Polarizing plate with surface protection film

Abstract

To provide a polarizing plate that can suppress the effects of ultraviolet light on polarizers, display elements, etc., and that prevents the generation of foreign matter. [Solution] A polarizing plate having a hard coat layer, a protective layer, and a polarizer in that order, and a surface protective film having a base layer and an adhesive layer provided on one side of the base layer, wherein the surface protective film is bonded to the surface of the hard coat layer of the polarizing plate via the adhesive layer, the hard coat layer contains an ultraviolet absorber, and the adhesive layer contains a base polymer having a reactive functional group and an isocyanate crosslinking agent, the content of the isocyanate crosslinking agent in the adhesive layer is 2 to 5 parts by weight per 100 parts by weight of the base polymer having the reactive functional group.

Description

[Technical Field]

[0001] This invention relates to a polarizing plate with a surface protective film. [Background technology]

[0002] In liquid crystal display devices, one of the most common image display devices, polarizers are arranged on both sides of the liquid crystal cell due to the image formation method. Polarizers are usually used as polarizers with a protective layer on at least one side, and from the viewpoint of improving the viewing angle, they can be used as polarizers with a phase difference layer, which further includes a phase difference layer. In addition, in organic electroluminescent (EL) display devices, a circular polarizer is provided on the viewing side to prevent problems such as reflection of ambient light and reflection of the background caused by the high reflectivity of organic EL elements. As a general circular polarizer, a device is known in which a polarizer and a phase difference layer (typically a λ / 4 plate) are stacked such that the slow axis of the phase difference layer forms an angle of approximately 45° with respect to the absorption axis of the polarizer (for example, Patent Document 1).

[0003] In the above-mentioned image display device, with respect to the polarizing plate (viewing-side polarizing plate) placed on the viewing side of the display element such as a liquid crystal cell or organic EL element, a scratch-resistant hard coat layer is provided on the protective layer placed on the viewing side of the polarizer. Furthermore, with respect to the viewing-side polarizing plate, an ultraviolet absorber is added to the adhesive layer used to bond the polarizer and the protective layer placed on its viewing side, thereby suppressing the effects of ultraviolet rays on the polarizer, display element, etc.

[0004] However, in adhesive layers to which ultraviolet absorbers are added, foreign matter (e.g., crystalline foreign matter) may be generated over time, and these may be visible as bright spots when an image display device using the polarizing plate is observed. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2006-171235 [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a polarizing plate that can suppress the effects of ultraviolet light on polarizers, display elements, etc., and that prevents the generation of foreign matter. [Means for solving the problem]

[0007] Incidentally, polarizing plates are usually handled in a state where a protective film is temporarily attached to the surface for the purpose of surface protection during the manufacturing process, inspection process, transportation process, etc., and this protective film is removed when the plate is put into use.

[0008] In an attempt to solve the above problem, the inventors tried adding an ultraviolet absorber to the hard coat layer provided in the protective layer. They found that while the generation of foreign matter in the adhesive layer was prevented, contamination could occur on the polarizing plate surface when the surface protective film was peeled off.

[0009] As a result of further investigation by the present inventors, it was found that by using a predetermined adhesive layer as the adhesive layer of the surface protective film, contamination of the polarizing plate surface can be suppressed, and as a result, the effects of ultraviolet rays on the polarizer, display element, etc. can be suppressed, and a polarizing plate in which the generation of foreign matter is prevented can be obtained.

[0010] According to one aspect of the present invention, a polarizing plate with a surface protective film is provided. The polarizing plate with a surface protective film includes a polarizing plate having a hard coat layer, a protective layer and a polarizer in that order, and a surface protective film having a base layer and an adhesive layer provided on one side of the base layer, and the surface protective film is bonded to the surface of the hard coat layer of the polarizing plate via the adhesive layer, wherein the hard coat layer contains an ultraviolet absorber, and the adhesive layer contains a base polymer having a reactive functional group and an isocyanate crosslinking agent, and the content of the isocyanate crosslinking agent in the adhesive layer is 2 to 5 parts by weight per 100 parts by weight of the base polymer having the reactive functional group. In one embodiment, when the surface protective film 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 0.2 N / 25 mm or less. In one embodiment, the polarizing plate has a phase difference layer on the side of the polarizer opposite to the side on which the protective layer is located. In one embodiment, the hard coat layer is a cured body of a hard coat layer forming composition comprising a curable compound and the ultraviolet absorber, wherein the content of the ultraviolet absorber in the hard coat layer is 0.1 to 3.0 parts by weight per 100 parts by weight of the curable compound. In one embodiment, the base polymer is a (meth)acrylic polymer having hydroxyl groups and / or carboxyl groups. In one embodiment, the UV absorber comprises at least one UV absorber selected from hydroxyphenyltriazine-based UV absorbers and benzotriazole-based UV absorbers. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a polarizing plate that can suppress the effects of ultraviolet light on polarizers, display elements, etc., and that prevents the generation of foreign matter. [Brief explanation of the drawing]

[0012] [Figure 1]Schematic cross-sectional view of a polarizing plate with a surface protection film according to one embodiment of the present invention. [Figure 2] Schematic cross-sectional view of a polarizing plate with a surface protection film according to one embodiment of the present invention. [Figure 3] Schematic cross-sectional view of a polarizing plate with a surface protection film according to one embodiment of the present invention.

Mode for Carrying Out the Invention

[0013] (Definition of Terms and Symbols) The definitions of terms and symbols in this specification are as follows. (1) Refractive Index (nx, ny, nz) "nx" is the refractive index in the direction where the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-Plane Phase Difference (Re) "Re(λ)" is the in-plane phase difference measured with light of wavelength λ nm at 23°C. For example, "Re(550)" is the in-plane phase difference measured with light of wavelength 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ) = (nx - ny) × d, where d (nm) is the thickness of the layer (film). (3) Phase Difference in the Thickness Direction (Rth) "Rth(λ)" is the phase difference in the thickness direction measured with light of wavelength λ nm at 23°C. For example, "Rth(550)" is the phase difference in the thickness direction measured with light of wavelength 550 nm at 23°C. Rth(λ) is obtained by the formula: Rth(λ) = (nx - nz) × d, where d (nm) is the thickness of the layer (film). (4) Nz Coefficient The Nz coefficient is obtained by Nz = Rth / Re. (5) Angle When referring to an angle in this specification, the angle includes both clockwise and counterclockwise directions with respect to the reference direction. Therefore, for example, "45°" means 45° clockwise or counterclockwise with respect to the reference direction.

[0014] The polarizing plate with a surface protection film according to an embodiment of the present invention includes a polarizing plate having a hard coat layer, a protective layer, and a polarizer in this order, a base material layer, and an adhesive layer provided on one side of the base material layer, and a surface protection film bonded to the surface of the hard coat layer of the polarizing plate through the adhesive layer. In the polarizing plate with a surface protection film of the present embodiment, the hard coat layer contains an ultraviolet absorber, the adhesive layer contains a base polymer having a reactive functional group and an isocyanate-based crosslinking agent, and the content of the isocyanate-based crosslinking agent in the adhesive layer is 2 to 5 parts by weight with respect to 100 parts by weight of the base polymer having the reactive functional group.

[0015] A. Overall configuration of the polarizing plate with a surface protection film FIG. 1 is a schematic cross-sectional view of a polarizing plate with a surface protection film according to one embodiment of the present invention. The polarizing plate with a surface protection film 100A includes a polarizing plate 10 having a hard coat layer 11, a protective layer 12, and a polarizer 13 in this order, and a surface protection film 20 having a base material layer 21 and an adhesive layer 22 provided on one side of the base material layer 21. The surface protection film 20 is bonded to the hard coat layer 11 of the polarizing plate 10 through the adhesive layer 22.

