TWI709490B - Polarizing film and image display device - Google Patents

Abstract

The present invention is a polarizing film having a polarizing element and a first transparent layer located on both sides of the polarizing element; in the polarizing film, the saturated moisture content of the first transparent layer is lower than that of the polarizing element; and The first transparent layer serves as a permeable film, and plays a function of helping to discharge water in the polarizer. The polarizing film of the present invention can suppress the decrease of the polarization degree of the end part even in a high temperature and high humidity environment.

Description

Polarizing film and image display device

The present invention relates to a polarizing film. The aforementioned polarizing film can be used alone or in the form of a laminated optical film to form an image display device such as a liquid crystal display device (LCD) and an organic EL display device.

BACKGROUND OF THE INVENTION In liquid crystal display devices, according to the image forming method, it is necessary and indispensable to arrange polarizing films on both sides of the glass substrate forming the surface of the liquid crystal panel. The polarizing film generally uses a polarizer composed of a polyvinyl alcohol-based film and a dichroic material such as iodine with a protective film attached to one or both sides through a polyvinyl alcohol-based adhesive or the like.

In addition, the polarizing film may be exposed to harsh environments depending on its usage or usage conditions. Therefore, the polarizing film is required to have durability that can maintain optical properties even in severe environments. For example, there are documents that propose to provide a urethane resin having a predetermined storage elastic modulus on at least one side of the polarizer (Patent Documents 1 and 2). According to the description of Patent Documents 1 and 2, the orthogonal transmittance of the polarizing film can be maintained at high temperatures.

Prior Art Documents Patent Documents Patent Document 1: Japanese Patent Application Publication No. 11-030715 Patent Document 2: Japanese Patent Application Publication No. 11-183726

Summary of the Invention Problems to be Solved by the Invention In addition, polarizing films may be used in high-temperature and high-humidity environments as well as in high-temperature environments. It is known that under the severe gas environment, the moisture in the gas environment will affect the optical characteristics of the polarizer, and the polarization degree will be greatly reduced at the end of the polarizing film. However, the urethane resins described in the above-mentioned Patent Documents 1 and 2 are provided on the polarizing material, and the decrease in the degree of polarization cannot be sufficiently suppressed at the end of the aforementioned polarizing film.

The object of the present invention is to provide a polarizing film, which can still suppress the decrease in the degree of polarization at the end under a high temperature and high humidity environment.

Moreover, the object of the present invention is to provide an image display device with the aforementioned polarizing film.

Means to Solve the Problem The inventors of the present invention actively reviewed and found that the above-mentioned problem can be solved by the following polarizing film, and completed the present invention.

That is, the present invention relates to a polarizing film having a polarizing member and a first transparent layer on both sides of the polarizing member. The polarizing film is characterized in that: the first transparent layer is at 85°C and 85% RH The saturated moisture content of the polarizer is lower than the saturated moisture content of the polarizer at 85°C and 85%RH; the first transparent layer acts as a permeable film to help discharge the moisture in the polarizer.

In the aforementioned polarizing film, the aforementioned first transparent layer is preferably formed directly on the polarizing member.

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

In the aforementioned polarizing film, a cured product of a forming material containing a urethane prepolymer can be used as the first transparent layer, and the urethane prepolymer is a reaction product of an isocyanate compound and a polyol. It is preferable to use at least any one selected from the group consisting of toluene diisocyanate and diphenylmethane diisocyanate as the aforementioned isocyanate compound.

In the aforementioned polarizing film, the first transparent layer preferably has a gradient distribution: the saturated moisture concentration in the first transparent layer at 85° C. and 85% R.H. gradually decreases from the polarizing member side to the side opposite to the polarizing member.

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

The aforementioned polarizing film is preferably: in the first transparent layer of at least one side of the first transparent layer on both sides of the polarizer, a second transparent layer is adjacent to the side opposite to the side with the polarizer; the second transparent layer The saturated moisture content at 85°C and 85% RH is lower than the saturated moisture content of the first transparent layer at 85°C and 85% RH; the moisture in the polarizing member sequentially penetrates the first transparent layer from the side of the polarizing member A transparent layer, the aforementioned second transparent layer.

In the aforementioned polarizing film, the aforementioned second transparent layer may be an adhesive layer.

In addition, in the polarizing film, the second transparent layer may be a protective film.

Furthermore, the present invention relates to an image display device having the aforementioned polarizing film.

Effects of the Invention Since the polarizer, which is a constituent element of the polarizing film, is formed of water-based materials, the polarizer can easily take in moisture in the gas environment. Therefore, it is conceivable that when the polarizing film is kept in a high temperature and high humidity environment, the saturated moisture content in the polarizing member will increase. As a result, the optical properties of the polarizing film tend to decrease. In particular, in a high-temperature and high-humidity environment, there is a large amount of moisture intruding into the polarizer. Therefore, it is conceivable that the polarization degree will be greatly reduced at the end of the polarizing film, and a phenomenon called end fading occurs.

The polarizing film of the present invention has a first transparent layer on both sides of the polarizing member, and the first transparent layer is used as a permeable film to help discharge moisture in the polarizing member. The saturated moisture content of the first transparent layer in a high temperature and high humidity environment is designed to be lower than that of the polarizer, so even if the moisture in the gas environment has penetrated into the polarizer, the moisture in the polarizer can still be activated Penetrate to the side of the first transparent layer (permeable film) with a saturated moisture content lower than that of the polarizer, so that the moisture in the polarizer can be discharged out of the polarizer through this effect. As described above, the polarizing film of the present invention has the aforementioned first transparent layer, thereby suppressing the increase in the saturated moisture content of the polarizer even in a high-temperature and high-humidity environment, thereby suppressing the amount of fading at the ends of the polarizing film.

