpose can be laminated on the peeled surface for use. Detailed description of such a method for manufacturing a polarizing element is described, for example, in Japanese Patent Application Publication No. 2012-73580. The entire contents of that publication are incorporated herein by reference.

[0027] The thickness of the polarizing element is, for example, less than 30 μm, preferably less than 15 μm, more preferably 1 μm to 12 μm, even more preferably 2 μm to 10 μm, and even more preferably 2 μm to 8 μm.

[0028] The polarizing element preferably exhibits absorption dichroism at any wavelength from 380 nm to 780 nm. The transmittance of the polarizing element is, for example, 41.0% or more, preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The polarization degree of the polarizing element is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0029] B-2. Protective layer The protective layer comprises any suitable film that can be used as a protective layer for a polarizing element. Specific examples of materials that form the main component of the film include cellulose resins such as triacetyl cellulose (TAC), or transparent resins such as polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polyether ether, polyurethane, polystyrene, polynorphine, polyolefin, (meth)acrylic acid, and acetate. Also, examples include thermosetting or UV-curing resins such as (meth)acrylic acid, urethane, (meth)acrylate urethane, epoxy, and silicone. In addition, examples include glassy polymers such as silicate polymers. Furthermore, polymer films described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As the material for this membrane, for example, a resin composition containing a thermoplastic resin having substituted or unsubstituted amide groups on the side chains, and a thermoplastic resin having substituted or unsubstituted phenyl and nitrile groups on the side chains can be used. Examples include resin compositions containing alternating copolymers of isobutylene and N-methylmaleimide, and acrylonitrile-styrene copolymers. The polymer membrane can, for example, be an extruded product of the above resin composition.

[0030] When the polarizing plate is applied to an image display device, the thickness of the protective layer (viewing-side protective layer 12) disposed on the side opposite to the display element is typically 300 μm or less, preferably 100 μm or less, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 60 μm.

[0031] When a polarizing plate is applied to an image display device, the thickness of the protective layer (inner protective layer) disposed on the side of the display element is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm, and even more preferably 10 μm to 60 μm.

[0032] In one embodiment, the inner protective layer is optically isotropic. In this specification, "optically isotropic" means that the in-plane phase difference Re(550) of the phase difference layer is 0 nm to 10 nm, and the phase difference Rth(550) in the thickness direction is -10 nm to +10 nm.

[0033] B-3. ​​Hard coating A hard coating is disposed on the viewing side of the viewing-side protective layer, forming the outermost layer on the viewing side of the polarizing plate. Typically, the hard coating can be formed directly on the viewing-side surface of the viewing-side protective layer.

[0034] The hard coating can be a hardened body (hardened resin) of a hardening composition or a molded body of a thermoplastic composition, preferably a hardened body of a hardening composition.

[0035] The hardening composition for forming a hard coating (hereinafter referred to as the hard coating forming composition) contains a hardening compound and an ultraviolet absorber.

[0036] Examples of curing compounds included in compositions for forming hard coatings include thermosetting compounds, ultraviolet-curing compounds, and electron beam-curing compounds. Types of curing compounds include polyester-based, acrylic-based, urethane-based, acrylate-based, amide-based, silicone-based, silicate-based, epoxy-based, melamine-based, oxetane-based, and acrylate-based compounds. Only one of these curing compounds may be used, or two or more may be used in combination.

[0037] Among these, compounds with high hardness, ability to be UV-cured, and excellent manufacturability are preferably acrylic, acrylate, and epoxy compounds, with acrylate compounds being the most preferred. UV-curable compounds include UV-curable monomers, oligomers, and polymers.

[0038] Specific examples of curable compounds include acrylic compounds (monomers and / or oligomers) having a plurality of UV-polymerizable functional groups, and preferably curable compounds having a plurality of (meth)acrylic groups. The number of functional groups ((meth)acrylic groups) in the curable compound is, for example, 3 or more, preferably 5 or more, and, for example, 30 or less, preferably 20 or less. The curable compound preferably further includes hydroxyl groups within its molecule.

[0039] Examples of curing compounds that can be used as monomers include: tricyclodecanediethanol diacrylate, tetrapentanetetrapentanetetradecane di(meth)acrylate, tetrapentanetetradecane tri(meth)acrylate, trimethylolpropane triacrylate, tetrapentanetetradecane tetra(meth)acrylate, dimethylolpropane tetraacrylate, ditetrapentanetetradecane hexa(meth)acrylate, 1,6-hexanediol (meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, dipropylene glycol diacrylate, isocyanurate tri(meth)acrylate, ethoxylated glycerol tri(meth)acrylate, ethoxylated tetrapentanetetradecane tetraacrylate, and oligomers or prepolymers thereof. These curing compounds can be used alone or in combination in multiples.

[0040] Examples of curable compounds that are monomers or oligomers include, for example, urethane (meth)acrylates and / or oligomers of urethane (meth)acrylates. The number of (meth)acrylic groups in the urethane (meth)acrylates and / or oligomers of urethane (meth)acrylates is, for example, 3 or more, preferably 4 or more, more preferably 6 or more, and, for example, 25 or less, preferably 20 or less.

[0041] The weight average molecular weight (or theoretical molecular weight) of urethane (meth)acrylate and / or urethane (meth)acrylate oligomers is, for example, 3000 or less, preferably 2500 or less, more preferably 2000 or less, and also, for example, 500 or more, preferably 800 or more. Furthermore, when the urethane (meth)acrylate and / or urethane (meth)acrylate oligomers are commercially available products, the theoretical molecular weight listed in the catalog accompanying the commercially available product shall be used.

[0042] As a UV absorber, any suitable UV absorber can be used as long as it is a compound that absorbs ultraviolet light (e.g., wavelength 355 nm). Examples of UV absorbers include: benzotriazole UV absorbers, benzophenone UV absorbers, triterpenoid UV absorbers, salicylate UV absorbers, and cyanoacrylate UV absorbers. Among these, triterpenoid UV absorbers or benzotriazole UV absorbers are preferred, and triterpenoid UV absorbers are especially preferred. Triterpenoid UV absorbers are more preferably composed of compounds containing hydroxyl groups, and especially preferably UV absorbers composed of hydroxyphenyl triterpenoid compounds (hydroxyphenyl triterpenoid UV absorbers). Only one UV absorber may be used, or two or more may be used in combination.

[0043] Examples of hydroxyphenyl triterpenoid UV absorbers include: the reaction product of 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triterpenoid-2-yl)-5-hydroxyphenyl with [(C10-C16 (mainly C12-C13)alkoxy)methyl]ethylene oxide (trade name "TINUVIN 400", manufactured by BASF); 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triterpenoid-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol; and the reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triterpenoid with (2-ethylhexyl) glycidyl acid (trade name "TINUVIN"). 405 (manufactured by BASF), 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-tris(Hexyl)oxy]phenol (trade name "TINUVIN 460", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-tris(Hexyl)oxy]phenol (trade name "TINUVIN 1577", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-tris(Hexyl)oxy]phenol (trade name "Adekastab") LA-46 (manufactured by ADEKA), 2-(2-hydroxy-4-[1-octoxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triphenylamine (trade name "TINUVIN 479", manufactured by BASF), and BASF's trade name "TINUVIN 477", etc.