[0016] FIG. 2 is a schematic cross-sectional view of a polarizing plate with a surface protection film according to another embodiment of the present invention. The polarizing plate with a surface protection film 100B includes a polarizing plate 10 having a hard coat layer 11, a protective layer 12, a polarizer 13, and a first retardation layer 15 in this order, and a surface protection film 20 having a base material layer 21 and an adhesive layer 22 provided on one side of the base material layer 21. The surface protection film 20 is bonded to the hard coat layer 11 of the polarizing plate 10 through the adhesive layer 22.

[0017] 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 with a surface protective film 100C includes a polarizing plate 10 having a hard coat layer 11, a protective layer 12, a polarizer 13, a first phase difference layer 15, and a second phase difference layer 16 in that order, and a surface protective film 20 having a base layer 21 and an adhesive layer 22 provided on one side of the base layer 21. The surface protective film 20 is bonded to the hard coat layer 11 of the polarizing plate 10 via the adhesive layer 22.

[0018] In the illustrated example, the lamination of the protective layer 12 and the polarizer 13, the lamination of the polarizer 13 and the first phase difference layer 15, and the lamination of the first phase difference layer 15 and the second phase difference layer 16 are performed via adhesive layers 14a, 14b, and 14c, respectively. However, these laminations may be performed directly without adhesive layers, depending on the purpose. Also, in the illustrated example, the protective layer is provided only on one side (the viewing side) of the polarizer 13, but protective layers may be provided on both sides of the polarizer as needed.

[0019] Although not shown in the diagram, the outermost layer on the polarizing plate side of a polarizing plate with a surface protective film may be provided with an adhesive layer for bonding the polarizing plate to an adjacent optical component. In this case, the adhesive layer may be protected by a release liner until it is put into use.

[0020] When the surface protective film is peeled off from a polarizing plate with a surface protective film according to an embodiment of the present invention 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 protective film can suitably protect the surface of the polarizing plate while it is temporarily attached to it, and can be easily peeled off when necessary.

[0021] B. Polarizing plate A polarizing plate has a hard coat layer, a protective layer, and a polarizer in that order. The polarizing plate may further have a phase difference layer if necessary.

[0022] B-1.Polarizer Polarizers are typically composed of a polyvinyl alcohol-based resin film containing a dichroic substance (e.g., iodine). Polarizers may be made of a single layer of resin film, or they may be made using a laminate of two or more layers.

[0023] Specific examples of polarizers composed of a single layer of resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) resin films, partially formalized PVA resin films, and partially saponified ethylene-vinyl acetate copolymer films, which have been subjected to dyeing and stretching treatments with dichroic substances such as iodine or dichroic dyes, as well as polyene-based oriented films such as dehydrated PVA or dehydrochlorinated polyvinyl chloride. Preferably, polarizers obtained by dyeing a PVA resin film with iodine and uniaxially stretching are used because they have excellent optical properties.

[0024] The above-mentioned iodine dyeing is carried out, for example, by immersing the PVA resin film in an iodine aqueous solution. The stretching ratio for the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment, or during the dyeing process. Alternatively, dyeing may be performed after stretching. If necessary, the PVA resin film may be subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc. For example, by immersing the PVA resin film in water and washing it before dyeing, not only can dirt and blocking inhibitors on the surface of the PVA resin film be washed away, but the PVA resin film can also be swollen to prevent uneven dyeing.

[0025] Specific examples of polarizers obtained using a laminate 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 a resin substrate, drying it to form a PVA-based resin layer on the resin substrate, and obtaining a laminate of the resin substrate and the PVA-based resin layer; or by stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. In this embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, stretching may, if necessary, further include air-stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. The resulting 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 the resin substrate may be peeled off from the resin substrate / polarizer laminate, and any appropriate protective layer may be laminated onto the peeled surface according to the purpose. Details of such a polarizer manufacturing method are described, for example, in Japanese Patent Application Publication No. 2012-73580. The entire description of that publication is incorporated herein by reference.

[0026] The thickness of the polarizer is, for example, 30 μm or less, preferably 15 μm or less, more preferably 1 μm to 12 μm, even more preferably 2 μm to 10 μm, and even more preferably 2 μm to 8 μm.

[0027] The polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The transmittance of the polarizer is, for example, 41.0% or more, preferably 43.0% to 46.0%, and more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0028] B-2.Protective layer The protective layer is composed of any suitable film that can be used as a protective layer for the polarizer. Specific examples of materials that make up the main component of the film include cellulosic resins such as triacetylcellulose (TAC), and transparent resins such as polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, polynorbornene, polyolefin, (meth)acrylic, and acetate. Thermosetting resins or UV-curing resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone can also be used. In addition, glassy polymers such as siloxane polymers can also be used. Polymer films described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As materials for this film, for example, a resin composition containing a thermoplastic resin having substituted or unsubstituted imide groups in its side chains, and a thermoplastic resin having substituted or unsubstituted phenyl groups and nitrile groups in its side chains can be used. Examples include a resin composition having an alternating copolymer of isobutene and N-methylmaleimide, and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extruded product of the above resin composition.

[0029] When a polarizing plate is applied to an image display device, the thickness of the protective layer (visibility-side protective layer 12) positioned on the opposite side of 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.

[0030] When a polarizing plate is applied to an image display device, the thickness of the protective layer (inner protective layer) placed on the display element side is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm, and even more preferably 10 μm to 60 μm.

[0031] 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.

[0032] B-3. ​​Hard coat layer The hard coat layer is provided on the viewing side of the viewing-side protective layer and constitutes the outermost viewing-side layer of the polarizing plate. Typically, the hard coat layer can be formed directly on the viewing-side surface of the viewing-side protective layer.

[0033] The hard coat layer may be a cured body (cured resin) of a curable composition or a molded body of a thermoplastic composition, preferably a cured body of a curable composition.

[0034] The curable composition for forming a hard coat layer (hereinafter referred to as the hard coat layer forming composition) comprises a curable compound and an ultraviolet absorber.

[0035] Examples of curable compounds included in hard coat layer forming compositions include thermosetting compounds, ultraviolet curable compounds, and electron beam curable compounds. Examples of curable compounds include polyester-based, acrylic-based, urethane-based, acrylic urethane-based, amide-based, silicone-based, silicate-based, epoxy-based, melamine-based, oxetane-based, and acrylic urethane-based compounds. These curable compounds may be used individually or in combination of two or more.

[0036] Among these, acrylic, acrylic urethane, and epoxy compounds are preferred due to their high hardness, UV curing capability, and excellent productivity, with acrylic urethane compounds being particularly preferred. UV-curable compounds include UV-curable monomers, oligomers, polymers, etc.

[0037] Specific examples of curable compounds include acrylic compounds (monomers and / or oligomers) having multiple UV-polymerizable functional groups, and preferably curable compounds having multiple (meth)acryloyl groups. The number of functional groups ((meth)acryloyl groups) in the curable compound is, for example, 3 or more, preferably 5 or more, and also, for example, 30 or less, preferably 20 or less. The curable compound preferably further contains a hydroxyl group in its molecule.

[0038] Examples of curable monomers include tricyclodecanedimethanol diacrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane triacrylate, pentaerythritol tetra(meth)acrylate, dimethylolpropane tetraacrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, dipropylene glycol diacrylate, isocyanuric acid tri(meth)acrylate, ethoxylated glycerin tri(meth)acrylate, ethoxylated pentaerythritol tetraacrylate, and their oligomers or prepolymers. These can be used individually or in combination.

