TW201743087A - Polarizing film, polarizing film with adhesive layer, and image display device - Google Patents

Abstract

This polarizing film has a first resin film on one surface of a polarizer that has a thickness of 10 [mu]m or less, while having a second resin film on the other surface of the polarizer; and the first resin film and the second resin film both have a water vapor permeability of 30 g/(m2·day) or less. This polarizing film also has a protective plate on a surface of the first resin film, said surface being on the reverse side of the polarizer-side surface. This polarizing film is obtained by laminating resin films having extremely low water vapor permeabilities on both surfaces of a polarizer that has a thickness of 10 [mu]m or less, and is able to suppress deterioration of the polarizer due to humidification (to have good humidification reliability), while being capable of suppressing the occurrence of through cracks even under severe thermal shock conditions.

Description

Polarizing film, polarizing film with adhesive layer and image display device

FIELD OF THE INVENTION The present invention relates to a polarizing film and a polarizing film having an adhesive layer of the polarizing film and the adhesive layer. Further, the present invention relates to an image display device comprising the polarizing film with the above-mentioned adhesive layer.

Background Art In various image display devices, a polarizing film is used to display an image. For example, a liquid crystal display device (LCD) is indispensable for arranging a polarizing film on both sides of a glass substrate forming a surface of a liquid crystal panel due to its image forming manner. Further, in the organic EL display device, in order to shield the specular reflection of the external light on the metal electrode, a circularly polarizing film in which the polarizing film and the quarter-wave plate are laminated is disposed on the viewing side of the organic light-emitting layer.

The polarizing film is generally formed by bonding a protective film on one side or both sides of a polarizing member by a polyvinyl alcohol-based adhesive, and the polarizing member is made of a polyvinyl alcohol-based film and a dichroic material such as iodine.

The polarizing film has the following problems: in a severe environment of thermal shock (for example, a thermal shock test at a temperature of -40 ° C and 85 ° C), the change in the contraction stress of the polarizer is easy in the absorption axis direction of the polarizer. Cracks (through cracks) are generated. Therefore, in order to suppress the shrinkage of the polarizer and to reduce the influence of thermal shock, the polarizing film usually uses a laminate which is adhered to a 40-80 μm triethylene cellulose (TAC) film on both sides of the polarizer. film. However, even in the case of the above-mentioned double-protected polarizing film, the change in the contraction stress of the polarizer cannot be ignored, and it is difficult to completely suppress the influence of the shrinkage, and it is inevitably on the optical film laminate including the polarizer. Produces a certain degree of contraction.

On the other hand, in recent years, the development of a video display device such as a liquid crystal display device has been reduced, and the polarizer has been required to be thinner. In the case of a thin polarizer having a thickness of 10 μm or less, since the change in the shrinkage stress is small, the through crack is less likely to occur. For example, a polarizing film which adheres a protective film to one side or both surfaces of a thin polarizing member having a thickness of 10 μm or less has been disclosed, and the occurrence of through cracks can be suppressed (for example, see Patent Document 1). In particular, if a double-sided protective polarizing film having a protective film adhered to both sides of the thin polarizing member is provided, the protective film disposed on both sides can suppress the amount of shrinkage of the polarizing member during the thermal shock test, thereby effectively The through crack is suppressed.

PRIOR ART DOCUMENT Patent Document Patent Document 1: JP-A-2015-152911

SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, on the other hand, a thin polarizer having a thickness of 10 μm or less has a problem that optical characteristics are easily lowered in a humidified environment. According to this, even if the double-sided protective polarizing film using the thin polarizer described in Patent Document 1 or the like differs depending on the type of the protective film, the polarizer is deteriorated by moisture in a humidified environment, and the optical of the polarizing film The characteristics are significantly reduced.

Therefore, in order to suppress the deterioration of the polarizing member caused by such moisture, it is currently considered to use a resin film having a very low moisture permeability (specifically, 30 g/(m ² .day or less) or less as a bonding film on both sides of the thin polarizing member. Protective film. However, when such a resin film having a very low moisture permeability is used as the protective film, although deterioration of the polarizing member in a humidifying environment can be suppressed, a thin polarizing member having a thickness of 10 μm or less is used, and the thin polarizing member is used. A protective film was bonded to both sides, but a new problem of through cracking in the polarizing film was found.

Therefore, in the present invention, an object of the present invention is to provide a polarizing film which is formed by a resin film having a very low moisture permeability in a two-layer layer of a polarizing member having a thickness of 10 μm or less, which can suppress deterioration of a polarizing member due to humidification ( Humidification reliability), and even in the harsh environment of thermal shock, the occurrence of through cracks can be suppressed.

Means for Solving the Problem In order to solve the above problems, the inventors have found the following polarizing film in order to solve the above problems, and have completed the present invention.

In other words, the polarizing film has a first resin film on one surface of the polarizing member having a thickness of 10 μm or less, and a second resin film on the other surface, the first resin film and the second resin film. The resin film has a moisture permeability of 30 g/(m ² .day or less), and has a protective plate on the opposite side surface of the first resin film having the polarizer side.

The linear expansion coefficient of the protective plate in the direction orthogonal to the absorption axis of the polarizer is preferably 1.0 × 10 ^-5 /K or less.

The linear expansion coefficient of the first resin film and the second resin film in the direction orthogonal to the absorption axis of the polarizer is preferably 5.0 × 10 ^-5 to 8.0 × 10 ^-5 /K.

When the first resin film and the second resin film are subjected to heat treatment at 85 ° C for 120 hours, the dimensional change rate in the direction orthogonal to the absorption axis of the polarizer is preferably -0.40 to 0%. .

The first resin film and the second resin film preferably have a breaking strength in a direction orthogonal to the absorption axis of the polarizer of 5 to 30 N.

The first resin film and the second resin film are preferably the same or different cycloolefin resin films.

The absolute value of the degree of change in the degree of polarization of the polarizing film after leaving it at 85 ° C and 85% R.H. for 500 hours is preferably less than 0.1%.

Moreover, the present invention relates to a polarizing film with an adhesive layer, characterized in that an adhesive layer is provided on the second resin film side of the polarizing film.

Furthermore, the present invention relates to an image display device characterized by comprising the above-mentioned polarizing film with an adhesive layer.

