JP6657142B2 - Polarizing film and image display device - Google Patents

Description

  The present invention relates to a polarizing film. The polarizing film can form an image display device such as a liquid crystal display device (LCD) and an organic EL display device by itself or as an optical film obtained by laminating the polarizing film.

  In a liquid crystal display device, it is indispensable to arrange polarizing films on both sides of a glass substrate forming a liquid crystal panel surface due to its image forming method. Generally, a polarizing film is used in which a protective film is bonded to one or both surfaces of a polyvinyl alcohol-based film and a polarizer made of a dichroic material such as iodine with a polyvinyl alcohol-based adhesive or the like. .

  Further, the polarizing film is exposed to a severe environment depending on the use application and use condition. Therefore, the polarizing film is required to have durability that can maintain optical characteristics even in a severe environment. For example, it has been proposed to provide a urethane resin having a predetermined storage modulus on at least one surface of a polarizer (Patent Documents 1 and 2). According to Patent Documents 1 and 2, it is described that the orthogonal transmittance of a polarizing film can be maintained even at a high temperature.

JP-A-11-030715 JP-A-11-183726

  Further, the polarizing film may be used in a high-temperature and high-humidity environment in addition to a high-temperature environment. Under such a severe environmental atmosphere, it was found that the moisture in the environmental atmosphere affected the optical properties of the polarizer, and the degree of polarization was greatly reduced at the end of the polarizing film. However, by providing the polarizer with the urethane resin as described in Patent Documents 1 and 2, it has not been possible to sufficiently suppress the decrease in the degree of polarization at the end of the polarizing film.

  An object of the present invention is to provide a polarizing film that can suppress a decrease in the degree of polarization at an end even under a high-temperature and high-humidity environment.

  Another object of the present invention is to provide an image display device having the polarizing film.

  As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by the following polarizing film and the like, and have accomplished the present invention.

That is, the present invention is a polarizer, and a polarizing film having a first transparent layer on both surfaces of the polarizer,
85 ° C., 85% RH of the first transparent layer. H. At 85 ° C. and 85% R.V. of the polarizer. H. Lower than the saturated moisture content in
The present invention relates to a polarizing film, wherein the first transparent layer functions as a osmotic membrane for assisting discharge of water from the polarizer.

  In the polarizing film, the first transparent layer is preferably formed directly on a polarizer.

  In the polarizing film, the thickness of the first transparent layer is preferably 3 μm or less.

  In the polarizing film, as the first transparent layer, a cured product of a forming material containing a urethane prepolymer which is a reaction product of an isocyanate compound and a polyhydric alcohol can be used. As the isocyanate compound, it is preferable to use at least one selected from tolylene diisocyanate and diphenylmethane diisocyanate.

  In the polarizing film, the first transparent layer may have an 85 ° C., 85% R.C. H. Preferably has a gradient distribution such that the saturated water concentration in the sample gradually decreases from the polarizer side toward the opposite side to the polarizer.

  In the polarizing film, the thickness of the polarizer is preferably 10 μm or less.

The polarizing film, the first transparent layer on at least one side of the first transparent layer having both sides of the polarizer, on the side opposite to the side having the polarizer, having a second transparent layer adjacent,
85 ° C., 85% RH of the second transparent layer. H. At 85 ° C. and 85% R.C. of the first transparent layer. H. Lower than the saturated moisture content in
It is preferable that the water in the polarizer permeates in the order of the first transparent layer and the second transparent layer from the polarizer side.

  In the polarizing film, the second transparent layer includes an adhesive layer.

  In the polarizing film, the second transparent layer includes a protective film.

  The present invention also relates to an image display device having the polarizing film.

  Since the polarizer, which is a component of the polarizing film, is formed of an aqueous material, moisture in an environmental atmosphere is easily taken into the polarizer. Therefore, when the polarizing film is held in a high-temperature and high-humidity environment, it is considered that the saturated moisture content in the polarizer increases. As a result, the optical characteristics of the polarizing film tend to decrease. Particularly, in a high-temperature and high-humidity environment, a large amount of water penetrates into the polarizer, so that the degree of polarization at the edge of the polarizing film is greatly reduced, and a phenomenon called edge color loss has occurred. it is conceivable that.

  The polarizing film of the present invention has, on both surfaces of the polarizer, a first transparent layer that functions as a permeable membrane that helps discharge moisture in the polarizer. Since the saturated moisture content of the first transparent layer under a high-temperature and high-humidity environment is designed to be lower than the saturated moisture content of the polarizer, even if moisture in the environmental atmosphere enters the polarizer, Of the polarizer can be positively transmitted to the first transparent layer (permeable membrane) side having a saturated moisture content lower than the saturated moisture content of the polarizer. Can be discharged. As described above, the polarizing film of the present invention, having the first transparent layer, can suppress an increase in the saturated moisture content of the polarizer even in a high-temperature and high-humidity environment. The amount can be suppressed.

It is an example of a schematic sectional view of the polarizing film of the present invention. It is an example of a schematic sectional view of the polarizing film of the present invention. It is an example of a schematic sectional view of the polarizing film of the present invention.

Hereinafter, the polarizing film of the present invention will be described with reference to FIGS.
The polarizing film of the present invention includes, for example, a polarizer P and first transparent layers 1a and 1b (a permeable membrane: assists in draining water) on both surfaces of the polarizer P, such as a polarizing film 11 shown in FIGS. Having a function of a film). As shown in FIGS. 1 to 3, the first transparent layers 1a and 1b are provided directly on the polarizer P to suppress an increase in the saturated moisture content of the polarizer in a high-temperature and high-humidity environment. This is preferable from the viewpoint of suppressing color loss at the end. Only one of the first transparent layers 1a and 1b may be provided directly on the polarizer P.