[0039] Examples of curable compounds that are monomers or oligomers include urethane (meth)acrylate and / or oligomers of urethane (meth)acrylate. The number of (meth)acryloyl groups in urethane (meth)acrylate and / or oligomers of urethane (meth)acrylate is, for example, 3 or more, preferably 4 or more, more preferably 6 or more, and also, for example, 25 or less, preferably 20 or less.

[0040] 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. If the urethane (meth)acrylate and / or urethane (meth)acrylate oligomers are commercially available products, the theoretical molecular weight listed in the catalog accompanying the product shall be used.

[0041] Any suitable UV absorber can be used as the UV absorber, 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, triazine UV absorbers, salicylate UV absorbers, and cyanoacrylate UV absorbers. Among these, triazine UV absorbers or benzotriazole UV absorbers are preferred, and triazine UV absorbers are particularly preferred. Triazine UV absorbers are more preferably composed of compounds having hydroxyl groups, and are particularly preferably UV absorbers composed of hydroxyphenyltriazine compounds (hydroxyphenyltriazine UV absorbers). Only one UV absorber may be used, or two or more may be used in combination.

[0042] Examples of hydroxyphenyltriazine-based UV absorbers include the reaction product of 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl)-5-hydroxyphenyl and [(C10-C16 (mainly C12-C13) alkyloxy)methyl]oxirane (trade name "TINUVIN 400", manufactured by BASF), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-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-triazine and (2-ethylhexyl)-glycidic acid ester (trade name "TINUVIN 400"). 405 (manufactured by BASF), 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (product name "TINUVIN 460", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol (product name "TINUVIN 1577", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]-phenol (product name "ADEKA Stab LA-46", manufactured by ADEKA Corporation), 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (product name "TINUVIN Examples include "479" (manufactured by BASF) and BASF's product name "TINUVIN 477".

[0043] Examples of benzotriazole-based UV absorbers (benzotriazole compounds) include 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (trade name "TINUVIN PS", manufactured by BASF), benzenepropanoic acid and ester compounds of 3-(2H-benzotriazole-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy(C7-9 side chain and linear alkyl) (trade name "TINUVIN 384-2", manufactured by BASF), octyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate and a mixture of 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate (trade name "TINUVIN Reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (product name "TINUVIN 900", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (product name "TINUVIN 928", manufactured by BASF), reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300 (product name "TINUVIN 1130", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-p-cresol (product 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-di-tert-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-tetramethylbutyl)phenol] (trade name "TINUVIN 360", manufactured by BASF), reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate and 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-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole (trade name "Sumisorb" 250", manufactured by Sumitomo Chemical Co., Ltd., 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole (product name "SEESORB 703", manufactured by Cipro Chemical Co., Ltd.), 2-(2H-benzotriazol-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalimidylmethyl)phenol (product name "SEESORB 706", manufactured by Cipro Chemical Co., Ltd.), 2-(4-benzoyloxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole (product name "SEESORB 7012BA", manufactured by Cipro Chemical Co., Ltd.), 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (product name "SEESORB 706", manufactured by Cipro Chemical Co., Ltd.) Examples include 73 (manufactured by Chemipro Chemical Co., Ltd.), 2,2'-methylenebis[6-(2H-benzotriazole-2-yl)-4-tert-octylphenol] (product name "ADEKA Stab LA-31", manufactured by ADEKA Corporation), 2-(2H-benzotriazole-2-yl)-p-cellulose (product name "ADEKA Stab LA-32", manufactured by ADEKA Corporation), 2-(5-chloro-2H-benzotriazole-2-yl)-6-tert-butyl-4-methylphenol (product name "ADEKA Stab LA-36", manufactured by ADEKA Corporation), etc.

[0044] The molecular weight of the UV absorber is preferably 100 to 1500, more preferably 200 to 1200, and even more preferably 200 to 1000. If a compound with a small molecular weight (for example, a compound with a molecular weight of 600 or less) is used as the UV absorber, the UV absorber tends to be concentrated near the surface.

[0045] The amount of UV absorber is, for example, 0.1 to 3.0 parts by weight, preferably 0.5 to 2.5 parts by weight, and more preferably 1.0 to 2.0 parts by weight, per 100 parts by weight of the total amount of curable compound. If the content is within this range, a hard coat layer with the desired hardness can be obtained while suppressing the effect of ultraviolet rays on polarizers and display elements.

[0046] The hard coat layer forming composition may further contain, in addition to the curable compound and UV absorber, any other suitable components depending on the purpose. Examples of other components include polymerization initiators, leveling agents, blocking inhibitors, dispersion stabilizers, thixotropes, and antioxidants. Such additives may be present individually or in combination of two or more. The type, combination, and content of additives can be appropriately determined according to the purpose and desired properties.

[0047] A hard coat layer can be formed by applying a hard coat layer-forming composition to one side of a protective layer and performing a curing treatment. Examples of curing treatments include irradiation with active energy rays such as ultraviolet light, and heat treatment. In the case of ultraviolet irradiation, the integrated light intensity can be 200 mJ to 400 mJ. Furthermore, after forming the hard coat layer, surface treatments such as corona treatment and plasma treatment may be applied to the hard coat layer.

[0048] The pencil hardness of the hard coat layer is, for example, F or higher, more preferably H or higher, and even more preferably 2H or higher.

[0049] The thickness of the hard coat layer is, for example, 1 μm to 30 μm, preferably 3 μm to 15 μm, and more preferably 5 μm to 12 μm.

[0050] B-4. First retardation layer The first retardation layer may have any suitable optical properties according to the purpose. The first retardation layer preferably exhibits a refractive index characteristic of nx > ny ≧ nz. 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, within a range that does not impair the effects of the present invention, ny < nz may occur.

[0051] In one embodiment, the first retardation layer may function as a λ / 4 plate. In this case, the in-plane retardation Re(550) of the first retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and still more preferably 130 nm to 160 nm.

[0052] In one embodiment, the angle θ formed between the slow axis of the first retardation layer and the absorption axis of the polarizer is, for example, 40° to 50°, preferably 42° to 48°, and still more preferably about 45°. When the angle θ is within such a range, by using the first retardation layer as a λ / 4 plate, a polarizer with a retardation layer having very excellent circular polarization characteristics (and as a result, very excellent antireflection characteristics) can be obtained.

[0053] The Nz coefficient of the first retardation layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3. By satisfying such a relationship, when the obtained polarizer with a retardation layer is used in an image display device, a very excellent reflected hue can be achieved.

[0054] The first retardation layer may exhibit an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light, or a flat wavelength dispersion characteristic in which the retardation value hardly changes depending on the wavelength of the measurement light. In one embodiment, the first retardation layer exhibits an inverse dispersion wavelength characteristic. In this case, Re(450) / Re(550) of the retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and 0.95 or less. With such a configuration, very excellent antireflection characteristics can be realized.

[0055] The absolute value of the photoelastic coefficient of the first retardation layer is preferably 2×10 ,

[0056] , m 2 / N or less, more preferably 2.0×10 -13 m 2 / N to 1.5×10 -11 m 2 / N, still more preferably 1.0×10 -12 m 2 / N to 1.2×10 -11 m 2 / N and contains a resin. If the absolute value of the photoelastic coefficient is within such a range, a change in retardation is unlikely to occur when shrinkage stress occurs during heating. As a result, thermal unevenness of the obtained image display device can be preferably prevented.

[0056] The first phase difference layer may be a stretched resin film or a liquid crystal alignment solidified layer. The thickness of the first phase difference layer, which is composed of a stretched resin film, is preferably 70 μm or less, and more preferably 45 μm to 60 μm. When the thickness of the first phase difference layer is within this range, curling during heating can be well suppressed while the curling during lamination can be well adjusted. Furthermore, in embodiments in which the first phase difference layer is composed of a polycarbonate resin film, as will be described later, the thickness of the first phase difference layer is preferably 40 μm or less, more preferably 10 μm to 40 μm, and even more preferably 20 μm to 30 μm. By composing the first phase difference layer as a polycarbonate resin film having such a thickness, it is possible to suppress the occurrence of curling while also contributing to improved bending durability and reflective hue.