Advantageous Effects of Invention As described above, this new discovery is a polarizing film which is a protective film for a resin film having a very low moisture permeability (specifically, 30 g/(m ² .day or less) in a two-layer layer of a thin polarizing member, although it is possible to suppress humidification. Deterioration of the polarizer (which can improve the humidification reliability), but a through crack occurs. The main cause of the occurrence of the through crack is that the resin film (protective film) having a very low moisture permeability generally has a large coefficient of linear expansion, a small dimensional change rate, and/or a breaking strength in a direction orthogonal to the absorption axis of the polarizing member. low. Further, it is considered that if the linear expansion coefficient of the protective film in the direction orthogonal to the absorption axis of the polarizing member is large, the difference in expansion and contraction in the thermal shock test becomes large, and the strain is increased, and as a result, the polarizing film is easily formed. A through crack occurred. It is also believed that if the dimensional change rate of the protective film in the direction orthogonal to the absorption axis of the polarizer is small, the protective film is not easily attached to the contraction of the polarizer during cooling in the thermal shock test, and the stress is accumulated. As a result, it is easy to cause a through crack in the polarizing film. Further, it is considered that if the breaking strength of the protective film in the direction orthogonal to the absorption axis of the polarizer is low, the brittleness of the protective film is likely to occur, and it is easy to cause a through crack in the polarizing film.

In the present invention, since the protective sheet is bonded to the first resin film of the polarizing film, even in a severe environment of thermal shock (for example, thermal shock test under temperature conditions of -40 ° C and 85 ° C), It is also possible to reduce the amount of shrinkage of the entire polarizing film in the direction orthogonal to the absorption axis of the polarizing member. Therefore, even in the two layers of the polarizing member, the protective film having a very low moisture permeability (in other words, a large linear expansion coefficient and a dimensional change) The protective film having a small rate and/or low breaking strength can also suppress the occurrence of through cracks in the polarizing film. In other words, the polarizing film of the present invention can achieve both suppression of deterioration of the polarizer due to humidification (improvement in humidification reliability) and suppression of occurrence of penetration cracks.

Moreover, the present invention can provide a polarizing film which can improve the humidifying reliability and suppress the occurrence of through cracks, and an image display device using the polarizing film having the adhesive layer.

In the polarizing film of the present invention, the polarizing film of the present invention has a first resin film on one surface of the polarizing member having a thickness of 10 μm or less and a second resin film on the other surface. Each of the resin film and the second resin film has a moisture permeability of 30 g/(m ² .day or less), and has a protective plate on the opposite side surface of the first resin film having the polarizer side.

In the present invention, as described above, since the protective sheet is bonded to the first resin film of the polarizing film, it is harsh even in thermal shock (for example, thermal shock test under temperature conditions of -40 ° C and 85 ° C) In the environment or in a humidified environment, the amount of shrinkage of the entire polarizing film in the direction orthogonal to the absorption axis of the polarizer can be reduced, and as a result, even if the two layers of the polarizer have a low moisture-permeable protective film, It is possible to suppress the occurrence of through cracks in the polarizing film.

The structure of the polarizing film of the present invention will be described in detail with reference to Fig. 1 . Further, the dimensions of the respective structures in Fig. 1 are shown as an example, and the present invention is not limited thereto.

As shown in FIG. 1, the polarizing film 1 of the present invention has a first resin film 3 on one surface of the polarizer 2 and a second resin film 4 on the other surface. Moreover, the protective sheet 5 is provided on the side of the first resin film 3 which does not have the polarizer 2 described above. The first resin film 3 and the second resin film 4 are adhered to the polarizer 2 through an adhesive layer (not shown). Further, the protective sheet 5 is adhered to the first resin film 3 through an adhesive layer or an adhesive layer (not shown). Further, the polarizing film 1 of the present invention may include a layer body other than the layer body (for example, an easy adhesive layer or various functional layers).

Further, the first resin film 3 is preferably disposed on the viewing side of the polarizer 2, and the second resin film 4 is preferably disposed on the image display unit side of the polarizer 2.

Each component will be described below.

(1) Polarizer In the present invention, a thin polarizer having a thickness of 10 μm or less is used. The thickness of the polarizer is preferably 8 μm or less, more preferably 7 μm or less, and further 6 μm or less from the viewpoint of reducing the thickness and suppressing the occurrence of the through crack. On the other hand, the thickness of the polarizing member is preferably 2 μm or more, and more preferably 3 μm or more. Such a thin polarizer has a small thickness unevenness, is excellent in visibility, and is excellent in durability against thermal shock due to small dimensional change.

A polarizing member can be used: a polarizing member using a polyvinyl alcohol resin. Examples of the polarizer include a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and ethylene. The vinyl acetate copolymer is a hydrophilic polymer film such as a partially saponified film, which adsorbs a dichroic substance of iodine or a dichroic dye and is uniaxially stretched; a dehydrated material of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride A polyene oriented film or the like. Among these, a polarizing member composed of a polyvinyl alcohol-based film and a dichroic material such as iodine is suitable.

A polarizing member which dyes a polyvinyl alcohol-based film with iodine and uniaxially stretches can be produced, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine for dyeing and extending it to 3 to 7 times the original length. . If necessary, it may contain boric acid, zinc sulfate or zinc chloride, or may be immersed in an aqueous solution of potassium iodide 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, it is possible to prevent unevenness in dyeing unevenness by swelling the polyvinyl alcohol-based film in addition to the stain or anti-caking agent on the surface of the polyvinyl alcohol-based film. . The extension may be carried out after dyeing with iodine, or may be extended while dyeing, or may be dyed with iodine after stretching. The extension can also be carried out in an aqueous solution or a water bath such as boric acid or potassium iodide.

It is preferable that the polarizer contains boric acid from the viewpoint of elongation stability or humidification reliability. In addition, the content of boric acid contained in the polarizer is preferably 22% by weight or less, more preferably 20% by weight or less, based on the total amount of the polarizer. From the viewpoint of elongation stability or humidification reliability, the boric acid content based on the total amount of the polarizers is preferably 10% by weight or more, and more preferably 12% by weight or more.

