JP7214397B2 - Polarizers, polarizing films, optical films, and image display devices - Google Patents

Description

The present invention relates to a polarizer having a durability-enhancing layer on at least one surface. Furthermore, the present invention relates to a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizer. The polarizing film can form an image display device such as a liquid crystal display device (LCD), an organic EL display device, a CRT, or a PDP as an optical film in which the polarizing film is laminated.

2. Description of the Related Art Liquid crystal display devices for watches, mobile phones, PDAs, laptop computers, monitors for personal computers, DVD players, TVs, etc. are rapidly expanding their market. A liquid crystal display device visualizes a polarized state by switching liquid crystal, and a polarizer is used from its display principle. In particular, in applications such as TVs, higher brightness, higher contrast, and wider viewing angles are increasingly required, and polarizing films are increasingly required to have higher transmittance, higher degree of polarization, and higher color reproducibility.

As a polarizer, since it has a high transmittance and a high degree of polarization, for example, an iodine-based polarizer having a structure in which iodine is adsorbed on polyvinyl alcohol (hereinafter also simply referred to as “PVA”) and stretched is most commonly widely used. in use. Generally, a polarizing film is obtained by laminating transparent protective films on both sides of a polarizer with a so-called water-based adhesive made by dissolving a polyvinyl alcohol-based material in water (Patent Document 1 below). As the transparent protective film, triacetyl cellulose or the like having high moisture permeability is used. When the water-based adhesive is used (so-called wet lamination), a drying step is required after bonding the polarizer and the transparent protective film.

On the other hand, active energy ray-curable adhesives have been proposed instead of the water-based adhesives. When a polarizing film is produced using an active energy ray-curable adhesive, the productivity of the polarizing film can be improved because a drying step is not required. For example, a radical polymerization type active energy ray-curable adhesive using an N-substituted amide-based monomer as a curable component has been proposed (Patent Document 2 below). The adhesive layer formed using the active energy ray-curable adhesive described in Patent Document 2 is sufficient for a water resistance test that evaluates the presence or absence of color loss and peeling after immersion in hot water at 60 ° C. for 6 hours. Clearable. However, in recent years, for adhesives for polarizing films, for example, the presence or absence of peeling when peeling off the edge nail after being immersed in water (saturated), for example, is evaluated to the extent that it can clear a more severe water resistance test. , further improvement in water resistance is being sought.

Patent Document 3 below reports a technique of forming a resin layer on the surface of a polarizer for the purpose of suppressing deterioration of the polarizer. It turns out that there is more room for

Japanese Patent Application Laid-Open No. 2001-296427 Japanese Unexamined Patent Application Publication No. 2012-052000 Japanese Patent Application Laid-Open No. 2000-199819

The present invention was developed in view of the above circumstances, and an object of the present invention is to provide a polarizer and a polarizing film in which deterioration of optical properties is suppressed even in a humidified environment.

A further object of the present invention is to provide an optical film using the polarizing film, and to provide an image display device using the polarizing film or the optical film.

As a result of intensive studies to solve the above problems, the present inventors have found that a durability-improving layer is formed on at least one surface of a polarizer using a curable composition containing a compound having a pseudo-buffering action as a raw material. By forming, even in a humid environment, it was found that deterioration of optical properties of a polarizer and a polarizing film provided with such a polarizer can be suppressed, and the present invention has been solved.

That is, the present invention provides a polarizer having a durability-improving layer on at least one surface, wherein the durability-improving layer has pH The present invention relates to a polarizer characterized by being formed from a curable composition containing a compound (A) having an increase of 3.0 or less.

In the polarizer, the compound (A) is preferably γ-butyrolactone (meth)acrylate.

In the polarizer, it is preferable that at least part of the compound (A) contained in the curable composition is polymerized.

In the polarizer, the curable composition preferably further contains a polymerization initiator.

In the polarizer, it is preferable that the durability-improving layer is formed of a cured product layer of the curable composition.

The present invention also relates to a polarizing film comprising any one of the polarizers described above.

In the polarizing film, it is preferable that a transparent protective film is laminated on at least one surface of the polarizer, and the transparent protective film is laminated on the durability improving layer side of the polarizer.

The polarizing film preferably further comprises an adhesive layer between the durability improving layer and the transparent protective film.

Further, according to the present invention, there is provided an optical film comprising at least one laminated polarizing film as described above, or an image using the polarizing film as described above, or an optical film as described above. It relates to a display device.

As described above, an iodine-based polarizer having a structure in which iodine is adsorbed on PVA and stretched is generally used as the polarizer. In the present invention, the polarizer is provided with a durability-enhancing layer on at least one surface thereof, and the durability-enhancing layer is a compound (A) having a pseudo-buffering effect, specifically in a titration test at 60 ° C. , the curable composition containing the compound (A) having a pH increase of 3.0 or less even when 0.5 equivalent of a basic component is added. Therefore, deterioration of the optical properties of the polarizer can be suppressed even in a humidified environment. The reason why such an effect is obtained is not clear, but by providing a durability-enhancing layer having a pseudo-buffering action on the surface of the polarizer, it is possible to reduce large pH fluctuations of the polarizer even in a humid environment. One possible reason is that the iodine complex present on the surface can be stabilized.

In addition, in the polarizing film according to the present invention in which a transparent protective film is laminated on at least one surface of the polarizer, for example, when an adhesive layer is interposed between the polarizer and the transparent protective film, in a humidified environment, can also suppress the deterioration of the optical properties of the polarizing film. Although the reason why such an effect is obtained is not clear, the durability-improving layer can reduce large pH fluctuations of the polarizer even in a humid environment. It is possible to suppress hydrolysis of covalent bonds and hydrogen bonds formed between the functional groups possessed. One possible reason for this is that the iodine complex present on the surface of the polarizer can be stabilized.

The polarizing film according to the present invention does not need to provide a transparent protective film on the durability-improving layer as long as it comprises a polarizer having the specific durability-improving layer on at least one surface. good. In such a polarizing film, the durability-improving layer suppresses deterioration of the optical properties of the polarizer in a humid environment, and the durability-improving layer also exerts a protective function in place of the transparent protective film.

The present invention relates to a polarizer having a durability-enhancing layer on at least one surface. Each configuration will be described below.

<Durability improving layer>
The durability-improving layer is formed of a curable composition containing a compound (A) that exhibits a pH increase of 3.0 or less even when 0.5 equivalent of a basic component is added in a titration test at 60°C.

Compound (A) is a compound that exhibits a pseudo-buffering action. For example, when adjusted to 100 ml of a 0.1 M aqueous solution, 0.1 M aqueous NaOH solution is added to measure the pH. is a compound that once stabilizes, exhibits an inflection point again and exhibits a behavior in which the pH rises. By exhibiting such a buffering action, large pH fluctuations of the polarizer can be reduced even in a humid environment.

Compound (A) can be used without any particular limitation as long as the compound (A) has a pH increase of 3.0 or less even when 0.5 equivalent of a basic component is added in a titration test at 60°C. Examples of such compounds include γ-butyrolactone (meth)acrylate.

The compound (A) may be contained in the curable composition as it is, or may be contained in a state in which at least a part of the compound (A) is polymerized. Moreover, at least a part of the compound (A) may be copolymerized with another copolymerizable monomer. When at least a part of the compound (A) is contained in the curable composition in a polymerized state, for example, at least one surface of the polarizer is coated with the curable composition using a coating method described later. A durability-improving layer may be formed by providing a layer and drying it as necessary.

If the content of the compound (A) in the durability-improving layer is too low, the deterioration of the optical properties of the polarizer may not be sufficiently suppressed in a humidified environment. Therefore, the content of compound (A) in the durability-improving layer is preferably 50% by weight or more, more preferably 70% by weight or more, and even more preferably 80% by weight or more.

The curable composition, which is a raw material for forming the durability-improving layer, may be composed only of the compound (A), but in addition to the compound (A), a polymerization initiator, a solvent, additives and A compound (B) represented by the general formula (1) may also be included.

When the curable composition contains a polymerization initiator in addition to the compound (A), and when the durability-improving layer is formed of a cured product layer of the curable composition, the compound (A) and Fixing the polymer in the vicinity of the polarizer enhances the durability of the polarizer. As a result, deterioration of the optical properties of the polarizer can be suitably suppressed, which is preferable. Regarding the method of forming the durability-improving layer from the cured product layer, for example, a curable composition containing at least the compound (A) and a polymerization initiator is applied to a polarizer and irradiated with an active energy ray to be described later. A method of curing a curable composition to form a cured product layer (durability improving layer) may be mentioned. Usable active energy rays will be described later.

In the present invention, it is preferable to use a photopolymerization initiator as the polymerization initiator. A photopolymerization initiator is appropriately selected depending on the active energy ray. When curing with ultraviolet light or visible light, a photopolymerization initiator that is cleaved with ultraviolet light or visible light is used. Examples of the photopolymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3′-dimethyl-4-methoxybenzophenone; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2 -propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenylketone and other aromatic ketone compounds; methoxyacetophenone, 2,2-dimethoxy- Acetophenone compounds such as 2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin methyl ether, Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; aromatic ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, thioxanthone compounds such as isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; camphorquinone; halogenated ketones; can give.