Modes for Carrying Out the Invention Hereinafter, the polarizing film of the present invention will be described with reference to Figs. 1 to 3. For example, the polarizing film of the present invention, the polarizing film 11 shown in FIGS. 1 to 3, has a polarizing member P, and first transparent layers 1a, 1b (permeable film: having a polarizing member P) on both sides of the polarizing member P. A layer of membrane function that can help water discharge). As shown in Figures 1 to 3, the first transparent layers 1a, 1b are directly disposed on the polarizing member P, which can suppress the increase in the saturated moisture content of the polarizer under high temperature and high humidity environment, thereby preventing the end of the polarizing film from fading , So better. In the first transparent layer 1a, 1b, only one layer may be directly disposed on the polarizer P.

Moreover, the polarizing film of the present invention can be, for example, the polarizing films 12, 13 shown in FIGS. 2 and 3, and at least the first transparent layers 1a, 1b provided on both sides of the polarizing member P of the polarizing film 11 On the single-sided first transparent layers 1a, 1b, a second transparent layer 2 (2a and/or 2b) is further provided. The polarizing film 12 of FIG. 2 is a situation in which a second transparent layer is further provided on the first transparent layer 1a of one side of the first transparent layers 1a and 1b on both sides; and the polarizing film 13 of FIG. 3 is on the first transparent layer 1a on both sides. A situation where second transparent layers 2a and 2b are further provided on the first transparent layers 1a and 1b on both sides of a transparent layer 11a and 1b. The second transparent layer 2 (2a and/or 2b) is directly arranged on the first transparent layer 1a, 1b, which can suppress the increase in the saturated moisture content of the polarizer in a high temperature and high humidity environment, thereby preventing the end of the polarizing film from fading , So better.

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

<Polarizer> The polarizer is not particularly limited, and various polarizers can be used. Examples of polarizers include hydrophilic polymer films such as polyvinyl alcohol-based films, partially formalized polyvinyl alcohol-based films, and ethylene-vinyl acetate copolymer-based partially saponified films that adsorb iodine or dichroic dyes. Color materials and uniaxially stretched, and polyene-based oriented films such as dehydrated polyvinyl alcohol or dehydrated polyvinyl chloride. Among them, a polarizer composed of a dichroic substance such as a polyvinyl alcohol-based film and iodine is more suitable. The thickness of the polarizers is not particularly limited, and is generally below 80 μm.

A polarizer formed by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretched can be dyed by, for example, immersing a polyvinyl alcohol-based film in an aqueous solution of iodine, and stretched to 3 to 7 times its original length. production. It can also be immersed in an aqueous solution containing boric acid or potassium iodide such as zinc sulfate, zinc chloride, etc., if necessary. Furthermore, if necessary, the polyvinyl alcohol-based film may be immersed in water for washing before dyeing. By washing the polyvinyl alcohol-based film with water, the dirt and anti-caking agent on the surface of the polyvinyl alcohol-based film can be cleaned. In addition, it also has the effect of swelling the polyvinyl alcohol-based film to prevent uneven dyeing. The extension may be performed after dyeing with iodine, or it may be extended while dyeing, or it may be dyed with iodine after extension. It can also be extended in aqueous solutions such as boric acid or potassium iodide or in a water bath.

In the present invention, a polarizer with a thickness of 10 μm or less can be used. From the viewpoint of thinning, the thickness of the polarizer is preferably 8 μm or less, more preferably 7 μm or less, and more preferably 6 μm or less. On the other hand, the thickness of the polarizer is 2 μm or more, more preferably 3 μm or more. This thin polarizer has less variation in thickness, good visibility and less dimensional change, so it has excellent durability against thermal shock.

As a thin polarizer, representative examples include: Japanese Patent No. 4751486, Japanese Patent No. 4751481, Japanese Patent No. 4815544, Japanese Patent No. 5048120, International Publication No. 2014/077599 Manual, International The thin polarizer described in the pamphlet of No. 2014/077636, etc., or the thin polarizer obtained by the manufacturing method described in the publication is disclosed.

The aforementioned polarizer is preferably constructed so that the optical characteristics expressed by the monomer transmittance T and the degree of polarization P satisfy the conditions of the following formula: P>-(10 ^0.929T-42.4 -1)×100 (but, T<42.3), or P ≧99.9 (Only, T≧42.3). In a word, the polarizer formed by satisfying the aforementioned conditions has the performance required for a liquid crystal television display using a large display element. Specifically, the contrast ratio is 1000:1 or more and the maximum brightness is 500cd/m ² or more. For other purposes, it can be attached to the viewing side of an organic EL display device.

In the manufacturing method including the elongation step and the dyeing step in the state of a laminate, from the viewpoint that it can be extended at a high magnification to improve the polarization performance, the aforementioned thin polarizer is such as Japanese Patent No. 4751486 and Japanese Patent No. 4751481 The specification and the specification of Japanese Patent No. 4815544 are preferably obtained by a method including the step of extending in an aqueous solution of boric acid, and it is particularly preferable to be included in the specification of Japanese Patent No. 4751481 and Japanese Patent No. 4815544. It is better to prepare it by the method of auxiliary air extension step before extension in boric acid aqueous solution. These thin polarizers can be produced by a manufacturing method including a step of extending a polyvinyl alcohol-based resin (hereinafter, also referred to as a PVA-based resin) layer and a resin substrate for stretching in the state of a laminate and a step of dyeing. According to this production method, even if the PVA-based resin layer is thin, it is supported by the resin base material for stretching, so it can be stretched without problems such as breakage due to stretching.

Generally speaking, the polarizer of the present invention uses a saturated moisture content of 10-40% by weight at 85°C and 85% R.H. From the viewpoint of suppressing the fading of the end portion, the saturated moisture content of the aforementioned polarizer may be 25% by weight or less, and further may be 18% by weight or less. In addition, under the relationship between the saturated moisture content of the polarizer and 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, there is no special lower limit.