  In addition, the polarizing film of the present invention includes, for example, at least one side of the first transparent layers 1a and 1b on both surfaces of the polarizer P of the polarizing film 11, like the polarizing films 12 and 13 shown in FIGS. The second transparent layer 2 (2a and / or 2b) can be further provided on the first transparent layers 1a and 1b. The polarizing film 12 of FIG. 2 has the first transparent layer 1a on one side of the first transparent layers 1a and 1b on both sides, and the polarizing film 13 of FIG. 3 has the first transparent layer on both sides of the first transparent layers 11a and 1b on both sides. This is a case where the second transparent layers 2a and 2b are further provided on the layers 1a and 1b. The second transparent layer 2 (2a and / or 2b) is provided directly on the first transparent layers 1a and 1b to suppress an increase in the saturated moisture content of the polarizer in a high-temperature and high-humidity environment. This is preferable from the viewpoint of suppressing color loss at the end.

  When an adhesive layer is used as the second transparent layer 2 in the polarizing films 12 and 13 of the present invention, a separator can be provided on the second transparent layer (adhesive layer). On the other hand, the polarizing films 11 to 13 of the present invention can be appropriately provided with a surface protective film.

<Polarizer>
The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include, for example, a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, a hydrophilic polymer film such as an ethylene-vinyl acetate copolymer-based partially saponified film, and dichroic properties of iodine and a dichroic dye. Examples thereof include a uniaxially stretched film obtained by adsorbing a substance, and a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrochlorinated product of polyvinyl chloride. Among these, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 80 μm or less.

  A polarizer which is obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching, for example, dyeing the polyvinyl alcohol-based film by immersing it in an aqueous solution of iodine and stretching the film to 3 to 7 times the original length can be produced. it can. If necessary, it can be immersed in an aqueous solution of potassium iodide or the like which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, dirt on the surface of the polyvinyl alcohol-based film and an anti-blocking agent can be washed off.Also, by swelling the polyvinyl alcohol-based film, the effect of preventing unevenness such as uneven dyeing can be obtained. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. Stretching can be performed in an aqueous solution of boric acid or potassium iodide or in a water bath.

  In the present invention, a polarizer having a thickness of 10 μm or less can be used. The thickness of the polarizer is preferably 8 μm or less, more preferably 7 μm or less, and further preferably 6 μm or less from the viewpoint of thinning. On the other hand, the thickness of the polarizer is preferably 2 μm or more, more preferably 3 μm or more. Such a thin polarizer has less thickness unevenness, is excellent in visibility, and has little dimensional change, and thus has excellent durability against thermal shock.

As a thin polarizer, typically,
Patent No. 4751486,
Patent No. 4,751,481,
Patent No. 4815544,
Patent No. 5048120,
WO 2014/077759 pamphlet,
International Publication No. 2014/077636 pamphlet,
And the like, or a thin polarizer obtained from the production method described therein.

The polarizer has an optical property represented by a single transmittance T and a degree of polarization P of the following formula: P>-(10 ^0.929T-42.4 -1) × 100 (where T <42.3); Or
It is configured to satisfy the condition of P ≧ 99.9 (where T ≧ 42.3). A polarizer configured to satisfy the above conditions has the performance required primarily as a display for a liquid crystal television using a large display element. Specifically, the contrast ratio is 1000: 1 or more and the maximum luminance is 500 cd / m ² or more. As another application, for example, it is bonded to the viewing side of the organic EL display device.

  Among the thin polarizers, Japanese Patent No. 4751486 and Patent Document 4 disclose that, among the production methods including a step of stretching in a state of a laminate and a step of dyeing, the polarizer can be stretched at a high magnification to improve polarization performance. Preferred are those obtained by a production method including a step of stretching in a boric acid aqueous solution as described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544, and particularly described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544. What is obtained by the manufacturing method including the process of auxiliary | assistant air stretching before extending | stretching in a boric acid aqueous solution which has a certain thing is preferable. These thin polarizers can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as a PVA-based resin) layer and a resin substrate for stretching in a laminated state and a step of dyeing. According to this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without any trouble such as breakage due to stretching because it is supported by the stretching resin base material.

  The polarizer of the present invention has a 85.degree. H. Is usually 10 to 40% by weight. The saturated water content of the polarizer may be 25% by weight or less, and further may be 18% by weight or less from the viewpoint of suppressing color loss at the edge. The saturated moisture content of the polarizer has no particular lower limit in relation to the first transparent layer as long as the saturated moisture content of the first transparent layer is lower than the saturated moisture content of the polarizer.

  The saturated water content of the polarizer of the present invention may be adjusted by any appropriate method. For example, there is a method of controlling by adjusting the conditions of the drying step in the manufacturing process of the polarizer.

<First transparent layer>
The first transparent layer is a layer that functions as a osmotic membrane to help discharge water from the polarizer. H. The one designed so that the saturated moisture percentage in the above is lower than the saturated moisture percentage of the polarizer is used. The saturated moisture content of the first transparent layers on both surfaces may be the same, or may be different as long as it is lower than the saturated moisture content of the polarizer. Further, the materials and thicknesses of the first transparent layers on both surfaces may be the same or different.