[0044] Examples of benzotriazole-based ultraviolet absorbers (benzotriazole compounds) include: 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (trade name "TINUVIN PS", manufactured by BASF), phenylpropane acid and ester compounds of 3-(2H-benzotriazole-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy (C7-9 side chain and straight-chain alkyl) (trade name "TINUVIN 384-2", manufactured by BASF), and a mixture of octyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate and 2-ethylhexyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate (trade name "TINUVIN"). 109 (manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN 900", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (trade name "TINUVIN 928", manufactured by BASF), the reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300 (trade name "TINUVIN 1130", manufactured by BASF), 2-(2H-benzotriazol-2-yl)p-cresol (trade name "TINUVIN") P, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN 234", manufactured by BASF), 2-[5-chloro-2H-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (trade name "TINUVIN 326", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-ditert-pentylphenol (trade name "TINUVIN 328", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (trade name "TINUVIN 329", manufactured by BASF), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3,[3-Tetramethylbutyl)phenol] (trade name "TINUVIN 360", manufactured by BASF), methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate reacting with polyethylene glycol 300 (trade name "TINUVIN 213", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (trade name "TINUVIN 571", manufactured by BASF), 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimide-methyl)-5-methylphenyl]benzotriazole (trade name "Sumisorb 250", manufactured by Sumitomo Chemical), 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole (trade name "SEESORB") 703 (manufactured by SHIPRO KASEI), 2-(2H-benzotriazol-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalimylmethyl)phenol (trade name "SEESORB 706", manufactured by SHIPRO KASEI), 2-(4-benzoyloxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole (manufactured by SHIPRO KASEI, trade name "SEESORB 7012BA"), 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (trade name "KEMISORB 73", manufactured by CHEMIPRO KASEI), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] (trade name "Adekastab") Products include: LA-31 (manufactured by ADEKA), 2-(2H-benzotriazol-2-yl)-p-cellulose (trade name "Adekastab LA-32", manufactured by ADEKA), and 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol (trade name "Adekastab LA-36", manufactured by ADEKA), etc.

[0045] The molecular weight of the ultraviolet absorber is preferably 100-1500, more preferably 200-1200, and even more preferably 200-1000. If a compound with a smaller molecular weight (e.g., a compound with a molecular weight of less than 600) is used as the ultraviolet absorber, the ultraviolet absorber tends to aggregate near the surface.

[0046] Relative to 100 parts by weight of the curing compound, the content of the ultraviolet absorber is, for example, 0.1 parts by weight to 3.0 parts by weight, preferably 0.5 parts by weight to 2.5 parts by weight, and more preferably 1.0 parts by weight to 2.0 parts by weight. If the content is within this range, the influence of ultraviolet rays on polarizing elements and display elements can be suppressed, and a hard coating with the desired hardness can be obtained.

[0047] In addition to the curing compound and the ultraviolet absorber, the composition for forming a hard coating may further contain any other suitable components, depending on the purpose. Examples of such other components include polymerization initiators, leveling agents, anti-blocking agents, dispersion stabilizers, thixotropic agents, and antioxidants. There may be only one such additive or two or more. The type, combination, and content of the additives can be appropriately set according to the purpose or desired characteristics.

[0048] A hard coating can be formed by applying a hard coating forming composition to one side of a protective layer and then performing a curing treatment. Examples of curing treatments include irradiation with active energy lines such as ultraviolet light or heat treatment. In the case of ultraviolet light irradiation, the cumulative light intensity can be 200 mJ to 400 mJ. Furthermore, after the hard coating is formed, surface treatments such as corona treatment or plasma treatment can be applied to the hard coating.

[0049] The hardness of the pencil with the hard coating is, for example, F or higher, more preferably H or higher, and even more preferably 2H or higher.

[0050] The thickness of the hard coating is, for example, 1 μm to 30 μm, preferably 3 μm to 15 μm, and even more preferably 5 μm to 12 μm.

[0051] B-4. First Phase Difference Layer The first retardation layer can have any suitable optical properties depending on the purpose. Preferably, the first retardation layer exhibits a refractive index characteristic showing the relationship nx > ny ≥ nz. Furthermore, here, "ny = nz" includes not only the case where ny and nz are exactly equal, but also the case where they are substantially equal. Therefore, without impairing the effects of the invention, ny can sometimes be... <nz。

[0052] In one embodiment, the first phase difference layer can function as a λ / 4 plate. In this case, the in-plane phase difference Re(550) of the first phase difference layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and even more preferably 130 nm to 160 nm.

[0053] In one embodiment, the angle θ between the slow axis of the first retardation layer and the absorption axis of the polarizing element is, for example, 40° to 50°, more preferably 42° to 48°, and even more preferably about 45°. If the angle θ is in this range, a polarizing plate with a retardation layer can be obtained by fabricating the first retardation layer into a λ / 4 plate, which has very excellent circular polarization characteristics (resulting in very excellent anti-reflection characteristics).

[0054] The Nz coefficient of the first phase retardation layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, even more preferably 0.9 to 1.5, and most preferably 0.9 to 1.3. By satisfying this relationship, when the obtained polarizing plate with the phase retardation layer is used in an image display device, very excellent reflective hue can be achieved.

[0055] The first phase retardation layer can exhibit inverse wavelength dispersion characteristics, where the phase difference value increases accordingly with the wavelength of the measurement light; it can also exhibit positive wavelength dispersion characteristics, where the phase difference value decreases accordingly with the wavelength of the measurement light; or it can exhibit flat wavelength dispersion characteristics, where the phase difference value hardly changes with the wavelength of the measurement light. In one embodiment, the first phase retardation layer exhibits inverse wavelength dispersion characteristics. In this case, the Re(450) / Re(550) of the phase retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and less than 0.95. With this configuration, very excellent anti-reflection characteristics can be achieved.

[0056] The first phase retardation layer comprises a resin with an absolute value of photoelasticity coefficient preferably below 2×10⁻¹¹ m² / N, more preferably 2.0×10⁻¹³ m² / N to 1.5×10⁻¹¹ m² / N, and even more preferably 1.0×10⁻¹² m² / N to 1.2×10⁻¹¹ m² / N. If the absolute value of the photoelasticity coefficient is within this range, phase difference changes are less likely to occur when shrinkage stress is generated during heating. As a result, thermal unevenness in the acquired image display device can be effectively prevented.

[0057] The first retardation layer can be an extension film of a resin film or a liquid crystal alignment and curing layer. The thickness of the first retardation layer, which includes the extension film of the resin film, is preferably 70 μm or less, more preferably 45 μm to 60 μm. If the thickness of the first retardation layer is within this range, curling during heating can be effectively suppressed, and curling during bonding can be effectively adjusted. Furthermore, as described later, in embodiments where the first retardation layer includes a polycarbonate-based resin film, the thickness of the first retardation layer is preferably 40 μm or less, more preferably 10 μm to 40 μm, and even more preferably 20 μm to 30 μm. By including a polycarbonate-based resin film of this thickness in the first retardation layer, curling can be suppressed, and it also contributes to improved bending durability and reflective hue.

[0058] Representative examples of resins capable of forming the first retardation layer include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins. These resins can be used alone or in combination (e.g., blending, copolymerization). When the first retardation layer comprises a resin film exhibiting inverse wavelength dispersion characteristics, polycarbonate resins or polyester carbonate resins (hereinafter sometimes simply referred to as polycarbonate resins) can be appropriately used.