Examples of the thin polarizer include, for example, Japanese Patent No. 4751486, Japanese Patent No. 4751481, Japanese Patent No. 4815544, Japanese Patent No. 5048120, International Publication No. 2014/077599, International Publication No. 2014 A thin polarizer described in the specification of No. 077636 or the like, or a thin polarizer obtained by the manufacturing method described in the above.

In the method of forming the thin polarizer, which includes the step of stretching in the state of the laminated body and the dyeing step, it is preferable that the polarizing performance can be improved by extending to a high magnification. In the specification of Japanese Patent No. 4751486, the specification of Japanese Patent No. 4751481, and the specification of Japanese Patent No. 4815544, a thin polarizing member is produced by a method comprising the step of stretching in an aqueous solution of boric acid, and particularly preferably: In the specification of Japanese Patent No. 4751481 and Japanese Patent No. 4815544, a thin polarizer is produced by a process comprising the step of assisting in the air extension in an aqueous solution of boric acid. The thin polarizing member can be obtained by a method comprising the steps of: extending a layer of a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) and a resin substrate for stretching in a laminated state; and a dyeing step . According to this production method, even if the PVA-based resin layer is thin, it can be extended by supporting the resin substrate for stretching without causing problems such as breakage due to elongation.

(2) The first resin film is formed of a material of the first resin film which is provided on one surface of the polarizer, and is a material which can form a film having transparency and a moisture permeability of 30 g/(m ² .day) or less. can. Specifically, a cycloolefin type resin film etc. are mentioned, for example.

The cycloolefin-based resin film is not particularly limited as long as it has a moisture permeability of 30 g/(m ² .day or less), and a known cycloolefin-based resin film can be used. The cycloolefin-based resin is a general term for a resin which is polymerized by using a cycloolefin as a polymerization unit, and is exemplified by, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. The resin described. Specific examples thereof include a ring-opening (co)polymer of a cyclic olefin, an addition polymer of a cycloolefin, a copolymer of a cycloolefin and an α-olefin such as ethylene or propylene (representatively a random copolymer), and the like. A graft polymer modified with an unsaturated carboxylic acid or a derivative thereof, and a hydride or the like. Specific examples of the cycloolefins include, for example, a norbornene-based monomer.

Various products are commercially available as cycloolefin resins. Specific examples include the trade name "ZEONEX" manufactured by ZEON Co., Ltd., "ZEONOR", the product name "ARTON" manufactured by JSR Co., Ltd., and the trade name of TICONA. "TOPAS" and the product name "APEL" manufactured by Mitsui Chemicals Co., Ltd.

The moisture permeability of the first resin film is 30 g/(m ² .day) or less, preferably 25 g/(m ² .day) or less, more preferably 20 g/(m ² .day) or less. Further, the lower limit of the moisture permeability is not particularly limited, but it is desirable to make the water vapor completely impermeable (i.e., 0 g / (m ² .day)). By setting the moisture permeability of the first resin film to the above range, deterioration of moisture of the polarizer can be suppressed.

The thickness of the first resin film is not particularly limited, and it is preferably 10 μm or more from the viewpoint of reducing the moisture permeability, improving the humidification reliability, and improving the fracture strength and further suppressing the penetration crack. It is 12 μm or more. On the other hand, from the viewpoint of thinning, it is preferably 40 μm or less, and more preferably 30 μm or less.

The linear expansion coefficient of the first resin film is not particularly limited. For example, the linear expansion coefficient in the direction orthogonal to the absorption axis of the polarizer is 5.0 × 10 ^-5 to 8.0 × 10 ^-5 / K can also be 5.5 × 10 ^-5 ~ 7.5 × 10 ^-5 /K. The polarizing film of the present invention can suppress the occurrence of through cracks even when a first resin film having extremely low moisture permeability and having a linear expansion coefficient in the above range is used. The coefficient of linear expansion can be measured by the measurement method described in the examples.

Further, the breaking strength of the first resin film is not particularly limited, and for example, the breaking strength in the direction orthogonal to the absorption axis of the polarizer is 5 to 30 N, and may be 8 to 25 N. It can also be 8~23N. The polarizing film of the present invention can suppress the occurrence of through cracks even when a first resin film having extremely low moisture permeability and having a breaking strength in the above range is used. The breaking strength can be measured by the measurement method described in the examples.

Moreover, the dimensional change rate when the first resin film is subjected to heat treatment for 120 hours at 85 ° C is not particularly limited, and for example, the dimensional change rate in the direction orthogonal to the absorption axis of the polarizer is exemplified. It is -0.40~0%, and can be -0.34~0%, or -0.33~-0.01%. In the polarizing film of the present invention, even when a first resin film having extremely low moisture permeability and having a dimensional change ratio in the above range is used, occurrence of through cracks can be suppressed. The dimensional change rate can be measured by the measurement method described in the examples.

From the viewpoint of the reliability of the humidification, the polarizer and the first resin film are usually adhered to each other by an adhesive such as an active energy ray-curable adhesive. The active energy ray-curable adhesive is an adhesive which is cured by an active energy ray such as an electron beam or an ultraviolet ray (radical hardening type or cation hardening type). For example, an electron ray hardening type or an ultraviolet curing type can be used. kind. As the active energy ray-curable adhesive, for example, a photo-radical curing type adhesive can be used. When a photo-radical curing type active energy ray-curable adhesive is used as the ultraviolet curing type, the adhesive contains a radical polymerizable compound and a photopolymerization initiator. The coating method of the subsequent agent can be appropriately selected depending on the viscosity of the adhesive or the target thickness. Examples of the coating method include, for example, a reverse coater, a gravure coater (direct, reverse or lithographic), a bar type reverse coater, a roll coater, a die-casting coater, a bar coater, and a scraper. Bar coater, etc. In addition to this, the coating may suitably be carried out by means of a dipping method or the like.

The surface of the first resin film which is not attached to the polarizer may be subjected to a hard coat layer, an antireflection treatment, or a treatment for preventing adhesion, diffusion, or antiglare.

(3) The second resin film has a second resin film on the opposite side surface of the polarizing material on which the first resin film has been formed. The material for forming the second resin film may be any material that can form a film having transparency and a moisture permeability of 30 g/(m ² .day) or less. Specifically, for example, a cycloolefin-based resin film or the like can be mentioned.