  The difference between the saturated moisture content of the polarizer and the saturated moisture content of the first transparent layer is preferably 1 to 20% by weight, and more preferably 3 to 15% by weight from the viewpoint of the function as a permeable membrane. Is preferred. It is to be noted that there is no problem if the difference in the saturated water content is too large, but if the difference is too small, a sufficient function as a permeable membrane cannot be exerted. Therefore, the control is preferably performed in the above range. The first transparent layer preferably has a saturated moisture content of usually 1 to 10% by weight, more preferably 3 to 8% by weight.

  The thickness of the first transparent layer is preferably 3 μm or less, more preferably 2 μm or less, further preferably 1.5 μm or less from the viewpoint of the function as a permeable membrane, thinning and optical reliability. Is more preferable, and further preferably 1 μm or less. If the first transparent layer is too thick, it may have a thickness, and consequently, it may not be able to exhibit its function as a permeable membrane because water is prevented from being discharged. On the other hand, the thickness of the first transparent layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, and further preferably 0.3 μm or more, from the viewpoint of ensuring the function as a permeable membrane. preferable.

  As a material for forming the first transparent layer, a material having transparency and satisfying the saturated moisture content can be used. Examples of such a material include a forming material containing a urethane prepolymer which is a reaction product of an isocyanate compound and a polyhydric alcohol.

  As the isocyanate compound, for example, a polyfunctional isocyanate compound is preferable, and specific examples thereof include a polyfunctional aromatic isocyanate compound, an alicyclic isocyanate, an aliphatic isocyanate compound, and a dimer thereof.

Examples of the polyfunctional aromatic isocyanate compound include phenylene diisocyanate, 2,4-tolylene diisosonate, 2,6-tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, , 4'-Toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalenediisocyanate, xylylene diisocyanate, methylene bis 4-phenyl isocyanate, p-phenylenediisocyanate, and the like .

  Examples of the polyfunctional alicyclic isocyanate compound include, for example, 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-bisisocyanatomethylcyclohexane, isophorone diisocyanate, hydrogen Additional diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated tetramethyl xylylene diisocyanate, and the like.

  Examples of the polyfunctional aliphatic isocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 4-trimethylhexamethylene diisocyanate and the like.

  Examples of the polyfunctional isocyanate compound include compounds having three or more isocyanate groups, such as tris (6-inocyanatehexyl) isocyanurate.

  Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 2-butyl-2-ethyl- 1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2- Examples thereof include methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol.

  In the present invention, it is preferable to use a urethane prepolymer having a rigid structure in which a cyclic structure (such as a benzene ring, a cyanurate ring, and an isocyanurate ring) occupies a large proportion in the structure. For example, one kind of the polyfunctional isocyanate compound may be used alone, or two or more kinds may be used in combination. From the viewpoint of adjusting the saturated moisture content, an aromatic isocyanate compound is preferable. Other polyfunctional isocyanate compounds can be used in combination with aromatic isocyanate compounds. In particular, among the aromatic isocyanate compounds, it is preferable to use at least one selected from tolylene diisocyanate and diphenylmethane diisocyanate as the isocyanate compound.

  As the urethane prepolymer, trimethylolpropane-tri-tolylene isocyanate and trimethylolpropane-tri-diphenylmethane diisocyanate are preferably used.

  In addition, as the urethane prepolymer, those in which a terminal isocyanate group is provided with a protective group can also be used. Protecting groups include oximes and lactams. When the isocyanate group is protected, the protecting group is dissociated from the isocyanate group by heating, and the isocyanate group reacts.

  Further, a reaction catalyst can be used to increase the reactivity of the isocyanate group. The reaction catalyst is not particularly limited, but a tin catalyst or an amine catalyst is preferred. One or more reaction catalysts can be used. The reaction catalyst is usually used in an amount of 5 parts by weight or less based on 100 parts by weight of the urethane prepolymer. If the amount of the reaction catalyst is large, the rate of the cross-linking reaction is increased, and foaming of the forming material occurs. Even if a foamed material is used, sufficient adhesiveness cannot be obtained. Usually, when a reaction catalyst is used, it is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 4 parts by weight.

  As the tin catalyst, any of an inorganic catalyst and an organic catalyst can be used, but an organic catalyst is preferable. Examples of the inorganic tin-based catalyst include stannous chloride, stannic chloride and the like. The organic tin catalyst preferably has at least one organic group such as an aliphatic group having a skeleton such as a methyl group, an ethyl group, an ether group, or an ester group, or an alicyclic group. Examples include tetra-n-butyltin, tri-n-butyltin acetate, n-butyltin trichloride, trimethyltin hydroxide, dimethyltin dichloride, dibutyltin dilaurate and the like.

  The amine catalyst is not particularly limited. For example, those having at least one organic group such as an alicyclic group such as quinocridine, amidine, and diazabicycloundecene are preferable. Other examples of the amine-based catalyst include triethylamine. Examples of other reaction catalysts include cobalt naphthenate, benzyltrimethylammonium hydroxide and the like.

  The urethane prepolymer is usually used as a solution. The solution may be a solvent system or an aqueous system such as an emulsion, a colloidal dispersion, or an aqueous solution. The organic solvent is not particularly limited as long as components constituting the forming material are uniformly dissolved. Examples of the organic solvent include toluene, methyl ethyl ketone, and ethyl acetate. In the case of using an aqueous system, for example, alcohols such as n-butyl alcohol and isopropyl alcohol, and ketones such as acetone can also be blended. In the case of using an aqueous system, a dispersant is used, or a functional group having low reactivity with isocyanate groups such as carboxylate, sulfonate and quaternary ammonium salt, or water dispersibility such as polyethylene glycol is used in the urethane prepolymer. It can be carried out by introducing components.