（式中、Ｒ^６およびＲ^７は－Ｈ、－ＣＨ_２ＣＨ_３、－ｉＰｒまたはＣｌを示し、Ｒ^６およびＲ^７は同一または異なっても良い）を単独で使用するか、あるいは一般式（３）で表される化合物と後述する３８０ｎｍ以上の光に対して高感度な光重合開始剤とを併用することが好ましい。一般式（３）で表される化合物を使用した場合、３８０ｎｍ以上の光に対して高感度な光重合開始剤を単独で使用した場合に比べて接着性に優れる。一般式（３）で表される化合物の中でも、Ｒ^６およびＲ^７が－ＣＨ_２ＣＨ_３であるジエチルチオキサントンが特に好ましい。硬化性組成物中の一般式（３）で表される化合物の組成比率は、化合物（Ａ）に対して、０．５～４．０重量％であることが好ましく、１．０～２．５重量％であることがより好ましい。 As the photopolymerization initiator, a compound represented by the following general formula (3);

(wherein R ⁶ and R ⁷ represent —H, —CH ₂ CH ₃ , —iPr or Cl, and R ⁶ and R ⁷ may be the same or different), or the general formula ( It is preferable to use the compound represented by 3) together with a photopolymerization initiator highly sensitive to light of 380 nm or longer, which will be described later. When the compound represented by the general formula (3) is used, the adhesiveness is excellent as compared with the case where a photopolymerization initiator highly sensitive to light of 380 nm or more is used alone. Among the compounds represented by general formula (3), diethylthioxanthone in which R ⁶ and R ⁷ are —CH ₂ CH ₃ is particularly preferred. The composition ratio of the compound represented by general formula (3) in the curable composition is preferably 0.5 to 4.0% by weight, preferably 1.0 to 2.0% by weight, relative to compound (A). 5% by weight is more preferred.

Moreover, it is preferable to add a polymerization initiation aid as necessary. Examples of polymerization initiation aids include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate. and ethyl 4-dimethylaminobenzoate is particularly preferred. When a polymerization initiation aid is used, the amount added is generally 0 to 5% by weight, preferably 0 to 4% by weight, most preferably 0 to 3% by weight, relative to the total amount of compound (A).

Moreover, a well-known photoinitiator can be used together as needed. Since the transparent protective film having UV absorbability does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator that is highly sensitive to light of 380 nm or more. Specifically, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 , 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole- 1-yl)-phenyl) titanium and the like.

（式中、Ｒ^８、Ｒ^９およびＲ^１０は－Ｈ、－ＣＨ_３、－ＣＨ_２ＣＨ_３、－ｉＰｒまたはＣｌを示し、Ｒ^８、Ｒ^９およびＲ^１０は同一または異なっても良い）を使用することが好ましい。一般式（４）で表される化合物としては、市販品でもある２－メチル－１－（４－メチルチオフェニル）－２－モルフォリノプロパン－１－オン（商品名：ＩＲＧＡＣＵＲＥ９０７ メーカー：ＢＡＳＦ）が好適に使用可能である。その他、２－ベンジル－２－ジメチルアミノ－１－（４－モルフォリノフェニル）－ブタノン－１（商品名：ＩＲＧＡＣＵＲＥ３６９ メーカー：ＢＡＳＦ）、２－（ジメチルアミノ）－２－［（４－メチルフェニル）メチル］－１－［４－（４－モルホリニル）フェニル］－１－ブタノン（商品名：ＩＲＧＡＣＵＲＥ３７９ メーカー：ＢＡＳＦ）が感度が高いため好ましい。 硬化性組成物中の一般式（４）で表される化合物の組成比率は、化合物（Ａ）に対して、０．５～４．０重量％であることが好ましく、１．０～２．５重量％であることがより好ましい。 In particular, as a photopolymerization initiator, in addition to the photopolymerization initiator of general formula (3), a compound represented by the following general formula (4);

(wherein R ⁸ , R ⁹ and R ¹⁰ represent —H, —CH ₃ , —CH ₂ CH ₃ , —iPr or Cl, and R ⁸ , R ⁹ and R ¹⁰ may be the same or different) It is preferred to use As the compound represented by the general formula (4), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: IRGACURE907, manufacturer: BASF), which is also a commercial product, is suitable. can be used for Other, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name: IRGACURE369 manufacturer: BASF), 2-(dimethylamino)-2-[(4-methylphenyl) Methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: IRGACURE379, manufacturer: BASF) is preferred because of its high sensitivity. The composition ratio of the compound represented by general formula (4) in the curable composition is preferably 0.5 to 4.0% by weight, preferably 1.0 to 2.0% by weight, relative to compound (A). 5% by weight is more preferred.

The solvent that the curable composition may contain is preferably a solvent that can stabilize and dissolve or disperse the compound (A), its polymer, the polymerization initiator, and the like. An organic solvent, water, or a mixed solvent thereof can be used as such a solvent. Examples of the solvent include esters such as ethyl acetate, butyl acetate and 2-hydroxyethyl acetate; ketones such as methyl ethyl ketone, acetone, cyclohexanone, methyl isobutyl ketone, diethyl ketone, methyl-n-propyl ketone and acetylacetone; tetrahydrofuran ( Cyclic ethers such as THF) and dioxane; Aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane; Aromatic hydrocarbons such as toluene and xylene; Methanol, ethanol, n-propanol, isopropanol, cyclohexanol aliphatic or alicyclic alcohols such as; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and diethylene glycol monoethyl ether; glycol ether acetates such as diethylene glycol monomethyl ether acetate and diethylene glycol monoethyl ether acetate; is selected from

Additives that the curable composition may contain include, for example, surfactants, plasticizers, tackifiers, low molecular weight polymers, polymerizable monomers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light Stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, titanium coupling agents, inorganic or organic fillers, metal powders, particles, foils and the like.

As for the method of forming the durability-improving layer on the polarizer using the curable composition, a method of directly immersing the polarizer in a treatment bath of the curable composition or a known coating method is appropriately used. Specific examples of the coating method include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and curtain coating, but are not limited to these.

When the curable composition contains a polymerization initiator, the durability improving layer may be formed by curing the curable composition on at least one surface of the polarizer to form a cured product layer, A durability improvement layer comprising an uncured curable composition is formed on at least one surface of a polarizer, laminated with a transparent protective film, and then the curable composition is cured to improve durability comprising a cured product layer. Layers may be formed.

<Polarizer>
There are no particular restrictions on the polarizer, and various types of polarizers can be used. As polarizers, for example, hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene/vinyl acetate copolymer films are coated with dichroic dyes such as iodine and dichroic dyes. Polyene-based oriented films such as those obtained by adsorbing an elastic material and uniaxially stretched, polyvinyl alcohol dehydrated products, polyvinyl chloride dehydrochlorinated products, and the like. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic substance such as iodine is suitable. The thickness of these polarizers is generally 1 to 30 μm.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. If necessary, it can be immersed in an aqueous solution of boric acid, potassium iodide, or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol film with water, dirt and anti-blocking agents on the surface of the polyvinyl alcohol film can be washed away, and by swelling the polyvinyl alcohol film, uneven dyeing and other unevenness can be prevented. be. Stretching may be performed after dyeing with iodine, stretching may be performed while dyeing, or dyeing with iodine may be performed after stretching. It can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

By the way, in mobile applications such as mobile phones, there is an increasing demand for a thin polarizer with a thickness of 10 μm or less from the viewpoint of design and compactness. deterioration tends to be noticeable. However, even if the polarizer according to the present invention is a thin polarizer having a thickness of 10 μm or less, since it has an optically improving layer on at least one surface, deterioration of optical properties is suppressed even in a humidified environment. there is The thickness of the polarizer is preferably 1 to 7 μm from the viewpoint of thinning. Such a thin polarizer is preferred because it has little unevenness in thickness, is excellent in visibility, has little dimensional change, and can be thinned as a polarizing film.

As a thin polarizer, typically, JP-A-51-069644, JP-A-2000-338329, WO2010/100917 pamphlet, PCT/JP2010/001460 specification, or Japanese Patent Application No. 2010- A thin polarizing film described in the specifications of No. 269002 and Japanese Patent Application No. 2010-263692 can be mentioned. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a laminate of a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) layer and a stretching resin substrate, and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching because it is supported by the stretching resin substrate.

As the thin polarizing film, among the manufacturing methods including the step of stretching and the step of dyeing in the state of a laminate, in that it can be stretched at a high magnification and the polarizing performance can be improved, WO2010/100917 pamphlet, PCT/ Those obtained by a production method including a step of stretching in an aqueous boric acid solution as described in JP2010/001460, or Japanese Patent Application No. 2010-269002 or Japanese Patent Application No. 2010-263692 are preferred, particularly It is preferable to obtain by a manufacturing method including a step of auxiliary stretching in the air before stretching in an aqueous boric acid solution, as described in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692.

The surface modification treatment of the polarizer may be performed before forming the durability-improving layer and the easy-adhesion layer, which will be described later. Examples of the surface modification treatment include corona treatment, plasma treatment, itro treatment, and the like, and corona treatment is particularly preferred. By performing corona treatment, reactive functional groups such as carbonyl groups and amino groups are generated on the surface of the polarizer, and adhesion to the durability-improving layer is improved. In addition, foreign matter on the surface is removed by the ashing effect, and unevenness on the surface is reduced, so that a polarizing film with excellent appearance characteristics can be produced.

で表される化合物（Ｂ）（ただし、Ｘは反応性基を含む官能基であり、Ｒ^１およびＲ^２はそれぞれ独立に、水素原子、置換基を有してもよい、脂肪族炭化水素基、アリール基、またはヘテロ環基を表す）を含有することが好ましい。偏光子上に化合物（Ｂ）を含有する易接着層を形成した場合、化合物（Ｂ）が有するホウ酸基および／またはホウ酸エステル基が、偏光子が有する水酸基などの官能基と反応し、さらに耐久性向上層を形成するための化合物（Ａ）とも反応する。このため、偏光子と耐久性向上層との密着性が向上するため好ましい。 In the polarizer according to the present invention, an easy-adhesion layer may be formed on the polarizer before forming the durability-improving layer, and the durability-improving layer may be formed on the easy-adhesion layer. The easy-adhesion layer has the following general formula (1):

Compound (B) represented by (wherein X is a functional group containing a reactive group, R ¹ and R ² are each independently a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent , an aryl group, or a heterocyclic group). When the easy-adhesion layer containing the compound (B) is formed on the polarizer, the boric acid groups and/or borate ester groups possessed by the compound (B) react with functional groups such as hydroxyl groups possessed by the polarizer, Furthermore, it also reacts with the compound (A) for forming the durability-improving layer. Therefore, it is preferable because the adhesion between the polarizer and the durability improving layer is improved.