The cycloolefin-based resin film may be a cycloolefin-based resin film as exemplified in the first resin film.

The moisture permeability of the second resin film is 30 g/(m ² .day) or less, preferably 25 g/(m ² .day) or less, more preferably 20 g/(m ² .day) or less. Further, the lower limit of the moisture permeability is not particularly limited, but it is desirable to make the water vapor completely impermeable (i.e., 0 g / (m ² .day)). By making the moisture permeability of the second resin film within the above range, deterioration of moisture of the polarizer can be suppressed.

The thickness of the second resin film is not particularly limited, and it is preferably 10 μm or more from the viewpoint of reducing the moisture permeability, improving the humidification reliability, and improving the fracture strength and further suppressing the penetration crack. It is 12 μm or more. On the other hand, from the viewpoint of thinning, it is preferably 40 μm or less, and more preferably 30 μm or less.

The linear expansion coefficient of the second resin film is not particularly limited, and for example, the linear expansion coefficient in the direction orthogonal to the absorption axis of the polarizer is 5.0 × 10 ^-5 to 8.0 × 10 ^-5 / K can also be 5.5 × 10 ^-5 ~ 7.5 × 10 ^-5 /K. The polarizing film of the present invention can suppress the occurrence of through cracks even when a second resin film having extremely low moisture permeability and having a linear expansion coefficient in the above range is used. The coefficient of linear expansion can be measured by the measurement method described in the examples.

Further, the breaking strength of the second resin film is not particularly limited, and for example, the breaking strength in the direction orthogonal to the absorption axis of the polarizer is 5 to 30 N, and may be 8 to 25 N. Can be 8~23N. The polarizing film of the present invention can suppress the occurrence of through cracks even when a second resin film having extremely low moisture permeability and having a breaking strength in the above range is used. The breaking strength can be measured by the measurement method described in the examples.

Moreover, the dimensional change rate when the second resin film is subjected to heat treatment for 120 hours at 85 ° C is not particularly limited, and for example, the dimensional change rate in the direction orthogonal to the absorption axis of the polarizer is exemplified. It is -0.40~0%, and can be -0.34~0%, or -0.33~-0.01%. In the polarizing film of the present invention, even when a second resin film having extremely low moisture permeability and having a dimensional change ratio in the above range is used, occurrence of through cracks can be suppressed. The dimensional change rate can be measured by the measurement method described in the examples.

The polarizer and the second resin film are usually adhered to each other through an adhesive. The subsequent agent may be an adhesive as exemplified in the first resin film.

On the surface of the second resin film which is not attached to the polarizer, a hard coat layer, an antireflection treatment or a treatment for preventing adhesion or diffusion or antiglare may be applied.

(4) Protective sheet The polarizing film of the present invention has a protective sheet on the side of the first resin film which does not have the polarizer. By providing the protective plate, the amount of contraction of the polarizer during the thermal shock test can be suppressed, and therefore, the occurrence of the through crack can be suppressed.

The protective sheet is not particularly limited as long as it is the following protective sheet: even when the polarizing film of the present invention is exposed to a thermal shock environment, the shrinkage of the polarizing film can be suppressed.

The linear expansion coefficient of the protective plate in the direction orthogonal to the absorption axis of the polarizing member is preferably 1.0 × 10 ^-5 /K or less, more preferably 9.0 × 10 ^-6 /K or less, and most desirably 8.0. ×10 ^-6 /K or less. When the linear expansion coefficient of the protective plate in the direction orthogonal to the absorption axis of the polarizer is within the above range, the protective plate can suppress the amount of contraction of the polarizer during the thermal shock test, thereby suppressing the penetration more effectively. The occurrence of cracks. Further, the lower limit of the coefficient of linear expansion is not particularly limited, and is, for example, preferably 1.0 × 10 ^-6 /K or more.

The thickness of the protective plate is not particularly limited, but is preferably 0.5 to 1.0 mm, more preferably 0.5 to 0.8 mm. When the thickness of the protective sheet is within the above range, the size is less likely to shrink, which is preferable.

The pencil hardness of the protective sheet is preferably 8H or more, and more preferably 10H or more. When the pencil hardness of the protective sheet is within the above range, the size is less likely to shrink, which is preferable. The aforementioned pencil hardness is a pencil hardness according to JIS K 5600-5-4.

The specific gravity of the protective sheet is preferably 2.0 or more, and more preferably 2.3 or more. When the specific gravity of the protective sheet is within the above range, the size is less likely to shrink, which is preferable.

The thermal conductivity of the protective sheet is preferably 2.0 W/(m.K) or less, more preferably 1.5 W/(m.K) or less. By setting the thermal conductivity of the protective plate within the above range, even in the thermal shock test, heat is not easily transmitted to the polarizer, and the amount of contraction of the polarizer in the direction orthogonal to the absorption axis of the polarizer can be suppressed. More ideal.

The material for forming the protective sheet is not particularly limited, and examples thereof include glass and acrylic sheets. Among these, glass is preferred.

The protective sheet and the first resin film are laminated through the adhesive layer or the adhesive layer. As the subsequent layer, the adhesive layer described in the present specification can be suitably used.

The above adhesive layer is not particularly limited, and a known adhesive layer can be used. Specifically, such an adhesive layer can be appropriately selected and used, for example, a (meth)acrylic polymer, a polyoxyalkylene polymer, a polyester, a polyurethane, a polyamide, a polyether, or the like. A polymer such as a fluorine-based or rubber-based polymer is used as an adhesive layer of the base polymer. Among these, the (meth)acrylic polymer is used as a base polymerization because it is excellent in optical transparency, exhibits moderate wettability, adhesion properties of cohesiveness and adhesion, and is excellent in weather resistance and heat resistance. Acrylic adhesives are preferred.

The (meth)acrylic polymer is not particularly limited, and examples thereof include a (meth)acrylic polymer obtained by polymerizing a monomer component containing an alkyl (meth) acrylate, and the foregoing. The alkyl (meth) acrylate has an alkyl group having 4 to 24 carbon atoms at the terminal of the ester group. Further, the alkyl (meth) acrylate means an alkyl acrylate and/or an alkyl methacrylate, and the (meth) of the present invention has the same meaning.