The saturated moisture content of the polarizer of the present invention can be adjusted by any appropriate method. For example, the method can be controlled by adjusting the conditions of the drying step in the manufacturing step of the polarizer.

<First transparent layer> The first transparent layer is a layer that functions as a permeable film to help discharge the moisture in the aforementioned polarizer. The saturated moisture content of the first transparent layer at 85°C and 85% RH is designed to be higher than the aforementioned The polarizer has a lower saturated moisture content. The saturated moisture content of the first transparent layer on both sides can be the same, and it can also be different as long as it is lower than the saturated moisture content of the aforementioned polarizer. In addition, the material and thickness of the first transparent layer on both sides are also the same, and may be the same or different.

From the viewpoint of the function as a permeable membrane, the difference between the saturated moisture content of the polarizer and the saturated moisture content of the first transparent layer is preferably 1-20% by weight, more preferably 3-15% by weight. In addition, there is no problem even if the aforementioned difference in saturation moisture content is too large, but on the other hand, if it is too small, the function of the permeable membrane will not be fully exhibited, so it is preferable to control it within the aforementioned range. Moreover, the saturated moisture content of the aforementioned first transparent layer is generally preferably 1-10% by weight, and more preferably 3-8% by weight.

From the viewpoint of function as a permeable membrane, thinning and optical reliability, the thickness of the first transparent layer is preferably 3 μm or less, more preferably 2 μm or less, and more preferably 1.5 μm or less, and even more preferably 1 μm or less. If the first transparent layer is too thick, the thickness of the first transparent layer may hinder the drainage of moisture and may not function as a permeable membrane. On the other hand, from the viewpoint of ensuring the function as a permeable membrane, the thickness of the first transparent layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more.

The material for forming the first transparent layer may be transparent and satisfy the saturated moisture content. The material may be, for example, a material containing a urethane prepolymer which is a reactant of an isocyanate compound and a polyol.

The isocyanate compound is preferably, for example, a polyfunctional isocyanate compound, and specific examples include polyfunctional aromatic isocyanate compounds, alicyclic isocyanates, aliphatic isocyanate compounds, or dimers of these.

Examples of polyfunctional aromatic isocyanate compounds include phenylene diisocyanate, 2,4-toluene isocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate Isocyanate, diisocyanate, methylene bis 4-phenyl isocyanate, p-phenylene diisocyanate, etc.

Examples of polyfunctional alicyclic isocyanate compounds include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, and 1,3-diisocyanate Methyl cyclohexane, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated toluene diisocyanate, hydrogenated toluene diisocyanate, hydrogenated tetramethyl diisocyanate, etc.

The polyfunctional aliphatic isocyanate compound includes, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3 -Butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, etc.

In addition, examples of the polyfunctional isocyanate compound include those having three or more isocyanate groups such as ginseng (6-isocyanatohexyl) trimer isocyanate.

Polyols include, for example, ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butanediol -2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol , 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerol, trimethylolpropane, neopentaerythritol, hexane Triol, polypropylene glycol, etc.

As the aforementioned urethane prepolymer, it is suitable to use in the present invention the rigidity of the cyclic structure (benzene ring, cyanurate ring, isocyanurate ring, etc.) in the molecular structure. Structurer. For example, the aforementioned polyfunctional isocyanate compound may be used alone or in combination of two or more, but from the viewpoint of adjusting the aforementioned saturated water content, an aromatic isocyanate compound is preferred. Other polyfunctional isocyanate compounds can also be used in combination with aromatic isocyanate compounds. Among the aromatic isocyanate compounds, it is particularly preferable to use at least any one selected from the group consisting of toluene diisocyanate and diphenylmethane diisocyanate as the aforementioned isocyanate compound.

The urethane prepolymer preferably uses trimethylolpropane-tris-toluene isocyanate and trimethylolpropane-tris-diphenylmethane diisocyanate.

In addition, the aforementioned urethane prepolymer can also be used for a terminal isocyanate group provided with a protective group. The protecting groups include oxime and lactam. When the isocyanate group is protected, the protective group is dissociated from the isocyanate group by heating, and the isocyanate group is reacted.

In addition, a reaction catalyst can be used in order to increase the reactivity of the isocyanate group. The reaction catalyst is not particularly limited, but it is desirably a tin-based catalyst or an amine-based catalyst. One type or two or more types of reaction catalysts can be used. The usage amount of the reaction catalyst is usually 5 parts by weight or less with respect to 100 parts by weight of the urethane prepolymer. Once the amount of reaction catalyst is large, the crosslinking reaction speed will increase and the forming material will foam. On the other hand, the foamed forming material cannot obtain sufficient adhesiveness. Generally, when the reaction catalyst is used, it is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 4 parts by weight.

The tin-based catalyst can be either inorganic or organic, but organic is preferred. Examples of the inorganic tin-based catalyst include stannous chloride and tin chloride. The organic tin-based catalyst preferably has at least one of the following organic groups: aliphatic groups and alicyclic groups with a skeleton such as methyl, ethyl, ether, and ester groups. Examples include tetra-n-butyl tin, tri-n-butyl tin acetate, n-butyl tin trichloride, trimethyl tin hydroxide, dimethyl tin dichloride, and dibutyl tin dilaurate.

啶、脒類、二氮雜雙環十一烯等脂環族基等有機基者。除此以外，胺系觸媒還可舉三乙胺等。另外，前述以外之反應觸媒可例示環烷酸鈷、氫氧化苄基三甲銨等。In addition, there are no particular limitations on the amine catalyst. It is better to have at least one such as

Organic groups such as pyridine, amidines, diazabicycloundecene and other alicyclic groups. In addition to this, triethylamine and the like can be mentioned as an amine catalyst. In addition, examples of reaction catalysts other than the foregoing include cobalt naphthenate and benzyltrimethylammonium hydroxide.