[0057] Typical examples of resins that can form the first phase difference 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 may be used individually or in combination (e.g., blended, copolymerized). When the first phase difference layer is composed of a resin film exhibiting inverse dispersion wavelength characteristics, polycarbonate resins or polyester carbonate resins (hereinafter sometimes simply referred to as polycarbonate resins) can be suitably used.

[0058] As the polycarbonate resin described above, any suitable polycarbonate resin can be used as long as the effects of the present invention are obtained. For example, the polycarbonate resin includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, and structural units derived from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic dimethanol, di, tri, or polyethylene glycol, and alkylene glycol or spiroglycol. Preferably, the polycarbonate resin includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, structural units derived from alicyclic dimethanol, and / or structural units derived from di, tri, or polyethylene glycol; more preferably, it includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, and structural units derived from di, tri, or polyethylene glycol. The polycarbonate resin may optionally include structural units derived from other dihydroxy compounds. Further details regarding polycarbonate resins suitably used in the present invention are described, for example, in Japanese Patent Publication No. 2014-10291, Japanese Patent Publication No. 2014-26266, Japanese Patent Publication No. 2015-212816, Japanese Patent Publication No. 2015-212817, and Japanese Patent Publication No. 2015-212818, and such descriptions are incorporated herein by reference.

[0059] The glass transition temperature of the above polycarbonate resin is preferably 110°C to 150°C, and more preferably 120°C to 140°C. If the glass transition temperature is excessively low, the heat resistance tends to be poor, which may cause dimensional changes after film molding and may also reduce the image quality of the image display device to which it is applied. If the glass transition temperature is excessively high, the molding stability during film molding may be poor and the transparency of the film may be impaired. The glass transition temperature is determined in accordance with JIS K 7121 (1987).

[0060] The molecular weight of the above polycarbonate resin can be expressed in terms of reduced viscosity. Reduced viscosity is measured using a Ubbelohde viscous tube at a temperature of 20.0°C ± 0.1°C, after precisely adjusting the polycarbonate concentration to 0.6 g / dL using methylene chloride as the solvent. The lower limit of the reduced viscosity is usually preferably 0.30 dL / g, more preferably 0.35 dL / g or higher. The upper limit of the reduced viscosity is usually preferably 1.20 dL / g, more preferably 1.00 dL / g, and even more preferably 0.80 dL / g. If the reduced viscosity is lower than the lower limit, the mechanical strength of the molded product may be reduced. On the other hand, if the reduced viscosity is higher than the upper limit, the fluidity during molding may decrease, which may lead to problems such as reduced productivity and moldability.

[0061] Commercially available polycarbonate resin films may be used. Specific examples of commercially available products include Teijin Corporation's "PureAce WR-S," "PureAce WR-W," and "PureAce WR-M," and Nitto Denko Corporation's "NRF."

[0062] The first phase difference layer is obtained, for example, by stretching a film formed from the polycarbonate resin described above. Any suitable molding process can be used to form the film from the polycarbonate resin. Specific examples include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP molding, cast coating (e.g., casting), calendering, and hot pressing. Extrusion molding or cast coating is preferred because it enhances the smoothness of the resulting film and provides good optical uniformity. Molding conditions can be appropriately set according to the composition and type of resin used, the desired properties of the phase difference layer, etc. As mentioned above, many polycarbonate resin film products are commercially available, so such commercially available films may be used directly for the stretching process.

[0063] The thickness of the resin film (unstretched film) can be set to any appropriate value depending on the desired thickness of the first phase difference layer, desired optical properties, stretching conditions, etc. Preferably, it is 50 μm to 300 μm.

[0064] The stretching described above can be carried out using any appropriate stretching method and conditions (e.g., stretching temperature, stretching ratio, stretching direction). Specifically, various stretching methods such as free-end stretching, fixed-end stretching, free-end shrinking, and fixed-end shrinking can be used individually, simultaneously, or sequentially. Regarding the stretching direction, it can be carried out in various directions and dimensions, such as the length direction, width direction, thickness direction, and diagonal direction. The stretching temperature is preferably between Tg-30°C and Tg+60°C, and more preferably between Tg-10°C and Tg+50°C, relative to the glass transition temperature (Tg) of the resin film.

[0065] By appropriately selecting the stretching method and stretching conditions described above, a phase difference film having the desired optical properties (e.g., refractive index properties, in-plane phase difference, Nz coefficient) can be obtained.

[0066] B-5. Second phase difference layer The second phase difference layer may be, for example, a so-called positive C plate whose refractive index characteristics exhibit the relationship nz>nx=ny. By using a positive C plate as the second phase difference layer, oblique reflections can be effectively prevented, and the anti-reflective function can be widened to a wider viewing angle. In this case, the phase difference Rth(550) in the thickness direction of the second phase difference layer is preferably -50nm to -300nm, more preferably -70nm to -250nm, even more preferably -90nm to -200nm, and particularly preferably -100nm to -180nm. Here, "nx=ny" includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. That is, the in-plane phase difference Re(550) of the second phase difference layer may be less than 10nm.

[0067] A second phase difference layer having the refractive index characteristic nz>nx=ny can be formed from any suitable material. Preferably, the second phase difference layer consists of a film containing a liquid crystal material fixed to a homeotropic orientation. The liquid crystal material (liquid crystal compound) that can be homeotropically oriented may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the phase difference layer are described in paragraphs

[0020] to

[0028] of Japanese Patent Application Publication No. 2002-333642. In this case, the thickness of the second phase difference layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and even more preferably 0.5 μm to 5 μm.

[0068] B-6.Adhesive layer As the adhesive layer, any suitable adhesive or tack layer applicable to optical applications may be used.

[0069] C. Surface protective film C-1. Base material layer The base layer is, for example, a resin film. Examples of constituent materials for the resin film include polyester, polyolefin, polyamide, polyimide, polycarbonate, polyacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, and polyfluoroethylene. Examples of polyester 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)acrylic acid ester copolymer, and ethylene-vinyl alcohol copolymer. Examples of polyamides include nylon 6, nylon 6,6, and partially aromatic polyamides. The base layer may consist of one material or two or more materials. The base layer may have a single-layer structure or a multilayer structure. Furthermore, if the base layer is a resin film, the base layer may be a stretched film or an unstretched film.

[0070] 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, it is possible to obtain a surface protective film that has sufficient strength as a support and appropriate flexibility.

[0071] C-2. Adhesive layer The adhesive layer is formed by 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 that can react with the isocyanate-based crosslinking agent. Through reaction with the isocyanate-based crosslinking agent, a crosslinked structure is formed in the base polymer, and an adhesive layer with desired adhesive properties can be obtained.

[0072] The thickness of the adhesive layer is, for example, 1 μm to 50 μm, preferably 2 μm to 30 μm, and more preferably 5 μm to 25 μm.

[0073] C-2-1. Base polymer having reactive functional groups Specific examples of base polymers having reactive functional groups include acrylic polymers, urethane polymers, and silicone polymers. Among these, acrylic polymers are preferred as base polymers having reactive functional groups from the viewpoint of transparency and flexibility in adhesive design. One type of base polymer may be used, or two or more types may be used in combination.

[0074] The above base polymer may have reactive functional groups in its main chain or side chains. The reactive functional groups of the base polymer may be any functional groups containing active hydrogen that can react with isocyanate-based crosslinking agent (B), and hydroxyl groups and carboxyl groups are preferred examples.