Examples of the aliphatic hydrocarbon group include linear or branched alkyl groups optionally having substituents having 1 to 20 carbon atoms, cyclic alkyl groups optionally having substituents having 3 to 20 carbon atoms, carbon Alkenyl groups having a number of 2 to 20 can be mentioned, and examples of the aryl group include a phenyl group optionally having a substituent of 6 to 20 carbon atoms, a naphthyl group optionally having a substituent of 10 to 20 carbon atoms, and the like. and the heterocyclic group includes, for example, a 5- or 6-membered ring group containing at least one heteroatom and optionally having a substituent. These may be linked together to form a ring. In formula (1), R ¹ and R ² are preferably a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms, most preferably a hydrogen atom.

The compound (B) represented by the general formula (1) may exist in the easy-adhesion layer in an unreacted state, or may intervene in a state in which each functional group is reacted. Further, "containing the compound (B) represented by the general formula (1) in the easy-adhesion layer" means that, for example, the compound (B) represented by the general formula (1) is contained in the easy-adhesion layer at least It means that there is one molecule. However, in order to improve the adhesion between the polarizer and the durability-enhancing layer and more preferably suppress the deterioration of the optical durability of the polarizer, the compound (B) represented by the general formula (1) is included. Using an easy-adhesion composition, it is preferable to form an easy-adhesion layer on at least a part of the surface of the polarizer on which the durability-improving layer is to be formed. It is more preferable to form an easy-adhesion layer.

X in the compound (B) represented by the general formula (1) is a functional group containing a reactive group. Examples of reactive groups included in X include hydroxyl group, amino group, aldehyde group, carboxyl group, vinyl group, (meth)acryl group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, α,β-unsaturated carbonyl group, mercapto group, halogen group and the like. However, in order to improve the adhesion between the polarizer and the durability improving layer by reacting with the carbon-carbon double bond of the monomer (A), the reactive group contained in X should be a vinyl group, ( It is preferably at least one reactive group selected from the group consisting of a meth)acryl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group and a mercapto group, and a (meth)acrylic group. , a styryl group and a (meth)acrylamide group.

で表される化合物（ただし、Ｙは有機基であり、Ｘ、Ｒ^１およびＲ^２は前記と同じ）が挙げられる。さらに好適には、以下の化合物（１ａ）～（１ｄ）が挙げられる。

Preferred specific examples of the compound (B) represented by the general formula (1) include the following general formula (1′)

(where Y is an organic group, and X, R ¹ and R ² are the same as above). More preferred are the following compounds (1a) to (1d).

In the present invention, the compound (B) represented by the general formula (1) may be one in which the reactive group and the boron atom are directly bonded. The compound (B) represented by (1) is one in which the reactive group and the boron atom are bonded via an organic group, that is, the compound (B) represented by the general formula (1′) is preferably For example, when the compound (B) represented by the general formula (1) is bonded to a reactive group via an oxygen atom bonded to a boron atom, the optical properties of the polarizer tend to deteriorate. On the other hand, the compound (B) represented by the general formula (1) does not have a boron-oxygen bond, but the boron atom and the organic group are bonded to each other, so that the boron-carbon bond is maintained while having a reactive In the case of containing a group (in the case of general formula (1')), deterioration of the optical properties of the polarizing film can be suppressed, which is preferable. The organic group specifically means an organic group having 1 to 20 carbon atoms which may have a substituent, and more specifically, for example, having a substituent having 1 to 20 carbon atoms. A linear or branched alkylene group which may be optionally substituted, a cyclic alkylene group which may have a substituent of 3 to 20 carbon atoms, a phenylene group which may have a substituent of 6 to 20 carbon atoms, a phenylene group which may have a substituent of 10 to 10 carbon atoms. A naphthylene group which may have 20 substituents may be mentioned.

As the compound (B) represented by the general formula (1), in addition to the compounds exemplified above, an ester of hydroxyethylacrylamide and boric acid, an ester of methylolacrylamide and boric acid, an ester of hydroxyethyl acrylate and boric acid, and esters of (meth)acrylates with boric acid, such as esters of hydroxybutyl acrylate and boric acid.

As a method for forming an easy-adhesion layer on the surface of the polarizer on which the durability-improving layer is to be formed, using an easy-adhesion composition containing the compound (B) represented by general formula (1), for example, the general formula A method of producing an easy-adhesion composition containing the compound (B) represented by (1) and applying it to the surface of the polarizer on which the durability-improving layer is to be formed can be used. In addition to the compound (B) represented by the general formula (1), the easy-adhesion composition may include a solvent, an additive, and a radically polymerizable compound to be described later.

When the easily-adhesive composition contains a solvent, the easily-adhesive composition may be applied to the surface of the polarizer on which the durability-improving layer is to be formed, and a drying step or curing treatment (such as heat treatment) may be performed as necessary. good.

Solvents and additives that the curable composition may contain can be used as the solvents and additives that the easy-adhesion composition may contain. As for the method of forming an easy-adhesion layer on a polarizer using an easy-adhesion composition, the same method as the method of forming a durability-enhancing layer on a polarizer using a curable composition can be used. is.

If the content of the compound (B) represented by the general formula (1) in the easy-adhesion layer is too low, the proportion of the compound (B) represented by the general formula (1) present on the surface of the easy-adhesion layer decreases. However, the easy-adhesion effect may decrease. Therefore, the content of the compound (B) represented by the general formula (1) in the easy-adhesion layer is preferably 1% by weight or more, more preferably 20% by weight or more, and 40% by weight or more. is more preferable.

In the present invention, if the easy-adhesion layer included in the polarizer is too thick, the cohesive force of the easy-adhesion layer may be reduced, and the easy-adhesion effect may be reduced. Therefore, the thickness of the easy-adhesion layer is preferably 2000 nm or less, more preferably 1000 nm or less, and even more preferably 500 nm or less. On the other hand, the minimum thickness for the easy-adhesion layer to sufficiently exhibit its effect includes at least the thickness of the monomolecular film of the compound represented by the general formula (1), preferably 1 nm or more, and more It is preferably 2 nm or more, more preferably 3 nm or more.

As described above, the compound (B) represented by the general formula (1) may be added together with the compound (A) into the curable composition not only for forming an easy-adhesion layer. In this case, the compound (B) reacts and/or interacts with the polarizer and the compound (A), whereby the compound (A) is more reliably fixed in the vicinity of the polarizer, thereby improving the durability of the polarizer. further increase. As a result, deterioration of the optical properties of the polarizer can be suitably suppressed, which is preferable.

The polarizing film according to the present invention includes a polarizer having, on at least one surface thereof, a durability-improving layer formed from a curable composition containing a compound (A) having a carbon-carbon double bond and a cyclic skeleton. Furthermore, the polarizing film according to the present invention may be obtained by laminating a transparent protective film on at least one surface of the polarizer. The polarizer and the transparent protective film may be laminated via a durability-improving layer, or the durability-improving layer provided in the polarizer and the transparent protective film may be further laminated via an adhesive layer. The adhesive layer will be described below.

<Adhesive layer>
The thickness of the adhesive layer is preferably 0.01 to 3.0 μm. If the thickness of the adhesive layer is too thin, the cohesive force of the adhesive layer will be insufficient and the peeling force will decrease, which is not preferable. If the thickness of the adhesive layer is too thick, the polarizing film is likely to be peeled off when stress is applied to the cross section of the polarizing film, which is not preferable because the peeling failure occurs due to impact. The thickness of the adhesive layer is more preferably 0.1-2.5 μm, most preferably 0.5-1.5 μm.

The adhesive layer is formed by curing the adhesive composition. The mode of curing the adhesive composition can be broadly classified into heat curing and active energy ray curing. Examples of thermosetting resins include polyvinyl alcohol resins, epoxy resins, unsaturated polyesters, urethane resins, acrylic resins, urea resins, melamine resins, and phenol resins, and if necessary, a curing agent is used in combination. Polyvinyl alcohol resins and epoxy resins are more preferably used as thermosetting resins. Active energy ray-curable resins can be broadly classified into electron beam curable, ultraviolet ray curable and visible light curable according to active energy ray. In addition, the mode of curing can be classified into a radically polymerizable adhesive composition and a cationic polymerizable adhesive composition. In the present invention, active energy rays with a wavelength range of 10 nm to less than 380 nm are expressed as ultraviolet rays, and active energy rays with a wavelength range of 380 nm to 800 nm are expressed as visible rays.

In the production of the polarizing film according to the present invention, it is preferably active energy ray-curable as described above. Furthermore, it is particularly preferred to be visible light curable using visible light of 380 nm to 450 nm.

Examples of the curable component contained in the radically polymerizable adhesive composition include radically polymerizable compounds used in the radically polymerizable adhesive composition. Examples of radically polymerizable compounds include compounds having radically polymerizable functional groups of carbon-carbon double bonds such as (meth)acryloyl groups and vinyl groups. These curable components can be either monofunctional radically polymerizable compounds or bifunctional or higher polyfunctional radically polymerizable compounds. Moreover, these radical polymerizable compounds can be used individually by 1 type or in combination of 2 or more types. As these radically polymerizable compounds, for example, compounds having a (meth)acryloyl group are suitable. In the present invention, (meth)acryloyl means an acryloyl group and/or a methacryloyl group, and "(meth)" has the same meaning below.

