Adhesive composition for polarizing film, polarizing film, optical film, and image display device

Abstract

The present application provides an adhesive composition for a polarizing film, which contains a cationic trapping agent having a coordination site capable of coordinating a metal component with 2 or more teeth, and a reactive group. In particular, the present application provides a polarizing film having a polarizer, and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer, wherein the adhesive layer is a cured product layer of the adhesive composition for a polarizing film. It is preferable that the polarizer contains a metal component capable of becoming a divalent metal cation in water.

Description

Technical Field

[0001] This invention relates to adhesive compositions for polarizing films, and more particularly to polarizing films comprising a polarizer and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer. This polarizing film can be used alone to form image display devices such as mobile phones, car navigation systems, computer monitors, and televisions, or it can be used as an optical film in which the polarizing film is laminated to form such image display devices. Background Technology

[0002] Liquid crystal displays (LCDs) are rapidly gaining market share in mobile phones, car navigation systems, computer monitors, and televisions. LCDs are devices that visualize the polarization state of liquid crystal switches, utilizing polarizing lenses based on their display principle. Especially in applications like televisions, there is an increasing demand for high brightness, high contrast, and wide viewing angles, leading to higher requirements for polarizing films such as high transmittance, high polarization degree, and high color reproduction.

[0003] As polarizers, those with high transmittance and high polarization are most commonly iodine-based polarizers, for example, those with a structure in which iodine is adsorbed onto polyvinyl alcohol (hereinafter also referred to as "PVA") and stretched. Generally, the polarizing film is a polarizing film on both sides of the polarizer, where a transparent protective film is bonded using a so-called aqueous adhesive made by dissolving a polyvinyl alcohol-based material in water (Patent Document 1 below). As the transparent protective film, a highly moisture-permeable material such as cellulose triacetate is used. When using the aforementioned aqueous adhesive (so-called wet lamination), a drying process is required after bonding the polarizer and the transparent protective film.

[0004] On the other hand, an active energy ray-curable adhesive has been proposed to replace the aforementioned water-based adhesive. When using an active energy ray-curable adhesive to manufacture polarizing films, the production rate of polarizing films can be improved because a drying process is not required. For example, a free radical polymerizable active energy ray-curable adhesive using N-substituted amide monomers as curing components has been proposed (Patent Document 2 below). The adhesive layer formed using the active energy ray-curable adhesive described in Patent Document 2 can sufficiently withstand water resistance tests, such as those evaluating whether there is discoloration or peeling after immersion in 60°C water for 6 hours. However, in recent years, polarizing films have been used not only in portable devices such as mobile phones but also in image display devices for automotive applications. In automotive applications, compared to portable device applications, durability tests under higher temperature and humidity conditions are required.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2001-296427

[0008] Patent Document 2: Japanese Patent Application Publication No. 2012-052000 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] As a durability test required for polarizing films used in automotive applications, there is, for example, a humidification durability test involving 1000 hours of exposure to an environment of 65°C and 95% humidity. Here, the inventors conducted a detailed study of the appearance of the polarizing film after this humidification durability test and discovered, particularly, that white, hazy bright spots originating from foreign matter appeared at the ends of the polarizing film, which, from an appearance perspective, constitute a product defect. This phenomenon was observed for the first time after a durability test in a high-temperature and high-humidity environment, and further research is necessary to address this new problem.

[0011] The present invention was developed in view of the above-mentioned actual situation, and its purpose is to provide an adhesive composition for polarizing films as raw materials, wherein the polarizing film suppresses the generation of bright spots from foreign matter even after a humidification durability test and has excellent appearance characteristics.

[0012] Furthermore, the present invention aims to provide a polarizing film that suppresses the generation of bright spots from foreign matter even after a humidification durability test and has excellent appearance characteristics.

[0013] Methods for solving problems

[0014] The above-mentioned problems can be solved by the following configuration. That is, the present invention relates to an adhesive composition for polarizing films, which contains a cation scavenger having a coordination site capable of coordinating a metal component with two or more teeth, and a reactive group.

[0015] In the above-mentioned adhesive composition for polarizing films, the reactive group is preferably at least one reactive group selected from vinyl, (meth)acryloyl, styrene, (meth)acrylamide, vinyl ether, epoxy, oxetyl, mercapto, and alkoxy.

[0016] In the above-mentioned adhesive composition for polarizing film, it is preferable that the coordination site of the cation scavenger has at least two nitrogen atoms, or that the coordination site of the cation scavenger has at least two oxygen atoms, and further, that the coordination site of the cation scavenger has at least one nitrogen atom and at least one oxygen atom.

[0017] In the above-mentioned adhesive composition for polarizing films, the cation scavenger is preferably selected from at least one of aminoalkylacrylamide, aminoalkyl acrylate, and compounds containing acetylacetyl groups or compounds containing acetylacetoxy groups reacting with primary amine compounds.

[0018] In the above-mentioned adhesive composition for polarizing films, it is preferable to further contain an active energy ray curing component.

[0019] In the above-mentioned adhesive composition for polarizing films, it is preferable that when the total amount of the adhesive composition for polarizing films is set to 100% by weight, the content of the above-mentioned cation scavenger is 0.5 to 15% by weight.

[0020] In addition, the present invention relates to a polarizing film comprising:

[0021] polarizer, and

[0022] An adhesive layer adjacent to the aforementioned polarizer or an optical film other than the aforementioned polarizer.

[0023] The adhesive layer described above is the cured layer of the adhesive composition for polarizing film described in any of the above claims.

[0024] In the above-mentioned polarizing film, the polarizer preferably contains a metal component that can become a divalent metal cation in water.

[0025] In the above-mentioned polarizing film, zinc is the preferred metal component.

[0026] In the above-described polarizing film, the preferred polarizing film comprises:

[0027] polarizer,

[0028] An optical film laminated to at least one side of the polarizer via an aqueous adhesive layer, and

[0029] The adhesive layer is disposed on the side of the optical film opposite to the aqueous adhesive layer.

[0030] In addition, the present invention relates to an optical film and an image display device, wherein the optical film is at least laminated with one polarizing film as described in any of the above claims, and the image display device uses the polarizing film as described in any of the above claims and / or the optical film described above.

[0031] The effects of the invention

[0032] For polarizing films used in automotive applications, excellent appearance characteristics are required, for example, even after a humidification durability test of 1000 hours in an environment of 65°C-95% humidity. In the case of polarizing films obtained by forming an adhesive layer using the adhesive composition for polarizing films of the present invention as a raw material, the adhesive composition for polarizing films contains a cationic scavenger, which has a coordination site capable of coordinating with metal components in a two-toothed or more manner, and a reactive group. Therefore, after the aforementioned humidification durability test, the generation of bright spots from foreign matter in the polarizing film can be significantly suppressed. As a result, the appearance characteristics of the polarizing film are excellent.

[0033] In particular, polarizing films obtained by forming an adhesive layer using the adhesive composition for polarizing films of the present invention exhibit excellent appearance characteristics even when the polarizing lens contains a metal component, especially zinc, that can become a divalent metal cation in water. The reason for this effect is not yet clear, but the following reasons can be presumed, for example.

[0034] For polarizing films comprising a polarizer and an adhesive layer adjacent to the polarizer or other optical films, during humidification durability testing, metallic components in the polarizer that can become divalent metal cations in water, particularly zinc, migrate from the polarizing film ends to the adhesive layer via vapor or condensation. Here, components other than those in the adhesive composition used as raw materials, such as oxalic acid, exist in the adhesive layer in an ionized state. However, as long as they do not bond with the metallic components to form oxalates, the oxalic acid is not detected as a foreign matter in the adhesive layer. However, during humidification durability testing, if specific metallic components from the polarizer are introduced into the adhesive layer from the ends, the ionized oxalic acid bonds with the metallic components, particularly forming oxalates at the ends of the adhesive layer. These oxalates appear as white bright spots and are detected as foreign matter. As a result, the appearance characteristics of the polarizing film deteriorate.

[0035] For polarizing films obtained by forming an adhesive layer using the polarizing film adhesive composition of the present invention as a raw material, even if a specific metal component contained in the polarizer is mixed into the adhesive layer from the end, the cationic scavenger can replenish the metal component. In particular, in the present invention, the cationic scavenger has coordination sites capable of coordinating with the metal component at least twice, thus the cationic scavenger can capture the metal component before oxalic acid bonds with it. It should be noted that this cationic scavenger, in addition to the coordination sites, also has reactive groups, thus entering the polymer constituting the adhesive during the stage of curing the polarizing film adhesive composition to form the adhesive layer. Therefore, the captured metal component also enters the polymer constituting the adhesive layer, thus suppressing the bonding of ionized oxalic acid with the metal component and the movement of oxalate from the end of the polarizing film to the interior. As a result, even after a humidification durability test, the appearance characteristics of the polarizing film are particularly improved.