[0059] As the aforementioned polycarbonate resin, any suitable polycarbonate resin can be used as long as the effects of the present invention are achieved. For example, the polycarbonate resin comprises structural units from genus dihydroxy compounds, structural units from isosorbide dihydroxy compounds, and structural units from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic diethanols, diethylene glycol, triethylene glycol, or polyethylene glycol, and alkyl diols or spirodiols. Preferably, the polycarbonate resin comprises structural units from genus dihydroxy compounds, structural units from isosorbide dihydroxy compounds, structural units from alicyclic diethanols, and / or structural units from diethylene glycol, triethylene glycol, or polyethylene glycol; more preferably, it comprises structural units from genus dihydroxy compounds, structural units from isosorbide dihydroxy compounds, and structural units from diethylene glycol, triethylene glycol, or polyethylene glycol. The polycarbonate resin may, as needed, contain structural units derived from other dihydroxy compounds. Furthermore, details of the polycarbonate resin suitable for use in this invention are described, for example, in Japanese Patent Application Publication Nos. 2014-10291, 2014-26266, 2015-212816, 2015-212817, and 2015-212818, which are incorporated herein by reference.

[0060] The preferred glass transition temperature of the aforementioned polycarbonate resin is between 110°C and 150°C, and more preferably between 120°C and 140°C. If the glass transition temperature is too low, the heat resistance tends to deteriorate, which may cause dimensional changes after film formation, and may also sometimes reduce the image quality of the applied image display device. If the glass transition temperature is too high, the forming stability during film formation may sometimes deteriorate, and may also impair the transparency of the film. Furthermore, the glass transition temperature is determined according to JIS K 7121 (1987).

[0061] The molecular weight of the aforementioned polycarbonate resin can be expressed by its reduced viscosity. Reduced viscosity is measured using dichloromethane as a solvent, with the polycarbonate concentration precisely prepared to 0.6 g / dL, and at a temperature of 20.0℃ ± 0.1℃ using an Ubbelohde viscometer. The lower limit of reduced viscosity is generally preferably 0.30 dL / g, more preferably 0.35 dL / g or higher. The upper limit of reduced viscosity is generally preferably 1.20 dL / g, more preferably 1.00 dL / g, and even more preferably 0.80 dL / g. When the reduced viscosity is less than the above lower limit, the mechanical strength of the molded article may decrease. On the other hand, when the reduced viscosity is greater than the above upper limit, the flowability during molding may decrease, leading to reduced productivity or formability.

[0062] As a polycarbonate-based resin film, commercially available films can be used. Specific examples of commercially available products include the products manufactured by Teijin Corporation under the brand names "PURE-ACE WR-S", "PURE-ACE WR-W", and "PURE-ACE WR-M", and the product manufactured by Nitto Denko Corporation under the brand name "NRF".

[0063] The first retardation layer is obtained, for example, by stretching a film formed from the aforementioned polycarbonate resin. Any suitable forming process can be used as a method for forming the film from the polycarbonate resin. Specific examples include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP (Fiber Reinforced Plastics) molding, casting (e.g., casting), calendering, and hot pressing. Extrusion molding or casting is preferred because it improves the smoothness of the obtained film and achieves good optical uniformity. The forming conditions can be appropriately set according to the composition and type of the resin used, and the desired characteristics of the retardation layer. Furthermore, as mentioned above, a large number of commercially available film products made from polycarbonate resins are available, so these commercially available films can be directly used for stretching.

[0064] The thickness of the resin film (unstretched film) can be set to any appropriate value based on the desired thickness of the first retardation layer, the desired optical properties, stretching conditions, etc. Preferably, it is 50 μm to 300 μm.

[0065] The aforementioned stretching can be performed using any suitable stretching method and under appropriate conditions (e.g., stretching temperature, stretching ratio, stretching direction). Specifically, various stretching methods such as free-end stretching, fixed-end stretching, free-end shrinkage, and fixed-end shrinkage can be used individually, or these methods can be used simultaneously or sequentially. Regarding the stretching direction, it can be performed in various directions or dimensions such as the length direction, width direction, thickness direction, and oblique direction. The stretching temperature relative to the glass transition temperature (Tg) of the resin film is preferably Tg-30℃ to Tg+60℃, more preferably Tg-10℃ to Tg+50℃.

[0066] By appropriately selecting the above-mentioned extension methods and conditions, it is possible to obtain a phase retardation film with the desired optical properties (e.g., refractive index characteristics, in-plane phase difference, Nz coefficient).

[0067] B-5. Second phase difference layer The second retardation layer can be, for example, a positive C-plate whose refractive index characteristics show a relationship of nz > nx = ny. By using a positive C-plate as the second retardation layer, oblique reflections can be effectively prevented, and a wide viewing angle of anti-reflection function can be achieved. In this case, the phase difference Rth(550) in the thickness direction of the second retardation layer is preferably -50 nm to -300 nm, more preferably -70 nm to -250 nm, further preferably -90 nm to -200 nm, and even more 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 retardation layer may not reach 10 nm.

[0068] The second retardation layer, having a refractive index characteristic of nz>nx=ny, can be formed from any suitable material. The second retardation layer is preferably a film containing a liquid crystal material fixed in a perpendicular alignment. The perpendicularly aligned liquid crystal material (liquid crystal compound) can be a liquid crystal monomer or a liquid crystal polymer. As a specific example of the liquid crystal compound and the method for forming the retardation layer, the liquid crystal compound and the method for forming the retardation layer described in Japanese Patent Application Publication Nos. 2002-333642

[0020] to

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

[0069] B-6. Next layer As an adhesive layer, any suitable adhesive or bonding agent layer that can be applied to optical applications can be used.

[0070] C. Surface protective film C-1. Substrate layer The substrate layer is, for example, a resin film. Examples of materials constituting the resin film include: polyester, polyolefin, polyamide, polyimide, polycarbonate, polyacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, and polyvinyl fluoride. Examples of polyesters include: polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. Examples of polyolefins include: polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylate copolymer, and ethylene-vinyl alcohol copolymer. Examples of polyamides include: nylon 6, nylon 6,6, and some aromatic polyamides. The substrate layer may contain one material or two or more materials. The substrate layer may have a single-layer structure or a multi-layer structure. Furthermore, when the substrate layer is a resin film, the substrate layer can be an extended film or an unextended film.

[0071] The thickness of the substrate layer is, for example, 10 μm to 200 μm, preferably 15 μm to 150 μm, more preferably 20 μm to 100 μm, and even more preferably 25 μm to 75 μm. If the thickness is within this range, the strength of the support in the surface protective film can be ensured, and a surface protective film with appropriate flexibility can be obtained.

[0072] C-2. Adhesive layer The adhesive layer is formed from an adhesive composition comprising a base polymer having reactive functional groups and an isocyanate-based crosslinking agent. The reactive functional groups of the base polymer are functional groups capable of reacting with the isocyanate-based crosslinking agent. By reacting with the isocyanate-based crosslinking agent, a crosslinked structure is formed in the base polymer, thereby obtaining an adhesive layer with the desired adhesive properties.

[0073] The thickness of the adhesive layer is, for example, 1 μm to 50 μm, preferably 2 μm to 30 μm, and even more preferably 5 μm to 25 μm.

[0074] C-2-1. Basic polymers with reactive functional groups Specific examples of base polymers with reactive functional groups include acrylic polymers, carbamate polymers, and silicone polymers. Among these, acrylic polymers are preferred as base polymers for their reactive functional groups, considering both transparency and freedom in adhesive design. Only one type of base polymer can be used, or two or more can be used in combination.