  Examples of the material for forming the first transparent layer other than the urethane prepolymer include a cyanoacrylate-based forming material and an epoxy-based forming material.

  The formation of the first transparent layer can be appropriately selected depending on the type of the forming material, and can be performed, for example, by applying the forming material to a polarizer or a resin film and then curing the applied material. The transparent layer can be obtained as a coating layer. Usually, after the application, drying is performed at about 30 to 100 ° C., preferably 50 to 80 ° C. for about 0.5 to 15 minutes to form a cured layer. Further, when the forming material contains an isocyanate component, annealing is performed at about 30 to 100 ° C., preferably 50 to 80 ° C. for about 0.5 to 24 hours to promote the reaction. Can be.

  The first transparent layer has a 85% R.C. H. It is preferable to have a structure having a gradient distribution such that the saturated moisture concentration in the above gradually decreases from the polarizer side toward the opposite side to the polarizer. With such a structure, the function as a permeable membrane can be more effectively exhibited.

<Second transparent layer>
In the polarizing film of the present invention, a second transparent layer can be further formed on the first transparent layer. As the second transparent layer, various layers can be formed, but from the viewpoint of exhibiting the function as a more permeable membrane, the second transparent layer having a saturated moisture content lower than that of the first transparent layer. It is preferred to provide a layer.

  The difference between the saturated moisture content of the first transparent layer and the saturated moisture content of the second transparent layer is preferably 0.1 to 8% by weight from the viewpoint of the function as a permeable membrane, and more preferably 0.5 to 8% by weight. It is preferably about 5% by weight. In addition, although there is no problem if the difference is too large, on the other hand, if the difference is too small, a sufficient function as a permeable membrane cannot be exerted. Therefore, it is preferable to control the difference in the above range. The saturated moisture content of the second transparent layer is preferably used in a range lower than the saturated moisture content of the first transparent layer, but is usually preferably 0.1 to 8% by weight. Those having a content of 0.5 to 5% by weight are preferably used.

  The thickness of the second transparent layer is about 1 to 100 μm from the viewpoint of the function as a permeable membrane. Preferably, it is 2 to 50 μm, more preferably 2 to 40 μm, and still more preferably 5 to 35 μm.

  The second transparent layer can be formed of, for example, a pressure-sensitive adhesive layer, an adhesive layer, a hard coat layer, or a resin film such as a protective film. Among them, the pressure-sensitive adhesive layer is preferable from the viewpoint of suppressing color loss at the edge of the polarizing film. When the second transparent layers are provided on both surfaces, the material and thickness of each second transparent layer may be the same or different.

≪Second transparent layer: adhesive layer≫
In forming the pressure-sensitive adhesive layer, an appropriate pressure-sensitive adhesive can be used, and the type thereof is not particularly limited. Examples of the adhesive include a rubber-based adhesive, an acrylic-based adhesive, a silicone-based adhesive, a urethane-based adhesive, and a vinyl alkyl ether-based adhesive.

  Among these pressure-sensitive adhesives, those having excellent optical transparency, exhibiting appropriate wettability, cohesiveness and adhesive pressure-sensitive adhesive properties and having excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used to exhibit such characteristics.

  As a method of forming the pressure-sensitive adhesive layer, for example, a method in which the pressure-sensitive adhesive is applied to a separator or the like that has been subjected to a release treatment, a polymerization solvent or the like is dried and removed to form a pressure-sensitive adhesive layer, and then transferred to the first transparent layer, Alternatively, it is produced by a method in which the pressure-sensitive adhesive is applied to the first transparent layer, and the polymerization solvent and the like are dried and removed to form a pressure-sensitive adhesive layer on the polarizer. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

  As the release-treated separator, a silicone release liner is preferably used. In the step of applying and drying the pressure-sensitive adhesive of the present invention on such a liner to form a pressure-sensitive adhesive layer, a method for drying the pressure-sensitive adhesive may be appropriately selected depending on the purpose. Preferably, a method of heating and drying the coating film is used. The heating and drying temperature is preferably from 40C to 200C, more preferably from 50C to 180C, and particularly preferably from 70C to 170C. By setting the heating temperature within the above range, a pressure-sensitive adhesive having excellent pressure-sensitive adhesive properties can be obtained.

  As the drying time, an appropriate time can be appropriately used. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

  Various methods are used for forming the pressure-sensitive adhesive layer. Specifically, for example, by roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples include a method such as an extrusion coating method.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm. Preferably, it is 2 to 50 μm, more preferably 2 to 40 μm, and still more preferably 5 to 35 μm.

  When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected by a sheet (separator) that has been subjected to a release treatment until it is practically used.

  As a constituent material of the separator, for example, polyethylene, polypropylene, polyethylene terephthalate, a plastic film such as a polyester film, paper, cloth, a porous material such as a nonwoven fabric, a net, a foamed sheet, a metal foil, and a laminate of these as appropriate Although a thin leaf body and the like can be mentioned, a plastic film is preferably used because of its excellent surface smoothness.

  The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. Examples of the plastic film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, and vinyl chloride film. Examples include a polymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The thickness of the separator is usually 5 to 200 μm, preferably about 5 to 100 μm. The separator, if necessary, silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release and antifouling treatment with silica powder, etc., coating type, kneading type, evaporation type For example, antistatic treatment such as antistatic treatment can also be performed. In particular, by appropriately subjecting the surface of the separator to a release treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment, the releasability from the pressure-sensitive adhesive layer can be further improved.