The aforementioned urethane prepolymer is generally used as a solution. The solution may be a solvent system, or an aqueous system such as emulsion, colloidal dispersion, and aqueous solution. The organic solvent is not particularly limited as long as it can uniformly dissolve the components constituting the forming material. Examples of organic solvents include toluene, methyl ethyl ketone, ethyl acetate and the like. In addition, when making an aqueous solution, alcohols such as n-butanol and isopropanol, and ketones such as acetone may also be blended. When preparing an aqueous solution, it can be carried out by using a dispersant, or by introducing a carboxylate, sulfonate, quaternary ammonium salt, etc. into the urethane prepolymer with low reactivity with isocyanate groups. Base, or water-dispersible components such as polyethylene glycol.

In addition to the aforementioned urethane prepolymer, the material forming the first transparent layer includes, for example, a cyanoacrylate-based forming material and an epoxy-based forming material.

The formation of the aforementioned first transparent layer can be appropriately selected according to the type of the aforementioned forming material. For example, it can be carried out by coating the forming material on a polarizer or a resin film and then curing, and it can be made in the form of a coating layer. Get a transparent layer. Generally speaking, after the aforementioned coating, it is dried at about 30-100°C, more preferably at 50-80°C for about 0.5-15 minutes, to form a hardened layer. In addition, when the aforementioned forming material contains an isocyanate component, in order to promote the reaction, an annealing treatment may be carried out at about 30 to 100°C, more preferably at 50 to 80°C, for about 0.5 to 24 hours.

Preferably, the first transparent layer has a structure with a gradient distribution: the saturated moisture concentration in the first transparent layer at 85° C. and 85% R.H. gradually decreases from the side of the polarizer to the side opposite to the polarizer. The structure can make it function as a permeable membrane more effectively.

<Second Transparent Layer> In the polarizing film of the present invention, a second transparent layer can be further formed on the aforementioned first transparent layer. Various layers can be formed as the second transparent layer, but from the viewpoint that the function of the permeable membrane can be more fully utilized, it is preferable to provide a second transparent layer having a saturated moisture content lower than that of the first transparent layer.

From the viewpoint of the function as a permeable membrane, the difference between the saturated moisture content of the first transparent layer and the saturated moisture content of the second transparent layer is preferably 0.1-8% by weight, more preferably 0.5-5% by weight. In addition, there is no problem even if the aforementioned difference is too large, but on the other hand, if it is too small, the function of the permeable membrane cannot be fully exhibited, so it is preferable to control it within the aforementioned range. In addition, the saturated moisture content of the aforementioned second transparent layer can be used in a range lower than the saturated moisture content of the aforementioned first transparent layer. Generally speaking, it is preferable to use 0.1-8% by weight, more preferably 0.5~ 5% by weight.

From the viewpoint of the function as a permeable membrane, the thickness of the second transparent layer is about 1-100 μm. It is preferably 2~50μm, more preferably 2~40μm, more preferably 5~35μm.

The aforementioned second transparent layer can be formed by, for example, a resin film such as an adhesive layer, an adhesive layer, a hard coat layer, or a protective film. From the viewpoint of suppressing fading at the ends of the polarizing film, the adhesive layer is preferred among them. When the second transparent layer is arranged on both sides, the thickness of the material of each second transparent layer can be the same or different.

≪Second transparent layer: Adhesive layer≫ Appropriate adhesives can be used for the formation of the adhesive layer, and there are no special restrictions on the type. Examples of the adhesive include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, and the like.

Among these adhesives, it is also suitable to use those having good optical transparency, showing appropriate wettability, cohesiveness and adhesive properties, and excellent weather resistance and heat resistance. Acrylic adhesives can be suitably used for those who can exhibit these characteristics.

The method of forming the adhesive layer can be produced by, for example, the following method: coating the aforementioned adhesive on a peel-off part, etc., and drying and removing the polymerization solvent to form an adhesive layer, and then transferring it to The method of the first transparent layer; or the method of coating the aforementioned adhesive on the first transparent layer and drying and removing the polymerization solvent to form the adhesive layer on the polarizer. In addition, one or more solvents other than the polymerization solvent may be added appropriately when applying the adhesive.

Polysilicon release liner material should be used for the separated parts after peeling treatment. In the step of coating the adhesive of the present invention on the lining material and drying to form an adhesive layer, the method of drying the adhesive may be appropriate and appropriate depending on the purpose. It is suitable to use a method of overheating and drying the above-mentioned coated film. The heating and drying temperature should be 40℃~200℃, more preferably 50℃~180℃, especially 70℃~170℃. By setting the heating temperature within the above range, an adhesive with excellent adhesive properties can be obtained.

The drying time can be appropriately used for an appropriate time. The above 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 can be used to form the adhesive layer. Specifically, for example, roll coating, touch roll coating, gravure coating, reverse coating, roll brush, spray cloth, dip roll coating, bar coating, knife coating, air knife coating, Methods such as curtain coating, lip coating, and extrusion coating using a die coater.

The thickness of the adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm. It is preferably 2~50μm, more preferably 2~40μm, more preferably 5~35μm.

When the aforementioned adhesive layer is exposed, the peeling-treated sheet (separator) can also be used to protect the adhesive layer until it can be used in practice.

The constituent materials of the aforementioned separator include, for example, plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and non-woven fabrics, meshes, foam sheets, and metals. Suitable sheets such as foils and laminates, etc., but from the viewpoint of excellent surface smoothness, plastic films are preferably used.

The plastic film is not particularly limited as long as it can protect the aforementioned adhesive layer. Examples include polyethylene film, polypropylene film, polybutene film, polypentadiene film, polymethylpentene film, and polyvinyl chloride. Film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-ethyl acetate copolymer film, etc.