[0075] The aforementioned base polymer may have reactive functional groups in its main chain or side chain. The reactive functional groups in the base polymer can be any functional groups containing active hydrogen capable of reacting with the isocyanate-based crosslinking agent (B), with hydroxyl and carboxyl groups being preferred examples.

[0076] As an acrylic polymer with reactive functional groups, an acrylic polymer with (meth)acrylate monomer units as the main backbone is preferably used. Such an acrylic polymer can be obtained, for example, by copolymerizing a monomer component containing (meth)acrylate and a monomer containing reactive functional groups (hereinafter, sometimes referred to as "reactive functional group-containing monomer"). Furthermore, in this specification, "(meth)acrylate" refers to acrylic acid and / or methacrylic acid.

[0077] As the aforementioned alkyl methacrylates, alkyl methacrylates having an alkyl group having 4 to 12 carbon atoms are preferred. Specific examples include: butyl methacrylate, isobutyl methacrylate, tributyl methacrylate, pentyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecanyl methacrylate, undecyl methacrylate, and dodecyl methacrylate. Alkyl methacrylates having an alkyl group having 4 to 12 carbon atoms may be used alone or in combination of two or more.

[0078] The content of alkyl (meth)acrylates having 4 to 12 carbon atoms is preferably 70% to 99.9% by weight, more preferably 80% to 99.5% by weight, and even more preferably 85% to 99% by weight, relative to the total amount of monomer components constituting acrylic polymers.

[0079] As the aforementioned monomers containing reactive functional groups, monomers with functional groups containing active hydrogen, such as hydroxyl or carboxyl groups, can be used. Specific examples include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylaurate (meth)acrylate, [4-(hydroxymethyl)cyclohexyl]methyl acrylate, and other hydroxyalkyl (meth)acrylate monomers containing hydroxyl groups; (meth)acrylate, iconic acid, maleic acid, β-carboxyethyl acrylate, and other carboxyl-containing monomers; N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-(2) N-(2-hydroxyethyl)acrylamide, N-(2-hydroxyethyl)methacrylamide, N-(2-hydroxypropyl)acrylamide, N-(2-hydroxypropyl)methacrylamide, N-(1-hydroxypropyl)acrylamide, N-(1-hydroxypropyl)methacrylamide, N-(3-hydroxypropyl)acrylamide, N-(3-hydroxypropyl)methacrylamide, N-(2-hydroxybutyl)acrylamide, N-(2-hydroxybutyl)methacrylamide, N-(3-hydroxybutyl)acrylamide, N-(3-hydroxybutyl)methacrylamide, N-(4-hydroxybutyl)acrylamide, N-(4-hydroxybutyl)methacrylamide, and other N-hydroxyalkyl (methyl)acrylamides. Monomers containing reactive functional groups can be used alone or in combination of two or more.

[0080] The content of reactive functional group monomers relative to the total amount of monomer components constituting acrylic polymers is preferably 0.1% to 30% by weight, more preferably 0.5% to 20% by weight, and even more preferably 1% to 15% by weight.

[0081] The monomer components constituting acrylic polymers may further include alkyl (meth)acrylates having alkyl groups with 4 to 12 carbon atoms and other monomers other than monomers containing reactive functional groups (hereinafter, sometimes referred to as "other comonomers"). Only one other comonomer may be used, or two or more may be used in combination.

[0082] Examples of other comonomers mentioned above include alkyl (meth)acrylates having alkyl groups other than 4 to 12 carbon atoms. Specific examples of alkyl (meth)acrylates having alkyl groups other than 4 to 12 carbon atoms include: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecanyl (meth)acrylate, octadecyl (meth)acrylate, nonadecanyl (meth)acrylate, eicosyl (meth)acrylate, etc.

[0083] Other specific examples of the aforementioned comonomers include: cyclic (meth)acrylamides such as N-(meth)acrylamide, N-acrylamide pyrrolidine; (meth)acrylamides, N-substituted (meth)acrylamides (e.g., N-ethyl(meth)acrylamide, N-n-butyl(meth)acrylamide, and other N-alkyl(meth)acrylamides); N,N-dimethyl(meth)acrylamide... Acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, N,N-di(tert-butyl)(meth)acrylamide, and other N,N-dialkyl(meth)acrylamides are noncyclic (meth)acrylamides; N-vinyl-2 N-vinylcyclic amides such as pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-hydroxylone, N-vinyl-2-caprolactone, N-vinyl-1,3-vinyl-2-one, and N-vinyl-3,5-hydroxylone; and aminoethyl methacrylate, N,N-dimethylaminoethyl methacrylate, and N,N-dimethyl methacrylate. Monomers containing amino groups, such as aminopropyl ester; monomers with maleimide skeletons, such as N-cyclohexylmaleimide and N-phenylmaleimide; and nitrogen-containing monomers such as N-methyl-iconimidinide, N-ethyl-iconimidinide, N-butyl-iconimidinide, N-2-ethylhexyl-iconimidinide, N-lauryl-iconimidinide, and N-cyclohexyl-iconimidinide.

[0084] Other specific examples of the aforementioned comonomers include: epoxy-containing monomers such as glycidyl methacrylate and allyl glycidyl ether; alkoxy-containing monomers such as methoxyethyl methacrylate, methoxypropyl methacrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; cyano-containing monomers such as acrylonitrile and methacrylonitrile; styrene-based monomers such as styrene and α-methylstyrene; α-olefins such as ethylene, propylene, isoprene, butadiene, and isobutylene; isocyanate-containing monomers such as 2-methacryloyloxyethyl isocyanate; vinyl ester-based monomers such as vinyl acetate and vinyl propionate; and vinyl ether-based monomers such as vinyl ethers. (Meth)acrylates containing heterocyclic rings, such as tetrahydrofurfuryl methacrylate; monomers containing halogen atoms, such as fluoro(meth)acrylates; monomers containing alkoxysilyl groups, such as 3-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane; monomers containing siloxane bonds, such as silicone (meth)acrylates; (meth)acrylates containing alicyclic hydrocarbon groups, such as cyclopentyl methacrylate, cyclohexyl methacrylate, methyl methacrylate, and isomethyl methacrylate; (meth)acrylates containing aromatic hydrocarbon groups, such as phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, and phenoxydiethylene glycol (meth)acrylate.

[0085] Other specific examples of the aforementioned comonomers include: ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, tetrapentyltetramethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetrapentyltetramethylene glycol tri(meth)acrylate, ditetrapentyltetramethylene glycol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, divinylbenzene, butyl di(meth)acrylate, and hexyl di(meth)acrylate, among other multifunctional monomers.

[0086] The content of the other comonomers mentioned above is preferably 29.9% by weight or less, more preferably 19.5% by weight or less, and even more preferably 14% by weight or less, relative to the total amount of monomer components constituting the acrylic polymer.

[0087] The weight-average molecular weight (Mw) of the aforementioned acrylic polymers is preferably 100,000 to 3,000,000, more preferably 200,000 to 2,000,000, and even more preferably 300,000 to 1,500,000. The weight-average molecular weight (Mw) refers to the value converted from standard polystyrene obtained by GPC (gel permeation chromatography). For example, a GPC apparatus named "HLC-8320GPC" (column: TSKgel GMH-H(S), manufactured by Tosoh Corporation) can be used.

[0088] The glass transition temperature (Tg) of the aforementioned acrylic polymers is preferably below 0°C (typically above -100°C), more preferably below -10°C, and even more preferably below -20°C. The glass transition temperature can be determined using a dynamic viscoelastic apparatus or calculated based on the FOX formula.