[0036] The polarizing film of the present invention exhibits excellent appearance characteristics even after a humidification durability test. Even when the polarizer of the polarizing film contains a metal component that can become a divalent metal cation in water, particularly zinc, the bonding between the ionized oxalic acid and the metal component, and consequently the movement of oxalate from the ends of the polarizing film to the interior, is suppressed because the adhesive composition for the polarizing film, which forms the adhesive layer, contains a specific cation scavenger. As a result, the appearance characteristics of the polarizing film are particularly improved even after a humidification durability test. Attached Figure Description

[0037] Figure 1 This is an example of a cross-sectional schematic diagram of a polarizing film according to one embodiment of the present invention.

[0038] Figure 2 This is another example of a cross-sectional schematic diagram of a polarizing film according to one embodiment of the present invention.

[0039] Symbol Explanation

[0040] 10. Polarizing film

[0041] 1. Polarizing mirror

[0042] 2. Water-based adhesives

[0043] 3, 4, 6 Optical films

[0044] 5. Adhesive layer

[0045] 7 Adhesive layer Detailed Implementation

[0046] Figure 1The diagram shows an example of a cross-sectional schematic of a polarizing film according to an embodiment of the present invention. The polarizing film 10 in this embodiment includes: a polarizer 1, and an adhesive layer 5 adjacent to a first optical film 4 other than the polarizer 1. More specifically, the polarizing film 10 includes: a polarizer 1, a first optical film (phase reversal film) 4 laminated on at least one side of the polarizer 1 via an aqueous adhesive layer 2, and an adhesive layer 5 disposed on the side of the first optical film (phase reversal film) 4 opposite to the aqueous adhesive layer 2. In particular, the polarizing film 10 of this embodiment has a second optical film (transparent protective film) 3 laminated on one side of the polarizer 1 via the aqueous adhesive layer 2, a first optical film (phase reversal film) 4 laminated on the other side of the polarizer 1 via the aqueous adhesive layer 2, an adhesive layer 5 laminated on the first optical film (phase reversal film) 4, and a third optical film (phase reversal film) 6 laminated on the adhesive layer 5. The polarizing film 10 is further laminated with an adhesive layer 7 on the third optical film 6, and is laminated to the image display unit, etc. via the adhesive layer 7.

[0047] Figure 2 Another example of a cross-sectional schematic diagram of a polarizing film according to an embodiment of the present invention is shown. In this embodiment, the polarizing film 10 includes a polarizer 1 and an adhesive layer 5 adjacent to the polarizer 1. More specifically, in this embodiment, a second optical film (transparent protective film) 3 is laminated on one side of the polarizer 1 via an aqueous adhesive layer 2, and a first optical film (phase reversal film) 4 is laminated on the other side of the polarizer 1 via an adhesive layer 5. The polarizing film 10 further has an adhesive layer 7 laminated on the optical film 4, and is laminated to an image display unit, etc., via the adhesive layer 7.

[0048] exist Figure 1 and Figure 2 In the polarizing film shown, the aqueous adhesive layer 2 can be suitably made of aqueous solutions of isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, waterborne polyesters, etc. (e.g., solid content concentration of 0.5–60% by weight). The thickness of the aqueous adhesive layer 2 is not particularly limited, but is typically around 0.01 μm to 0.5 μm after drying.

[0049] for Figure 1 and Figure 2Regarding the polarizing film 10 shown, during the humidification durability test, the metallic components contained in the polarizer 1, particularly zinc, which can become divalent metal cations in water, migrate to the adhesive layer 5 at the end of the polarizing film 10 via vapor and condensation. Here, in the adhesive layer 5, components other than those contained in the adhesive composition used as raw materials, such as oxalic acid, exist in an ionized state. However, as long as they do not bond with the metallic components to form oxalates, the oxalic acid will not be detected as a foreign substance in the adhesive layer. However, if a specific metallic component contained in the polarizer 10 mixes into the adhesive layer 5 during the humidification durability test, the ionized oxalic acid bonds with the metallic components to form oxalates, appearing as white bright spots, and is detected as a foreign substance. Figure 1 and Figure 2 The polarizing film 10 shown can significantly suppress the generation of bright spots from foreign matter in the adhesive layer.

[0050] In this invention, the polarizing film comprises: a polarizer, and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer. Figure 1 The polarizing film 10 shown includes an adhesive layer 5 adjacent to the optical film (phase retardation film) 4 other than the polarizer 1. Additionally, in Figure 2 The polarizing film 10 shown includes an adhesive layer 5 adjacent to the polarizing mirror 1. Hereinafter, the adhesive composition for polarizing films of the present invention, which forms the raw material of this adhesive layer, will be described.

[0051] <Adhesive layer>

[0052] The adhesive layer is formed from the cured layer of the polarizing film adhesive composition of the present invention. The polarizing film adhesive composition of the present invention is particularly preferably an active energy ray curable adhesive composition, such as one that is electron beam curable, ultraviolet curable, or visible light curable. As for the thickness of the adhesive layer after drying, from the viewpoint of balancing improved appearance characteristics of the polarizing film and adhesive strength, it is preferably 0.1 μm to 5.0 μm, more preferably 0.5 μm to 3.0 μm. The active energy ray curable adhesive composition contains an active energy ray curable component; an example is a cationic polymeric adhesive composition containing a free radical polymeric adhesive composition and a cationic polymeric compound, wherein the free radical polymeric adhesive composition contains the free radical polymeric compound as the active energy ray curable component. In the present invention, active energy rays with a wavelength range of 10 nm to less than 380 nm are referred to as ultraviolet light, and active energy rays with a wavelength range of 380 nm to 800 nm are referred to as visible light.

[0053] The adhesive composition for polarizing films of the present invention contains a cation scavenger, which has a coordination site capable of coordinating a metal component with two or more teeth, and a reactive group.

[0054] The reactive groups in a cationic scavenger are necessary for reacting with free radical polymerizable compounds or cationic polymerizable compounds and for the cationic scavenger to enter the polymer constituting the adhesive layer. Preferably, the reactive groups are selected from at least one of vinyl, (meth)acryloyl, styrene, (meth)acrylamido, vinyl ether, epoxy, oxetyl, and mercapto groups.

[0055] The coordination sites of the cation scavenger are structures that can coordinate with metal components in a dodecanotic or more manner. Examples include structures with at least two nitrogen atoms (i), structures with at least two oxygen atoms (ii), and structures with at least one nitrogen atom and at least one oxygen atom (iii).

[0056] Examples of cation scavengers having the above structure (i) include compounds having two or more nitrogen atoms in their molecules and reactive groups such as acryloyl groups, such as aminoalkyl acrylamides like dimethylaminopropylacrylamide, reactants of 2-acetylacetoxyethyl methacrylate with ethylenediamine, and reactants of compounds containing acetylacetyl groups or compounds containing acetylacetoxy groups with primary amine compounds.

[0057] As cation scavengers possessing the above structure (ii), examples include compounds having two or more oxygen atoms in their molecules and reactive groups such as alkoxy groups, such as 3-trimethoxysilylpropyl succinic anhydride.

[0058] Examples of cation scavengers having the above-described structure (iii) include compounds having one or more nitrogen atoms and one or more oxygen atoms in their molecules, and having reactive groups such as an acryloyl group, such as aminoalkyl acrylates like N,N-dimethylaminoethyl acrylate.

[0059] From the viewpoint of improving the appearance of the polarizing film, when the total amount of the adhesive composition for the polarizing film is set to 100% by weight, the content of the cation scavenger is preferably 0.5 to 15% by weight, more preferably 1 to 10% by weight.

[0060] As monomeric components constituting a free radical polymerizable adhesive composition, free radical polymerizable compounds can be listed. Examples of free radical polymerizable compounds include compounds having free radical polymerizable functional groups such as (meth)acryloyl or vinyl groups (carbon-carbon double bonds). These monomeric components can be either monofunctional free radical polymerizable compounds or polyfunctional free radical polymerizable compounds having two or more polymerizable functional groups. Furthermore, these free radical polymerizable compounds can be used alone or in combination of two or more. As these free radical polymerizable compounds, compounds having a (meth)acryloyl group are preferred, for example. It should be noted that in this invention, (meth)acryloyl refers to acryloyl and / or methacryloyl, and "(meth)" has the same meaning below.