The thickness of the aforementioned separator is usually 5 to 200 μm, and preferably about 5 to 100 μm. The aforementioned separation parts can also be used for mold release and antifouling treatment, as well as coating type, by using silicone, fluorine, long-chain alkyl, or fatty acid amide-based mold release agents, silica powder, etc. Antistatic treatment such as kneading type and vapor deposition type. In particular, by appropriately applying peeling treatments such as silicone treatment, long-chain alkyl treatment, fluorine treatment, etc., to the surface of the separator, the peelability from the adhesive layer can be further improved.

≪Second transparent layer: protective film≫ The material constituting the aforementioned protective film is preferably one that is excellent in transparency, mechanical strength, thermal stability, moisture barrier, and isotropy. Examples include: polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; polymethyl methacrylate Acrylic polymers such as esters; styrene polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin); and polycarbonate polymers. In addition, the following polymers can also be cited as examples of the polymers forming the above-mentioned protective film: polyethylene, polypropylene, polyolefins having cyclic or even norbornene structures, such as polyolefin polymers of ethylene-propylene copolymers , Vinyl chloride-based polymers, nylon and aromatic polyamides and other amide-based polymers, imine-based polymers, turbid polymers, polyether-based polymers, polyether ether ketone-based polymers, polystyrene Sulfur polymer, vinyl alcohol polymer, chlorinated vinylidene polymer, vinyl butyral polymer, aryl ester polymer, polyoxymethylene polymer, epoxy polymer or any of the above-mentioned polymers Blends and so on.

In addition, the protective film may contain one or more arbitrary appropriate additives. Examples of additives include ultraviolet absorbers, antioxidants, slip agents, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. The content of the aforementioned thermoplastic resin in the transparent protective film is preferably 50-100% by weight, preferably 50-99% by weight, more preferably 60-98% by weight, particularly preferably 70-97% by weight. In the transparent protective film, when the content of the thermoplastic resin is 50% by weight or less, the thermoplastic resin may not fully exhibit its inherent high transparency.

The aforementioned protective film can also use a retardation film, a brightness enhancement film, a diffusion film, etc. Examples of the retardation film include those having a frontal retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more. The frontal phase difference is usually controlled in the range of 40~200nm, and the thickness direction phase difference is usually controlled in the range of 80~300nm. When a retardation film is used as a protective film, since the retardation film can also function as a polarizer protective film, thickness reduction can be achieved.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film. The stretching temperature, stretching ratio, etc. can be appropriately set according to the retardation value, film material and thickness.

The thickness of the protective film can be appropriately determined, but it is generally about 1 to 500 μm from the viewpoint of workability such as strength and handling, and thin layer properties. In particular, it is preferably 1~300μm, preferably 5~200μm, more preferably 5~150μm, and particularly suitable when the thickness is 20~100μm.

Functional layers such as hard coating, anti-reflection layer, anti-adhesion layer, diffusion layer and even anti-glare layer can be provided on the surface of the protective film that is not adhered to the polarizing member. In addition, functional layers such as the above-mentioned hard coat, anti-reflection layer, anti-adhesion layer, diffusion layer, or anti-glare layer can be provided in addition to the protective film itself, and can also be provided as an individual separate from the protective film.

The aforementioned protective film (second transparent layer) may be directly attached to the first transparent layer.

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

From the viewpoints of inspection and management, the base film of the surface protection film can be selected from isotropic or nearly isotropic film materials. The film material may include, for example, polyester resins such as polyethylene terephthalate film, cellulose resins, acetate resins, polyether turpentine resins, polycarbonate resins, polyamide resins, Polyimide resin, polyolefin resin, and acrylic resin are transparent polymers. Among them, polyester resins are suitable. The base film can be used as a laminate of one or more film materials, or an extension of the aforementioned film can be used. The thickness of the substrate film is usually 500 μm or less, preferably 10 to 200 μm.

The adhesive that forms the adhesive layer of the surface protective film can be appropriately selected from (meth)acrylic polymers, polysiloxane polymers, polyester, polyurethane, polyamide, polyether, fluorine or Polymers such as rubber are used as adhesives for base polymers. From the viewpoints of transparency, weather resistance, heat resistance, etc., an acrylic adhesive using an acrylic polymer as the base polymer is suitable. The thickness of the adhesive layer (dry film thickness) can be determined according to the required adhesive force. Usually it is about 1-100μm, preferably 5-50μm.

In addition, for the surface protection film, it is also possible to provide a peeling treatment layer on the opposite side of the base film where the adhesive layer is provided through low adhesion materials such as silicone treatment, long-chain alkyl treatment, and fluorine treatment.

<Other optical layers> In actual use, the polarizing film of the present invention can be used as an optical film laminated with other optical layers. The optical layer is not particularly limited, and one layer or two or more layers such as reflectors and semi-transmissive plates, retardation plates (including 1/2 and 1/4 wavelength plates), viewing angle compensation films, etc. can be used. An optical layer of a liquid crystal display device etc. is formed. Particularly preferred: a reflective polarizing film or a semi-transmissive polarizing film formed by laminating a reflective plate or a semi-transmissive reflector on the polarizing film of the present invention, and an elliptical polarizing film formed by laminating a phase difference plate on the polarizing film Thin film or circular polarizing film, wide viewing angle polarizing film formed by laminating viewing angle compensation film on polarizing film, or polarizing film formed by laminating brightness enhancement film on polarizing film.

The optical film formed by laminating the above-mentioned optical layer on the polarizing film can also be formed in a sequential manner in the manufacturing process of liquid crystal display devices, etc., but the optical film is pre-laminated into an optical film in terms of quality stability and assembly operations. It has the advantage of improving the manufacturing steps of liquid crystal display devices. An appropriate bonding mechanism such as an adhesive layer can be used for lamination. When following the above-mentioned polarizing film and other optical films, the optical axis of the polarizing film and other optical films can be set to an appropriate arrangement angle in accordance with the desired retardation characteristics.