[0075] As acrylic polymers having reactive functional groups, those with a monomer unit of alkyl (meth)acrylate as the main backbone can be preferably used. Such acrylic polymers can be obtained, for example, by copolymerizing a monomer component containing alkyl (meth)acrylate and a monomer containing a reactive functional group (hereinafter sometimes referred to as "reactive functional group-containing monomer"). In this specification, "(meth)acrylic" means acrylic and / or methacrylic.

[0076] As the alkyl (meth)acrylate ester mentioned above, alkyl (meth)acrylate esters having an alkyl group with 4 to 12 carbon atoms are preferred. Specific examples include butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, etc. The alkyl (meth)acrylate ester having an alkyl group with 4 to 12 carbon atoms may be used alone or in combination of two or more types.

[0077] The content of alkyl (meth)acrylate ester having an alkyl group with 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 the acrylic polymer.

[0078] As the above-mentioned monomers containing reactive functional groups, monomers having functional groups containing active hydrogen, such as hydroxyl groups and carboxyl groups, are used. Specific examples include hydroxyl group-containing monomers such as hydroxyalkyl(meth)acrylates like 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-hydroxylauryl(meth)acrylate, and [4-(hydroxymethyl)cyclohexyl]methyl acrylate; carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, and β-carboxyethyl acrylate; and N-methylolacrylamide and N-methylolmethacrylamide. Examples include N-hydroxyalkyl(meth)acrylamides such as 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, and N-(4-hydroxybutyl)methacrylamide. The monomer containing the reactive functional group may be used alone or in combination of two or more.

[0079] The content of the reactive functional group-containing monomer 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, relative to the total amount of monomer components constituting the acrylic polymer.

[0080] The monomer components constituting the acrylic polymer may further include other monomers other than the alkyl (meth)acrylate esters having an alkyl group with 4 to 12 carbon atoms and the monomers containing reactive functional groups (hereinafter sometimes referred to as "other copolymer monomers"). The other copolymer monomers may be used individually or in combination of two or more.

[0081] Other copolymer monomers mentioned above include alkyl (meth)acrylates having alkyl groups other than those with 4 to 12 carbon atoms. Specific examples of alkyl (meth)acrylates having alkyl groups other than those with 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, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, and the like.

[0082] Other specific examples of the above copolymer monomers include cyclic (meth)acrylamides such as N-(meth)acrylmorpholine and N-acrylloylpyrrolidine; acyclic (meth)acrylamides such as (meth)acrylamides, N-substituted (meth)acrylamides (e.g., N-alkyl (meth)acrylamides such as N-ethyl (meth)acrylamide and Nn-butyl (meth)acrylamide); N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, and N,N-dialkyl (meth)acrylamide); and N-vinyl-2-pyrrolidone, N-vinyl-2-pyrrolidone. Examples include nitrogen atom-containing monomers such as N-vinylcyclic amides such as nyl-2-piperidone, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholindione; monomers having an amino group such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylate; monomers having a maleimide skeleton such as N-cyclohexylmaleimide and N-phenylmaleimide; itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-2-ethylhexylitaconimide, N-laurylitaconimide, and N-cyclohexylitaconimide.

[0083] Further specific examples of the above-mentioned other copolymer monomers include: monomers having epoxy groups such as glycidyl (meth)acrylate and allyl glycidyl ether; monomers having alkoxy groups such as methoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; monomers having cyano groups such as acrylonitrile and methacrylonitrile; styrene monomers such as styrene and α-methylstyrene; α-olefins such as ethylene, propylene, isoprene, butadiene, and isobutylene; monomers having isocyanate groups such as 2-methacryloyloxyethyl isocyanate; vinyl ester monomers such as vinyl acetate and vinyl propionate; and vinyl ether monomers such as vinyl ether. Examples include: heterocyclic (meth)acrylic acid esters such as tetrahydrofurfuryl (meth)acrylate; monomers having halogen atoms such as fluorine (meth)acrylate; monomers having alkoxysilyl groups such as 3-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane; monomers having siloxane bonds such as silicone (meth)acrylate; (meth)acrylates having alicyclic hydrocarbon groups such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, bornyl (meth)acrylate, and isobornyl (meth)acrylate; (meth)acrylates having aromatic hydrocarbon groups such as phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxydiethylene glycol (meth)acrylate; and others.

[0084] Further specific examples of the other copolymer monomers mentioned above include polyfunctional monomers such as 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, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, divinylbenzene, butyl di(meth)acrylate, and hexyl di(meth)acrylate.

[0085] The content of the above-mentioned other copolymer monomers 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.

[0086] The weight-average molecular weight (Mw) of the above acrylic polymer 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 obtained by GPC (gel permeation chromatography) on a standard polystyrene basis. As a GPC apparatus, for example, the model name "HLC-8320GPC" (column: TSKgel GMH-H(S), manufactured by Tosoh Corporation) can be used.

[0087] The glass transition temperature (Tg) of the above acrylic polymer is preferably 0°C or lower (usually -100°C or higher), more preferably -10°C or lower, and even more preferably -20°C or lower. The glass transition temperature can be determined by measurement using a dynamic viscoelastic device or by calculation using FOX's formula.

[0088] The polymerization method for the above acrylic polymer is not particularly limited and can be polymerized by known methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization. Furthermore, the resulting copolymer may be either a random copolymer or a block copolymer.

[0089] The urethane polymer having the above-mentioned reactive functional group is a urethane polymer having a functional group that can react with an isocyanate crosslinking agent on its main chain or side chain. Preferably, the urethane polymer is a urethane polymer (urethane resin) obtained by reacting a polyol with a polyisocyanate compound.

[0090] The silicone polymer having the above-mentioned reactive functional group is a silicone polymer having a functional group on its main chain or side chain that can react with an isocyanate crosslinking agent. Preferably, such a silicone polymer is obtained by blending or agglomerating silicone polymers (silicone resins).

[0091] The content of the base polymer having reactive functional groups in the adhesive layer (in other words, the adhesive composition from which 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. The upper limit of the base polymer content is not particularly limited, and for example, the total content of the base polymer and the isocyanate crosslinking agent may be such that it accounts for 100% by weight of the adhesive layer.

[0092] C-2-2. Isocyanate-based crosslinking agents As an isocyanate-based crosslinking agent, polyisocyanates having two or more isocyanate groups in one molecule are used. Specific examples include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), and dimer acid diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate (IPDI), and 1,3-bis(isocyanatomethyl)cyclohexane; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate (XDI); and modified polyisocyanates obtained by modifying the above isocyanate compounds with allophanate bonds, biuret bonds, isocyanurate bonds, uretdione bonds, urea bonds, carbodiimide bonds, uretonimine bonds, oxadiazinetrione bonds, etc. The isocyanate crosslinking agent may be used alone or in combination of two or more types. Furthermore, it is possible to use a combination of a bifunctional isocyanate compound and a trifunctional or more isocyanate compound.

[0093] As isocyanate-based crosslinking agents, commercially available products such as Takenate 300S, Takenate 500, Takenate 600, Takenate D165N, Takenate D178N (all manufactured by Mitsui Chemicals, Inc.), Sumijoule T80, Sumijoule L, Desmodule N3400 (all manufactured by Sumika Bayer Urethane Co., Ltd.), Myrionate MR, Myrionate MT, Coronate L, Coronate HL, Coronate HX (all manufactured by Tosoh Corporation) can be used.