[0089] There are no particular limitations on the polymerization method of the aforementioned acrylic polymers; polymerization can be carried out using known methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization. Furthermore, the obtained copolymer can be either a random copolymer or a block copolymer.

[0090] The aforementioned urethane polymers with reactive functional groups are urethane polymers having functional groups on the main chain or side chain that can react with isocyanate crosslinking agents. Examples of such urethane polymers include urethane polymers (urethane resins) obtained by reacting a polyol with a polyisocyanate compound.

[0091] The aforementioned silicone polymers with reactive functional groups are silicone polymers that have functional groups on the main chain or side chain that can react with isocyanate-based crosslinking agents. Preferably, such silicone polymers are those obtained by blending or agglomerating silicone polymers (silicone resins).

[0092] The content of the base polymer with reactive functional groups in the adhesive layer (in other words, the adhesive composition after the solvent has been dried and removed) is, for example, 50% by weight or more, preferably 60% by weight or more, and more preferably 70% by weight or more. There is no particular upper limit to the content of the base polymer; for example, the total content of the base polymer and the isocyanate crosslinking agent can be 100% by weight of the adhesive layer.

[0093] C-2-2. Isocyanate-based crosslinking agent As an isocyanate-based crosslinking agent, it is used for polyisocyanates having two or more isocyanate groups in one molecule. Specific examples include: aliphatic polyisocyanates such as trimethylene diisocyanate, butyl diisocyanate, hexamethylene diisocyanate (HDI), and dimer diisocyanate; alicyclic isocyanates such as cyclopentyl diisocyanate, cyclohexyl diisocyanate, and isophorone diisocyanate (IPDI); alicyclic isocyanates such as 1,3-bis(isocyanomethyl)cyclohexane; aromatic isocyanates such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and phenyl dimethyl diisocyanate (XDI); and polyisocyanate modified forms obtained by modifying the above isocyanate compounds with urea-formate bonds, biuret bonds, isocyanurate bonds, urea-dione bonds, urea bonds, carbodiimide bonds, urea-ketimide bonds, and acetyltrione bonds. One isocyanate crosslinking agent can be used alone, or two or more can be used in combination. Alternatively, difunctional isocyanate compounds can be used in combination with trifunctional or higher isocyanate compounds.

[0094] As isocyanate-based crosslinking agents, commercially available products such as Takenate 300S, Takenate 500, Takenate 600, Takenate D165N, Takenate D178N (and above, manufactured by Mitsui Chemicals), Sumidur T80, Sumidur L, Desmodur N3400 (and above, manufactured by Sumika Bayer Urethane), Millionate MR, Millionate MT, Coronate L, Coronate HL, and Coronate HX (and above, manufactured by Tosoh Corporation) can be used.

[0095] The content of the isocyanate-based crosslinking agent in the adhesive layer is typically 2 to 5 parts by weight relative to 100 parts by weight of the base polymer with reactive functional groups, preferably 2 to 3.5 parts by weight, more preferably 2 to 3 parts by weight, and even more preferably 2 to 2.5 parts by weight. Furthermore, the ratio of the molar equivalent of the isocyanate groups of the base polymer to the molar equivalent of the reactive functional groups in the adhesive layer is preferably, for example, 0.05 to 1.5, or for example, 0.07 to 1.3. If the content of the crosslinking agent in the adhesive layer is within this range, a surface protective film that can suppress contamination of the hard coating surface during peeling and can be easily peeled off without paste residue can be obtained.

[0096] C-2-3. Other ingredients In the adhesive composition forming the adhesive layer, in addition to the base polymer having reactive functional groups and the isocyanate-based crosslinking agent mentioned above, any other suitable components may be included, depending on the purpose.

[0097] Other components mentioned above may include: polymerization catalysts, crosslinking catalysts, solvents, antistatic agents, surfactants, silane coupling agents, adhesive agents, plasticizers, softeners, deterioration inhibitors, fillers, colorants, ultraviolet absorbers, antioxidants, etc.

[0098] Examples of antistatic agents include: cationic antistatic agents with cationic functional groups (such as primary, secondary, and tertiary amino groups), such as quaternary ammonium salts and pyridinium salts; anionic antistatic agents with anionic functional groups, such as sulfonates, sulfates, phosphonates, and phosphates; zwitterionic antistatic agents, such as alkyl betaines and their derivatives, imidazolines and their derivatives, and alanine and its derivatives; nonionic antistatic agents, such as amino alcohols and their derivatives, glycerol and its derivatives, and polyethylene glycol and its derivatives; and ionicly conductive polymers obtained by polymerizing or copolymerizing monomers with ionicly conductive groups, as represented by the above-mentioned cationic, anionic, and zwitterionic antistatic agents. Only one antistatic agent may be used, or two or more may be used in combination.

[0099] The content of the antistatic agent relative to 100 parts by weight of the base polymer having reactive functional groups is, for example, 0.01 parts by weight to 30 parts by weight, more preferably 0.02 parts by weight to 20 parts by weight, and even more preferably 0.03 parts by weight to 10 parts by weight.

[0100] Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and biionic surfactants. Among these, nonionic surfactants, anionic surfactants, and cationic surfactants are preferred. Only one type of surfactant may be used, or two or more may be used in combination.

[0101] Examples of nonionic surfactants include: polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, and polyoxyethylene sorbitan monolaurate; polyoxyethylene glycerol ether fatty acid esters; polyoxyethylene-polyoxypropylene block copolymers; saturated fatty acid esters such as ethyl octanoate, ethyl decanoate, methyl laurate, butyl laurate, methyl myristate, isopropyl myristate, methyl palmitate, isopropyl palmitate, methyl stearate, butyl stearate, methyl betaine, butyl laurate, butyl stearate, isopropyl myristate, and isopropyl palmitate; and fatty acid amides such as laurylamine, palmitamide, stearylamine, and betaine.

[0102] Examples of anionic surfactants include: alkyl sulfates such as lauryl sulfate and octadecyl sulfate; fatty acid salts; alkylbenzene sulfonates such as nonylbenzene sulfonate and dodecylbenzene sulfonate; naphthalene sulfonates such as dodecylnaphthalene sulfonate; alkyl diphenyl ether disulfonates such as dodecyl diphenyl ether disulfonate; polyoxyethylene alkyl ether sulfates such as polyoxyethylene octadecyl ether sulfate and polyoxyethylene lauryl ether sulfate; polyoxyethylene alkyl phenyl ether sulfates such as polyoxyethylene lauryl phenyl ether sulfate; polyoxyethylene styrene phenyl ether sulfate; lauryl sulfosuccinate, polyoxyethylene lauryl sulfosuccinate, dioctyl sulfosuccinate (sodium dioctyl sulfosuccinate), and other sulfosuccinates; polyoxyethylene alkyl ether phosphates; and polyoxyethylene alkyl ether acetates. When anionic surfactants form salts, these salts can be, for example, metal salts such as sodium, potassium, calcium, and magnesium salts (preferably monovalent metal salts), ammonium salts, and amine salts.