The polarizing film or optical film of the present invention can be suitably used in the formation of various image display devices such as liquid crystal display devices and organic EL display devices. The formation of the liquid crystal display device can be performed according to conventional knowledge. That is, the liquid crystal display device is generally formed by appropriately assembling the liquid crystal cell, the polarizing film or the optical film, and the component parts such as the lighting system according to the demand, and installing the driving circuit. In the present invention, except for the polarizing film of the present invention Or the optical film is not particularly limited except for this point, and it can follow conventional knowledge. Any type of liquid crystal cell, such as IPS type and VA type, can also be used, but the IPS type is particularly preferred.

It can form 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 an appropriate liquid crystal display device using a backlight or a reflective plate as an illumination system. At this time, the polarizing film or optical film of the present invention can be arranged on one side or both sides of the liquid crystal cell. When polarizing films or optical films are arranged on both sides, they may be the same or different. In addition, when forming a liquid crystal display device, one layer or two or more layers such as diffuser, anti-glare layer, anti-reflection film, protective plate, ridge array, lens array sheet, light diffusion plate, Suitable parts such as backlights. Example

Hereinafter, examples will be given to illustrate the present invention, but the present invention is not limited by the examples shown below. As for the parts and% in each case, all are based on weight. Below, the room temperature storage conditions that are not specifically specified are all 23°C and 65% R.H.

(Production of thin polarizer A) Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA-copolymer-PET) film (thickness: 100μm) with a water absorption rate of 0.75% and Tg75°C on one side of the substrate Apply corona treatment, and coat the corona-treated surface at 25℃ at a ratio of 9:1 containing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetyl acetonitrile modified PVA (Polymerization degree 1200, acetyl acetamide modification degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gohsefimer Z200") aqueous solution and dried to form a PVA-based resin with a thickness of 11 μm Layer to produce a laminate. The obtained laminate was subjected to uniaxial extension of the free end 2.0 times in the longitudinal direction (longitudinal direction) between rollers with different peripheral speeds in an oven at 120°C (air-assisted extension). Next, the layered body was immersed in an insoluble bath (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 30° C. for 30 seconds (insoluble treatment). Then, immersed in a dyeing bath with a liquid temperature of 30°C while adjusting the iodine concentration and immersion time so that the polarizing plate had a predetermined transmittance. In this example, it was immersed in an iodine aqueous solution obtained by mixing 0.2 parts by weight of iodine and 1.0 part by weight of potassium iodide with respect to 100 parts by weight of water for 60 seconds (dyeing treatment). Then, it was immersed in a crosslinking bath (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) at a liquid temperature of 30°C for 30 seconds (crosslinking treatment ). After that, the laminate was immersed in a boric acid aqueous solution 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 relative to 100 parts by weight of water), and placed between rolls of different peripheral speeds Uniaxial stretching is performed in the longitudinal direction (long-side direction) to achieve a total stretching magnification of 5.5 times (underwater stretching). After that, the layered body was immersed in a washing bath (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 30°C (washing treatment). In the manner described above, an optical thin film laminate including a polarizer with a thickness of 5 μm was produced.

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

(Protective film production) Protective film: The easy-adhesive surface of the (meth)acrylic resin film with a lactone ring structure with a thickness of 40 μm is subjected to corona treatment for use.

<Material for forming the first transparent layer (barrier layer)> Forming material A: 75% ethyl acetate solution of urethane prepolymer composed of toluene diisocyanate and trimethylolpropane (Tosoh (East) (Cao) company, brand name "CORONATE L") 100 parts, add dioctyl dilaurate-based catalyst (Tokyo FINE CHIMICAL company, brand name "Embilizer OL-1" 0.1 part, and methyl isobutyl The base ketone is used as a solvent to prepare a urethane prepolymer coating solution with a solid content of 10%. Forming material B: One of the urethane prepolymers composed of diphenylmethane diisocyanate and trimethylolpropane is used 75% ethyl acetate solution (manufactured by Tosoh Corporation, trade name "CORONATE 2067"), except that the same catalyst and solvent as the forming agent A were used to prepare a coating solution. Forming material C: use 75% ethyl acetate solution of urethane prepolymer composed of hexamethylene diisocyanate and trimethylolpropane (manufactured by Tosoh Co., Ltd., trade name "CORONATE HL". A coating solution was prepared by using the same catalyst and solvent as the forming agent A. Forming material D: 80 parts of urethane acrylate resin (manufactured by Nippon Gosei Co., Ltd., product name "Ultra UV-1700") was added with ethyl acetate Acrylic amide (manufactured by Koto, product name "HEAA") and photopolymerization initiator (manufactured by Ciba Japan, product name "IRGACURE 907"), and methyl isobutyl ketone as a solvent to prepare solid components A 10% urethane acrylate coating solution.

<Forming the second transparent layer (adhesive layer)> (Adhesive preparation) 100 parts of butyl acrylate, 3 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate and 0.3 part of 2,2´-azobisisobutyronitrile , And ethyl acetate are added to a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer, and a stirring device to prepare a solution. Next, the solution was stirred while blowing nitrogen gas, and reacted at 55°C for 8 hours to prepare a solution containing an acrylic polymer with a weight average molecular weight of 2.2 million. In addition, ethyl acetate was added to the solution containing the acrylic polymer to obtain an acrylic polymer solution whose solid content was adjusted to 30%.

With respect to 100 parts of the solid content of the aforementioned acrylic polymer solution, a crosslinking agent mainly composed of a compound having an isocyanate group as a crosslinking agent (manufactured by Japan Polyurethane Co., Ltd., trade name "CORONATE L" ) 0.5 part and 0.075 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KMB-403") as a silane coupling agent to prepare an adhesive solution. Apply the adhesive solution to the surface of a release sheet (separator) composed of a polyethylene terephthalate film (thickness 38μm) after a peeling treatment so that the thickness after drying is 20μm , And allowed to dry to form an adhesive layer.