[0061] Examples of monofunctional free radical polymerizable compounds include (meth)acrylamide derivatives having a (meth)acrylamide group. (meth)acrylamide derivatives are preferred in terms of ensuring adhesion to polarizers and various transparent protective films, as well as in terms of fast polymerization speed and excellent productivity. Specific examples of (meth)acrylamide derivatives include: N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, N-hexyl (meth)acrylamide, and other N-alkyl (meth)acrylamide derivatives; N-hydroxymethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, N-hydroxymethyl-N-propyl (meth)acrylamide, and other N-hydroxyalkyl (meth)acrylamide derivatives; aminomethyl (meth)acrylamide, aminoethyl (meth)acrylamide, and other N-aminoalkyl (meth)acrylamide derivatives; N-methoxymethylacrylamide, N-ethoxymethylacrylamide, and other N-alkoxy (meth)acrylamide derivatives; mercaptomethyl (meth)acrylamide, mercaptoethyl (meth)acrylamide, and other N-mercaptoalkyl (meth)acrylamide derivatives; and so on. In addition, heterocyclic (meth)acrylamide derivatives in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle can be exemplified by, for example, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine, etc.

[0062] Among the aforementioned (meth)acrylamide derivatives, N-hydroxyalkyl (meth)acrylamide derivatives are preferred from the perspective of adhesion to polarizing mirrors and various transparent protective films. In addition, various (meth)acrylic acid derivatives having (meth)acryloyloxy groups can be listed as monofunctional free radical polymerizable compounds. Specific examples include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, 2-methyl-2-nitropropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, tert-pentyl methacrylate, 3-pentyl methacrylate, 2,2-dimethylbutyl methacrylate, n-hexyl methacrylate, hexadecyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, 4-methyl-2-propylpentyl methacrylate, n-octadecyl methacrylate, and other alkyl esters of methacrylate (1-20 carbon atoms).

[0063] In addition, examples of the aforementioned (meth)acrylic acid derivatives include: cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, and other cycloalkyl (meth)acrylates; benzyl (meth)acrylate and other aralkyl (meth)acrylates; 2-isoborneol (meth)acrylate, 2-norborneol methyl (meth)acrylate, 2-norborneol methyl (meth)acrylate, 5-norbornen-2-yl methyl (meth)acrylate, 3-methyl-2-norborneol methyl (meth)acrylate, and (meth)acrylic acid... Polycyclic (meth)acrylates such as dicyclopentenyl ester, dicyclopentenoxyethyl ester, and dicyclopentyl ester; (meth)acrylates containing alkoxy or phenoxy groups such as 2-methoxyethyl ester, 2-ethoxyethyl ester, 2-methoxymethoxyethyl ester, 3-methoxybutyl ester, ethyl carbitol ester, phenoxyethyl ester, and alkylphenoxy polyethylene glycol ester; etc.

[0064] In addition, examples of the above-mentioned (meth)acrylic acid derivatives include: 2-hydroxyethyl (meth)acrylic acid, 2-hydroxypropyl (meth)acrylic acid, 3-hydroxypropyl (meth)acrylic acid, 2-hydroxybutyl (meth)acrylic acid, 4-hydroxybutyl (meth)acrylic acid, 6-hydroxyhexyl (meth)acrylic acid, 8-hydroxyoctyl (meth)acrylic acid, 10-hydroxydecyl (meth)acrylic acid, 12-hydroxylaurate (meth)acrylic acid, etc.; hydroxyalkyl (meth)acrylic acid esters such as [4-(hydroxymethyl)cyclohexyl]methyl acrylate, cyclohexanediol mono(meth)acrylic acid, 2-hydroxy-3-phenoxypropyl (meth)acrylic acid, etc.; glycidyl (meth)acrylic acid, 4-hydroxybutyl (meth)acrylic acid glycidyl ether, etc., containing epoxy groups; 2,2,2-trifluoroethyl (meth)acrylic acid, etc. Halogenated (meth)acrylates such as 2,2,2-trifluoroethyl ethyl ester, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, and 3-chloro-2-hydroxypropyl (meth)acrylate; alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate; oxy-heterocyclic butyl (meth)acrylates such as 3-oxetane butyl methyl (meth)acrylate, 3-methyloxetane butyl methyl (meth)acrylate, 3-ethyloxetane butyl methyl (meth)acrylate, 3-butyloxetane butyl methyl (meth)acrylate, and 3-hexyloxetane butyl methyl (meth)acrylate; heterocyclic (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and butyrolactone (meth)acrylate; neopentyl glycol (meth)acrylate adducts of hydroxypentanoic acid; and p-phenylphenol (meth)acrylate.

[0065] In addition, examples of monofunctional free radical polymerizable compounds include: (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and other carboxyl-containing monomers.

[0066] In addition, examples of monofunctional free radical polymerizable compounds include: N-vinylpyrrolidone, N-vinyl-ε-caprolactam, methylvinylpyrrolidone, and other lactam vinyl monomers; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazolium, and vinylpyrrole. Vinyl monomers containing nitrogen-containing heterocycles, such as azoles and vinylmorpholine.

[0067] Furthermore, as a monofunctional radical polymerizable compound, a radical polymerizable compound having an active methylene group can be used. A radical polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acryloyl group at the end or in the molecule, and having an active methylene group. Examples of active methylene groups include acetoacetyl, alkoxymalonyl, or cyanoacetyl. The preferred active methylene group is acetoacetyl. Specific examples of free radical polymerizable compounds containing an active methylene group include: 2-acetylacetoxyethyl methacrylate, 2-acetylacetoxyethyl propyl methacrylate, 2-acetylacetoxyethyl-1-methylethyl methacrylate, and other acetylacetoxyethyl alkyl methacrylates; 2-ethoxymalonyl ethyl methacrylate, 2-cyanoacetoxyethyl methacrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl)acrylamide, N-(4-acetylacetoxyethylmethylbenzyl)acrylamide, N-(2-acetylacetylaminoethyl)acrylamide, etc. The preferred free radical polymerizable compound containing an active methylene group is an acetylacetoxyethyl alkyl methacrylate.

[0068] In addition, examples of multifunctional free radical polymerizable compounds having two or more polymerizable functional groups include: tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, cyclic trimethylolpropane formal(meth)acrylate, and dimethylolpropane formal(meth)acrylate. Esterifications of methacrylic acid and polyols, such as alkyldiol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and EO-modified diglycerol tetra(meth)acrylate, as well as 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. Specific examples include ARONIX M-220 (manufactured by Toa Synthetic Co., Ltd.), LIGHT ACRYLATE 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), LIGHT ACRYLATE DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), LIGHT ACRYLATE DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer Co., Ltd.), and CD-536 (manufactured by Sartomer Co., Ltd.). In addition, as needed, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, and various (meth)acrylate monomers can be listed.

[0069] In the polarizing film adhesive composition of the present invention, in addition to free radical polymerizable compounds, acrylic oligomers formed by polymerizing (meth)acrylic acid monomers may also be included. By including acrylic oligomers in the adhesive composition, curing shrinkage when the composition is irradiated with active energy rays and cured, and interfacial stress between the adhesive layer and the adhered objects such as polarizers and optical films, can be reduced. As a result, the reduction in adhesion between the adhesive layer and the adhered objects can be suppressed.

[0070] Considering workability and uniformity during application, a low viscosity is preferred for the adhesive composition used in polarizing films; therefore, the acrylic oligomer synthesized from (meth)acrylic acid monomers is also preferably low viscosity. As a low-viscosity acrylic oligomer capable of preventing curing shrinkage of the adhesive layer, its weight-average molecular weight (Mw) is preferably 15,000 or less, more preferably 10,000 or less, and particularly preferably 5,000 or less. On the other hand, to sufficiently suppress curing shrinkage of the cured layer (adhesive layer), the weight-average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1,000 or more, and particularly preferably 1,500 or more.Examples of (meth)acrylic acid monomers constituting acrylic oligomers include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, 2-methyl-2-nitropropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, tert-pentyl methacrylate, 3-pentyl methacrylate, 2,2-dimethylbutyl methacrylate, n-hexyl methacrylate, etc. Cetyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, 4-methyl-2-propylpentyl methacrylate, n-octadecyl methacrylate, and other alkyl methacrylates (1-20 carbon atoms), as well as cycloalkyl methacrylates (e.g., cyclohexyl methacrylate, cyclopentyl methacrylate, etc.), aralkyl methacrylates (e.g., benzyl methacrylate, etc.), polycyclic methacrylates (e.g., 2-isobornyl methacrylate, 2-norbornyl methacrylate, etc.). Borneol methyl ester, 5-norbornen-2-yl methyl methacrylate, 3-methyl-2-norbornol methyl methacrylate, etc.; hydroxyl-containing (meth)acrylates (e.g., hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,3-dihydroxypropyl methyl butyl methacrylate, etc.); alkoxy or phenoxy (meth)acrylates (2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-methoxymethoxyethyl methacrylate, 3-methoxybutyl methacrylate). Ethyl carbitol acrylate (meth)acrylate, phenoxyethyl acrylate (meth)acrylate, etc.), epoxy-containing meth)acrylates (e.g., glycidyl acrylate (meth)acrylate, etc.), halogen-containing meth)acrylates (e.g., 2,2,2-trifluoroethyl meth)acrylate, 2,2,2-trifluoroethyl meth)acrylate, tetrafluoropropyl meth)acrylate, hexafluoropropyl meth)acrylate, octafluoropentyl meth)acrylate, heptadecafluorodecyl meth)acrylate, etc.), alkylaminoalkyl meth)acrylates (e.g., dimethylaminoethyl meth)acrylate, etc.). These meth)acrylates can be used alone or in combination of two or more. Specific examples of acrylic oligomers (E) include "ARUFON" manufactured by Toa Synthetic Co., Ltd., "ACTFLOW" manufactured by Soken Chemical Co., Ltd., and "JONCRYL" manufactured by BASF Japan Ltd.