で表される化合物（ただし、Ｒ^３は水素原子またはメチル基であり、Ｒ^４およびＲ^５はそれぞれ独立に、水素原子、アルキル基、ヒドロキシアルキル基、アルコキシアルキル基または環状エーテル基であって、Ｒ^４およびＲ^５は環状複素環を形成してもよい）が挙げられる。アルキル基、ヒドロキシアルキル基、および／またはアルコキシアルキル基のアルキル部分の炭素数は特に限定されないが、例えば１～４個のものが例示される。また、Ｒ^４およびＲ^５が形成してもよい環状複素環は、例えばＮ－アクリロイルモルホリンなどが挙げられる。 Examples of monofunctional radically polymerizable compounds include the following general formula (2):

(where R ³ is a hydrogen atom or a methyl group, R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, or a cyclic ether group, R ⁴ and R ⁵ may form a cyclic heterocycle). Although the number of carbon atoms in the alkyl portion of the alkyl group, hydroxyalkyl group and/or alkoxyalkyl group is not particularly limited, examples thereof include 1 to 4 carbon atoms. In addition, examples of the cyclic heterocycle that may be formed by R ⁴ and R ⁵ include N-acryloylmorpholine.

Specific examples of the compound represented by the general formula (2) include N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl ( N-alkyl group-containing (meth)acrylamide derivatives such as meth)acrylamide, N-butyl (meth)acrylamide, N-hexyl (meth)acrylamide; N-methylol (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, N -N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as -methylol-N-propane (meth)acrylamide; N-alkoxy group-containing (meth)acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide; be done. Further, examples of the cyclic ether group-containing (meth)acrylamide derivatives include heterocycle-containing (meth)acrylamide derivatives in which the nitrogen atom of the (meth)acrylamide group forms a heterocyclic ring, such as N-acryloylmorpholine, N -acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine and the like. Among these, N-hydroxyethylacrylamide and N-acryloylmorpholine are preferably used because of their excellent reactivity, the ability to obtain a cured product with a high elastic modulus, and their excellent adhesion to a polarizer. can.

From the standpoint of improving the adhesiveness and water resistance when the polarizer and the transparent protective film are adhered via the adhesive layer, the content of the compound represented by the general formula (2) in the adhesive composition is 0.5. It is preferably 01 to 80% by weight, more preferably 5 to 40% by weight.

Moreover, the adhesive composition used in the present invention may contain other monofunctional radically polymerizable compounds as a curable component in addition to the compound represented by the general formula (2). Examples of monofunctional radically polymerizable compounds include various (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl ( meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl ( Examples include (meth)acrylic acid (C1-20) alkyl esters such as meth)acrylate and n-octadecyl (meth)acrylate.

Examples of the (meth)acrylic acid derivative include cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; 2-isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, dicyclopentenyl (meth) ) Polycyclic (meth)acrylates such as acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, 2-ethoxy Ethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, alkylphenoxy polyethylene glycol (meth) acrylate, etc. alkoxy group- or phenoxy group-containing (meth)acrylates; and the like. Among these, dicyclopentenyloxyethyl acrylate and phenoxyethyl acrylate are preferred because of their excellent adhesion to various protective films.

Further, the (meth)acrylic acid derivatives include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4- Hydroxyalkyl (meth)acrylates such as hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate and 12-hydroxylauryl (meth)acrylate and hydroxyl group-containing (meth)acrylates such as [4-(hydroxymethyl)cyclohexyl]methylacrylate, cyclohexanedimethanol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate; glycidyl (meth)acrylate, Epoxy group-containing (meth)acrylates such as 4-hydroxybutyl (meth)acrylate glycidyl ether; 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate, tetra Halogen-containing (meth)acrylates such as fluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, etc. ) acrylates; alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate; 3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth)acrylate, 3-ethyl-oxetanylmethyl (meth)acrylate , 3-Butyl-oxetanylmethyl (meth)acrylate, 3-hexyloxetanylmethyl (meth)acrylate, and other oxetane group-containing (meth)acrylates; Tetrahydrofurfuryl (meth)acrylate, butyrolactone (meth)acrylate, and other heterocycles and (meth) acrylates, hydroxypivalic acid neopentyl glycol (meth) acrylic acid adducts, p-phenylphenol (meth) acrylate and the like. Among these, 2-hydroxy-3-phenoxypropyl acrylate is preferable because of its excellent adhesion to various protective films.

Examples of monofunctional radically polymerizable compounds include carboxyl group-containing monomers such as (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and isocrotonic acid.

Examples of monofunctional radically polymerizable compounds include lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, Vinyl-based monomers having a nitrogen-containing heterocyclic ring such as vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine are included.

In the adhesive composition used in the present invention, among monofunctional radically polymerizable compounds, hydroxyl group-containing (meth)acrylates having high polarity, carboxyl group-containing (meth)acrylates, phosphoric acid group-containing (meth)acrylates, etc. is included, adhesion to various substrates is improved. The content of the hydroxyl group-containing (meth)acrylate is preferably 1% by weight to 30% by weight based on the resin composition. If the content is too high, the water absorption rate of the cured product may increase and the water resistance may deteriorate. The content of the carboxyl group-containing (meth)acrylate is preferably 1% by weight to 20% by weight relative to the resin composition. When the content is too large, the optical durability of the polarizing film is lowered, which is not preferable. Phosphate group-containing (meth)acrylates include 2-(meth)acryloyloxyethyl acid phosphate, and the content thereof is 0.1% by weight to 10% by weight relative to the resin composition. preferable. When the content is too large, the optical durability of the polarizing film is lowered, which is not preferable.

Moreover, a radically polymerizable compound having an active methylene group can be used as the monofunctional radically polymerizable compound. A radically polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acrylic group at the end or in the molecule and an active methylene group. Active methylene groups include, for example, an acetoacetyl group, an alkoxymalonyl group, a cyanoacetyl group, and the like. Preferably, the active methylene group is an acetoacetyl group. Specific examples of radically polymerizable compounds having an active methylene group include 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, 2-acetoacetoxy-1-methylethyl (meth)acrylate, and the like. 2-ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl) acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, N-(2-acetoacetylaminoethyl)acrylamide and the like. The radically polymerizable compound having an active methylene group is preferably acetoacetoxyalkyl (meth)acrylate.

In addition, as the polyfunctional radically polymerizable compound having two or more functions, for example, polyfunctional (meth)acrylamide derivatives such as N,N'-methylenebis(meth)acrylamide, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, (meth) acrylate, 1,6-hexanediol di(meth) acrylate, 1,9-nonanediol di(meth) acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth) ) acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri( (Meth)acrylic acid and polyhydric alcohols such as meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, EO-modified diglycerin tetra(meth)acrylate 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. Specific examples include Aronix M-220 (manufactured by Toagosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DCP-A (Kyoeisha Chemical Co., Ltd.) (manufactured by Sartomer), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer) and the like are preferable. Various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, various (meth)acrylate monomers, and the like can also be used as necessary. In addition, the polyfunctional (meth)acrylamide derivative has a high polymerization rate and excellent productivity, and also has excellent crosslinkability when the resin composition is cured. Therefore, it is preferable to include it in the adhesive composition.

From the viewpoint of achieving both adhesion to polarizers and various transparent protective films and optical durability in harsh environments, a combination of a monofunctional radically polymerizable compound and a multifunctional radically polymerizable compound is used as the radically polymerizable compound. is preferred. Generally, it is preferable to use 3 to 80% by weight of the monofunctional radically polymerizable compound and 20 to 97% by weight of the multifunctional radically polymerizable compound together with respect to 100% by weight of the radically polymerizable compound.

The adhesive composition used in the present invention can be used as an active energy ray-curable adhesive composition when the curable component is used as the active energy ray-curable component. When the active energy ray-curable adhesive composition uses an electron beam or the like as the active energy ray, the active energy ray-curable adhesive composition does not need to contain a photopolymerization initiator, When ultraviolet rays or visible rays are used as active energy rays, it is preferable to contain a photopolymerization initiator. As the photopolymerization initiator, the same one as used for forming the durability improving layer can be used.

When a radically polymerizable compound having an active methylene group is used as the radically polymerizable compound in the active energy ray-curable adhesive composition, it is preferably used in combination with a radical polymerization initiator capable of abstraction of hydrogen. According to such a configuration, the adhesiveness of the adhesive layer of the polarizing film is remarkably improved even immediately after being taken out from a high-humidity environment or water (in a non-dried state). Although the reason for this is not clear, the following causes are conceivable. In other words, the radically polymerizable compound having an active methylene group is incorporated into the main chain and/or side chain of the base polymer in the adhesive layer while being polymerized together with other radically polymerizable compounds constituting the adhesive layer, resulting in adhesion. to form an agent layer. In the polymerization process, if a radical polymerization initiator having a hydrogen abstraction action is present, hydrogen is abstracted from the radically polymerizable compound having an active methylene group while the base polymer constituting the adhesive layer is being formed, and the methylene group is formed. Radicals are generated. Then, the methylene groups generated by the radicals react with the hydroxyl groups of the polarizer such as PVA to form covalent bonds between the adhesive layer and the polarizer. As a result, it is presumed that the adhesiveness of the adhesive layer of the polarizing film is remarkably improved even in a non-dried state.

In the present invention, the radical polymerization initiator having a hydrogen abstraction action includes, for example, a thioxanthone-based radical polymerization initiator, a benzophenone-based radical polymerization initiator, and the like. The radical polymerization initiator is preferably a thioxanthone radical polymerization initiator. Examples of the thioxanthone-based radical polymerization initiator include compounds represented by the above general formula (3). Specific examples of the compound represented by formula (3) include thioxanthone, dimethylthioxanthone, diethylthioxanthone, isopropylthioxanthone, and chlorothioxanthone. Among the compounds represented by general formula (3), diethylthioxanthone in which R ⁶ and R ⁷ are —CH ₂ CH ₃ is particularly preferred.

When the active energy ray-curable adhesive composition contains a radically polymerizable compound having an active methylene group and a radical polymerization initiator capable of abstracting hydrogen, the total amount of the curable components is 100% by weight. At this time, it is preferable to contain 1 to 50% by weight of the radically polymerizable compound having an active methylene group and 0.1 to 10% by weight of the radical polymerization initiator based on the total amount of the adhesive composition.