≪Second transparent layer: protective film≫
The material constituting the protective film is preferably a material having excellent transparency, mechanical strength, heat stability, moisture barrier properties, isotropy, and the like. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; acrylic polymers such as polymethyl methacrylate; styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin) Polymers, polycarbonate polymers and the like. In addition, polyethylene, polypropylene, polyolefin having a cyclo- or norbornene structure, polyolefin polymers such as ethylene-propylene copolymer, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, and sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Blends of polymers and the like are also mentioned as examples of the polymer forming the protective film.

  The protective film may contain one or more optional additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent, and the like. The content of the thermoplastic resin in the protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When the content of the thermoplastic resin in the protective film is 50% by weight or less, high transparency or the like inherent to the thermoplastic resin may not be sufficiently exhibited.

  As the protective film, a retardation film, a brightness enhancement film, a diffusion film and the like can also be used. Examples of the retardation film include those having a front retardation of 40 nm or more and / or a thickness direction retardation of 80 nm or more. The front phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. When a retardation film is used as the protective film, the thickness can be reduced because the retardation film also functions as a polarizer protective film.

  Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film. The stretching temperature, stretching ratio, and the like are appropriately set depending on the retardation value, the material and thickness of the film.

  Although the thickness of the protective film can be determined as appropriate, it is generally about 1 to 500 μm from the viewpoint of workability such as strength and handleability, and thinness. The thickness is particularly preferably 1 to 300 μm, more preferably 5 to 200 μm, further more preferably 5 to 150 μm, particularly preferably 20 to 100 μm.

  A functional layer such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer can be provided on the surface of the protective film on which the polarizer is not adhered. The functional layers such as the hard coat layer, the antireflection layer, the anti-sticking layer, the diffusion layer and the antiglare layer can be provided on the protective film itself, or separately provided separately from the protective film. it can.

  The protective film (second transparent layer) can be directly bonded to the first transparent layer.

<Surface protection film>
The polarizing film of the present invention can be provided with a surface protective film. The surface protection film usually has a base film and an adhesive layer, and protects the polarizer via the adhesive layer.

  As the base film of the surface protective film, a film material having or close to isotropic is selected from the viewpoints of testability and controllability. Examples of the film material include a polyester resin such as a polyethylene terephthalate film, a cellulose resin, an acetate resin, a polyether sulfone resin, a polycarbonate resin, a polyamide resin, a polyimide resin, a polyolefin resin, and an acrylic resin. A transparent polymer such as a resin can be used. Of these, polyester resins are preferred. The base film may be used as a laminate of one or more film materials, or a stretched product of the above film. The thickness of the base film is generally 500 μm or less, preferably 10 to 200 μm.

  Examples of the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer of the surface protective film include a pressure-sensitive adhesive having a base polymer of (meth) acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer. Can be appropriately selected and used. From the viewpoints of transparency, weather resistance, heat resistance and the like, an acrylic pressure-sensitive adhesive containing an acrylic polymer as a base polymer is preferred. The thickness (dry film thickness) of the pressure-sensitive adhesive layer is determined according to the required pressure-sensitive adhesive strength. Usually, it is about 1 to 100 μm, preferably 5 to 50 μm.

  In addition, on the surface protective film, a release treatment layer can be provided on the surface opposite to the surface on which the pressure-sensitive adhesive layer of the base film is provided, using a low-adhesion material such as silicone treatment, long-chain alkyl treatment, or fluorine treatment. .

<Other optical layers>
The polarizing film of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited. For example, it is used for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including a wavelength plate such as や or や), a viewing angle compensation film, and the like. One or more optical layers that may be used may be used. In particular, a reflective polarizing film or a transflective polarizing film in which a polarizing plate or a transflective reflecting plate is further laminated on the polarizing film of the present invention, an elliptically polarizing film or a circularly polarized light in which a retardation plate is further laminated on a polarizing film A wide viewing angle polarizing film in which a viewing angle compensation film is further laminated on a film or a polarizing film, or a polarizing film in which a brightness enhancement film is further laminated on a polarizing film is preferable.

  An optical film obtained by laminating the above-mentioned optical layer on a polarizing film can also be formed by a method of sequentially laminating the optical film in a manufacturing process of a liquid crystal display device or the like. It is excellent in stability, assembling work, and the like, and has an advantage that a manufacturing process of a liquid crystal display device or the like can be improved. For the lamination, an appropriate adhesive means such as a pressure-sensitive adhesive layer can be used. In bonding the above-mentioned polarizing film and other optical films, their optical axes can be arranged at an appropriate angle depending on the intended retardation characteristics and the like.

  The polarizing film or optical film of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device and an organic EL display device. The formation of the liquid crystal display device can be performed according to a conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell and a polarizing film or an optical film and, if necessary, an illumination system and incorporating a drive circuit. There is no particular limitation except that a polarizing film or an optical film according to the present invention is used, and the present invention can be applied to a conventional method. The liquid crystal cell may be of any type, such as an IPS type or a VA type, but is particularly suitable for the IPS type.

  An appropriate liquid crystal display device such as a liquid crystal display device in which a polarizing film or an optical film is arranged on one or both sides of a liquid crystal cell, or a lighting system using a backlight or a reflector can be formed. In that case, the polarizing film or the optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When a polarizing film or an optical film is provided on both sides, they may be the same or different. Further, when forming the liquid crystal display device, for example, a suitable component such as a diffusion plate, an anti-glare layer, an antireflection film, a protection plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, etc. Two or more layers can be arranged.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples described below. In addition, all parts and% in each example are based on weight. The room temperature storage conditions not particularly specified below are all 23 ° C., 65% R.D. H. It is.