[0071] The amount of acrylic oligomers in the composition is typically preferred to be 15 parts by weight or less, relative to the total amount of monomer components in 100 parts by weight. Excessive content of acrylic oligomers in the composition can lead to a sharp decrease in the reaction rate when the composition is irradiated with active energy rays, resulting in poor curing. On the other hand, to sufficiently suppress curing shrinkage of the adhesive layer, it is preferable to contain 3 parts by weight or more of acrylic oligomers in the composition.

[0072] In the case of using free radical polymerizable compounds, the photopolymerization initiator can be appropriately selected based on the active energy of the radiation. In the case of curing by ultraviolet or visible light, a photopolymerization initiator that undergoes ultraviolet or visible light pyrolysis is used. Examples of such photopolymerization initiators include: benzoyl, benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, and other benzophenone compounds; aromatic ketone compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)one, α-hydroxy-α,α′-dimethylacetophenone, 2-methyl-2-hydroxyphenylacetone, α-hydroxycyclohexylphenyl ketone, and other aromatic ketone compounds; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one, and other acetophenone compounds; benzoin methyl ether. Benzoin ethers, such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisolein methyl ether; aromatic ketals, such as benzoin dimethyl ketal; aromatic sulfonyl chlorides, such as 2-naphthalenesulfonyl chloride; photoactive oximes, such as 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthones, such as 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone; camphorquinone; haloketones; acylphosphine oxides; and acylphosphonates.

[0073] When the total amount of the active energy ray curable adhesive composition is set to 100% by weight, the amount of the above-mentioned photopolymerization initiator is 20% by weight or less. The amount of the photopolymerization initiator is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, and even more preferably 0.1 to 5% by weight.

[0074] Furthermore, when using the polarizing film curable adhesive of the present invention in a visible light curable form containing a free radical polymerizable compound as a curing component, it is particularly preferable to use a photopolymerization initiator that is highly sensitive to light above 380 nm. The photopolymerization initiator that is highly sensitive to light above 380 nm will be described later.

[0075] As the above-mentioned photopolymerization initiator, it is preferred to use the compound shown in general formula (1) alone; or to use the compound shown in general formula (1) in combination with the photopolymerization initiator with high sensitivity to light above 380 nm described later.

[0076] [Chemical Formula 1]

[0077]

[0078] (where R is in the formula) 1 and R 2 Represents -H, -CH2CH3, -iPr, or Cl, R 1 and R 2 (These may be the same or different). When using the compound shown in general formula (1), the adhesion is superior compared to using a photopolymerization initiator with high sensitivity to light above 380 nm alone. Among the compounds shown in general formula (1), R is particularly preferred. 1 and R 2 The compound is diethylthioxanthone with the formula -CH2CH3. The composition ratio of the compound represented by general formula (1) in the adhesive composition is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, and even more preferably 0.9 to 3 parts by weight, relative to 100 parts by weight of the total curing component.

[0079] In addition, it is preferable to add a polymerization initiator as needed. Examples of polymerization initiators include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate, with ethyl 4-dimethylaminobenzoate being particularly preferred. When using a polymerization initiator, its amount added relative to 100 parts by weight of the total curing component is typically 0 to 5 parts by weight, preferably 0 to 4 parts by weight, and most preferably 0 to 3 parts by weight.

[0080] In addition, known photopolymerization initiators can be used in combination as needed. Since transparent protective films with UV absorption capabilities do not transmit light below 380 nm, photopolymerization initiators that are highly sensitive to light above 380 nm are preferred. Examples include: 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis(η5-2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium, etc.

[0081] In particular, in addition to photopolymerization initiators of general formula (1), compounds represented by the following general formula (2) are preferably further used as photopolymerization initiators.

[0082] [Chemical Formula 2]

[0083]

[0084] (where R is in the formula) 3 R 4 and R 5 Represents H, -CH3, -CH2CH3, -iPr, or Cl, R 3 R 4 and R 5 (These may be the same or different). As the compound represented by general formula (2), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one (trade name: Omnirad 907, manufacturer: IGM Resins), which is commercially available, can be used appropriately. In addition, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (trade name: Omnirad 369, manufacturer: IGM Resins) and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone (trade name: Omnirad 379, manufacturer: IGM Resins) are preferred due to their high sensitivity.

[0085] In this invention, a hydroxyl-containing photopolymerization initiator is preferably used among the aforementioned photopolymerization initiators. When the active energy ray-curable adhesive composition contains a hydroxyl-containing photopolymerization initiator as a polymerization initiator, the solubility of the adhesive layer with a high concentration of component A on the polarizer side is improved, and the curing properties of the adhesive layer are improved. Examples of photopolymerization initiators containing hydroxyl groups include: 2-methyl-2-hydroxyphenylacetone (trade name "DAROCUR1173", manufactured by BASF), 1-hydroxycyclohexylphenyl ketone (trade name: Omnirad 184, manufacturer: IGM Resins), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one (trade name: Omnirad 2959, manufacturer: IGM Resins), and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanoyl)-benzyl]phenyl}-2-methyl-propane-1-one (trade name: Omnirad 127, manufacturer: IGM Resins). 1-hydroxycyclohexylphenyl ketone is particularly preferred due to its excellent solubility in adhesive layers with high concentrations of component A.

[0086] Cationic polymeric compounds used in cationic polymeric adhesive compositions can be classified into monofunctional cationic polymeric compounds having one cationic polymeric functional group within the molecule, and polyfunctional cationic polymeric compounds having two or more cationic polymeric functional groups within the molecule. Since monofunctional cationic polymeric compounds have lower liquid viscosity, the liquid viscosity of the resin composition can be reduced by including a monofunctional cationic polymeric compound in the resin composition. Furthermore, monofunctional cationic polymeric compounds generally possess functional groups exhibiting various functions; by including a monofunctional cationic polymeric compound in the cationic polymeric adhesive composition, various functions can be exhibited in the cationic polymeric adhesive composition and / or the cured cationic polymeric adhesive composition. Polyfunctional cationic polymeric compounds are preferred because they can cause three-dimensional crosslinking in the cured cationic polymeric adhesive composition. Regarding the ratio of monofunctional cationic polymeric compounds to polyfunctional cationic polymeric compounds, it is preferable to mix the polyfunctional cationic polymeric compounds in the range of 10 to 1000 parts by weight relative to 100 parts by weight of the monofunctional cationic polymeric compound. Examples of cationic polymeric functional groups include epoxy groups, oxetyl groups, and vinyl ether groups. Examples of compounds containing epoxy groups include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds. Due to their excellent curability and adhesive properties, alicyclic epoxy compounds are particularly preferred as the cationic polymeric adhesive composition of the present invention. Examples of alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, caprolactone-modified versions of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, trimethylcaprolactone-modified versions, and valproic acid-modified versions. Specific examples include CELLOXIDE 2021, CELLOXIDE 2021A, CELLOXIDE 2021P, CELLOXIDE2081, CELLOXIDE2083, CELLOXIDE 2085 (all manufactured by Celero Chemical Industry Co., Ltd.), Cyracure UVR-6105, Cyracure UVR-6107, Cyracure 30, and R-6110 (all manufactured by Dow Chemical Japan Ltd.). Compounds containing oxocyclic butyl groups are preferred because they improve the curability of cationic polymeric curable adhesive compositions and reduce the liquid viscosity of the composition.Examples of compounds containing oxetane groups include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetane)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, di[(3-ethyl-3-oxetane)methyl] ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, and phenolic varnish oxetane. Commercially available examples include ARON OXETANE OXT-101, ARON OXETANE OXT-121, ARON OXETANE OXT-211, ARON OXETANE OXT-221, and ARON OXETANE OXT-212 (all manufactured by Toa Synthetic Co., Ltd.). Compounds containing vinyl ether groups are preferred because they improve the curability of cationic polymerizable adhesive compositions and reduce the liquid viscosity of the composition. Examples of compounds containing a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, cyclohexanediethanol divinyl ether, cyclohexanediethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, and pentaerythritol-type tetravinyl ether.