As described above, in the present invention, a radical is generated in the methylene group of a radically polymerizable compound having an active methylene group in the presence of a radical polymerization initiator having a hydrogen abstraction action, and the methylene group and a polarizer such as PVA are generated. reacts with the hydroxyl group of to form a covalent bond. Therefore, in order to generate a radical in the methylene group of the radical polymerizable compound having an active methylene group and sufficiently form such a covalent bond, when the total amount of the curable component is 100% by weight, radicals having an active methylene group It preferably contains 1 to 50% by weight of the polymerizable compound, more preferably 3 to 30% by weight. In order to sufficiently improve the water resistance and improve the adhesion in a non-dry state, the content of the radically polymerizable compound having an active methylene group is preferably 1% by weight or more. On the other hand, if it exceeds 50% by weight, the curing failure of the adhesive layer may occur. The radical polymerization initiator having a hydrogen abstraction action is preferably contained in an amount of 0.1 to 10% by weight, more preferably 0.3 to 9% by weight, based on the total amount of the adhesive composition. . In order to allow the hydrogen abstraction reaction to proceed sufficiently, it is preferable to use 0.1% by weight or more of the radical polymerization initiator. On the other hand, if it exceeds 10% by weight, it may not dissolve completely in the composition.

The cationically polymerizable compound used in the cationically curable adhesive composition includes a monofunctional cationically polymerizable compound having one cationically polymerizable functional group in the molecule and a cationically polymerizable compound having two cationically polymerizable functional groups in the molecule. It is classified into polyfunctional cationically polymerizable compounds having the above. Since the monofunctional cationically polymerizable compound has a relatively low liquid viscosity, the liquid viscosity of the resin composition can be lowered by including it in the resin composition. In addition, monofunctional cationically polymerizable compounds often have functional groups that exhibit various functions. can be made The polyfunctional cationically polymerizable compound is preferably contained in the resin composition because it can three-dimensionally crosslink the cured product of the resin composition. The ratio of the monofunctional cationically polymerizable compound and the polyfunctional cationically polymerizable compound is such that 100 parts by weight of the monofunctional cationically polymerizable compound is mixed with 10 parts by weight to 1000 parts by weight of the polyfunctional cationically polymerizable compound. is preferred. Examples of cationic polymerizable functional groups include epoxy groups, oxetanyl groups, and vinyl ether groups. Compounds having an epoxy group include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds. , it is particularly preferred to contain an alicyclic epoxy compound. Alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, caprolactone-modified products of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and trimethylcaprolactone-modified products. and valerolactone modified products, and specifically, Celoxide 2021, Celoxide 2021A, Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085 (manufactured by Daicel Chemical Industries, Ltd., Cyracure UVR-6105, Cyracure UVR -6107, Cyracure 30, R-6110 (manufactured by Dow Chemical Japan Co., Ltd.), etc. A compound having an oxetanyl group improves the curability of the cationic polymerization curable adhesive composition of the present invention. 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl -3-oxetanyl)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, di[(3-ethyl-3-oxetanyl)methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl) ) oxetane, phenol novolac oxetane and the like, including Aron oxetane OXT-101, Aron oxetane OXT-121, Aron oxetane OXT-211, Aron oxetane OXT-221, Aron oxetane OXT-212 (manufactured by Toagosei Co., Ltd.), etc. A compound having a vinyl ether group has the effect of improving the curability of the cationically polymerizable adhesive composition of the present invention and reducing the liquid viscosity of the composition, and is therefore preferably contained. Compounds having a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol vinyl ether, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, cyclohexanedimethanol monovinyl ether, tricyclodecane. Vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, pentaerythritol type tetravinyl ether, etc. .

The cationic polymerization curable adhesive composition contains at least one compound selected from the epoxy group-containing compounds, oxetanyl group-containing compounds, and vinyl ether group-containing compounds described above as a curable component, all of which are cationic. A photo cationic polymerization initiator is added because the composition is cured by polymerization. This cationic photopolymerization initiator generates cationic species or Lewis acid upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays and electron beams, and initiates the polymerization reaction of epoxy groups and oxetanyl groups. As the photocationic polymerization initiator, a photoacid generator described later is preferably used. When the adhesive composition used in the present invention is curable with visible light, it is preferable to use a cationic photopolymerization initiator that is particularly sensitive to light of 380 nm or more. In general, since it is a compound that exhibits maximum absorption in a wavelength region near or shorter than 300 nm, a photosensitizer that exhibits maximum absorption in a wavelength region longer than that, specifically longer than 380 nm, is added. , and can promote the generation of cationic species or acid from the photocationic polymerization initiator by responding to light of wavelengths around this range. Examples of photosensitizers include anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, and the like. You may use it in mixture of 2 or more types. Anthracene compounds are particularly preferable because of their excellent photosensitizing effect, and specific examples thereof include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Kasei Co., Ltd.). The content of the photosensitizer is preferably 0.1 wt % to 5 wt %, more preferably 0.5 wt % to 3 wt %.

The adhesive composition used in the present invention preferably contains the following components in addition to the above components.

The active energy ray-curable adhesive composition used in the present invention may contain an acrylic oligomer obtained by polymerizing a (meth)acrylic monomer in addition to the curable component related to the radically polymerizable compound. By containing a component in the active energy ray-curable adhesive composition, curing shrinkage when the composition is irradiated and cured with an active energy ray is reduced, and the adhesive, a polarizer, a transparent protective film, etc. Interfacial stress with the adherend can be reduced. As a result, deterioration in adhesion between the adhesive layer and the adherend can be suppressed. In order to sufficiently suppress curing shrinkage of the cured product layer (adhesive layer), the content of the acrylic oligomer is preferably 20% by weight or less, and 15% by weight, based on the total amount of the adhesive composition. % or less. If the content of the acrylic oligomer in the adhesive composition is too high, the reaction rate when the composition is irradiated with an active energy ray will decrease significantly, resulting in poor curing in some cases. On the other hand, the content of the acrylic oligomer is preferably 3% by weight or more, more preferably 5% by weight or more, relative to the total amount of the adhesive composition.

Considering workability and uniformity during coating, the active energy ray-curable adhesive composition preferably has a low viscosity. is preferably The acrylic oligomer which has a low viscosity and can prevent curing shrinkage of the adhesive layer preferably has a weight-average molecular weight (Mw) of 15,000 or less, more preferably 10,000 or less, and particularly 5,000 or less. preferable. On the other hand, in order to sufficiently suppress curing shrinkage of the cured product layer (adhesive layer), the weight average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1000 or more. 1500 or more is particularly preferable. Specific examples of the (meth)acrylic monomer constituting the acrylic oligomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, 2-methyl- 2-nitropropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, S-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl ( (Meth)acrylic acid (C1-20) alkyl esters such as meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, N-octadecyl (meth)acrylate, and further, for example, cycloalkyl (meth) ) acrylates (e.g., cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), aralkyl (meth) acrylates (e.g., benzyl (meth) acrylate, etc.), polycyclic (meth) acrylates (e.g., 2-isobornyl (meth) ) acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, etc.), hydroxyl group-containing (meth) ) Acrylic esters (e.g., hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate, etc.), alkoxy group- or phenoxy group-containing (meth)acryl Acid esters (2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxy ethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic acid esters (e.g., glycidyl (meth)acrylate, etc.), halogen-containing (meth)acrylic acid esters (e.g., 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2- trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, etc.), alkylaminoalkyl (meth)acrylate acrylates (eg, dimethylaminoethyl (meth)acrylate, etc.), and the like. These (meth)acrylates can be used alone or in combination of two or more. Specific examples of acrylic oligomers include "ARUFON" manufactured by Toagosei Co., Ltd., "ACT FLOW" manufactured by Soken Chemical Co., Ltd., and "JONCRYL" manufactured by BASF Japan.

The active energy ray-curable adhesive composition may contain a photoacid generator. When the active energy ray-curable adhesive composition contains a photoacid generator, the water resistance and durability of the adhesive layer can be dramatically improved compared to when the photoacid generator is not contained. can. The photoacid generator can be represented by the following general formula (5).

（ただし、Ｌ^＋は、任意のオニウムカチオンを表す。また、Ｘ^－は、ＰＦ_６ ^－、ＳｂＦ_６ ^－、ＡｓＦ_６ ^－、ＳｂＣｌ_６ ^－、ＢｉＣｌ_５ ^－、ＳｎＣｌ_６ ^－、ＣｌＯ_４ ^－、ジチオカルバメートアニオン、ＳＣＮ－よりからなる群より選択されるカウンターアニオンを表す。） general formula (5)

(wherein L ⁺ represents any onium cation, and X ⁻ is PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , SbCl ₆ ⁻ , BiCl ₅ ⁻ , SnCl ₆ ⁻ , ClO ₄ ⁻ , dithiocarbamate represents a counter anion selected from the group consisting of an anion and SCN-.)

Next, the counter anion X ⁻ in general formula (5) will be explained.

The counter anion X 1 ⁻ in general formula (5) is not particularly limited in principle, but is preferably a non-nucleophilic anion. When the counter anion X ⁻ is a non-nucleophilic anion, nucleophilic reactions in cations coexisting in the molecule and various materials used in combination are unlikely to occur, and as a result, the photoacid generator represented by general formula (4) itself It is possible to improve the aging stability of the composition using it. A non-nucleophilic anion as used herein refers to an anion having a low ability to cause a nucleophilic reaction. Such anions include PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , SbCl ₆ ⁻ , BiCl ₅ ⁻ , SnCl ₆ ⁻ , ClO ₄ ⁻ , dithiocarbamate anions, SCN ⁻ and the like.

Specifically, "Cyracure UVI-6992", "Cyracure UVI-6974" (manufactured by Dow Chemical Japan Co., Ltd.), "ADEKA OPTOMER SP150", "ADEKA OPTOMER SP152", "ADEKA OPTOMER SP170", "Adeka Optomer SP172" (manufactured by ADEKA Corporation), "IRGACURE250" (manufactured by Ciba Specialty Chemicals), "CI-5102", "CI-2855" (manufactured by Nippon Soda Co., Ltd.), "San-Aid SI-60L", "San-Aid SI-80L", "San-Aid SI-100L", "San-Aid SI-110L", "San-Aid SI-180L" (manufactured by Sanshin Chemical Co., Ltd.), "CPI-100P", "CPI-100A" (manufactured by San-Apro Co., Ltd.), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044", "WPI-054", "WPI-055", "WPAG-281", "WPAG-567", and "WPAG-596" (manufactured by Wako Pure Chemical Industries, Ltd.) are preferred specific examples of the photoacid generator of the present invention.