(Production of thin polarizer A)
One side of an amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and Tg of 75 ° C. is subjected to a corona treatment, and the corona treated surface is treated with polyvinyl chloride. Alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6%, degree of saponification 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. An aqueous solution containing (trade name: Gosefimer Z200) at a ratio of 9: 1 was applied and dried at 25 ° C. to form a 11 μm-thick PVA-based resin layer, thereby producing a laminate.
The obtained laminate was uniaxially stretched 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120 ° C. (free-air auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 30 ° C. (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilizing treatment).
Next, it was immersed in a dyeing bath at a liquid temperature of 30 ° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 parts by weight of iodine was added to 100 parts by weight of water, and the resultant was immersed in an aqueous solution of iodine obtained by mixing 1.0 part by weight of potassium iodide for 60 seconds (dyeing treatment). .
Next, it was immersed in a crosslinking bath at a liquid temperature of 30 ° C. (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds. (Crosslinking treatment).
Thereafter, the laminate is immersed in an aqueous solution of boric acid at a liquid temperature of 70 ° C. (an aqueous solution obtained by mixing 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water). Meanwhile, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) so that the total stretching ratio was 5.5 times (underwater stretching treatment).
Thereafter, the laminate was immersed in a washing bath at a liquid temperature of 30 ° C. (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) (washing treatment).
Thus, an optical film laminate including a 5 μm-thick polarizer was obtained.

(Preparation of polarizer B (polarizer having a thickness of 12 μm))
A 30 μm thick polyvinyl alcohol film having an average polymerization degree of 2400 and a saponification degree of 99.9 mol% was immersed in warm water at 30 ° C. for 60 seconds to swell. Next, the film was immersed in a 0.3% aqueous solution of iodine / potassium iodide (weight ratio = 0.5 / 8), and the film was dyed while being stretched to 3.5 times. Thereafter, the film was stretched in an aqueous borate solution at 65 ° C. so that the total stretching ratio became 6 times. After stretching, drying was performed in an oven at 40 ° C. for 3 minutes to obtain a PVA-based polarizer. The thickness of the obtained polarizer was 12 μm.

(Preparation of protective film)
Protective film: A (meth) acrylic resin film having a lactone ring structure having a thickness of 40 μm was subjected to a corona treatment on an easily-adhered surface and used.

<Material for forming first transparent layer (block layer)>
Forming material A: 100 parts of a 75% ethyl acetate solution of a urethane prepolymer composed of tolylene diisocyanate and trimethylolpropane (manufactured by Tosoh Corporation, trade name "Coronate L") in 100 parts of a dioctyltin dilaurate-based catalyst (manufactured by Tokyo Fine Chemical Company, trade name) 0.1 part of "Envirizer OL-1" was added, and a urethane prepolymer coating liquid was prepared with methyl isobutyl ketone as a solvent at a solid content concentration of 10%.
Forming material B: Using the same catalyst and solvent as for forming agent A, except that a 75% ethyl acetate solution of urethane prepolymer composed of diphenylmethane diisocyanate and trimethylolpropane (trade name "Coronate 2067" manufactured by Tosoh Corporation) was used. To prepare a coating solution.
Forming Material C: The same catalyst and solvent as those of Forming Agent A except that a 75% ethyl acetate solution of urethane prepolymer composed of hexamethylene diisocyanate and trimethylolpropane (trade name “Coronate HL” manufactured by Tosoh Corporation) was used. To prepare a coating solution.
Forming material D: 80 parts of urethane acrylate resin (manufactured by Nippon Gohsei Co., Ltd., product name "Shikko UV-1700"), hydroxyethyl acrylamide (manufactured by Kojin Co., product name "HEAA") and photopolymerization initiator (Ciba Japan) (Product name: Irgacure 907) was added, and a urethane acrylate coating solution was prepared using methyl isobutyl ketone as a solvent to a solid content concentration of 10%.

<Formation of second transparent layer (adhesive layer)>
(Preparation of adhesive)
100 parts of butyl acrylate, 3 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate and 2,2′-azobisisobutyi were placed in a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer. A solution was prepared by adding 0.3 parts of lonitrile together with ethyl acetate. Next, the solution was stirred while blowing nitrogen gas into it, and reacted at 55 ° C. for 8 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight of 2.2 million. Further, ethyl acetate was added to the solution containing the acrylic polymer to obtain an acrylic polymer solution whose solid content concentration was adjusted to 30%.

  A crosslinking agent having a compound having 0.5 part of an isocyanate group as a main component (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") with respect to 100 parts of the solid content of the acrylic polymer solution. And 0.075 part of γ-glycidoxypropyltrimethoxysilane (trade name “KMB-403” manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent in this order, and a pressure-sensitive adhesive solution Was prepared. The above-mentioned pressure-sensitive adhesive solution is applied to the surface of a release sheet (separator) composed of a peeled polyethylene terephthalate film (thickness: 38 μm) so that the thickness after drying becomes 20 μm, and dried to form a pressure-sensitive adhesive layer. Formed.

Example 1
<Preparation of polarizing film with first transparent layer on both sides>
The material A for forming the first transparent layer is applied to the surface of the polarizer A of the optical film laminate by a bar coater, and then subjected to a heat treatment at 60 ° C. for 12 hours, to thereby form a urethane resin layer having a thickness of 1 μm. Was formed. Next, after the amorphous PET base material is peeled off, the material A for forming the first transparent layer is applied to the peeled surface (polarizer) with a bar coater, and then heat-treated at 60 ° C. for 12 hours. Then, a urethane resin layer having a thickness of 1 μm was formed, and a polarizing film having first transparent layers on both surfaces was produced. The optical characteristics of the obtained polarizing film were such that the single transmittance was 42.8% and the degree of polarization was 99.99%.