[0087] The cationic polymerizable adhesive composition contains at least one compound selected from the above-described compounds having epoxy groups, oxetyl groups, and vinyl ether groups as a curing component. These are all substances that are cured by cationic polymerization, and therefore a photocationic polymerization initiator is incorporated. This photocationic polymerization initiator generates cationic species or Lewis acids upon irradiation with active energy rays such as visible light, ultraviolet light, X-rays, and electron beams, thereby initiating the polymerization reaction of epoxy groups and oxetyl groups. As a photocationic polymerization initiator, a photoacid generator described later can be suitably used. Furthermore, when using the cationic polymerizable adhesive composition as a visible light curable material, a photocationic polymerization initiator with high sensitivity to light above 380 nm is particularly preferred. However, photocationic polymerization initiators are compounds that typically exhibit maximum absorption in the wavelength region around 300 nm or shorter than 300 nm. Therefore, by incorporating a photosensitizer that exhibits maximum absorption in a longer wavelength region, specifically longer than 380 nm, light at nearby wavelengths can be sensed, promoting the generation of cationic species or acids from the photocationic polymerization initiator. Examples of photosensitizers include anthracene compounds, pyrene compounds, carbonyl compounds, organosulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreducing pigments. Two or more of these can also be used in combination. Anthracene compounds are particularly preferred due to their excellent photosensitizing effect; specific examples include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Chemical Co., Ltd.). The photosensitizer content is preferably 0.1% to 5% by weight, more preferably 0.5% to 3% by weight.

[0088] The various components of the polarizing film of the present invention will be described below. In the present invention, the polarizing film includes: a polarizing lens, and an adhesive layer adjacent to the polarizing lens or an optical film other than the polarizing lens.

[0089] <Polarizing Filter>

[0090] Polyvinyl alcohol (PVA) films, suitable for use in polarizers, are made from PVA or its derivatives. Examples of PVA derivatives include PVA formal and PVA acetal. Additionally, derivatives of PVA modified with olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid and their alkyl esters, and acrylamide, are also examples. Typically, PVAs with a degree of polymerization of approximately 1000–10000 and a degree of saponification of approximately 80–100 mol% are used.

[0091] Polyvinyl alcohol (PVA) films may contain additives such as plasticizers. Examples of plasticizers include polyols and their condensates, such as glycerol, diglycerol, triglyceride, ethylene glycol, propylene glycol, and polyethylene glycol. There are no particular restrictions on the amount of plasticizer used, but less than 20% by weight is suitable in PVA films.

[0092] When manufacturing a polarizing lens, a dyeing process is performed to stain the polyvinyl alcohol film with iodine, and a stretching process is performed to stretch the polyvinyl alcohol film in at least one direction. Generally, a series of processes including swelling, dyeing, crosslinking, stretching, washing and drying can be used to process the polyvinyl alcohol film.

[0093] The swelling process can be performed, for example, by immersing the polyvinyl alcohol (PVA) film in a swelling bath (water bath). This treatment allows the PVA film to swell while simultaneously cleaning the surface of the film from dirt and anti-blocking agents, thereby preventing uneven dyeing and other irregularities. Glycerin, potassium iodide, etc., can also be appropriately added to the swelling bath. The temperature of the swelling bath is typically around 20–60°C, and the immersion time is typically around 0.1–10 minutes.

[0094] The dyeing process can be carried out, for example, by immersing a polyvinyl alcohol film in an iodine solution. The iodine solution is typically an aqueous solution containing iodine and potassium iodide as a dissolving agent. The iodine concentration is typically about 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight. The potassium iodide concentration is typically about 0.01 to 10% by weight, preferably 0.02 to 8% by weight.

[0095] In the iodine dyeing process, the temperature of the iodine solution is typically around 20–50°C, preferably 25–40°C. The immersion time is typically around 10–300 seconds, preferably in the range of 20–240 seconds. During iodine dyeing, the concentration of the iodine solution, the immersion temperature of the polyvinyl alcohol film in the iodine solution, and the immersion time are preferably adjusted in a manner that ensures the iodine and potassium content in the polyvinyl alcohol film reaches the above-mentioned ranges.

[0096] The crosslinking process can be carried out, for example, by immersing an iodine-dyed polyvinyl alcohol film in a treatment bath containing a crosslinking agent. Any suitable crosslinking agent can be used. Specific examples of crosslinking agents include boric acid, boron compounds such as borax, glyoxal, and glutaraldehyde. These crosslinking agents can be used alone or in combination. The solvent for the solution used in the crosslinking bath is usually water, but an organic solvent miscible with water can also be added appropriately. The crosslinking agent is usually used at a ratio of 1 to 10 parts by weight relative to 100 parts by weight of the solvent. Preferably, the solution of the crosslinking bath further contains auxiliaries such as iodides. The concentration of the auxiliaries is preferably 0.05 to 15% by weight, more preferably 0.5 to 8% by weight. The temperature of the crosslinking bath is usually around 20 to 70°C, preferably 40 to 60°C. The immersion time in the crosslinking bath is usually around 1 second to 15 minutes, preferably 5 seconds to 10 minutes.

[0097] The stretching process is the process of stretching a polyvinyl alcohol (PVA) film in at least one direction. Generally, the PVA film is stretched unidirectionally along the transport direction (length direction). There are no particular limitations on the stretching method; either wet stretching or dry stretching can be used. In the case of wet stretching, the PVA film is stretched to a given ratio in a processing bath. The solution for the stretching bath can be a solution obtained by adding compounds necessary for various processes to a solvent such as water or an organic solvent (e.g., ethanol). Examples of dry stretching methods include, for instance, roller stretching, heated roller stretching, and compression stretching. In the manufacture of polarizing mirrors, the stretching process can be performed at any stage. Specifically, it can be performed simultaneously with swelling, dyeing, and crosslinking, or at any time before or after these processes. Furthermore, stretching can be performed in multiple stages. The cumulative stretch ratio of the PVA film is typically 5 times or more, preferably around 5 to 7 times.

[0098] In this invention, the polarizer preferably contains a metal component that can become a divalent metal cation in water, more preferably magnesium, calcium, copper, or zinc, and particularly preferably zinc. By including zinc in the polarizer, the tendency for the transmittance of the polarizing film to decrease and for hue to deteriorate after heating tests can be suppressed. When the polarizer contains zinc, the zinc content in the polarizer is preferably 0.002 to 2% by weight, more preferably 0.01 to 1% by weight.

[0099] In this invention, it is preferable that the polarizer contains sulfate ions. By including sulfate ions in the polarizer, there is a tendency to suppress the decrease in the transmittance of the polarizing film after heating. When the polarizer contains sulfate ions, the sulfate ion content in the polarizer is preferably 0.02 to 0.45% by weight, more preferably 0.05 to 0.35% by weight, and even more preferably 0.1 to 0.25% by weight. It should be noted that the sulfate ion content in the polarizer can be calculated based on the sulfur atom content.

[0100] To ensure the polarizer contains zinc, it is preferable to perform a zinc impregnation treatment during the polarizer manufacturing process. Furthermore, to ensure the polarizer contains sulfate ions, it is preferable to perform a sulfate ion treatment during the polarizer manufacturing process.

[0101] Zinc impregnation treatment can be carried out, for example, by impregnating a polyvinyl alcohol membrane in a zinc salt solution. As the zinc salt, inorganic chlorine compounds such as aqueous solutions of zinc halides (e.g., zinc chloride, zinc iodide), zinc sulfate, and zinc acetate are preferred. Various zinc complexes can also be used in the zinc impregnation treatment. Furthermore, when the zinc salt solution is an aqueous solution containing potassium and iodide ions, such as potassium iodide, zinc ion impregnation is facilitated, and therefore preferred. The concentration of potassium iodide in the zinc salt solution is preferably set to about 0.5 to 10% by weight, and more preferably 1 to 8% by weight.

[0102] Sulfate ion treatment can be carried out, for example, by impregnating a polyvinyl alcohol membrane in an aqueous solution containing a metal sulfate salt. Preferably, the metal sulfate salt is one that readily separates into sulfate ions and metal ions in the treatment solution and is readily introduced into the polyvinyl alcohol membrane in an ionic state. Examples of metals that form the metal sulfate salt include alkali metals such as sodium and potassium; alkaline earth metals such as magnesium and calcium; and transition metals such as cobalt, nickel, zinc, chromium, aluminum, copper, manganese, and iron.

[0103] In the manufacture of the polarizer, the aforementioned zinc infiltration treatment and sulfate ion treatment can be performed at any stage. That is, the zinc infiltration treatment and sulfate ion treatment can be performed before or after the dyeing process. The zinc infiltration treatment and sulfate ion treatment can also be performed simultaneously. In this invention, it is preferable to use zinc sulfate as both the zinc salt and the metal sulfate salt, and to impregnate the polyvinyl alcohol film in a treatment bath containing zinc sulfate while simultaneously performing the zinc infiltration treatment and sulfate ion treatment. Alternatively, the zinc salt and the metal sulfate salt can be pre-existing in the dyeing solution, and the zinc infiltration treatment and / or sulfate ion treatment can be performed simultaneously with the dyeing process. The zinc infiltration treatment and sulfate ion treatment can also be performed simultaneously with stretching.