Example 1 <Preparation of a polarizing film with a first transparent layer on both sides> The first transparent layer forming material A was coated on the surface of the polarizer A of the optical film laminate with a bar coater, and then applied at 60°C A 12-hour heat treatment was used to produce a urethane resin layer with a thickness of 1 μm. Next, after peeling off the amorphous PET substrate, the first transparent layer forming material A was coated on the peeling surface (polarizer) with a bar coater, and then heat-treated at 60°C for 12 hours, thereby A urethane resin layer with a thickness of 1 μm was formed, and a polarizing film with a first transparent layer on both sides was produced. The optical properties of the obtained polarizing film are monomer transmittance 42.8% and polarization degree 99.99%.

<Polarizing film with first and second transparent layers: Making a polarizing film with adhesive layer> Next, the first transparent layers on both sides of the polarizing film are bonded and formed on the release sheet (separator) The adhesive layer on the treated surface was peeled off to produce a polarizing film with adhesive layers on both sides.

Examples 2 to 3, Comparative Examples 1 to 6 The type of polarizer, the forming material of the first transparent layer, and the thickness in Example 1 were changed as shown in Table 1, except that it was the same as in Example 1. , And produced a single-sided protective polarizing film with a first transparent layer and a polarizing film with adhesive layers on both sides. The optical properties of the obtained single-sided protective polarizing film are that all monomers have a transmittance of 42.8% and a degree of polarization of 99.99%.

In addition, 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 forming agent D with a bar coater, and then heating at 60°C for 1 minute. After heating, a high-pressure mercury lamp was used to irradiate the coating layer with ultraviolet light with an accumulated light amount of 300 mJ/cm ² to form a urethane acrylate resin layer with a thickness of 1 μm. In Comparative Examples 4 and 5, the polarizer B (thickness 12 μm) was used instead of the polarizer A (thickness 5 μm).

Example 4 <Preparation of a polarizing film with first and second transparent layers> The first transparent layer forming material A was coated on the surface of the polarizer A of the optical film laminate with a bar coater, and then coated The above-mentioned protective film ((meth)acrylic resin film) is attached to the good forming agent A, and the heat treatment is performed at 60°C for 12 hours to produce a urethane resin layer with a thickness of 1μm ( The first transparent layer) is a laminated protective film layer (the second transparent layer). Next, after peeling off the amorphous PET substrate, the first transparent layer forming material A was coated on the peeling surface (polarizer) with the same bar coater, and then the protective film was attached to the coated Forming agent A, and heat treatment at 60 ℃ for 12 hours, to produce a thickness of 1μm urethane resin layer and protective film layer, and produced on both sides of the first transparent layer and second Polarizing film for transparent layer. The optical properties of the obtained polarizing film are monomer transmittance 42.8% and polarization degree 99.99%.

The following evaluations were performed on the polarizing films with the first and second transparent layers prepared in the above-mentioned Examples and Comparative Examples. The results are shown in Table 1.

<Measurement of the saturated moisture content of the polarizer> The polarizers produced in the examples and comparative examples were individually taken out before bonding, and a sample of about 50 mg was collected. Using a moisture adsorption and desorption measuring device (IGA-Sorp, manufactured by Hiden), place the sample in an environment of 85°C and 0%RH until the weight does not change, and measure the weight of the state after the moisture is completely removed (W1 ), then place it in an environment of 85°C and 85%RH and observe its weight change. The weight (W2) of the sample is measured at the time point when the weight change of the sample stops (saturated state). The saturated moisture content was measured by the following formula.

<Measure the saturated moisture content of the first transparent layer> The first transparent layer forming material prepared in the examples and comparative examples was applied to aluminum foil with a bar coater to make the thickness 10μm. After forming the first transparent layer in the same manner as in the example and the comparative example, it was cut into a size of 10×10 mm, and a sample was taken. Using a moisture adsorption and desorption measuring device (IGA-Sorp, manufactured by Hiden), place the sample in an environment of 85°C and 0%RH until the weight does not change, and measure the weight of the state after the moisture is completely removed (W1 ), then place it in an environment of 85°C and 85%RH and observe its weight change. The weight (W2) of the sample is measured at the time point when the weight change of the sample stops (saturated state). After subtracting the weight of aluminum foil of the same size that was measured in advance from each weight, the saturated moisture content was measured by the following formula.

≪Second transparent layer: Adhesive layer≫ Approximately 50 mg of the sample was collected from the adhesive layer of the polarizing film with the adhesive layer produced in the Examples and Comparative Examples. Using a moisture absorption and desorption measuring device (IGA-Sorp, manufactured by Hiden), place the sample in an environment of 85°C and 0%RH until the weight does not change, and measure the weight of the state after the moisture is completely removed (W1 ), then place it in an environment of 8585%RH and observe its weight change. The weight (W2) of the sample is measured at the time point when the weight change of the sample stops (saturated state). The saturated moisture content was measured by the following formula.

≪Second transparent layer: protective film≫ Cut the protective film into a size of 10×10mm and take samples. Using a moisture adsorption and desorption measuring device (IGA-Sorp, manufactured by Hiden), place the sample in an environment of 85°C and 0%RH until the weight does not change, and measure the weight of the state after the moisture is completely removed (W1 ), then place it in an environment of 85°C and 85%RH and observe its weight change. The weight (W2) of the sample is measured at the time point when the weight change of the sample stops (saturated state). The saturated moisture content was measured by the following formula.

[Math 1]

＜Single transmittance T and polarization degree P of polarizers＞ Use the spectroscopic transmittance measuring device with integrating sphere (Dot-3c of Murakami Color Technology Research Institute) to measure the single-sided protective polarizing film's single-sided protective polarizing film transmittance T and polarization Degree P. In addition, the degree of polarization P is the transmittance (parallel transmittance: Tp) when two identical polarizing films are overlapped with their transmission axes in parallel and the transmittance when the two transmission axes are overlapped orthogonally (orthogonal transmission) Rate: Tc) is obtained by applying the following formula. Polarization degree P(%)={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100 The transmittance is so that the complete polarization obtained through the Glan-Taylor polarizer is 100% It is expressed by the Y value obtained by calibrating the luminous efficacy of 2 degree field of view (C light source) of JIS Z8701.