<Polarizing film with first and second transparent layers: production of polarizing film with pressure-sensitive adhesive layer>
Next, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet (separator) was bonded to the first transparent layers on both surfaces of the polarizing film to produce a polarizing film with a double-sided pressure-sensitive adhesive layer.

Examples 2-3 and Comparative Examples 1-6
Example 1 A one-sided protective polarizing film with a first transparent layer in the same manner as in Example 1 except that the type of polarizer, the forming material of the first transparent layer, and the thickness were changed as shown in Table 1. And the polarizing film with a double-sided adhesive layer was produced. The optical properties of the obtained one-sided protective polarizing film were 42.8% in transmittance and 99.99% in degree of polarization in each case.

In Comparative Examples 1 and 4, the first transparent layer was not formed.
The first transparent layer of Comparative Example 3 was formed by applying the above-mentioned forming agent D with a bar coater and then heating at 60 ° C. for 1 minute. After heating, the coating layer was irradiated with an ultraviolet ray having an integrated light amount of 300 mJ / cm ^{2 by} a high-pressure mercury lamp to form a urethane acrylate resin layer having a thickness of 1 μm. In Comparative Examples 4 and 5, a polarizer B (12 μm in thickness) was used instead of the polarizer A (5 μm in thickness).

Example 4
<Preparation of polarizing film with first and second transparent layers>
After the forming material A of the first transparent layer is applied to the surface of the polarizer A of the optical film laminate by a bar coater, the protective film ((meth) acrylic resin film) is attached on the applied forming agent A. The resultant was subjected to heat treatment at 60 ° C. for 12 hours to form a protective film layer (second transparent layer) laminated with a urethane resin layer (first transparent layer) having a thickness of 1 μm. Next, after the amorphous PET base material is peeled off, the material A for forming the first transparent layer is similarly applied to the peeled surface (polarizer) by a bar coater, and the protective material A is applied on the applied forming agent A. The film is laminated and subjected to a heat treatment at 60 ° C. for 12 hours to form a urethane resin layer and a protective film layer having a thickness of 1 μm, thereby producing a polarizing film having a first transparent layer and a second transparent layer on both surfaces. did. The optical characteristics of the obtained polarizing film were such that the single transmittance was 42.8% and the degree of polarization was 99.99%.

  The following evaluation was performed about the polarizing film with the 1st and 2nd transparent layers obtained by the said Example and the comparative example. Table 1 shows the results.

<Measurement of saturated moisture content of polarizer>
Before bonding the polarizers produced in the examples and comparative examples, they were individually taken out and about 50 mg of a sample was collected. Using a moisture adsorption / desorption measuring device (IGA-Sorp, manufactured by Hidden), the sample was subjected to 85 ° C. 0% R.V. H. The weight (W1) in a state where the water was completely removed by leaving the apparatus under the environment of no weight change until the weight change was completely eliminated, and then measured at 85 ° C. and 85% RH. H. Under the same environment, and a change in weight was observed. When the sample no longer changed in weight (saturated state), its weight (W2) was measured. The saturated moisture content was measured by the following equation.

<Measurement of saturated moisture content of first transparent layer>
After forming the first transparent layer in the same manner as in Examples and Comparative Examples except that the first transparent layer forming material prepared in Examples and Comparative Examples was applied to aluminum foil with a bar coater so as to have a thickness of 10 μm. The sample was cut out to a size of 10 × 10 mm and a sample was collected. Using a moisture adsorption / desorption measuring device (IGA-Sorp, manufactured by Hidden), the sample was subjected to 85 ° C. 0% R.V. H. The weight (W1) in a state where the water was completely removed by leaving the apparatus under the environment of no weight change until the weight change was completely eliminated, and then measured at 85 ° C. and 85% RH. H. Under the same environment, and a change in weight was observed. When the sample no longer changed in weight (saturated state), its weight (W2) was measured. An aluminum foil was cut out from each weight in the same size, and the saturated moisture content was measured by the following formula except for the weight of the aluminum foil measured in advance.

≪Second transparent layer: adhesive layer≫
About 50 mg of a sample was collected from the pressure-sensitive adhesive layer of the polarizing film with a pressure-sensitive adhesive layer produced in the examples and the comparative examples. Using a moisture adsorption / desorption measuring device (IGA-Sorp, manufactured by Hidden), the sample was subjected to 85 ° C. 0% R.V. H. The weight (W1) in a state where the water content was completely removed by allowing the sample to stand under the environment of no change in weight was measured, and then 8585% R.C. H. Under the same environment, and a change in weight was observed. When the sample no longer changed in weight (saturated state), its weight (W2) was measured. The saturated moisture content was measured from the following equation.

≪Second transparent layer: protective film≫
The protective film was cut out to a size of 10 × 10 mm, and a sample was collected. Using a moisture adsorption / desorption measuring device (IGA-Sorp, manufactured by Hidden), the sample was subjected to 85 ° C. 0% R.V. H. The weight (W1) in a state where the water was completely removed by leaving the apparatus under the environment of no weight change until the weight change was completely eliminated, and then measured at 85 ° C. and 85% RH. H. Under the same environment, and a change in weight was observed. When the sample no longer changed in weight (saturated state), its weight (W2) was measured. The saturated moisture content was measured from the following equation.