[0104] In zinc impregnation and sulfate ion treatment, the zinc and sulfate ion content in the polarizer are adjusted by modifying the concentrations of the zinc salt solution and the metal sulfate solution, the immersion temperature of the polyvinyl alcohol film in the treatment bath, and the immersion time. In zinc impregnation and sulfate ion treatment, the temperature of the zinc salt solution and the metal sulfate solution is typically around 15–85°C, preferably 25–70°C. The immersion time is typically around 1–120 seconds, preferably in the range of 3–90 seconds. The concentrations of the zinc salt solution and the metal sulfate solution vary depending on the type of zinc salt and metal sulfate, typically ranging from 0.5–20% by weight, preferably 1–10% by weight, and more preferably 2–7% by weight. By setting the zinc salt concentration and the metal sulfate concentration within this range, the zinc and sulfate ion content in the polarizer can be set within the aforementioned preferred ranges.

[0105] The polyvinyl alcohol film (stretch film) that has undergone the above treatments is then subjected to a water washing process and a drying process, using the usual method.

[0106] The washing process is typically performed by immersing a polyvinyl alcohol (PVA) membrane in a water bath. The water bath can be pure water or an aqueous solution of an iodide (e.g., potassium iodide, sodium iodide, etc.). The concentration of the iodide aqueous solution is preferably 0.1–10% by weight. Additives such as zinc sulfate or zinc chloride may also be added to the iodide aqueous solution.

[0107] The washing temperature is typically 5–50°C, preferably 10–45°C, and more preferably 15–40°C. The immersion time is typically 10–300 seconds, preferably 20–240 seconds. The washing process can be performed only once or multiple times as needed. When performing multiple washing processes, the type and concentration of additives in the water bath used for each treatment can be adjusted appropriately.

[0108] The drying process of the polyvinyl alcohol film can be carried out by any suitable method (e.g., natural drying, air drying, heat drying). The thickness of the polarizer after the drying process is preferably 3–20 μm.

[0109] In this invention, the obtained polarizer undergoes surface modification treatment. Examples of surface modification treatments include corona treatment, plasma treatment, and ITRO treatment, with corona treatment being particularly preferred. By performing corona treatment, reactive functional groups such as carbonyl and amino groups are generated on the surface of the polarizer, improving its adhesion to the durability-enhancing layer. Furthermore, surface impurities can be removed or surface unevenness can be reduced through ashing, thereby producing a polarizing film with excellent appearance properties.

[0110] <Optical film>

[0111] In this invention, the optical film included in the polarizing film can be, for example, a transparent protective film or a phase retardation film. It should be noted that not only the polarizer but also the optical film can undergo surface modification treatment. Examples of surface modification treatments include corona treatment, plasma treatment, and ITRO treatment, with corona treatment being particularly preferred.

[0112] As materials for transparent protective films, thermoplastic resins with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy can be used. Specific examples of such thermoplastic resins include cellulose resins such as cellulose triacetate, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The transparent protective film may contain one or more suitable additives. Examples of additives include: ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. The content of the aforementioned thermoplastic resin in the transparent protective film is preferably 50–100% by weight, more preferably 50–99% by weight, further preferably 60–98% by weight, and particularly preferably 70–97% by weight. When the content of the aforementioned thermoplastic resin in the transparent protective film is less than 50% by weight, there are concerns that the high transparency inherent in the thermoplastic resin may not be fully expressed.

[0113] Furthermore, as the material for forming the transparent protective film, materials with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy are preferred, especially those with a moisture permeability of 150 g / m². 2 / less than 24h, especially preferred is 140g / m 2 / less than 24h, further preferably 120g / m 2 / less than 24 hours.

[0114] Functional layers such as a hard coating, anti-reflective layer, anti-adhesion layer, diffusion layer, or anti-glare layer can be applied to the side of the transparent protective film that is not bonded to the polarizer. It should be noted that the aforementioned functional layers such as the hard coating, anti-reflective layer, anti-adhesion layer, diffusion layer, and anti-glare layer can be used not only to protect the transparent protective film itself, but also to be separately applied as layers different from the transparent protective film.

[0115] The thickness of the transparent protective film can be appropriately determined. Generally, considering factors such as strength, processability, and thinness, it is approximately 1–500 μm, preferably 1–300 μm, and more preferably 5–200 μm. Further preferably, it is 10–200 μm, and more preferably 20–80 μm.

[0116] As the aforementioned transparent protective film, a phase retardation film with a frontal phase difference of 40 nm or more and / or a thickness direction phase difference of 80 nm or more can be used. Typically, the frontal phase difference is controlled within the range of 40–200 nm, and the thickness direction phase difference is typically controlled within the range of 80–300 nm. When a phase retardation film is used as a transparent protective film, it also functions as a transparent protective film, thus enabling thinner designs.

[0117] Examples of phase retardation films include: birefringent films formed by unidirectional or bidirectional stretching of polymer raw materials; alignment films of liquid crystal polymers; and phase retardation films formed by using a film to support an alignment layer of liquid crystal polymers. The thickness of phase retardation films is not particularly limited, generally ranging from 20 to 150 μm.

[0118] As a phase retardation film, an inverse wavelength dispersion type phase retardation film that satisfies the following equations (1) to (3) can be used:

[0119] 0.70<Re

[450] / Re

[550] <0.97···(1)

[0120] 1.5×10 -3 <Δn<6×10 -3 ···(2)

[0121] 1.13 < NZ < 1.50 ···(3)

[0122] (In the formula, Re

[450] and Re

[550] are the in-plane phase difference values ​​of the phase difference film measured at 23℃ using light with wavelengths of 450nm and 550nm, respectively. Δn is nx-ny, i.e., in-plane birefringence, when the refractive indices of the slow axis and fast axis of the phase difference film are set to nx and ny, respectively. NZ is the ratio of nx-nz to nx-ny when nz is set as the refractive index of the thickness direction of the phase difference film, where nx-nz is the thickness direction birefringence and nx-ny is the in-plane birefringence).

[0123] The polarizing film of the present invention can be manufactured, for example, by the following manufacturing method.

[0124] A method for manufacturing a polarizing film, the polarizing film comprising: a polarizer, and an adhesive layer adjacent to a first optical film other than the polarizer, the adhesive layer being a cured layer of the adhesive composition for polarizing films of the present invention, the method comprising: a first bonding step of bonding the polarizer and the first optical film together via an aqueous adhesive layer; and a second bonding step of bonding the first optical film and a second optical film together via the adhesive layer. The polarizer preferably contains a metal component capable of becoming a divalent metal cation in water, particularly zinc. Furthermore, the adhesive layer is preferably formed by curing an active energy radiation-curable adhesive composition.

[0125] Alternatively, the polarizing film of the present invention can also be manufactured by the following manufacturing method.

[0126] A method for manufacturing a polarizing film, the polarizing film comprising: a polarizer and an adhesive layer adjacent to the polarizer, the method comprising: a first bonding step of bonding the polarizer and a first optical film together via the adhesive layer. The polarizer preferably contains a metal component capable of becoming a divalent metal cation in water, particularly zinc. Furthermore, the adhesive layer is preferably formed by curing a cured layer of an active energy radiation-curable adhesive composition.

[0127] In the above bonding process, various adhesive compositions are applied to the substrates such as polarizers and optical films, the substrates are then bonded together, and the adhesive composition is cured. Methods for applying the adhesive composition can be selected appropriately based on the viscosity and target thickness of the adhesive composition; examples include: reverse coaters, gravure coaters (direct, reverse, or offset), rod reverse coaters, roller coaters, die coaters, wire-wound rod coaters, and bar coaters. The bonding of the substrates such as polarizers and optical films can be performed using roller laminators, etc.

[0128] The aforementioned adhesive layer is formed by the cured layer of the adhesive composition for polarizing films of the present invention. Particularly preferred is the cured layer of an adhesive composition that is curable by active energy rays such as electron beam curability, ultraviolet curability, or visible light curability, which contains a cationic scavenger having coordination sites capable of coordinating with metal components in a two-toothed or greater manner, and reactive groups. In the bonding process, the adhesive composition is cured by irradiation with active energy rays (electron beam, ultraviolet light, visible light, etc.) to form the adhesive layer. The irradiation direction of the active energy rays (electron beam, ultraviolet light, visible light, etc.) can be any suitable direction. When manufacturing the polarizing film of the present invention on a continuous production line, the linear velocity varies depending on the curing time of the adhesive composition, preferably 5 to 100 m / min, more preferably 10 to 50 m / min, and even more preferably 20 to 30 m / min. If the linear velocity is too low, productivity is insufficient, or excessive damage to the transparent protective film occurs, making it impossible to produce a polarizing film capable of withstanding durability tests, etc. When the linear velocity is too high, the curing of the curable resin composition may become insufficient, and the target adhesion may not be achieved.