The alkyl (meth) acrylate can be exemplified by an alkyl (meth) acrylate having a linear or branched alkyl group having 4 to 24 carbon atoms, which is preferable in that the balance of adhesion properties can be easily obtained. An alkyl (meth) acrylate having a linear or branched alkyl group having 4 to 9 carbon atoms. These alkyl (meth) acrylates may be used alone or in combination of two or more.

The monomer component other than the alkyl (meth) acrylate may be contained as a monofunctional monomer component in the monomer component which forms a (meth)acrylic-type polymer. Examples of such a comonomer include a cyclic nitrogen-containing monomer, a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and a monomer having a cyclic ether group.

Further, in addition to the monofunctional monomer, the monomer component forming the (meth)acrylic polymer may contain a polyfunctional monomer as needed in order to adjust the cohesive force of the adhesive. The aforementioned polyfunctional single system has at least two monomers having a polymerizable functional group having an unsaturated double bond such as a (meth) acryl fluorenyl group or a vinyl group, and, for example, may be exemplified by dipentaerythritol. Hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate. The polyfunctional monomer may be used alone or in combination of two or more.

In the production of such a (meth)acrylic polymer, a known production method such as various types of radical polymerization such as solution polymerization or ultraviolet polymerization, such as radiation polymerization, bulk polymerization, or emulsion polymerization can be appropriately selected. Further, the obtained (meth)acrylic polymer may be any of a random copolymer, a block copolymer, a graft copolymer and the like.

The polymerization initiator, the chain transfer agent, the emulsifier and the like used in the radical polymerization are not particularly limited, and those known in the art can be appropriately selected and used. Further, the weight average molecular weight of the (meth)acrylic polymer can be controlled by the amount of the polymerization initiator, the chain transfer agent used, and the reaction conditions, and the amount of use can be appropriately adjusted according to the types thereof.

The (meth)acrylic polymer used in the present invention preferably has a weight average molecular weight of 400,000 to 4,000,000. By making the weight average molecular weight more than 400,000, the durability of the adhesive layer can be satisfied, or the cohesive force of the adhesive layer can be suppressed to be reduced to generate residual glue. On the other hand, when the weight average molecular weight is more than 4,000,000, the adhesiveness tends to be lowered. Furthermore, the viscosity of the adhesive in the solution system becomes too high and there is a case where coating is difficult. Further, the weight average molecular weight means a value measured by GPC (gel permeation chromatography) and calculated by polystyrene conversion. Further, it is difficult to measure the molecular weight of the (meth)acrylic polymer obtained by radiation polymerization.

The adhesive composition used in the present invention may contain a crosslinking agent. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, a polyfluorene crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, and a decane crosslinking. A crosslinking agent such as an alkyl etherified melamine-based crosslinking agent, a metal chelate-based crosslinking agent, or a peroxide may be used alone or in combination of two or more. As the crosslinking agent, an isocyanate crosslinking agent or an epoxy crosslinking agent is preferably used.

The above-mentioned crosslinking agent may be used singly or in combination of two or more kinds, and the total content thereof is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the (meth)acrylic polymer. Crosslinker.

The adhesive composition used in the present invention may contain a (meth)acrylic oligomer in order to enhance the adhesion. Further, in the adhesive composition used in the present invention, a decane coupling agent may be contained in order to improve the water resistance of the interface when the adhesive layer is applied to a hydrophilic adherend such as glass.

Further, the adhesive composition used in the present invention may contain other known additives. For example, a polyether compound such as a polyalkylene glycol such as polypropylene glycol or a coloring agent may be appropriately added depending on the use. Powders, dyes, surfactants, plasticizers, adhesion-imparting agents, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, photosensitizers, ultraviolet absorbers, polymerization inhibitors, etc. Inorganic or organic fillers, metal powders, particulates, foils, and the like. Further, a redox system to which a reducing agent is added may be employed within a controllable range.

The method of forming the adhesive layer can be carried out by a known method.

In addition, as the adhesive layer for laminating the protective sheet and the first resin film, "LUCIACS" manufactured by Nitto Denko Co., Ltd., "CLEARFIT" manufactured by Mitsubishi Resin Co., Ltd., and Di Ruihe ( A commercially available product such as an adhesive layer (adhesive sheet) such as "Optical Elastic Resin (SVR)" manufactured by DEXERIALS.

The absolute value of the degree of change in the degree of polarization of the polarizing film of the present invention after leaving it at 85 ° C and 85% R.H. for 500 hours is preferably less than 0.1%, more preferably 0.05% or less, and most preferably 0.03% or less. The polarizing film of the present invention bonds the protective sheet to the first resin film, and therefore, even in a severe environment of thermal shock (for example, thermal shock test under temperature conditions of -40 ° C and 85 ° C), the polarizing film is entirely The shrinkage force is also extremely reduced. Further, since the low moisture permeability protective film is used, deterioration of the moisture of the polarizer can be suppressed, and as a result, the change in the degree of polarization is small and the optical characteristics are excellent even when exposed to a severe environment. .

2. Polarizing film with an adhesive layer The polarizing film with an adhesive layer of the present invention is characterized in that it has an adhesive layer on the second resin film side of the polarizing film.

The pressure-sensitive adhesive layer may be laminated on the side of the second resin film which is not provided with the polarizer. Specifically, the polarizing film 10 with an adhesive layer of the present invention has a protective sheet 5, a first resin film 3, a polarizing element 2, a second resin film 4, and an adhesive layer 6 in this order as shown in FIG.

In the polarizing film with an adhesive layer of the present invention, the adhesive composition can be formed by directly applying an adhesive composition to the second resin film having the polarizing film of the protective sheet, and removing the solvent by heat drying or the like to form an adhesive layer. Further, an adhesive layer formed on a support or the like may be transferred onto the second resin film of the polarizing film to form a polarizing film with an adhesive layer.

The adhesive composition can be suitably used in the present specification. Among them, an acrylic adhesive having a (meth)acrylic polymer as a base polymer is preferred.