[0103] Examples of cationic surfactants include: alkyltrimethylammonium chloride, stearyltrimethylammonium chloride, lauryltrimethylammonium chloride, hexadecyltrimethylammonium chloride, tallow alkyltrimethylammonium chloride, benzyltrimethylammonium chloride, stearyltrimethylammonium bromide, benzyltrimethylammonium bromide, distearate dimethylammonium chloride, dicosyldimethylammonium chloride, dioctyldimethylammonium chloride, di(POE)oleenylmethylammonium chloride (2EO), benzylalkylammonium chloride, alkylbenzylalkylammonium chloride, alkyldimethylbenzylalkylammonium chloride, benzyl chloride, stearyldimethylbenzylammonium chloride, lanolin-derived quaternary ammonium salts, diethylaminoethyl acetylamine stearate, dimethylaminopropyl acetylamine stearate, benzylaminopropyldimethylhydroxypropylammonium chloride, sepyl chloride, cetyl chloride, tallulin alkylbenzylhydroxyethyl imidazoline, benzyl ammonium salts, etc.

[0104] The surfactant preferably has a molecular weight of 100 to 10,000, more preferably 200 to 5,000, and even more preferably 300 to 3,000. If the molecular weight is within this range, a surface protective film with excellent peelability can be obtained.

[0105] The surfactant content relative to 100 parts by weight of the base polymer with reactive functional groups is, for example, 0.01 parts by weight to 30 parts by weight, more preferably 0.02 parts by weight to 20 parts by weight, and even more preferably 0.03 parts by weight to 10 parts by weight. If the content is within this range, a surface protective film with excellent peelability can be obtained.

[0106] C-3. Method for preparing surface protective film A surface protective film can be obtained by applying an adhesive composition to a substrate layer and drying off the solvent as needed to form an adhesive layer on the substrate layer. Alternatively, a surface protective film can be obtained by forming an adhesive layer by applying an adhesive composition to a supporting substrate and drying it, and then transferring the adhesive layer to the substrate layer.

[0107] As a drying method, any suitable method may be used. The preferred heating and drying temperature is 40°C to 200°C, more preferably 50°C to 180°C, and even more preferably 70°C to 170°C. The preferred drying time is 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, even more preferably 10 seconds to 10 minutes, and most preferably 10 seconds to 5 minutes.

[0108] Crosslinking can be initiated by heating or aging, either simultaneously with or after solvent drying. The heating temperature and time are appropriately set according to the type of monomer or crosslinking agent, for example, approximately 1 minute to 7 days at 20°C to 160°C. [Example]

[0109] The present invention will now be described in more detail with reference to embodiments and comparative examples. However, the present invention is not limited thereto. Furthermore, in the following description, unless otherwise explicitly stated, "parts" and "%" are based on weight.

[0110] (1) Method for measuring thickness The measurements were taken using the product name "Linear Gauge MODEL D-10HS" (manufactured by Ozaki Seisakusho Co., Ltd.). (2) Method for measuring peel strength The protective film was cut into pieces 25 mm wide and 100 mm long. At 23°C and 50% RH, the adhesive layer was bonded to the hard coating surface of the polarizing plate using a 2 kg roller in one pass. After being placed in the same environment for 30 minutes, the peel strength (N / 25 mm) was measured using a tensile compression testing machine (Minebea, TG-1kN) according to JIS Z 0237:2000, at a peel speed of 0.3 m / min and a peel angle of 180 degrees. (3) Method for determining the hardness of hard coatings The protective layer with a hard coating was attached to a glass plate with an adhesive with a thickness of 50 μm, and the scratch hardness (pencil method) was measured according to the description in Section 4, Part 5 of JIS K 5600.

[0111] [Manufacturing Example 1A: Preparation of Composition A for Hard Coating Formation] As the resin contained in the hard coating, for every 100 parts by weight, a UV-curable acrylic resin (manufactured by DIC Corporation, trade name "LUXIDIA 17-806", solids content 80%) is mixed with 3 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name "OMNIRAD907"), 0.01 parts by weight of a leveling agent (manufactured by DIC Corporation, trade name "PC4100", solids content 40%), and 1.3 parts by weight of a UV absorber (manufactured by BASF Corporation, trade name "Tinuvin 326"). The mixture is diluted with a PGM / cyclopentanone mixed solvent (weight ratio 63 / 37) to achieve a solids content concentration of 36%, thus preparing composition A for forming the hard coating.

[0112] [Manufacturing Example 1B: Preparation of Composition B for Hard Coating Formation] Without adding any ultraviolet absorbers, composition B for forming a hard coating was prepared in the same manner as in manufacturing example 1A.

[0113] [Manufacturing Example 2A: Preparation of Adhesive Composition A] In a reaction vessel equipped with a thermometer, stirrer, condenser, and nitrogen inlet, 100 parts by weight of 2-ethylhexyl acrylate (2EHA) and 4 parts by weight of hydroxyethyl acrylate (HEA) as monomer components, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 150 parts by weight of ethyl acetate were added together. The mixture was slowly stirred at 23°C while nitrogen was introduced for nitrogen purging. The liquid temperature was then maintained at approximately 65°C for 6 hours to obtain a solution of acrylic polymer (concentration 40% by weight).

[0114] Toluene (73 parts by weight) and acetone (10 parts by weight) were added to 250 parts by weight of an acrylic polymer solution (100 parts by weight of polymer), and diluted to a concentration of 30% by weight. Then, 2 parts by weight of an isocyanate-based crosslinking agent (Tosoh's "Coronate HX" (100% solids)) and 4 parts by weight of a 0.5% solution of dioctyltin laurate (Tokyo Fine Chemical's "Embilizer OL-1") (0.02 parts by weight of solids) were added to this solution as a crosslinking catalyst, and the mixture was stirred to prepare acrylic adhesive composition A. The isocyanate equivalent of the crosslinking agent in this composition is 0.3 times the hydroxyl equivalent of the base polymer.

[0115] [Manufacturing Example 2B: Preparation of Adhesive Composition B] In a reaction vessel equipped with a thermometer, stirrer, condenser, and nitrogen inlet, 100 parts by weight of 2-ethylhexyl acrylate (2EHA), 10 parts by weight of 4-hydroxybutyl acrylate, and 0.02 parts by weight of acrylic acid (AA) as monomer components, along with 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator and 150 parts by weight of ethyl acetate, were added together. The mixture was slowly stirred at 23°C while nitrogen was introduced for nitrogen purging. The liquid temperature was then maintained at approximately 65°C for 6 hours to obtain a solution of acrylic polymer (concentration 40% by weight).

[0116] Toluene (73 parts by weight) and acetone (10 parts by weight) were added to 250 parts by weight of an acrylic polymer solution (100 parts by weight of polymer), and diluted to a concentration of 30% by weight. Then, 3.5 parts by weight of an isocyanate-based crosslinking agent (Tosoh's "Coronate HX" (100% solids)) and 4 parts by weight of a 0.5% solution of dioctyltin laurate (Tokyo Fine Chemicals' "Embilizer OL-1") (0.02 parts by weight of solids) were added to this solution as a crosslinking catalyst, and the mixture was stirred to prepare acrylic adhesive composition B. The isocyanate equivalent of the crosslinking agent in this composition is 0.28 times the hydroxyl equivalent of the base polymer.

[0117] [Manufacturing Example 2C: Preparation of Adhesive Composition C] Acrylic adhesive composition C was prepared in the same manner as in Manufacturing Example 2A, with 5 parts by weight of isocyanate crosslinking agent added relative to 100 parts by weight of acrylic polymer.