The content of the photoacid generator is 10% by weight or less, preferably 0.01 to 10% by weight, and preferably 0.05 to 5% by weight, based on the total amount of the adhesive composition. More preferably, 0.1 to 3% by weight is particularly preferable.

In the active energy ray-curable adhesive composition, a photoacid generator and a compound containing either an alkoxy group or an epoxy group can be used in combination in the active energy ray-curable adhesive composition.

When using a compound having one or more epoxy groups in the molecule or a polymer (epoxy resin) having two or more epoxy groups in the molecule, two functional groups reactive with epoxy groups are added to the molecule. You may use together the compound which has two or more. Examples of functional groups reactive with epoxy groups include carboxyl groups, phenolic hydroxyl groups, mercapto groups, and primary or secondary aromatic amino groups. Considering three-dimensional curability, it is particularly preferable to have two or more of these functional groups in one molecule.

Polymers having one or more epoxy groups in the molecule include, for example, epoxy resins, bisphenol A type epoxy resins derived from bisphenol A and epichlorohydrin, bisphenol F type epoxy resins derived from bisphenol F and epichlorohydrin. resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, alicyclic epoxy resin, diphenyl ether type epoxy resin, hydroquinone type epoxy resin, Naphthalene type epoxy resin, biphenyl type epoxy resin, fluorene type epoxy resin, polyfunctional epoxy resin such as trifunctional epoxy resin and tetrafunctional epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin , isocyanurate type epoxy resins, aliphatic chain epoxy resins, etc. These epoxy resins may be halogenated or hydrogenated. Examples of commercially available epoxy resin products include JER Coat 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, YX4000 manufactured by Japan Epoxy Resin Co., Ltd., and Epiclon manufactured by DIC Corporation. 830, EXA835LV, HP4032D, HP820, EP4100 series, EP4000 series, EPU series manufactured by ADEKA Corporation, Celoxide series manufactured by Daicel Chemical Industries, Ltd. (2021, 2021P, 2083, 2085, 3000, etc.), Epolead series, EHPE series, Nippon Steel Chemical Co., Ltd. YD series, YDF series, YDCN series, YDB series, phenoxy resin (polyhydroxy polyether synthesized from bisphenols and epichlorohydrin and having epoxy groups at both ends; YP series, etc.), Denacol series manufactured by Nagase Chemtex Co., Ltd., Epolite series manufactured by Kyoeisha Chemical Co., Ltd., and the like, but are not limited to these. These epoxy resins may be used in combination of two or more.

The compound having an alkoxyl group in the molecule is not particularly limited as long as it has one or more alkoxyl groups in the molecule, and known compounds can be used. Representative examples of such compounds include melamine compounds, amino resins, silane coupling agents, and the like.

The compounding amount of the compound containing either an alkoxy group or an epoxy group is usually 30% by weight or less with respect to the total amount of the adhesive composition. It may decrease and the impact resistance to the drop test may deteriorate. More preferably, the content of the compound in the composition is 20% by weight or less. On the other hand, from the viewpoint of water resistance, the content of the compound in the composition is preferably 2% by weight or more, more preferably 5% by weight or more.

When the adhesive composition used in the present invention is active energy ray-curable, the silane coupling agent is preferably an active energy ray-curable compound, but not active energy ray-curable. The same water resistance can be imparted even with

As specific examples of the silane coupling agent, the organosilicon compounds exemplified above can be used.

The blending amount of the silane coupling agent is preferably in the range of 0.01 to 20% by weight, preferably 0.05 to 15% by weight, and 0.1 to 10% by weight, based on the total amount of the adhesive composition. % is more preferred. If the amount exceeds 20% by weight, the storage stability of the adhesive composition deteriorates.

When the adhesive composition used in the present invention contains a compound having a vinyl ether group, it is preferable because the adhesive water resistance between the polarizer and the adhesive layer is improved. Although the reason why such an effect is obtained is not clear, it is speculated that one of the reasons is that the vinyl ether group of the compound interacts with the polarizer, thereby increasing the adhesion between the polarizer and the adhesive layer. be. The compound is preferably a radically polymerizable compound having a vinyl ether group in order to further increase the water resistance of the adhesion between the polarizer and the adhesive layer. Also, the content of the compound is preferably 0.1 to 19% by weight with respect to the total amount of the adhesive composition.

The adhesive compositions used in the present invention may contain compounds that undergo keto-enol tautomerism. For example, in an adhesive composition containing a cross-linking agent or an adhesive composition that can be used by blending a cross-linking agent, an aspect containing a compound that causes the above-mentioned keto-enol tautomerism can be preferably employed. As a result, excessive increase in viscosity and gelation of the adhesive composition after incorporation of the organometallic compound, as well as formation of microgels, can be suppressed, and the effect of extending the pot life of the composition can be realized.

Various β-dicarbonyl compounds can be used as the compound that causes keto-enol tautomerism. Specific examples include acetylacetone, 2,4-hexanedione, 3,5-heptanedione, 2-methylhexane-3,5-dione, 6-methylheptane-2,4-dione, 2,6-dimethylheptane- β-diketones such as 3,5-diones; acetoacetates such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate and tert-butyl acetoacetate; ethyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, propionyl acetic acid propionyl acetate esters such as tert-butyl; isobutyryl acetate esters such as ethyl isobutyryl acetate, ethyl isobutyryl acetate, isopropyl isobutyryl acetate, tert-butyl isobutyryl acetate; malonic esters such as methyl malonate and ethyl malonate; mentioned. Among the preferred compounds are acetylacetone and acetoacetates. Compounds that cause such keto-enol tautomerism may be used alone or in combination of two or more.

The amount of the compound that causes keto-enol tautomerism is, for example, 0.05 to 10 parts by weight, preferably 0.2 to 3 parts by weight (for example, 0.3 parts by weight to 2 parts by weight). If the amount of the compound used is less than 0.05 parts by weight per 1 part by weight of the organometallic compound, it may be difficult to exhibit sufficient effects. On the other hand, if the amount of the compound used exceeds 10 parts by weight per 1 part by weight of the organometallic compound, it may excessively interact with the organometallic compound, making it difficult to achieve the intended water resistance.

Further, the adhesive composition used in the present invention may contain various additives as other optional components within a range that does not impair the object and effect of the present invention. Examples of such additives include epoxy resins, polyamides, polyamideimides, polyurethanes, polybutadiene, polychloroprene, polyethers, polyesters, styrene-butadiene block copolymers, petroleum resins, xylene resins, ketone resins, cellulose resins, fluorine-based oligomers, Polymers or oligomers such as silicone-based oligomers and polysulfide-based oligomers; polymerization inhibitors such as phenothiazine and 2,6-di-t-butyl-4-methylphenol; polymerization initiation aids; leveling agents; wettability improvers; plasticizers; ultraviolet absorbers; inorganic fillers; pigments;

The above additives are generally 0-10% by weight, preferably 0-5% by weight, most preferably 0-3% by weight, based on the total amount of the adhesive composition.

From the viewpoint of coatability, the viscosity of the adhesive composition used in the present invention is preferably 100 cp or less at 25°C. On the other hand, when the adhesive composition of the present invention exceeds 100 cp at 25° C., the temperature of the adhesive composition can be controlled at the time of coating to adjust it to 100 cp or less. A more preferred range of viscosity is 1-80 cp, most preferably 10-50 cp. The viscosity can be measured using an E-type viscometer TVE22LT manufactured by Toki Sangyo Co., Ltd.

From the viewpoint of safety, the adhesive composition used in the present invention preferably uses a material with low skin irritation as the curable component. For skin irritation, P.S. I. It can be judged by the index of I. P. I. I is widely used as an indicator of the degree of skin damage and is measured by the Draize method. The measured value is displayed in the range of 0 to 8, and the lower the value, the lower the irritation. P. I. I is preferably 4 or less, more preferably 3 or less, most preferably 2 or less.

<Polarizing film>
The polarizing film according to the present invention includes a polarizer having, on at least one surface thereof, a durability-improving layer formed from a curable composition containing a compound (A) having a carbon-carbon double bond and a cyclic skeleton. Furthermore, the polarizing film according to the present invention may be obtained by laminating a transparent protective film on at least one surface of the polarizer. Further, preferably, an adhesive layer is further provided between the durability improving layer and the transparent protective film. A polarizing film further comprising an adhesive layer between the durability improving layer and the transparent protective film will be described below as an example.

The polarizing film according to the present invention is produced by, for example, the following production method;
A first coating step of applying a curable composition containing the compound (A) to the bonding surface of the polarizer to form a durability-improving layer, and a curing step of curing the curable composition constituting the durability-improving layer. and a second coating step of applying the adhesive composition to the bonding surface of the transparent protective film, and a bonding step of bonding the durability-improving layer-forming surface of the polarizer and the adhesive composition-coated surface of the transparent protective film. and an adhesion step of bonding the polarizer and the transparent protective film via the adhesive layer obtained by irradiating the active energy ray from the polarizer surface side or the transparent protective film side to cure the adhesive composition. It can be manufactured by a method for manufacturing a polarizing film including. Before the first coating step, an easy-adhesion layer forming step of forming an easy-adhesion layer on at least one surface of the polarizer is added, and the curable composition is applied to the easy-adhesion layer-forming surface of the polarizer. A first application step may be performed. Furthermore, before the step of forming the easy-adhesion layer, a treatment step of performing a surface modification treatment on at least one surface of the polarizer may be performed.