Various methods can be used for the coating method of the adhesive composition. Specific examples thereof include roll coating, contact roll coating, gravure coating, reverse coating, rolling brush coating, spray coating, immersion roller coating, bar coating, knife coating, and pneumatic blade coating. A method such as curtain coating, lip coating, or extrusion coating using a die-casting coater or the like.

The heating and drying temperature is preferably from 30 ° C to 200 ° C, more preferably from 40 ° C to 180 ° C, and most preferably from 80 ° C to 150 ° C. By setting the heating temperature to the above range, an adhesive layer having excellent adhesive properties can be obtained. The drying time can be appropriately adjusted to the appropriate time. The above drying time is preferably 5 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and most preferably 1 minute to 8 minutes.

For the aforementioned support, for example, a sheet (partition) which has been subjected to peeling treatment can be used. It is preferred to use a polyoxynitride release liner for the release treated sheet.

Examples of the constituent material of the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film; porous materials such as paper, cloth, and nonwoven fabric; mesh, foamed sheet, and metal. A plastic film is suitably used from the viewpoint of excellent surface smoothness, such as a foil and a suitable sheet such as a laminate.

Examples of the plastic film include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, and polyethylene terephthalate. A diester film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, or the like.

The thickness of the separator is usually 5 to 200 μm, preferably 5 to 100 μm. If necessary, the separator may be subjected to mold release and antifouling treatment using a polyfluorene-based, fluorine-based, long-chain alkyl-based or fatty acid-amide-based release agent, bismuth powder, or the like, or a coating type. Antistatic treatment such as kneading type, vapor deposition type, etc. In particular, the peeling property from the above-mentioned adhesive layer can be further improved by appropriately performing a release treatment such as polyfluorination treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the separator.

Further, the release-treated sheet used in the production of the above-mentioned polarizing film with an adhesive layer can be directly used as a separator of a polarizing film with an adhesive layer, and can be simplified on the step surface.

Further, in the polarizing film with the adhesive layer, when the adhesive layer is formed, a fixed layer may be formed on the surface of the second resin film, or various adhesion treatments such as corona treatment and plasma treatment may be performed to form an adhesive layer. Agent layer. Further, the surface of the adhesive layer can be easily treated.

The thickness of the adhesive layer is not particularly limited, and is, for example, preferably 5 to 100 μm, and preferably 10 to 50 μm.

In the polarizing film with an adhesive layer of the present invention, a double-sided protective polarizing film having a polarizing member thickness of 10 μm or less is used. Therefore, the entire polarizing film with an adhesive layer can be thinned. The thickness of the polarizing film with the adhesive layer can be made 70 μm or less.

The polarizing film of the adhesive layer of the present invention can be adhered to an image display unit such as a liquid crystal cell through the adhesive layer. In particular, the polarizing film with an adhesive layer of the present invention can be suitably used as a viewing-side polarizing film of a liquid crystal display device.

3. Image display device The image display device of the present invention is characterized by having the above-mentioned polarizing film with an adhesive layer.

The image display device of the present invention may have a polarizing film with an adhesive layer of the present invention, and other structures may have the same structure as a conventional image display device.

The image display device of the present invention comprises the above-mentioned polarizing film with an adhesive layer, and thus has high reliability.

EXAMPLES Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited to the examples. In addition, the parts and % in each case are on a weight basis.

Production Example 1 (manufacture of polarizing film (1)) An amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film having a water absorption ratio of 0.75% and a Tg of 75 ° C (thickness: 100 μm) On one side of the substrate, corona treatment was applied, and the corona treated surface was coated with polyvinyl alcohol at a ratio of 9:1 at 25 ° C (degree of polymerization: 4200, degree of saponification: 99.2 mol%) And acetonitrile-based modified PVA (degree of polymerization: 1200, acetyl sulfonate degree: 4.6%, saponification degree: 99.0% by mole, manufactured by Japan Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z200" The aqueous solution was dried to form a PVA-based resin layer having a thickness of 11 μm, and a laminate was produced. The obtained laminate was subjected to a uniaxial extension of the free end in the longitudinal direction (longitudinal direction) between the rolls having different peripheral speeds in an oven at 120 ° C to 2.0 times (air assisted extension treatment). Next, the laminate was immersed in an insolubilization bath (boric acid aqueous solution prepared by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) at an liquid temperature of 30 ° C for 30 seconds (insolubilization treatment). Next, while adjusting the iodine concentration and the immersion time, the film was immersed in a dye bath having a liquid temperature of 30 ° C to form a predetermined transmittance of the polarizing plate. In the present embodiment, it was immersed in an aqueous iodine solution prepared by mixing 0.2 part by weight of iodine with respect to 100 parts by weight of water and mixing 1.0 part by weight of potassium iodide (dyeing treatment). Subsequently, the mixture was immersed in a crosslinking bath at a liquid temperature of 30 ° C (aqueous solution of boric acid prepared by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid) with respect to 100 parts by weight of water (crosslinking treatment). Then, the laminate was immersed in a boric acid aqueous solution (4.5 parts by weight of boric acid and 5 parts by weight of potassium iodide added to 100 parts by weight of water, and the mixture was mixed at a peripheral temperature). The cylinders are uniaxially extended in the longitudinal direction (long direction) so that the total stretching ratio is 5.5 times (water stretching treatment). Then, the laminate was immersed in a washing bath at a liquid temperature of 30 ° C (an aqueous solution prepared by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) (washing treatment). According to the above, an optical film laminate including a polarizing member having a thickness of 5 μm can be obtained. The polarizing member thus obtained had a boric acid content of 20% by weight.

(Preparation of an adhesive applied to a transparent protective film) 40 parts by weight of N-hydroxyethyl acrylamide (HEAA), 60 parts by weight of acrylofolfolin (ACMO), and a photoinitiator "IRGACURE 819" ( 3 parts by weight of BASF Corporation, and an ultraviolet curing type adhesive was prepared.