<Single transmittance T and degree of polarization P of polarizer>
The single transmittance T and the degree of polarization P of the obtained one-sided protective polarizing film were measured using a spectral transmittance meter with an integrating sphere (Dot-3c of Murakami Color Research Laboratory).
The degree of polarization P is such that the transmittance (parallel transmittance: Tp) when two identical polarizing films are overlapped so that their transmission axes are parallel and that the two transmission films are orthogonal to each other. It is determined by applying the combined transmittance (orthogonal transmittance: Tc) to the following equation. Degree of polarization P (%) = {(Tp−Tc) / (Tp + Tc)} ^1/2 × 100
Each transmittance is represented by a Y value obtained by adjusting luminosity by a 2-degree field of view (C light source) according to JIS Z8701, with 100% of completely polarized light obtained through a Glan-Teller prism polarizer.

(Preparation of evaluation sample)
With respect to the polarizing films with the first and second transparent layers (polarizing films with double-sided adhesive) obtained in Examples 1 to 3 and Comparative Examples 1 to 6, after exfoliating the release sheet on one side, the exposed adhesive was used. The sample in which the above protective film was bonded to the agent layer was cut into 50 mm × 50 mm, and bonded to a 1.2 to 1.5 mm thick alkali glass (a micro slide glass manufactured by Matsunami Glass Co., Ltd.).
Further, with respect to the polarizing film with the first and second transparent layers obtained in Example 4, the adhesive formed on the release-treated surface of the release sheet (separator) on the second transparent layer (protective film) on one side. The adhesive layer (the second transparent layer of Example 1 and the like) was laminated and cut into 50 mm × 50 mm, and then laminated on 1.2-1.5 mm thick alkali glass (Matsunami Glass Co., Ltd., micro slide glass). Together, a sample was prepared.

<Confirmation of moisture gradient in first transparent layer>
Put the above sample in a closed container, put a sufficient amount of heavy water that does not volatilize during the test, put the container tightly closed, hold the container in a high temperature environment of 80 ° C for 500 hours, and immediately after taking it out, -100 ° C or less Then, a sample having immobilized heavy water ions was obtained by flash freezing. After etching the heavy water-immobilized sample from the protective film side with Ar gas cluster ions to remove the protective film, TOF-SIMS analysis is performed to measure the distribution of heavy water ions (D ⁻ ) in the depth direction, The water gradient in the first transparent layer was confirmed. The case where the water gradient was confirmed (with a permeable membrane function) was marked with “〇”, and the case where it was not confirmed (without the permeable membrane function) was marked with “×”.
Equipment: ULVAC-PHI, TRIFT-V
Etching Ion: Ar gas cluster ion irradiation Primary ion: _Bi ^{3 2+}
Primary ion acceleration voltage: 30 kV
Measurement electrode: negative ion Measurement temperature: -100 ° C or less Measurement area: 100 μm square

<Durability>
The above sample was subjected to 85 ° C 85% R. H. After being kept in a high-temperature, high-humidity environment for 500 hours, left at room temperature (23 ° C., 65% RH), the amount of color loss at the end was measured with a differential interference microscope (Olympus, product name “MX-61L”). It was measured under the following conditions. The color loss at the end is defined as the distance between the straight line connecting the corner closest to the center of the four diagonal lines of the sample and the part lighter than the center. The average value of the four corners was taken as the color loss at the end of the sample.
Equipment: Olympus MX-61L
Measurement conditions Lens magnification: 5 times ISO: 200
Shutter speed: 1/100
Reflected light quantity: scale 0
White balance: Auto transmitted light controller: LG-PS2
Transmitted light amount: Scale 5
Transmitted light polarization direction: Direction of crossed Nicols with respect to the transmission axis of the polarizing film. "Measurement impossible" in Table 1 means that the measurement area (color loss area) is outside the visual field of the optical microscope that measures color loss at the end. There are cases.

P Polarizer 1a First transparent layer 1b First transparent layer 2a Second transparent layer (adhesive layer)
2b Second transparent layer (adhesive layer)

Claims (7)

Iodine-containing polarizer, and a polarizing film having a first transparent layer on both sides of the polarizer,
The thickness of the polarizer is 10 μm or less,
85 ° C., 85% RH of the first transparent layer. H. At 85 ° C. and 85% R.V. of the polarizer. H. Lower than the saturated moisture content in
The thickness of the first transparent layer is 3 μm or less,
The first transparent layer is a cured product of a forming material containing a urethane prepolymer that is a reaction product of an isocyanate compound containing at least one selected from tolylene diisocyanate and diphenylmethane diisocyanate with a polyhydric alcohol,
The polarizing film according to claim 1, wherein the first transparent layer functions as a permeable membrane that assists in discharging water from the polarizer.   The polarizing film according to claim 1, wherein the first transparent layer is formed directly on a polarizer.   The first transparent layer has a 85% R.C. H. 3. The polarizing film according to claim 1, wherein the saturated film has a gradient distribution such that the saturated water concentration gradually decreases from the polarizer side toward the side opposite to the polarizer. In the first transparent layer on at least one side of the first transparent layer having on both sides of the polarizer, on the opposite side to the side having the polarizer, having a second transparent layer adjacent,
85 ° C., 85% RH of the second transparent layer. H. At 85 ° C. and 85% R.C. of the first transparent layer. H. Lower than the saturated moisture content in
The polarizing film according to any one of claims 1 to 3, wherein moisture in the polarizer penetrates from the polarizer side in the order of the first transparent layer and the second transparent layer.   The polarizing film according to claim 4, wherein the second transparent layer is a pressure-sensitive adhesive layer. The polarizing film according to claim 4 , wherein the second transparent layer is a protective film. An image display device comprising the polarizing film according to claim 1.

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