Not only the polarizer but also the transparent protective film may be subjected to surface modification treatment. Examples of the surface modification treatment include corona treatment, plasma treatment, itro treatment, and the like, and corona treatment is particularly preferred.

The method of applying the adhesive composition to the transparent protective film is appropriately selected depending on the viscosity of the adhesive composition and the desired thickness. Roll coaters, die coaters, bar coaters, rod coaters and the like can be mentioned. The viscosity of the adhesive composition used in the present invention is preferably 3-100 mPa·s, more preferably 5-50 mPa·s, and most preferably 10-30 mPa·s. When the viscosity of the adhesive composition is high, the surface smoothness after application is poor, resulting in poor appearance, which is not preferable. The adhesive composition used in the present invention can be applied by heating or cooling the composition to adjust the viscosity to a preferred range.

A polarizer and a transparent protective film are laminated via the adhesive composition coated as described above. A roll laminator or the like can be used to bond the polarizer and the transparent protective film together.

The adhesive composition used in the present invention is preferably used as an active energy ray-curable adhesive composition. The active energy ray-curable adhesive composition can be used in electron beam-curable, ultraviolet-curable, or visible light-curable modes. From the viewpoint of productivity, the adhesive composition is preferably a visible light-curable adhesive composition.

In the active energy ray-curable adhesive composition, after laminating the polarizer and the transparent protective film, the active energy ray (electron beam, ultraviolet rays, visible light, etc.) is irradiated to cure the active energy ray-curable adhesive composition. Cures to form an adhesive layer. The irradiation direction of the active energy rays (electron beam, ultraviolet rays, visible rays, etc.) can be any suitable direction. Preferably, irradiation is performed from the transparent protective film side. When irradiated from the polarizer side, the polarizer may be deteriorated by active energy rays (electron beams, ultraviolet rays, visible rays, etc.).

In the electron beam curability, any appropriate electron beam irradiation conditions can be adopted as long as the conditions are such that the active energy ray-curable adhesive composition can be cured. For example, electron beam irradiation preferably has an acceleration voltage of 5 kV to 300 kV, more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the adhesive, resulting in insufficient curing. may give The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. If the irradiation dose is less than 5 kGy, the adhesive will be insufficiently cured, and if it exceeds 100 kGy, the transparent protective film and polarizer will be damaged, the mechanical strength will decrease and yellowing will occur, and the desired optical properties will not be obtained. can't

The electron beam irradiation is usually carried out in an inert gas, but if necessary, it may be carried out in the atmosphere or under the condition that a little oxygen is introduced. Although it depends on the material of the transparent protective film, by appropriately introducing oxygen, the surface of the transparent protective film that is exposed to the electron beam first is intentionally inhibited by oxygen, and damage to the transparent protective film can be prevented. Efficient electron beam irradiation can be achieved.

In the method for producing a polarizing film according to the present invention, as the active energy ray, one containing visible light in the wavelength range of 380 nm to 450 nm, particularly the active energy ray with the highest irradiation amount of visible light in the wavelength range of 380 nm to 450 nm is used. is preferred. In UV curing and visible light curing, when using a transparent protective film imparted with UV absorption ability (ultraviolet opaque transparent protective film), it absorbs light with a wavelength shorter than about 380 nm. The light does not reach the active energy ray-curable adhesive composition and does not contribute to its polymerization reaction. Furthermore, light with a wavelength shorter than 380 nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, causing defects such as curling and wrinkling of the polarizing film. Therefore, when ultraviolet curability or visible light curability is adopted in the present invention, it is preferable to use a device that does not emit light with a wavelength shorter than 380 nm as an active energy ray generator, and more specifically, a wavelength range of 380 nm. The ratio of the integrated illuminance of ~440 nm and the integrated illuminance of the wavelength range of 250 to 370 nm is preferably 100:0 to 100:50, more preferably 100:0 to 100:40. As the active energy ray according to the present invention, a gallium-filled metal halide lamp and an LED light source emitting light in a wavelength range of 380 to 440 nm are preferable. Alternatively, ultraviolet rays from low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, extra high pressure mercury lamps, incandescent lamps, xenon lamps, halogen lamps, carbon arc lamps, metal halide lamps, fluorescent lamps, tungsten lamps, gallium lamps, excimer lasers, or sunlight. A light source containing visible light can be used, and a band-pass filter can be used to cut off ultraviolet light with a wavelength shorter than 380 nm. In order to prevent the curling of the polarizing film while improving the adhesion performance of the adhesive layer between the polarizer and the transparent protective film, a gallium-filled metal halide lamp is used, and light with a wavelength shorter than 380 nm can be blocked. It is preferable to use an active energy ray obtained through a bandpass filter or an active energy ray with a wavelength of 405 nm obtained using an LED light source.

In ultraviolet curing or visible light curing, it is preferable to heat the active energy ray-curable adhesive composition before irradiation with ultraviolet rays or visible rays (pre-irradiation heating), in which case the temperature is heated to 40°C or higher. It is preferable to heat to 50° C. or higher. It is also preferable to heat the active energy ray-curable adhesive composition after irradiation with ultraviolet light or visible light (post-irradiation heating). Warming is more preferred.

The active energy ray-curable adhesive composition used in the present invention is particularly suitable for forming an adhesive layer for bonding a polarizer and a transparent protective film having a light transmittance of less than 5% at a wavelength of 365 nm. It is possible. Here, the active energy ray-curable adhesive composition according to the present invention contains the photopolymerization initiator of general formula (3) described above, so that ultraviolet rays can be irradiated through a transparent protective film having UV absorption ability. can be used to cure the adhesive layer. Therefore, the adhesive layer can be cured even in a polarizing film in which transparent protective films having UV absorption ability are laminated on both sides of a polarizer. However, of course, the adhesive layer can be cured even in a polarizing film laminated with a transparent protective film having no UV absorption ability. The transparent protective film having UV absorbability means a transparent protective film having a transmittance of less than 10% for light of 380 nm.

Examples of the method for imparting UV absorption ability to the transparent protective film include a method of incorporating an ultraviolet absorber into the transparent protective film and a method of laminating a surface treatment layer containing an ultraviolet absorber on the surface of the transparent protective film.

Specific examples of the ultraviolet absorber include conventionally known oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, triazine compounds, and the like. .

After bonding the polarizer and the transparent protective film together, an active energy ray (electron beam, ultraviolet light, visible light, etc.) is irradiated to cure the active energy ray-curable adhesive composition to form an adhesive layer. The irradiation direction of the active energy rays (electron beam, ultraviolet rays, visible rays, etc.) can be any suitable direction. Preferably, irradiation is performed from the transparent protective film side. When irradiated from the polarizer side, the polarizer may be deteriorated by active energy rays (electron beams, ultraviolet rays, visible rays, etc.).

When the polarizing film according to the present invention is produced in a continuous line, the line speed is preferably 1 to 500 m/min, more preferably 5 to 300 m/min, more preferably 10 to 300 m/min, although it depends on the curing time of the adhesive composition. 100 m/min. If the line speed is too low, the productivity is poor, or the damage to the transparent protective film is too great, and a polarizing film that can withstand a durability test or the like cannot be produced. If the line speed is too high, the curing of the adhesive composition may be insufficient and the intended adhesiveness may not be obtained.

In the polarizing film of the present invention, the polarizer and the transparent protective film are preferably laminated via an adhesive layer formed by a cured product layer of the active energy ray-curable adhesive composition. A second easy-adhesion layer can be provided between the transparent protective film and the adhesive layer. The second easy-adhesion layer can be formed of various resins having, for example, a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone system, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, or the like. These polymer resins can be used singly or in combination of two or more. Other additives may be added to form the second easy-adhesion layer. More specifically, stabilizers such as tackifiers, ultraviolet absorbers, antioxidants, and heat stabilizers may be used.

The second easy-adhesion layer is usually provided in advance on the transparent protective film, and the second easy-adhesion layer side of the transparent protective film and the polarizer are bonded together with an adhesive layer. Formation of the second easy-adhesion layer is carried out by coating the material for forming the second easy-adhesion layer on the transparent protective film by a known technique, followed by drying. The material for forming the second easy-adhesion layer is usually prepared as a solution diluted to an appropriate concentration in consideration of the thickness after drying, the smoothness of coating, and the like. The thickness of the second easy-adhesion layer after drying is 0.01 to 5 μm, preferably 0.02 to 2 μm, more preferably 0.05 to 1 μm. A plurality of second easy-adhesion layers can be provided, and in this case also, the total thickness of the second easy-adhesion layers is preferably within the above range.

<Transparent protective film>
As the transparent protective film, a film having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropy, etc. is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrenes such as polystyrene and acrylonitrile-styrene copolymer (AS resin). and polycarbonate-based polymers. In addition, polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, polyolefin-based polymers such as ethylene/propylene copolymers, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamides, imide-based polymers, and sulfone-based polymers , polyethersulfone-based polymer, polyetheretherketone-based polymer, polyphenylene sulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, epoxy-based polymer, or the above Blends of polymers are also examples of polymers that form the transparent protective film. One or more of any suitable additives may be contained in the transparent protective film. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . If the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

Further, as the transparent protective film, the polymer film described in JP-A-2001-343529 (WO01/37007), for example, (A) a thermoplastic resin having a substituted and/or unsubstituted imide group in a side chain, Included are resin compositions containing thermoplastic resins having substituted and/or unsubstituted phenyl and nitrile groups in the chain. A specific example is a film of a resin composition containing an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer. A film made of a mixed extruded product of a resin composition or the like can be used as the film. Since these films have a small retardation and a small photoelastic coefficient, problems such as unevenness due to distortion of the polarizing film can be eliminated.

In the polarizing film, the transparent protective film preferably has a moisture permeability of 150 g/m ² /24h or less. According to such a configuration, it is difficult for moisture in the air to enter the polarizing film, and a change in the moisture content of the polarizing film itself can be suppressed. As a result, curling and dimensional changes of the polarizing film caused by the storage environment can be suppressed.