[0094] The content of isocyanate-based crosslinking agent in the adhesive layer is typically 2 to 5 parts by weight, 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, per 100 parts by weight of the base polymer having reactive functional groups. Furthermore, the content of isocyanate-based crosslinking agent in the adhesive layer is preferably such that the ratio of the molar equivalent of isocyanate groups to the molar equivalent of reactive functional groups of the base polymer is, for example, 0.05 to 1.5, or for example, 0.07 to 1.3. If the crosslinking agent content in the adhesive layer is within this range, a surface protective film can be obtained that can be easily peeled off without adhesive residue while suppressing contamination of the hard coat layer surface when peeled off.

[0095] C-2-3. Other ingredients The adhesive composition forming the adhesive layer may, depending on the purpose, further include any other suitable components in addition to the base polymer having the reactive functional group and the isocyanate-based crosslinking agent.

[0096] Other components mentioned above include polymerization catalysts, crosslinking catalysts, solvents, antistatic agents, surfactants, silane coupling agents, tackifiers, plasticizers, softeners, degradation inhibitors, fillers, colorants, UV absorbers, and antioxidants.

[0097] Examples of antistatic agents include cationic antistatic agents having cationic functional groups (e.g., primary amino groups, secondary amino groups, tertiary amino groups, etc.) such as quaternary ammonium salts and pyridinium salts; anionic antistatic agents having anionic functional groups such as sulfonates, sulfate esters, phosphonates, and phosphate esters; amphoteric 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, glycerin and its derivatives, and polyethylene glycol and its derivatives; and ionic conductive polymers obtained by polymerizing or copolymerizing monomers having ionic conductive groups as described above for cationic, anionic, and amphoteric antistatic agents. The antistatic agent may be used alone or in combination of two or more types.

[0098] The amount of antistatic agent is, for example, 0.01 to 30 parts by weight, preferably 0.02 to 20 parts by weight, and more preferably 0.03 to 10 parts by weight, per 100 parts by weight of the base polymer having reactive functional groups.

[0099] Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, nonionic surfactants, anionic surfactants, and cationic surfactants are preferred. A single surfactant may be used, or two or more may be used in combination.

[0100] 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 glyceryl ether fatty acid esters; polyoxyethylene-polyoxypropylene block copolymers; saturated fatty acid esters such as ethyl caprylate, ethyl caprate, methyl laurate, butyl laurate, methyl myristate, isopropyl myristate, methyl palmitate, isopropyl palmitate, methyl stearate, butyl stearate, methyl behenate, butyl lauryl stearate, butyl stearate, isopropyl myristate, and isopropyl palmitate; and fatty acid amides such as lauric acid amide, palmitic acid amide, stearic acid amide, and behenic acid amide.

[0101] Examples of anionic surfactants include alkyl sulfates such as lauryl sulfate and octadecyl sulfate; fatty acid salts; alkylbenzene sulfonates such as nonylbenzenesulfonate and dodecylbenzenesulfonate; naphthalene sulfonates such as dodecylnaphthalenesulfonate; alkyldiphenyl ether disulfonates such as dodecyldiphenyl ether disulfonate; polyoxyethylene alkyl ether sulfates such as polyoxyethylene octadecyl ether sulfate and polyoxyethylene lauryl ether sulfate; polyoxyethylene alkylphenyl ether sulfates such as polyoxyethylene laurylphenyl ether sulfate; polyoxyethylene styrene phenyl ether sulfate; sulfosuccinates such as lauryl sulfosuccinate, polyoxyethylene lauryl sulfosuccinate, and dioctyl sulfosuccinate (sodium dioctyl sulfosuccinate); polyoxyethylene alkyl ether phosphates; polyoxyethylene alkyl ether acetates; and the like. When an anionic surfactant forms a salt, the salt may be, for example, a metal salt (preferably a monovalent metal salt) such as a sodium salt, potassium salt, calcium salt, or magnesium salt, an ammonium salt, or an amine salt.

[0102] Cationic surfactants include alkyltrimethylammonium chloride, stearyltrimethylammonium chloride, lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, alkyltrimethylammonium tallow chloride, behenyltrimethylammonium chloride, stearyltrimethylammonium bromide, behenyltrimethylammonium bromide, distearyldimethylammonium chloride, dicocoyldimethylammonium chloride, dioctyldimethylammonium chloride, di(POE)oleylmethylammonium chloride (2EO), benzalkonium chloride, alkylbenzalkonium chloride, alkyldimethylbenzalkonium chloride, benzethonium chloride, stearyldimethylbenzylammonium chloride, lanolin-derived quaternary ammonium salts, diethylaminoethyl stearate, dimethylaminopropyl stearate, behenamidepropyldimethylhydroxypropylammonium chloride, stearoylcoraminoformylmethylpyridinium chloride, cetylpyridinium chloride, tall oil alkylbenzylhydroxyethylimidazolinium chloride, and benzylammonium salts.

[0103] The molecular weight of the surfactant is preferably 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.

[0104] The surfactant content is, for example, 0.01 to 30 parts by weight, preferably 0.02 to 20 parts by weight, and more preferably 0.03 to 10 parts by weight, per 100 parts by weight of the base polymer having a reactive functional group. If the content is within this range, a surface protective film with excellent peelability can be obtained.

[0105] C-3. Method for manufacturing surface protective film An adhesive layer can be formed on the substrate layer by applying the adhesive composition onto a substrate layer and drying and removing the solvent as necessary, thereby obtaining a surface protective film. Alternatively, an adhesive layer can be formed by applying and drying the adhesive composition onto a support substrate, and then transferring the adhesive layer to the substrate layer to obtain a surface protective film.

[0106] Any suitable drying method can be employed. The heating and drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and even more preferably 70°C to 170°C. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, even more preferably 10 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

[0107] Crosslinking can be advanced by heating or aging simultaneously with or after the drying of the solvent. The heating temperature and heating time are set appropriately depending on the type of monomer or crosslinking agent, and may be, for example, 20°C to 160°C for 1 minute to 7 days. [Examples]

[0108] The present invention will be described more specifically below with reference to examples and comparative examples. However, the present invention is not limited in any way to these. In the following description, "parts" and "%" refer to weight unless otherwise specified.

[0109] (1) Method for measuring thickness Measurements were taken using the product name "Linear Gauge MODEL D-10HS" (manufactured by Ozaki Seisakusho Co., Ltd.). (2) Method for measuring peeling force The surface protection film was cut to a size of 25 mm in width and 100 mm in length. Under conditions of 23°C and 50% RH, the adhesive layer side was bonded to the hard coat layer surface of the polarizing plate, and a 2 kg roll was passed back and forth once to press it down. After leaving it in the same conditions for 30 minutes, the peel strength (N / 25 mm) was measured using a tensile and compression testing machine (Minebea, "TG-1kN") in accordance with JIS Z 0237:2000, under conditions of a peel speed of 0.3 m / min and a peel angle of 180 degrees. (3) Method for measuring the hardness of the hard coat layer The protective layer with a hard coat was attached to a glass plate via an adhesive with a thickness of 50 μm, and the scratch hardness was measured according to the scratch hardness (pencil method) described in Section 4 of Part 5 of JIS K 5600.

[0110] [Manufacturing Example 1A: Preparation of Composition A for Hard Coat Layer Formation] As the resin to be included in the hard coat layer, 100 parts by weight of UV-curable acrylate resin (manufactured by DIC Corporation, trade name "Luxidia 17-806", solids content 80%) was mixed with 3 parts by weight of a photopolymerization initiator (manufactured by BASF, 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, trade name "Tinuvin 326"). This mixture was diluted with a PGM / cyclopentanone mixed solvent (weight ratio 63 / 37) to a solids content concentration of 36% to prepare composition A for forming the hard coat layer.