[0129] In practical applications, the polarizing film of the present invention can be fabricated into an optical film laminated with other optical layers. There are no particular limitations on the optical layer; for example, one or more layers of reflective plates, semi-transparent plates, phase retardation plates (including half-wave plates, quarter-wave plates, etc.), viewing angle compensation films, and other optical layers sometimes used in the formation of liquid crystal display devices can be used. Particularly preferred are reflective polarizing films or semi-transparent polarizing films formed by further laminating reflective plates or semi-transparent reflective plates onto the polarizing film of the present invention; elliptical polarizing films or circular polarizing films formed by further laminating phase retardation plates onto the polarizing film; wide-viewing-angle polarizing films formed by further laminating viewing angle compensation films onto the polarizing film; and polarizing films formed by further laminating brightness-enhancing films onto the polarizing film.

[0130] The optical film formed by stacking the aforementioned optical layers on a polarizing film can also be formed by sequentially stacking them one by one during the manufacturing process of liquid crystal display devices, etc. However, pre-stacking optical films has advantages such as superior quality stability and assembly operation, thereby improving the manufacturing process of liquid crystal display devices, etc. Suitable bonding methods such as adhesive layers can be used during the stacking. When bonding the aforementioned polarizing film and other optical films, their optical axes can be configured at suitable angles according to the target phase difference characteristics, etc.

[0131] An adhesive layer for bonding with other components such as liquid crystal cells can also be provided on the aforementioned polarizing film or optical film having at least one layer of polarizing film. There are no particular limitations on the adhesive forming the adhesive layer; adhesives using polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorinated polymers, and rubber polymers as the base polymer can be suitably selected. Acrylic adhesives, which exhibit excellent optical transparency and moderate wetting, cohesiveness, and adhesion properties, as well as excellent weather resistance and heat resistance, are particularly preferred.

[0132] The adhesive layer can be provided on one or both sides of the polarizing film or optical film in the form of a laminate of layers with different compositions or types. Furthermore, when provided on both sides, adhesive layers with different compositions, types, and thicknesses can be formed on the front and back surfaces of the polarizing film or optical film. The thickness of the adhesive layer can be appropriately determined according to the intended use, adhesion strength, etc., and is typically 1–100 μm, preferably 5–30 μm, and particularly preferably 10–20 μm.

[0133] The exposed surface of the adhesive layer is temporarily covered by an adhesive diaphragm until it is put into actual use to prevent contamination. This prevents contact with the adhesive layer under normal handling conditions. As the diaphragm, suitable diaphragms as previously specified can be used, in addition to the thickness requirements described above, by coating suitable thin materials such as plastic films, rubber sheets, paper, cloth, nonwoven fabrics, meshes, foam sheets, metal foils, and their laminates with suitable release agents such as silicone, long-chain alkyl, fluorine, and molybdenum sulfide as needed.

[0134] The polarizing film or optical film of the present invention can be preferably used in the formation of various devices such as liquid crystal display devices. The formation of a liquid crystal display device can be performed in a conventional manner. That is, a liquid crystal display device is typically formed by appropriately assembling a liquid crystal cell with a polarizing film or optical film, and components such as an illumination system used as needed, and incorporating a driving circuit. In the present invention, there are no particular limitations except for the use of the polarizing film or optical film of the present invention, and conventional methods can be followed. Regarding the liquid crystal cell, any type of liquid crystal cell, such as TN type, STN type, or π type, can be used.

[0135] Suitable liquid crystal display devices can be formed, such as liquid crystal display devices in which polarizing films or optical films are disposed on one or both sides of the liquid crystal cell, and liquid crystal display devices that use backlights or reflectors in the lighting system. In this case, the polarizing film or optical film of the present invention can be disposed on one or both sides of the liquid crystal cell. When polarizing films or optical films are disposed on both sides, they can be the same or different. Furthermore, during the formation of the liquid crystal display device, one or more suitable components such as diffuser plates, anti-glare layers, anti-reflective films, protective plates, prism arrays, lens array sheets, light diffuser plates, and backlights can be disposed at appropriate positions.

[0136] Example

[0137] The following describes embodiments of the present invention, but the implementation of the present invention is not limited to these.

[0138] <Manufacturing of Polarizing Lenses>

[0139] A polyvinyl alcohol (PVA) film with an average degree of polymerization of 2700 and a thickness of 45 μm was subjected to stretching and conveying while being dyed on rollers at different circumferential speeds. First, the PVA film was immersed in a water bath at 30°C for 1 minute to swell, and then stretched 1.2 times in the conveying direction (first stretch). Next, it was immersed in an aqueous solution of potassium iodide (0.03 wt%) and iodine (0.3 wt%) (liquid temperature 30°C) for 1 minute, and then stretched 3 times in the conveying direction while being dyed (unstretched film reference) (second stretch). Then, the stretched film was immersed in an aqueous solution of boric acid (4 wt%), potassium iodide (5 wt%), and zinc sulfate (3.5 wt%) (bath solution) for 30 seconds, and stretched 6 times in the conveying direction (unstretched film reference) (third stretch). The stretched film was then dried to obtain polarizer 1. The thickness of polarizer 1 after drying was 18 μm.

[0140] <Active Energy Rays>

[0141] As an active energy beam, a visible light (gallium-encased metal halide lamp) irradiation device was used: FusionUV Systems, Inc., Light HAMMER10, valve: V valve, peak illuminance: 1600 mW / cm². 2 Cumulative radiation dose 1000 mJ / cm 2 (Wavelength 380–440 nm). It should be noted that the illuminance of visible light was measured using the Sola-Check system manufactured by Solatell.

[0142] <Panel Lighting Test>

[0143] The on-dash monitor (TKH703) manufactured by MAXWIN was disassembled, and the LCD panel was removed. The polarizing film attached to the visible side of the LCD panel was peeled off. Instead, the polarizing film of each embodiment and comparative example was cut to the same size as the polarizing film obtained from the LCD panel and bonded to it via an adhesive layer (20 μm thick) in the same manner as the peeled polarizing film along the transmission axis to obtain the LCD panel.

[0144] The LCD panel obtained above was placed in an environment of 65°C and 95% humidity for 1000 hours, and then placed in a normal temperature and humidity environment for 24 hours. It was then reinstalled in a monitor frame obtained by disassembling the LCD panel, and a black image was displayed and confirmed by visual observation. The results were categorized as follows: cases where only a black image was displayed were marked as ○, and cases where a part of the image showed a white, hazy display defect were marked as ×.

[0145] <Third Optical Film>

[0146] The third optical film (phase difference film) used in the polarization film configuration described below is manufactured by the manufacturing method described below.

[0147] In a high-pressure reactor equipped with a stirrer, condenser, nitrogen inlet pipe, and thermometer, 48 parts by weight of hydroxypropyl methylcellulose (Shin-Etsu Chemical, trade name Metolose 60SH-50), 1560 parts by weight of distilled water, 8161 parts by weight of diisopropyl fumarate, 240 parts by weight of 3-ethyl-3-oxetanebutyl methyl acrylate, and 45 parts by weight of tert-butyl peroxypentanoate as a polymerization initiator were added. After nitrogen bubbling for 1 hour, the mixture was stirred and maintained at 49°C for 24 hours to carry out free radical suspension polymerization. The mixture was then cooled to room temperature, and the resulting suspension containing polymer particles was centrifuged. The obtained polymer was washed twice with distilled water and twice with methanol, and then dried under reduced pressure.

[0148] The obtained fumarate resin (a polymer with negative birefringence) was dissolved in a toluene / methyl ethyl ketone mixed solution (50 wt% / 50 wt% toluene / methyl ethyl ketone) to prepare a 20% solution. Then, 5 parts by weight of tributyl trimellitate as a plasticizer were added to 100 parts by weight of the fumarate resin to prepare a paste.

[0149] A biaxially oriented polyester (75 μm thick, 1350 mm wide) film was used as the support membrane. The tensile modulus (MD) of the support at 140 °C was 800 MPa.

[0150] The support film winding is placed in the feed section of the film-forming apparatus, and while the support film is fed out and transported downstream, it is heated in a heating furnace. The heating temperature is adjusted by changing the temperature of the atmosphere inside the heating furnace. The heating time is adjusted by changing the transport speed of the support. The adhesive prepared in Synthesis Example A is coated onto the heat-treated support to achieve a dried film thickness of 6.3 μm, and then dried at 140°C. The dried coating film and the support are wound together to form a laminate.

[0151] The aforementioned laminate was placed in the feed section of the stretching apparatus, and while being fed out and transported downstream, it underwent unidirectional stretching at its free end in a stretching furnace at a temperature of 140°C. The support was then peeled off from the stretched laminate to obtain a 6 μm thick retardation film. The stretching ratio was adjusted so that the in-plane retardation of the retardation film after peeling off the support was 35 nm.