On the surface of the polarizing material (thickness: 5 μm) of the optical film laminate, the ultraviolet curable adhesive was applied under the conditions that the thickness of the adhesive layer was 0.1 μm, and the transparent protective film was adhered ( (1st resin film) (a cycloolefin film (product name: ZF12-025-1300UHC, manufactured by Japan ZEON Co., Ltd.) having a thickness of 27 μm, and a moisture permeability at 40 ° C and 92% RH: 17 g / ( m ² .day), linear expansion coefficient: 6 × 10 ^-5 /K, dimensional change rate: -0.33%, breaking strength: 13 N), and ultraviolet rays were irradiated as an active energy ray to harden the adhesive. UV irradiation is a metal halide lamp sealed with gallium. Irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc., bulb: V-bulb, peak illumination: 1600 mW/cm ² , cumulative exposure 1000/ mJ/cm ² (wavelength: 380 to 440 nm), and the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Next, the amorphous PET substrate was peeled off, and the ultraviolet curable adhesive was applied to the surface after the curing, and the thickness of the adhesive layer was 0.1 μm, and the image subjected to corona treatment was adhered. Display unit side transparent protective film (second resin film) (a olefin-based film having a thickness of 13 μm (trade name: ZF-014-1330, manufactured by Japan ZEON Co., Ltd.), at 40 ° C, 92% RH Moisture permeability: 12g / (m ² .day), coefficient of linear expansion: 7.1 × 10 ^-5 / K, dimensional change rate: -0.01%, breaking strength: 9N), after irradiating ultraviolet rays as above, hardening the adhesive A double-sided protective polarizing film (1) using a thin polarizing member was produced.

Production Example 2 (Production of Polarizing Film (2)) The ultraviolet curable adhesive agent produced in Example 1 was hardened on the surface of a polarizing member (thickness: 5 μm) of the optical film laminate produced in Production Example 1. The thickness of the adhesive layer was 0.1 μm, and the transparent protective film (the 27 μm thick cycloolefin film (trade name: ZD12-099063-C1300UHC, manufactured by Japan ZEON) was bonded. ), moisture permeability at 40 ° C, 92% RH: 24 g / (m ² .day), coefficient of linear expansion: 6.3 × 10 ^-5 / K, dimensional change rate: -0.28%, breaking strength: 20 N), The ultraviolet rays which are the active energy rays are irradiated to harden the adhesive. UV irradiation is a metal halide lamp sealed with gallium. Irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc., bulb: V-bulb, peak illumination: 1600 mW/cm ² , cumulative exposure 1000/ mJ/cm ² (wavelength: 380 to 440 nm), and the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Next, the amorphous PET substrate was peeled off, and the ultraviolet curable adhesive agent produced in Example 1 was coated on the peeled surface, and the thickness of the adhesive layer was 0.1 μm, and the image display unit was bonded. Side transparent protective film (cycloolefin film of 13 μm thickness (trade name: ZF-014-1330, manufactured by ZEON Co., Ltd.), moisture permeability at 40 ° C, 92% RH: 12 g / (m) ² .day), linear expansion coefficient: 7.1×10 ^-5 /K, dimensional change rate: -0.01%, breaking strength: 9N), after irradiating ultraviolet rays as above, hardening the adhesive, and producing a thin polarized light The double-sided protective polarizing film (2).

Production Example 3 (Production of Polarizing Film (3)) On the surface of a polarizing member (thickness: 5 μm) of the optical film laminate produced in Production Example 1, a polyvinyl alcohol-based adhesive was applied to the thickness of the adhesive layer. It is 0.1 μm, and is bonded to a transparent protective film (a 40 μm thick acrylic film (trade name: HX-40UC-1330, manufactured by KANEKA Co., Ltd.) at 40 ° C, 92% RH. Moisture permeability: 70 g / (m ² .day), coefficient of linear expansion: 4.3 × 10 ^-5 / K, dimensional change rate: -0.5%, breaking strength: 39 N), and drying was carried out at 50 ° C for 5 minutes. Next, the amorphous PET substrate was peeled off, and a polyvinyl alcohol-based adhesive was applied to the surface of the peeled surface to have a thickness of the adhesive layer of 0.1 μm, and the image display unit side transparent protective film (acrylic system having a thickness of 20 μm) was bonded. Film (trade name: RV-20UB-1330, manufactured by Toyo Kohan Co., Ltd.), moisture permeability at 40 ° C, 92% RH: 170 g / (m ² .day), linear expansion coefficient: 5.6 × 10 ^-5 /K, dimensional change rate: -0.35%, breaking strength: 19 N), and drying was carried out at 50 ° C for 5 minutes to prepare a double-sided protective polarizing film (3) using a thin polarizing member.

Example 1 Adhesive sheet (thickness: 150 μm, Nitto Denko Co., Ltd. adhesive sheet "LUCIACS" (trade name) was prepared on the side protective protective film of the double-sided protective polarizing film (1) obtained in Production Example 1. )) an adhesive layer is formed, and a protective sheet (a cover glass having a thickness of 500 μm, a linear expansion coefficient: 8 × 10 ^-6 /K, a pencil hardness: 10H, a specific gravity: 2.5, a thermal conductivity: 1 W) is laminated on the adhesive layer. /(m.K)), forming a polarizing film with a protective sheet.

Example 2 A polarizing film with a protective sheet was formed in the same manner as in Example 1 except that the double-sided protective polarizing film (2) obtained in Production Example 2 was used.

Comparative Examples 1 to 3 In Comparative Examples 1 to 3, the double-sided protective polarizing films (1) to (3) (with no build-up protective sheets) obtained in Production Examples 1 to 3 were directly used.

The moisture permeability of the protective film used in the examples and the comparative examples, the linear expansion coefficient of the protective film and the protective sheet, the polarizing film of the protective film obtained in the examples, and the dimensional change ratio of the polarizing film used in the comparative example and The occurrence of the through crack was measured by the following method.

<Transparency of Transparent Protective Film> The measurement of the moisture permeability was measured in accordance with the moisture permeability test (cup method) of JIS Z0208. The sample which has been cut into a diameter of 6 cm is placed in a moisture permeable cup (opening diameter: diameter 6 cm) which has been placed with about 15 g of calcium chloride, and placed in a thermostat having a temperature of 40 ° C and a humidity of 92% RH. The weight increase of calcium chloride before and after standing for 24 hours was measured, and the moisture permeability (g/(m ² .day)) was determined.