[0111] [Manufacturing Example 1B: Preparation of Composition B for Hard Coat Layer Formation] Composition B for forming a hard coat layer was prepared in the same manner as in Production Example 1A, except that an ultraviolet absorber was not added.

[0112] [Manufacturing Example 2A: Preparation of Adhesive Composition A] In a reaction vessel equipped with a thermometer, stirrer, condenser, and nitrogen gas inlet tube, 100 parts by weight of 2-ethylhexyl acrylate (2EHA), 4 parts by weight of hydroxyethyl acrylate (HEA), and 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as monomer components, along with 150 parts by weight of ethyl acetate, were charged. The mixture was then gently stirred at 23°C while nitrogen gas was introduced to purge the mixture with nitrogen. Subsequently, the polymerization reaction was carried out for 6 hours while maintaining the liquid temperature at around 65°C to obtain a solution of acrylic polymer (concentration 40% by weight).

[0113] To 250 parts by weight of an acrylic polymer solution (100 parts by weight of polymer), 73 parts by weight of toluene and 10 parts by weight of acetylacetone were added to dilute the solution to a concentration of 30% by weight. To this solution, 2 parts by weight of an isocyanate-based crosslinking agent (Tosoh Corporation's "Coronate HX" (100% solids)) and 4 parts by weight of a 0.5% solution of dioctyl sulphurate (Tokyo Fine Chemical's "Envirizer OL-1") (0.02 parts by weight of solids) were added as a crosslinking catalyst and stirred to prepare acrylic adhesive composition A. In this composition, the isocyanate equivalent of the crosslinking agent was 0.3 times the hydroxyl group equivalent of the base polymer.

[0114] [Manufacturing Example 2B: Preparation of Adhesive Composition B] In a reaction vessel equipped with a thermometer, stirrer, condenser, and nitrogen gas inlet tube, 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, were charged together with 150 parts by weight of ethyl acetate. Nitrogen gas was introduced and the mixture was purged with nitrogen while gently stirring at 23°C. Subsequently, the polymerization reaction was carried out for 6 hours while maintaining the liquid temperature at around 65°C to obtain a solution of acrylic polymer (concentration 40% by weight).

[0115] To 250 parts by weight of an acrylic polymer solution (100 parts by weight of polymer), 73 parts by weight of toluene and 10 parts by weight of acetylacetone were added to dilute the solution to a concentration of 30% by weight. To this solution, 3.5 parts by weight of an isocyanate-based crosslinking agent (Tosoh Corporation's "Coronate HX" (100% solids)) and 4 parts by weight of a 0.5% solution of dioctyl sulphurate (Tokyo Fine Chemical's "Envirizer OL-1") (0.02 parts by weight of solids) were added as a crosslinking catalyst, and the mixture was stirred to prepare acrylic adhesive composition B. In this composition, the isocyanate equivalent of the crosslinking agent was 0.28 times the hydroxyl group equivalent of the base polymer.

[0116] [Manufacturing Example 2C: Preparation of Adhesive Composition C] Acrylic adhesive composition C was prepared in the same manner as in Production Example 2A, except that the amount of isocyanate-based crosslinking agent added was 5 parts by weight per 100 parts by weight of acrylic polymer. In this composition, the isocyanate equivalent of the crosslinking agent was 0.76 times the hydroxyl group equivalent of the base polymer.

[0117] [Manufacturing Example 2D: Preparation of Adhesive Composition D] Acrylic adhesive composition D was prepared in the same manner as in Production Example 2B, except that the amount of isocyanate-based crosslinking agent added was 1 part by weight per 100 parts by weight of acrylic polymer. In this composition, the isocyanate equivalent of the crosslinking agent was 0.08 times the hydroxyl group equivalent of the base polymer.

[0118] [Manufacturing Example 2E: Preparation of Adhesive Composition E] Acrylic adhesive composition E was prepared in the same manner as in Production Example 2B, except that the amount of isocyanate-based crosslinking agent added was 6 parts by weight per 100 parts by weight of acrylic polymer. In this composition, the isocyanate equivalent of the crosslinking agent was 0.48 times the hydroxyl group equivalent of the base polymer.

[0119] [Manufacturing Example 2F: Preparation of Adhesive Composition F] Acrylic adhesive composition F was prepared in the same manner as in Production Example 2A, except that the amount of isocyanate-based crosslinking agent added was 8 parts by weight per 100 parts by weight of acrylic polymer. The isocyanate equivalent of the crosslinking agent in this composition was 1.21 times the hydroxyl group equivalent of the base polymer.

[0120] [Example 1] 1. Preparation of surface protective film The above adhesive composition A was applied to one side of a 38 μm thick polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "T100C38"), and dried at 130°C for 0.5 minutes to form a 10 μm thick adhesive layer and obtain a surface protective film.

[0121] 2. Fabrication of polarizing plates 2-1. Fabrication of polarizers As a thermoplastic resin substrate, an amorphous isophthalic copolymer polyethylene terephthalate film (thickness: 100 μm) in a long length with a Tg of approximately 75°C was used, and one side of this resin substrate was subjected to corona treatment. A PVA aqueous solution (coating solution) was prepared by dissolving 100 parts by weight of a PVA-based resin, which was prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosephymer") in a weight ratio of 9:1, with 13 parts by weight of potassium iodide. A PVA aqueous solution was applied to the corona-treated surface of a resin substrate and dried at 60°C to form a 13 μm thick PVA-based resin layer, thereby creating a laminate. The resulting laminate was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) in an oven at 130°C (air-assisted stretching). Next, the laminate was immersed for 30 seconds in an insolubilization bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) (insolubilization treatment). Next, the polarizers were immersed for 60 seconds in a staining bath at a liquid temperature of 30°C (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) while adjusting the concentration so that the final transmittance (Ts) of the polarizers obtained would be the desired value (staining treatment). Next, the material was immersed for 30 seconds 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) (crosslinking treatment). Subsequently, the laminate was immersed in a boric acid aqueous solution (boric acid concentration 4% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70°C, and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to achieve a total stretch ratio of 5.5 times (underwater stretching treatment). Subsequently, the laminate was immersed in a washing bath at a liquid temperature of 20°C (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (washing treatment). Subsequently, the material was dried in an oven maintained at approximately 90°C while being brought into contact with a SUS (stainless steel) heated roll whose surface temperature was maintained at approximately 75°C (drying shrinkage treatment). In this way, a polarizer with a thickness of 5 μm was formed on the resin substrate, and a laminate having a resin substrate / polarizer configuration was obtained.

[0122] 2-2. Fabrication and lamination of protective layers with hard coat layer The above-mentioned hard coat layer forming composition A was applied to one side of a 25 μm thick TAC film (manufactured by Fujifilm Corporation, product name "TJ25UL") and heated at 80°C for 1 minute. After heating, the coated layer was exposed to a high-pressure mercury lamp with an integrated light intensity of 220 mJ / cm². 2 The coated layer was cured by irradiation with ultraviolet light. This resulted in a protective layer with a hard coat (HC) layer on one side, with a thickness of 7 μm and a hardness of 2H.

[0123] A protective layer with an HC layer was bonded to the polarizer side of the laminate obtained in 2-1 via an ultraviolet-curing adhesive (thickness after curing: 1.5 μm). Subsequently, the resin substrate was peeled off from the polarizer to obtain a polarizing plate having the configuration of [HC layer / TAC film / adhesive layer / polarizer].