[0118] [Manufacturing Example 2D: Preparation of Adhesive Composition D] Acrylic adhesive composition D was prepared in the same manner as in Manufacturing Example 2B, with the amount of isocyanate-based crosslinking agent added set to 1 part by weight relative to 100 parts by weight of acrylic polymer. The isocyanate equivalent of the crosslinking agent in this composition was 0.08 times the hydroxyl equivalent of the base polymer.

[0119] [Manufacturing Example 2E: Preparation of Adhesive Composition E] Acrylic adhesive composition E was prepared in the same manner as in Manufacturing Example 2B, with 6 parts by weight of isocyanate-based crosslinking agent added relative to 100 parts by weight of acrylic polymer.

[0120] [Manufacturing Example 2F: Preparation of Adhesive Composition F] Acrylic adhesive composition F was prepared in the same manner as in Manufacturing Example 2A, with 8 parts by weight of isocyanate-based crosslinking agent added relative to 100 parts by weight of acrylic polymer.

[0121] [Example 1] 1. Preparation of surface protective film The adhesive composition A was coated on one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "T100C38") with a thickness of 38 μm, and dried at 130°C for 0.5 minutes to form an adhesive layer with a thickness of 10 μm, thereby obtaining a surface protective film.

[0122] 2. Production of polarizing plates 2-1. Fabrication of polarizing elements As a thermoplastic resin substrate, a strip-shaped amorphous polyethylene terephthalate copolymer film (thickness: 100 μm) with a Tg of approximately 75°C was used to perform corona treatment on one side of the resin substrate. A PVA aqueous solution (coating solution) was prepared by adding 13 parts by weight of potassium iodide to 100 parts by weight of a PVA-based resin made by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetylated modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER") in a weight ratio of 9:1. The above-mentioned PVA aqueous solution is coated on the corona-treated surface of the resin substrate and dried at 60°C to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate. The obtained laminate is uniaxially extended (air-assisted extension process) to 2.4 times in the longitudinal direction (length direction) in an oven at 130°C. Subsequently, the laminate was immersed in an insoluble bath at a liquid temperature of 40°C (an aqueous solution of boric acid prepared by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insoluble treatment). Subsequently, the polarizing element was immersed in a staining bath at a liquid temperature of 30°C (an iodine aqueous solution prepared by mixing iodine and potassium iodide in a weight ratio of 1:7 relative to 100 parts by weight of water) for 60 seconds while adjusting the concentration to achieve the desired monomer transmittance (Ts) of the final polarizing element. Subsequently, the sample was immersed in a crosslinking bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (crosslinking treatment). Then, while immersing the laminate in a boric acid aqueous solution (boric acid concentration of 4 wt% and potassium iodide concentration of 5 wt%) at a liquid temperature of 70°C, it is uniaxially stretched (underwater stretching treatment) in the longitudinal direction (length direction) between rollers with different circumferential speeds, with a total stretch ratio of 5.5 times. Then, the laminate is immersed in a cleaning bath at a liquid temperature of 20°C (an aqueous solution of 4 parts by weight of potassium iodide mixed with 100 parts by weight of water) (cleaning treatment). Then, it is dried in an oven at approximately 90°C while being in contact with SUS heating rollers at a surface temperature of 75°C (drying shrinkage treatment). Thus, a polarizing element with a thickness of 5 μm is formed on a resin substrate to obtain a laminate consisting of a resin substrate and a polarizing element.

[0123] 2-2. Fabrication and lamination of a protective layer with a hard coating The aforementioned hard coating composition A was applied to one side of a 25 μm thick TAC film (manufactured by Fujifilm, product name "TJ25UL"). The film was heated at 80°C for 1 minute, and then irradiated with ultraviolet light at a cumulative intensity of 220 mJ / cm² using a high-pressure mercury lamp to harden the coating. This resulted in a protective layer with a 7 μm thick, 2H hard coating (HC) layer on one side.

[0124] On the polarizing element side of the laminate obtained in 2-1, a protective layer with an HC layer is bonded together using an ultraviolet-curable adhesive (cured to a thickness of 1.5 μm). Then, the resin substrate is peeled off from the polarizing element to obtain a polarizing plate having a structure of [HC layer / TAC film / adhesive layer / polarizing element].

[0125] 2-3. Fabrication of the First Phase Difference Layer Polymerization was carried out in a batch polymerization apparatus consisting of two vertical reactors equipped with agitators and reflux coolers controlled at 100°C. 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)en-9-yl]methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), 42.28 parts by mass (0.139 mol) of spirodiol (SPG), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10⁻² parts by mass (6.78 × 10⁻⁵ mol) of calcium acetate monohydrate as a catalyst were added. After purging the reactor with nitrogen under reduced pressure, it was heated with a heat transfer medium, and stirring was initiated when the internal temperature reached 100°C. Forty minutes after the start of heating, the internal temperature reached 220°C and was maintained at this temperature. Simultaneously, depressurization was initiated, reaching 13.3 kPa after 90 minutes at 220°C. Phenol vapor, a byproduct of the polymerization reaction, was introduced into a 100°C reflux cooler to return a certain amount of monomer components contained in the phenol vapor to the reactor. Uncondensed phenol vapor was recovered by introducing it into a 45°C condenser. Nitrogen was introduced into the first reactor to temporarily restore the pressure to atmospheric pressure. The oligomerized reaction liquid in the first reactor was then transferred to the second reactor. Subsequently, heating and depressurization were initiated in the second reactor, reaching an internal temperature of 240°C and a pressure of 0.2 kPa after 50 minutes. Polymerization then proceeded until a specific stirring force was achieved. At the point where the specific stirring force was reached, nitrogen was introduced into the reactor to restore the pressure. The resulting polyester carbonate resin was extruded into water, and the filament was cut to obtain granules.

[0126] The obtained polyester carbonate resin (granules) was vacuum dried at 80°C for 5 hours. A film-forming apparatus equipped with a single-screw extruder (manufactured by Toshiba Machinery, cylinder set temperature: 250°C), a T-die (width 200 mm, set temperature: 250°C), a cooling roller (set temperature: 120~130°C), and a winding machine was used to produce a 130 μm thick elongated resin film. The elongated resin film was then stretched to obtain a 48 μm thick phase difference film as the first phase difference layer. The stretching conditions were: stretching temperature 143°C in the width direction and stretching ratio 2.8 times. The obtained phase difference film had a Re(550) of 141 nm, a Re(450) / Re(550) ratio of 0.86, and an Nz coefficient of 1.12.

[0127] 2-4. Fabrication of a polarizing plate with a phase retardation layer A phase retardation film (manufactured by Dai Nippon Printing Co., Ltd., "MCP-N") with a refractive index characteristic satisfying the relationship nz>nx=ny and a phase difference Rth(550) of -135 nm in the thickness direction is used as the second phase retardation layer. The first and second phase retardation layers prepared in step 2-3 above are bonded together using an ultraviolet-curing adhesive. Then, the first phase retardation layer of the laminate of the first and second phase retardation layers is bonded to the polarizing element surface of the polarizing plate prepared in step 2-2 above using an acrylic adhesive layer with a thickness of 12 μm. At this time, the bonding is performed such that the slow axis of the first phase retardation layer is at a 45° angle to the absorption axis of the polarizing element. An acrylic adhesive layer (15 μm thick) and a release liner are sequentially deposited on the surface of the second phase retardation layer of the obtained laminate to obtain a polarizing plate with a phase retardation layer consisting of [HC layer / TAC film / adhesive layer / polarizing element / adhesive layer / first phase retardation layer / adhesive layer / second phase retardation layer / adhesive layer / release liner].