<Dimensional Change Rate> Modulation The double-sided protective polarizing film used in the examples and the comparative examples was cut into a sample having a size of 100 mm × 100 mm (the absorption axis direction of the polarizer was 100 mm). The sample was autoclaved at 50 ° C and 0.5 MPa for 15 minutes, taken out from the autoclave, and left at room temperature (23 ° C) for 24 hours. Then, it was placed in an oven at 85 ° C for 120 hours. After taking out from the oven, the protective film was peeled off from the sample, and each of the protective films was measured using a non-contact two-dimensional image analyzing device (trade name: QVA606L1L-C, MITUTOYO Co., Ltd.). The length of the protective film. The dimensional change rate was calculated from the measured values before and after the treatment according to the following formula. Dimensional change rate (%) = {(L _{0 -} L ₁ ) / L ₁ } × 100 L ₀ : length of the initial protective film in the direction orthogonal to the absorption axis of the polarizer (100 mm) L ₁ : heating The length of the protective film placed in the environment in the direction orthogonal to the absorption axis of the polarizer

<Measurement of Linear Expansion Coefficient> The linear expansion coefficient was measured using a thermomechanical analyzer (product name: TMA7100, manufactured by High-Tech Science Co., Ltd.). Specifically, a sample (length 20 mm × width 5 mm) was cut out from the protective film used in the examples and the comparative examples, and the sample was placed in a jig for tensile measurement at a tensile load of 20 mN and a temperature increase rate of 10 ° C / The linear expansion coefficient was obtained by measuring four cycles (thermal shock conditions) at -40 ° C to 85 ° C. Further, the linear expansion coefficient was measured in a direction orthogonal to the absorption axis of the polarizer.

<Measurement of the breaking strength> After the protective film used in the examples and the comparative examples was cut into a size of 100 mm × 100 mm, a precision universal testing machine (AUTOGRAPH) (product name: AG-IS, manufactured by Shimadzu Corporation) was used as the stretching. The test machine was subjected to a tensile test at a tensile speed of 300 mm/min, a distance between the chucks of 100 mm, and a room temperature (23 ° C) to obtain a stress-strain curve. The stress at the time of fracture of the protective film was determined as the breaking strength. Further, the measurement of the breaking strength was carried out in the direction orthogonal to the absorption axis of the polarizing member.

<Measurement of Polarization Change (ΔP) of Polarizing Film> The polarizing film obtained in the examples and the comparative examples was placed in a constant temperature and humidity machine at 85 ° C / 85% RH for 500 hours. The degree of polarization of the polarizing film before and after the input was measured using a spectrophotometer (V7100, manufactured by JASCO Corporation) equipped with an integrating sphere, and the amount of change ΔP in the degree of polarization was obtained by the following formula. The amount of change in the degree of polarization ΔP (%) = (the degree of polarization before the input (%)) - (the degree of polarization after the input (%)) In addition, the degree of polarization P is obtained by taking the following transmittance into the following equation. Calculate: Transmittance (parallel transmittance: Tp) when two identical polarizing films are superposed in such a manner that their transmission axes are parallel, and two identical polarizing films are orthogonal to each other Transmittance at the time of lamination (orthogonal transmittance: Tc). Polarization P(%)={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100 Each transmittance is 100% of the total polarization obtained by the Glan-Taylor polarizer. The second-degree field of view (C light source) of JIS Z8701 is expressed by the Y value of the visual sensitivity correction.

<Confirmation of Through Cracks: Thermal Shock Test> The adhesive layer was provided on the side of the transparent protective film on the image display unit side of the double-sided protective polarizing film prepared in the examples and the comparative examples to prepare a polarizing film with an adhesive layer. The polarizing film with the adhesive layer was cut into 50 mm × 150 mm (the absorption axis direction was 50 mm), and bonded to a 0.5 mm thick alkali-free glass to prepare a sample. The sample was placed in an environment of thermal shock of -40 to 85 ° C for 30 minutes × 100 times, and then taken out to visually confirm whether or not a through crack (number of strips) occurred on the polarizing film. The test was carried out 10 times.

[Table 1]

1‧‧‧ polarizing film
2‧‧‧ polarizer
3‧‧‧1st resin film
4‧‧‧2nd resin film
5‧‧‧Protection board
6‧‧‧Adhesive layer
10‧‧‧Polarized film with adhesive layer

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view schematically showing an embodiment of a polarizing film of the present invention. Fig. 2 is a cross-sectional view schematically showing an embodiment of a polarizing film with an adhesive layer of the present invention.

1‧‧‧ polarizing film

2‧‧‧ polarizer

3‧‧‧1st resin film

4‧‧‧2nd resin film

5‧‧‧Protection board

Claims (9)

A polarizing film having a first resin film on one surface of a polarizing member having a thickness of 10 μm or less and a second resin film on the other surface; and a moisture permeability of the first resin film and the second resin film are 30 g/(m ² .day) or less, and a protective plate is provided on the opposite side surface of the first resin film having the polarizer side. The polarizing film of claim 1, wherein the protective sheet has a linear expansion coefficient in a direction orthogonal to an absorption axis of the polarizing member of 1.0 × 10 ^-5 /K or less. The polarizing film according to claim 1 or 2, wherein the first resin film and the second resin film have a linear expansion coefficient in a direction orthogonal to an absorption axis of the polarizer of 5.0 × 10 ^-5 to 8.0 × 10 ^{- 5} / K. The polarizing film according to any one of claims 1 to 3, wherein the first resin film and the second resin film are subjected to heat treatment at 85 ° C for 120 hours, and the like, and the absorption axis of the polarizing member are The dimensional change rate in the orthogonal direction is -0.40 to 0%. The polarizing film according to any one of claims 1 to 4, wherein the first resin film and the second resin film have a breaking strength in a direction orthogonal to an absorption axis of the polarizer of 5 to 30 N. The polarizing film according to any one of claims 1 to 5, wherein the first resin film and the second resin film are the same or different cycloolefin resin films. The polarizing film according to any one of claims 1 to 6, wherein the absolute value of the degree of change in the degree of polarization after leaving it at 85 ° C and 85% R.H. for 500 hours is less than 0.1%. A polarizing film with an adhesive layer, wherein the second resin film side of the polarizing film according to any one of claims 1 to 7 has an adhesive layer. An image display device characterized by having a polarizing film as in the adhesive layer of claim 8.