[0124] 2-3. Fabrication of the first phase difference layer Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled to 100°C. The mixture consisted of 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), 42.28 parts by mass (0.139 mol) of spiroglycol (SPG), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10⁻¹⁶ calcium acetate monohydrate as a catalyst. -2 Part of mass (6.78×10 -5A mol (mol) of polymer was added. After purging the reactor with reduced pressure using nitrogen, the reactor was heated with a heat transfer medium, and stirring was started when the internal temperature reached 100°C. Forty minutes after the start of heating, the internal temperature was raised to 220°C, and while controlling the pressure to maintain this temperature, the pressure was reduced to 13.3 kPa 90 minutes after reaching 220°C. The phenol vapor produced as a by-product of the polymerization reaction was directed to a reflux condenser at 100°C, and the monomer components contained in the phenol vapor were returned to the reactor. The uncondensed phenol vapor was directed to a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor to restore the pressure to atmospheric pressure, and then the oligomerized reaction mixture in the first reactor was transferred to the second reactor. Next, heating and depressurization in the second reactor were started, and the internal temperature reached 240°C and the pressure 0.2 kPa in 50 minutes. Polymerization was then allowed to proceed until the predetermined stirring power was reached. Once the predetermined power level was reached, nitrogen was introduced into the reactor to restore pressure, and the resulting polyester carbonate resin was extruded into water. The strands were then cut to obtain pellets.

[0125] The obtained polyester carbonate resin (pellets) was vacuum-dried at 80°C for 5 hours. Then, a long resin film with a thickness of 130 μm was produced using a film-making apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder setting temperature: 250°C), a T-die (width 200 mm, setting temperature: 250°C), a chill roll (setting temperature: 120~130°C), and a winding machine. The obtained long resin film was stretched while adjusting to obtain a predetermined phase difference to obtain a phase difference film with a thickness of 48 μm as the first phase difference layer. The stretching conditions were a stretching temperature of 143°C and a stretching ratio of 2.8 times in the width direction. The Re(550) of the obtained phase difference film was 141 nm, Re(450) / Re(550) was 0.86, and the Nz coefficient was 1.12.

[0126] 2-4. Fabrication of polarizing plates with phase difference layer A phase difference film (manufactured by Dai Nippon Printing Co., Ltd., "MCP-N") with refractive index characteristics satisfying the relationship nz>nx=ny and a phase difference Rth(550) in the thickness direction of -135nm was used as the second phase difference layer. The first phase difference layer and the second phase difference layer prepared in 2-3 above were bonded together via an ultraviolet-curing adhesive. Subsequently, the first phase difference layer surface of the laminate of the first phase difference layer / second phase difference layer was bonded to the polarizer surface of the polarizer plate prepared in 2-2 above via a 12 μm thick acrylic adhesive layer. At that time, the bonding was carried out so that the slow axis of the first phase difference layer and the absorption axis of the polarizer formed a 45° angle. An acrylic adhesive layer (15 μm thick) and a release liner were laminated in this order onto the surface of the second phase difference layer of the obtained laminate to obtain a polarizing plate with a phase difference layer having the configuration of [HC layer / TAC film / adhesive layer / polarizer / adhesive layer / first phase difference layer / adhesive layer / second phase difference layer / adhesive layer / release liner].

[0127] 3. Fabrication of polarizing plates with surface protective film A polarizing plate with a surface protective film was obtained by laminating the surface protective film prepared in step 1 onto the HC layer surface of the polarizing plate with a phase difference layer prepared in step 2.

[0128] [Example 2] A polarizing plate with a surface protective film was obtained in the same manner as in Example 1, except that the surface protective film was prepared using adhesive composition B instead of adhesive composition A.

[0129] [Example 3] A polarizing plate with a surface protective film was obtained in the same manner as in Example 1, except that the surface protective film was prepared using adhesive composition C instead of adhesive composition A.

[0130] [Comparative Example 1] A polarizing plate with a surface protective film was obtained in the same manner as in Example 1, except that the surface protective film was prepared using adhesive composition D instead of adhesive composition A.

[0131] [Comparative Example 2] A polarizing plate with a surface protective film was obtained in the same manner as in Example 1, except that the surface protective film was prepared using adhesive composition E instead of adhesive composition A.

[0132] [Comparative Example 3] A polarizing plate with a surface protective film was obtained in the same manner as in Example 1, except that the surface protective film was prepared using adhesive composition F instead of adhesive composition A.

[0133] [Reference example 1] A polarizing plate with a surface protective film was obtained in the same manner as in Example 1, except that hard coat layer forming composition B was used instead of hard coat layer forming composition A, and adhesive composition C was used instead of adhesive composition A to prepare the surface protective film.

[0134] [Reference example 2] A polarizing plate with a surface protective film was obtained in the same manner as in Example 1, except that hard coat layer forming composition B was used instead of hard coat layer forming composition A, and adhesive composition E was used instead of adhesive composition A to prepare the surface protective film.

[0135] [Reference example 3] A polarizing plate with a surface protective film was obtained in the same manner as in Example 1, except that hard coat layer forming composition B was used instead of hard coat layer forming composition A, and adhesive composition F was used instead of adhesive composition A to prepare the surface protective film.

[0136] <Contamination Assessment> Polarizing plates with surface protection films obtained in the examples, comparative examples, and reference examples were cut to a size of 40 mm x 40 mm, the release liner was peeled off, and the plates were bonded to a glass plate to prepare evaluation samples. The evaluation samples were placed in an oven at a temperature of 60°C and a relative humidity of 90%, and after 120 hours, they were removed and the surface protection film was peeled off. Adhesive tape was applied to a portion of the hard coat layer side surface of the polarizing plate and then peeled off to remove any adhering substances from the surface. Subsequently, in a darkroom with a three-wavelength fluorescent lamp installed, the reflected light from the hard coat layer side surface in the area where the adhering substances were removed with adhesive tape and in the other areas was visually observed and evaluated according to the following criteria (N=2). ≪Evaluation Criteria≫ Lv.1: No change in either area. Level 2: Slight whitening is present in other areas (areas where the attached substance was not removed with adhesive tape). Lv.3: Severe whitening present in other areas, not visible outside of a darkroom. Level 4: Severe whitening is present in other areas, visible even outside of a darkroom.

[0137] The results of the contamination assessment, along with the peeling force, are shown in Table 1. [Table 1]

[0138] As shown in Table 1, in the examples using a surface protection film having an adhesive layer with an isocyanate-based crosslinking agent content within a predetermined range, contamination of the peeled surface when the surface protection film was peeled off was suppressed. On the other hand, in Comparative Example 1, where the isocyanate-based crosslinking agent content in the adhesive layer was low, the peeling force of the surface protection film was greater than the desired range, and in Comparative Examples 2 and 3, where the isocyanate-based crosslinking agent content in the adhesive layer was high, contamination of the peeled surface when the surface protection film was peeled off was observed. Furthermore, when no UV absorber was added to the hard coat layer, no contamination problem occurred even with a high isocyanate-based crosslinking agent content in the adhesive layer. [Industrial applicability]

[0139] 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 displays and organic EL displays. [Explanation of Symbols]

[0140] 100 Polarizing plates with surface protection film 20 Surface protective film 21 Base material layer 22 Adhesive layer 10 Polarizing plates 11. Hard court layer 12 Protective layer 13 Polarizer 14 Adhesive layer 15. First phase difference layer 16. Second Phase Difference Layer

Claims

[Claim 1] A polarizing plate having a hard coat layer, a protective layer, and a polarizer in that order, and a surface protective film having a base layer and an adhesive layer provided on one side of the base layer, which is bonded to the surface of the hard coat layer of the polarizing plate via the adhesive layer, The hard coat layer contains an ultraviolet absorber, The adhesive layer comprises a base polymer having a reactive functional group and an isocyanate-based crosslinking agent. A polarizing plate with a surface protective film, wherein the content of the isocyanate-based crosslinking agent in the adhesive layer is 2 to 5 parts by weight per 100 parts by weight of the base polymer having the reactive functional group.

Images