[0128] 3. Fabrication of polarizing plates with protective surface film The surface protective film prepared in step 1 is laminated onto the HC layer surface of the polarizing plate with phase difference layer prepared in step 2 to obtain a polarizing plate with surface protective film.

[0129] [Example 2] A surface protective film was prepared by using adhesive composition B instead of adhesive composition A. Otherwise, a polarizing plate with a surface protective film was obtained in the same manner as in Example 1.

[0130] [Example 3] A surface protective film is prepared by using adhesive composition C instead of adhesive composition A. Otherwise, a polarizing plate with a surface protective film is obtained in the same manner as in Example 1.

[0131] [Comparative Example 1] A surface protective film is prepared by using adhesive composition D instead of adhesive composition A. Otherwise, a polarizing plate with a surface protective film is obtained in the same manner as in Example 1.

[0132] [Comparative Example 2] A surface protective film is prepared by using adhesive composition E instead of adhesive composition A. Otherwise, a polarizing plate with a surface protective film is obtained in the same manner as in Example 1.

[0133] [Comparative Example 3] A surface protective film is prepared by using adhesive composition F instead of adhesive composition A. Otherwise, a polarizing plate with a surface protective film is obtained in the same manner as in Example 1.

[0134] [Reference Example 1] A surface protective film is prepared by using a hard coating forming composition B instead of a hard coating forming composition A, and by using an adhesive composition C instead of an adhesive composition A. Otherwise, a polarizing plate with a surface protective film is obtained in the same manner as in Example 1.

[0135] [Reference Example 2] A surface protective film is prepared by using a hard coating forming composition B instead of a hard coating forming composition A, and by using an adhesive composition E instead of an adhesive composition A. Otherwise, a polarizing plate with a surface protective film is obtained in the same manner as in Example 1.

[0136] [Reference Example 3] A surface protective film is prepared by using a hard coating forming composition B instead of a hard coating forming composition A, and by using an adhesive composition F instead of an adhesive composition A. Otherwise, a polarizing plate with a surface protective film is obtained in the same manner as in Example 1.

[0137] <Pollution Assessment> The polarizing plates with surface protective films obtained in the examples, comparative examples, and reference examples were cut into 40 mm × 40 mm sizes. The release liner was peeled off and bonded to a glass plate to prepare evaluation samples. The evaluation samples were placed in an oven at 60°C and 90% relative humidity for 120 hours, then removed and the surface protective film was peeled off. Adhesive tape was applied to a portion of the hard-coated side surface of the polarizing plate and then peeled off to remove the adhering material. Then, in a dark room equipped with three-wavelength fluorescent lamps, the reflected light from the hard-coated side surface in the area where the adhering material was removed with the adhesive tape and in other areas was visually observed, and the evaluation was performed according to the following criteria (N=2). Evaluation Criteria Lv.1: No change in either region Lv.2: Light whitening is present in other areas (areas where the attached material was not removed by the adhesive tape). Lv.3: Exhibits deep whitening in other areas, making it undetectable in dark outdoor environments. Lv.4: Exhibits deep whitening in other areas, but is visible even in dark outdoor environments.

[0138] The results of the pollution assessment are presented together with the stripping force in Table 1. [Table 1] Adhesive layer HC layer Pollution assessment Peeling force Basic polymer composition The amount of isocyanate-based crosslinking agent added The presence or absence of UV absorbers N1 N2 N / 25 mm Comparative Example 1 2EHA / 4HBA / AA= 100 / 10 / 0.02 1 have Lv.1 Lv.1 0.4 Example 1 2EHA / HEA=100 / 4 2 have Lv.1 Lv.1 0.2 Example 2 2EHA / 4HBA / AA= 100 / 10 / 0.02 3.5 have Lv.1 Lv.2 0.1 Example 3 2EHA / HEA=100 / 4 5 have Lv.3 Lv.3 0.1 Comparative Example 2 2EHA / 4HBA / AA= 100 / 10 / 0.02 6 have Lv.4 Lv.4 0.1 Comparative Example 3 2EHA / HEA=100 / 4 8 have Lv.4 Lv.4 0.1 Reference Example 1 2EHA / HEA=100 / 4 5 none Lv.1 Lv.1 0.1 See Example 2 2EHA / 4HBA / AA= 100 / 10 / 0.02 6 none Lv.1 Lv.1 0.1 See Example 3 2EHA / HEA=100 / 4 8 none Lv.1 Lv.1 0.1

[0139] As described in Table 1, in the embodiments using a surface protective film with an adhesive layer having an isocyanate-based crosslinking agent content within a specific range, contamination of the peel surface during the removal of the surface protective film was suppressed. On the other hand, in Comparative Example 1, where the content of isocyanate-based crosslinking agent in the adhesive layer was low, the peel force of the surface protective film was greater than the desired range. In Comparative Examples 2 and 3, where the content of isocyanate-based crosslinking agent in the adhesive layer was high, contamination of the peel surface during the removal of the surface protective film was confirmed. Furthermore, when no ultraviolet absorber was added to the hard coating, no contamination problem occurred even if the content of isocyanate-based crosslinking agent in the adhesive layer was high. [Industrial Applicability]

[0140] The polarizing plate with a surface protective film of the present invention can be preferably used in the manufacture of image display devices such as liquid crystal display devices and organic EL display devices.

[0141] 10:Polarizing plate 11: Hard coating 12: Protective layer 13: Polarizing element 14(14a,14b,14c): Next layer 15: First phase difference layer 16: Second phase difference layer 20: Surface protective film 21: Substrate layer 22: Adhesive layer 100 (100A, 100B, 100C): Polarizing plates with a protective surface film.

Claims

1. A polarizing plate with a surface protective film, comprising: a polarizing plate having a hard coating layer, a protective layer, and a polarizing element in sequence; and a surface protective film having a substrate layer and an adhesive layer disposed on one side of the substrate layer, and being adhered to the surface of the hard coating layer of the polarizing plate via the adhesive layer; the hard coating layer comprising an ultraviolet absorber; the adhesive layer comprising a base polymer having reactive functional groups and an isocyanate-based crosslinking agent; the content of the isocyanate-based crosslinking agent in the adhesive layer being 2 to 2.5 parts by weight relative to 100 parts by weight of the base polymer having reactive functional groups; and the peeling force of the surface protective film being 0.2 N / 25 mm or less when peeled at a peeling speed of 0.3 m / min, a peeling temperature of 23°C, and a peeling angle of 180°.

2. The polarizing plate with a surface protective film as claimed in claim 1, wherein the polarizing plate has a phase difference layer on the side opposite to the side where the polarizing element is disposed.

3. The polarizing plate with a surface protective film as claimed in claim 1 or 2, wherein the hard coating is a hardened body comprising a hard coating forming composition containing a curing compound and the ultraviolet absorber, wherein the content of the ultraviolet absorber in the hard coating is 0.1 parts by weight to 3.0 parts by weight relative to 100 parts by weight of the curing compound.

4. The polarizing plate with a protective film as claimed in claim 1 or 2, wherein the base polymer is a (meth)acrylic polymer having hydroxyl and / or carboxyl groups.

5. The polarizing plate with a protective film as claimed in claim 1 or 2, wherein the ultraviolet absorber comprises at least one ultraviolet absorber selected from hydroxyphenyl triazole ultraviolet absorbers and benzotriazole ultraviolet absorbers.

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