(Preparation of evaluation samples) The polarizing films with first and second transparent layers (polarizing films with adhesive layers on both sides) prepared in Examples 1 to 3 and Comparative Examples 1 to 6 were made of one-sided After the release sheet is peeled off, the above-mentioned protective film is attached to the exposed adhesive layer, and it is cut into 50mm×50mm, and then attached to 1.2~1.5mm thick alkali glass (manufactured by Matsuba Glass Co., Ltd., glass Sheet), and make a sample. In addition, the polarizing film with the first and second transparent layers produced in Example 4 is the adhesive layer (Example 1) that has been formed on the release surface of the release sheet (separator). The second transparent layer) is attached to the second transparent layer (protective film) on one side, and it is cut into 50mm×50mm, and then attached to 1.2~1.5mm thick alkali glass (made by Matsuba Glass Co., Ltd., Slide), and make a sample.

<Confirm the moisture gradient in the first transparent layer> Put the above sample in a closed container and put a sufficient amount of heavy water that will not completely volatilize during the test. After sealing the container, keep the container together at a high temperature of 80℃ After 500 hours, it was taken out and immediately frozen to below -100°C to obtain a sample with immobilized heavy water ions. For the sample immobilized with heavy water, the protective film was etched with Ar gas cluster ions from the protective film side, and then TOF-SIMS analysis was performed to measure the distribution of heavy water ions (D-) in the depth direction, and confirm the first Water gradient in the transparent layer. When the moisture gradient is confirmed (with permeable membrane function), it is evaluated as "○", and when no moisture gradient is confirmed (without permeable membrane function), it is evaluated as "×". Device: ULVAC-PHI, TRIFT-V Etching ion: Ar gas cluster ion irradiation Primary ion: Bi ₃ ^{2 +} Primary ion acceleration voltage: 30kV Measuring electrode: negative ion Measuring temperature: below -100°C Measuring area: 100μm square

<Durability> After keeping the above sample under a high temperature and high humidity environment of 85℃85%RH for 500 hours, after leaving it at room temperature (23℃65%RH), under the following conditions, an interference phase contrast microscope (manufactured by Olympus) , Product name "MX-61L") Measure the amount of end fading. The amount of end fading is on the diagonal line of the four corners of the sample. In the part where the color becomes lighter than the center, the straight line distance connecting the corner closest to the center is defined as the end fading. And the average value of the four corners is defined as the amount of discoloration at the end of the sample. Device: manufactured by Olympus, MX-61L Measurement conditions Lens magnification: 5 times ISO: 200 Shutter speed: 1/100 Reflected light: scale 0 White balance: Automatic transmitted light controller: LG-PS2 Transmitted light: scale 5 Polarized light Direction: The direction of polarization is orthogonal to the transmission axis of the polarizing film. "Unable to measure" in Table 1 means that there is a measurement area (fading area) outside the field of view of the optical microscope that is measuring the end fading.

[Table 1]

P‧‧‧Polarizer 1a, 1b‧‧‧First transparent layer 2, 2a, 2b‧‧‧Second transparent layer (adhesive layer) 11, 12, 13‧‧‧ Polarizing film

Fig. 1 is an example of a schematic cross-sectional view of the polarizing film of the present invention. Fig. 2 is an example of a schematic cross-sectional view of the polarizing film of the present invention. Fig. 3 is an example of a schematic cross-sectional view of the polarizing film of the present invention.

P‧‧‧Polarizer

1a、1b‧‧‧First transparent layer

11‧‧‧Polarizing film

Claims (11)

A polarizing film having a polarizing member and a first transparent layer on both sides of the polarizing member. The polarizing film is characterized in that the saturated moisture content of the first transparent layer at 85°C and 85% RH is lower than that of the polarizing member. The saturated moisture content is lower at 85°C and 85%RH; the aforementioned first transparent layer acts as a permeable membrane to help discharge the moisture in the aforementioned polarizer. The polarizing film of claim 1, wherein the first transparent layer is directly formed on the polarizing member. The polarizing film of claim 1, wherein the thickness of the first transparent layer is 3 μm or less. The polarizing film of claim 1, wherein the first transparent layer is a cured product of a forming material containing a urethane prepolymer, and the urethane prepolymer is a reaction product of an isocyanate compound and a polyol. The polarizing film according to claim 4, wherein the aforementioned isocyanate compound contains at least one selected from toluene diisocyanate and diphenylmethane diisocyanate. The polarizing film of claim 1, wherein the first transparent layer has a gradient distribution: the saturated moisture concentration in the first transparent layer at 85°C and 85% RH is from the side of the polarizer to the side opposite to the polarizer Gradually decreases. The polarizing film of claim 1, wherein the thickness of the aforementioned polarizing member is 10 μm or less. Such as the polarizing film of any one of claims 1 to 7, which In the first transparent layer on at least one side of the first transparent layer on both sides of the polarizer, there is a second transparent layer adjacent to the side opposite to the side with the polarizer; the second transparent layer is at 85°C, 85°C The saturated moisture content under %RH is lower than the saturated moisture content of the aforementioned first transparent layer at 85℃ and 85%RH; the moisture in the aforementioned polarizer penetrates the aforementioned first transparent layer, the aforementioned The second transparent layer. The polarizing film of claim 8, wherein the aforementioned second transparent layer is an adhesive layer. The polarizing film of claim 8, wherein the aforementioned second transparent layer is a protective film. An image display device having the polarizing film according to any one of claims 1 to 10.

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