[0152] Example 1

[0153] As an adhesive, an aqueous solution containing polyvinyl alcohol resin with acetylacetyl groups (average degree of polymerization 1200, degree of saponification 98.5 mol%, degree of acetylation 5 mol%) and hydroxymethyl melamine in a weight ratio of 3:1 was used. Using this adhesive, a second optical film (a cellulose triacetate film with a hard coating (manufactured by Fujifilm Co., Ltd., trade name "TG40UL", film thickness 40 μm)) was laminated on one side (the visible side) of the polarizer 1 using a roller laminator at a temperature of 30°C, and a first optical film (a cycloolefin film with phase difference (manufactured by Zeon Co., Ltd., trade name "ZT12", film thickness 17 μm)) was laminated on the other side (the image display unit side) of the polarizer 1 (the thickness of each aqueous adhesive layer was 0.1 μm). The film was then dried in an oven to produce a laminated film with optical films stacked on both sides of the polarizer.

[0154] Next, using an MCD coating machine (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roller line count: 1000 lines / inch, rotation speed 140% / pair linear speed), an adhesive composition adjusted to the proportions described in Table 1 was applied to the cyclic olefin film side with phase difference of the above-obtained laminated film, and the thickness was increased to 1 μm. This was then laminated onto the third optical film (film thickness 6 μm) using a roller lathe. Then, the adhesive composition was cured by irradiating the third optical film side with visible light through an active energy irradiation device, followed by hot air drying at 70°C for 3 minutes to obtain a polarizing film. The thickness of the dried adhesive layer was 1 μm, and the lamination was performed at a lamination linear speed of 25 m / min.

[0155] A polarizing film (500μm × 500μm) of Example 1 was bonded to one side of 0.7mm thick alkali-free glass via an adhesive layer (20μm thick), thus preparing a sample for humidification durability testing. This sample was placed in an environment of 65°C–95% humidity, and humidification durability tests were conducted for 500 or 1000 hours of exposure. For the humidification durability testing evaluation sample after the durability test, on the other side of the alkali-free glass where the polarizing film of Example 1 was bonded, an orthogonal Nicol polarizing film was bonded via an adhesive layer (20μm thick) with the transmission axes of each polarizing film perpendicular to the others. The sample was then placed under a backlight (with the polarizing film of Example 1 on the upper surface), and the number of bright spots from foreign matter within a 500μm × 500μm area was investigated by visual observation of the polarizing film of Example 1.

[0156] Examples 2-11 and Comparative Examples 1-10

[0157] The formulation of the adhesive composition and the thickness of the dried adhesive layer were changed to the conditions described in Table 1. Otherwise, the number of bright spots from foreign matter was investigated using the same method as in Example 1.

[0158] The details of each component listed in Table 1 are as follows.

[0159] • "FA1DDM" (unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone); trade name "PLACCELFA1DDM", manufactured by Daicel Co., Ltd.

[0160] • "ACMO" (acryloylmorpholine); trade name "ACMO", manufactured by KJ Chemical Co., Ltd.

[0161] • "9EG-A" (PEG400# diacrylate); trade name "LIGHT ACRYLATE 9EG-A", manufactured by Kyoei Chemical Co., Ltd.

[0162] • "UP-1190" (an acrylic oligomer formed by polymerizing (meth)acrylic acid monomers); trade name "ARUFON UP-1190", manufactured by Toa Synthetic Co., Ltd.

[0163] • "AAEM" (2-acetylacetoxyethyl methacrylate) (forms a cation scavenger when used in combination with ethylenediamine); trade name "AAEM", manufactured by Mitsubishi Chemical Corporation.

[0164] • "Ethylene diamine" (which forms a cation scavenger when used in combination with AAEM); trade name "Ethylene diamine", manufactured by Fujifilm and Koei Tecmo Chemical Co., Ltd.

[0165] • "DMAPAA" (Dimethylaminopropylacrylamide) (Cat scavenger); trade name "DMAPAA", manufactured by KJ Chemical Co., Ltd.

[0166] • "DMAEA" (N,N-dimethylaminoethyl acrylate) (cation scavenger); trade name "DMAEA", manufactured by KJ Chemical Co., Ltd.

[0167] • "X-12-967C" (3-trimethoxysilylpropylsuccinic anhydride) (cation scavenger); trade name "X-12-967C", manufactured by Shin-Etsu Chemical Co., Ltd.

[0168] • "Acrylic acid" (acrylic acid derivative) (additive); trade name "Acrylic acid", manufactured by Fujifilm and Kazumitsu Chemical Co., Ltd.

[0169] • "HOA-MS" (2-Acryloyloxyethyl succinate) (additive); trade name "HOA-MS", manufactured by Kyoei Chemical Co., Ltd.

[0170] • "HOA-HH" (2-Acryloyloxyethyl hexahydrophthalate) (additive); trade name "HOA-HH", manufactured by Kyoei Chemical Co., Ltd.

[0171] • "M-5300" (ω-carboxylated polycaprolactone (n≈2) monoacrylate) (additive); trade name "ARONIX M-5300", manufactured by Toa Synthetic Co., Ltd.

[0172] • "DMAA" (dimethylacrylamide) (additive); trade name "DMAA", manufactured by KJ Chemical Co., Ltd.

[0173] • "QM-HA05" (quaternary ammonium salt ionic liquid with olefinic unsaturated bonds) (additive); trade name "QM-HA05", manufactured by KJ Chemical Co., Ltd.

[0174] • "QM-KA05" (quaternary ammonium salt ionic liquid with olefinic unsaturated bonds) (additive); trade name "QM-KA05", manufactured by KJ Chemical Co., Ltd.

[0175] • "Omn.907" (2-Methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone) (additive); trade name "Omnirad 907", manufactured by IGM Resins.

[0176] • "DETX-S" (2,4-dimethylthioxanthone) (additive); trade name "KAYACURE DETX-S", manufactured by Nippon Kayaku Co., Ltd.

[0177]

[0178] According to the results in Table 1, the polarizing film having an adhesive layer formed from the adhesive compositions for polarizing films of Examples 1-11 exhibits a low number of bright spots even after immersion in an environment of 65°C and 95% for 1000 hours, resulting in excellent appearance characteristics. On the other hand, the polarizing film having an adhesive layer formed from the adhesive compositions of Comparative Examples 2-10 exhibits a high number of bright spots and deteriorates in appearance characteristics after immersion in an environment of 65°C and 95% for 500 hours. The adhesive compositions of Comparative Examples 2-10 contain additives that do not have coordination sites capable of coordinating metal components with two or more teeth.

Claims

1. A polarizing film comprising: polarizer, and An adhesive layer adjacent to the polarizer or an optical film other than the polarizer. The adhesive layer is a cured layer of an adhesive composition for polarizing films, and the adhesive layer contains oxalic acid. The adhesive composition for the polarizing film contains a compound with a functional group having carbon-carbon double bonds that is capable of free radical polymerization and a cation scavenger. The cation scavenger has a coordination site capable of coordinating with the metal component in a dodecanotic or more manner, and a reactive group. The reactive group of the cation scavenger is selected from at least one reactive group selected from vinyl, (meth)acryloyl, styryl, (meth)acrylamido, vinyl ether, epoxy, oxetyl, mercapto, and alkoxy. The polarizer contains a metal component that can become a divalent metal cation in water.

2. The polarizing film according to claim 1, wherein, The cation scavenger has a coordination site with at least two nitrogen atoms.

3. The polarizing film according to claim 1, wherein, The cation scavenger has a coordination site with at least two oxygen atoms.

4. The polarizing film according to claim 1, wherein, The cation scavenger has a coordination site having at least one nitrogen atom and at least one oxygen atom.

5. The polarizing film according to claim 1, wherein, The cation scavenger is selected from at least one of aminoalkylacrylamide, aminoalkyl acrylate, and compounds containing acetylacetyl groups or compounds containing acetylacetoxy groups reacting with primary amine compounds.

6. The polarizing film according to claim 1, wherein, The adhesive composition for polarizing films also contains active energy ray curing components.

7. The polarizing film according to claim 1, wherein, When the total amount of the adhesive composition for polarizing film is set to 100% by weight, the content of the cation scavenger is 0.5 to 15% by weight.

8. The polarizing film according to claim 1, wherein, The metal component is zinc.

9. The polarizing film according to any one of claims 1 to 7, The polarizing film comprises: polarizer, An optical film laminated to at least one side of the polarizer via an aqueous adhesive layer, and The adhesive layer is disposed on the side of the optical film opposite to the aqueous adhesive layer.

10. An optical film having at least one polarizing film as described in any one of claims 1 to 9 stacked thereon.

11. An image display device that uses the polarizing film according to any one of claims 1 to 9.

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