The transparent protective film provided on one or both sides of the polarizer preferably has excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc., and particularly has a moisture permeability of 150 g/m ² /. More preferably 24 h or less, particularly preferably 120 g/m ² /24 h or less, and even more preferably 5 to 70 g/m ² /24 h or less. The moisture permeability is determined by the method described in Examples.

Materials for forming the transparent protective film that satisfies the low moisture permeability include, for example, polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate resins; arylate resins; amide resins such as nylon and aromatic polyamide; , a polyolefin polymer such as an ethylene/propylene copolymer, a cyclic olefin resin having a cyclo or norbornene structure, a (meth)acrylic resin, or a mixture thereof. Among these resins, polycarbonate-based resins, cyclic polyolefin-based resins, and (meth)acrylic-based resins are preferred, and cyclic polyolefin-based resins and (meth)acrylic-based resins are particularly preferred.

The thickness of the transparent protective film can be determined as appropriate, but is generally preferably 5 to 100 μm from the viewpoints of strength, workability such as handleability, and thinness. 10 to 60 μm is particularly preferable, and 13 to 40 μm is more preferable.

A roll laminator can be used to bond the polarizer and the protective film together. The method of laminating the protective films on both sides of the polarizer includes the method of laminating the polarizer and one protective film and then laminating another protective film, and the method of laminating the polarizer and two protective films at the same time. Selected from matching methods. Entrapped air bubbles generated during lamination can be significantly reduced by adopting the former method, that is, a method of laminating a polarizer and a protective film and then laminating another protective film. It is preferable because

<Optical film>
The polarizing film of the present invention can be used as an optical film laminated with other optical layers in practical use. The optical layer is not particularly limited. Examples thereof include optical layers that are sometimes used in the formation of display devices and the like. These optical layers can be used as the base film of the base film with an easy-adhesion layer in the present invention. It has a functional group. Therefore, on at least one surface of the retardation film containing at least a reactive functional group on the surface, easy adhesion treated retardation film comprising the compound represented by the general formula (1), especially the general formula (1) Retardation film with an easy-adhesion layer in which an easy-adhesion layer containing a compound represented by is formed improves the adhesion between the retardation film and the adhesive layer, and as a result, the adhesion is particularly improved. preferable.

As the retardation film, a film having a front retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more can be used. The front retardation is usually controlled in the range of 40-200 nm, and the thickness direction retardation is usually controlled in the range of 80-300 nm.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an oriented film of a liquid crystal polymer, and a film in which an oriented layer of a liquid crystal polymer is supported. Although the thickness of the retardation film is not particularly limited, it is generally about 20 to 150 μm.

As the retardation film, the following formulas (1) to (3):
0.70<Re[450]/Re[550]<0.97 (1)
1.5×10−3<Δn<6×10−3 (2)
1.13<NZ<1.50 (3)
(Wherein, Re [450] and Re [550] are the in-plane retardation values of the retardation film measured with light having wavelengths of 450 nm and 550 nm, respectively, at 23 ° C., and Δn is the slow phase of the retardation film In-plane birefringence that is nx-ny when the refractive indices in the axial direction and the fast axis direction are nx and ny, respectively, and NZ is the refractive index in the thickness direction of the retardation film, (ratio of nx-nz, which is birefringence in the thickness direction, to nx-ny, which is in-plane birefringence) may be used.

The polarizing film and the optical film having at least one layer of polarizing film laminated thereon may be provided with an adhesive layer for adhering to other members such as a liquid crystal cell. The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer is not particularly limited, but for example, an acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based polymer, rubber-based polymer, or the like is appropriately selected. can be used as In particular, those having excellent optical transparency, suitable wettability, cohesiveness, and adhesive properties such as acrylic pressure-sensitive adhesives, and excellent weather resistance and heat resistance can be preferably used.

The adhesive layer can also be provided on one side or both sides of the polarizing film or the optical film as a superimposed layer of different compositions or types. Further, when the adhesive layer is provided on both sides, the front and back surfaces of the polarizing film or the optical film may have adhesive layers with different compositions, types, thicknesses, and the like. The thickness of the adhesive layer can be appropriately determined according to the purpose of use, adhesive strength, etc., and is generally 1 to 500 μm, preferably 1 to 200 μm, particularly preferably 1 to 100 μm.

The exposed surface of the adhesive layer is temporarily covered by a separator for the purpose of preventing contamination, etc., until the adhesive layer is put into practical use. This prevents contact with the adhesive layer during normal handling conditions. As the separator, excluding the above thickness conditions, suitable thin sheets such as plastic films, rubber sheets, paper, cloth, non-woven fabrics, nets, foam sheets, metal foils, and laminates thereof may be used. An appropriate release agent according to the prior art, such as one coated with an appropriate release agent such as chain alkyl, fluorine, or molybdenum sulfide, can be used.

<Image display device>
The polarizing film or optical film of the present invention can be preferably used for forming various devices such as liquid crystal display devices. Formation of the liquid crystal display device can be carried out according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, a polarizing film or an optical film, and, if necessary, an illumination system, and incorporating a driving circuit. There is no particular limitation except that the polarizing film or optical film according to the invention is used, and conventional methods can be applied. As for the liquid crystal cell, any type such as TN type, STN type, or π type can be used.

Appropriate liquid crystal displays can be formed, such as a liquid crystal display having a polarizing film or an optical film arranged on one or both sides of a liquid crystal cell, or a liquid crystal display using a backlight or a reflector for an illumination system. In that case, the polarizing film or optical film according to the present invention can be placed on one side or both sides of the liquid crystal cell. When polarizing films or optical films are provided on both sides, they may be the same or different. Furthermore, when forming a liquid crystal display device, for example, appropriate parts such as a diffuser plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, and a backlight are arranged in a single layer or at an appropriate position. Two or more layers can be arranged.

Examples of the present invention are described below, but embodiments of the present invention are not limited to these.

<Polarizer>
First, a laminate in which a PVA layer having a thickness of 9 μm is formed on an amorphous PET base material is subjected to auxiliary stretching in the air at a stretching temperature of 130° C. to form a stretched laminate, and then the stretched laminate is dyed to form a colored laminate. Further, the colored laminate is stretched integrally with the amorphous PET substrate by stretching in boric acid water at a stretching temperature of 65 degrees so that the total stretching ratio is 5.94 times. An optical film laminate was produced. By such two-stage stretching, the PVA molecules of the PVA layer formed on the amorphous PET substrate are highly oriented, and the iodine adsorbed by the dyeing is highly oriented in one direction as a polyiodine ion complex. Thus, an optical film laminate including a PVA layer having a thickness of 5 μm, which constitutes a thin polarizer, was obtained.

<Transparent protective film>
100 parts by weight of the imidized MS resin described in Production Example 1 of JP-A-2010-284840 and 0.62 parts by weight of a triazine-based UV absorber (trade name: T-712, manufactured by Adeka Co., Ltd.) were mixed in a twin-screw kneader. and mixed at 220° C. to prepare resin pellets. The obtained resin pellets were dried at 100.5 kPa and 100° C. for 12 hours, and extruded from a T-die at a die temperature of 270° C. using a single screw extruder to form a film (thickness: 160 μm). Furthermore, the film is stretched in the transport direction under an atmosphere of 150 ° C. (thickness 80 μm), then applied with an easy-adhesive agent containing a water-based urethane resin, and then stretched in the direction perpendicular to the film transport direction in an atmosphere of 150 ° C. As a result, a transparent protective film having a thickness of 40 μm (water vapor transmission rate of 58 g/m ² /24 h) was obtained.

<Active energy ray>
Visible light (gallium-encapsulated metal halide lamp) as the active energy ray Irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc. Bulb: V bulb Peak illuminance: 1600 mW/cm ² , integrated irradiation amount 1000/mJ/cm ² (wavelength 380- 440 nm) was used. The illuminance of visible light was measured using a Sola-Check system manufactured by Solatell.

(Titration test of compound (A))
γ-Butyrolactone acrylate (GBLA) was selected as the compound (A), and a titration test was conducted to confirm that GBLA exhibits a pseudo-buffering action. As shown in Table 1, 0.1 M_NaOH aqueous solution was added dropwise to 0.1 M_GBLA aqueous solution adjusted to 60 ° C., and the pH increase was measured. However, the pH increased by only 2.5 compared to before the addition. From the results of this titration test, it can be understood that GBLA exhibits a pseudo-buffering effect.

(Adjustment of curable composition)
An adhesive composition containing 3 parts by weight of IRGACURE 907 (polymerization initiator, manufactured by BASF) and 3% by weight of KAYACURE DETX-S (polymerization initiator, manufactured by Nippon Kayaku Co., Ltd.) was prepared with respect to 100 parts by weight of GBLA.

(Adjustment of easily adhesive composition)
Acryloylmorpholine 5.1 parts by weight, Olfine EXP4200 (manufactured by Nisshin Chemical Co., Ltd.) 0.2 parts by weight, pure water 87 parts per 6.9 parts by weight of isopropyl alcohol solution of 4-vinylphenylboronic acid adjusted to 15% by weight An easily adhesive composition containing .9 parts by weight was prepared.

<Polarizer with Easy Adhesion Layer>
Using a wire bar (manufactured by Daiichi Rika Co., Ltd., No. 2), the easy-adhesion composition was applied to the PVA surface of the optical film laminate containing the 5 μm-thick PVA layer of the polarizer, and The solvent was removed by air-drying for 2 minutes, and the polarizer with an easily bonding layer was produced.

(Adhesive Composition Adjustment)
1,9-nonanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) 100 parts by weight, IRGACURE 907 (polymerization initiator, manufactured by BASF) 3 parts by weight, KAYACURE DETX-S (polymerization initiator, manufactured by Nippon Kayaku Co., Ltd.) An adhesive composition containing 3% by weight was prepared.

(Preparation of polarizing film)
Example 1
An MCD coater (manufactured by Fuji Machine Co., Ltd.) (cell shape: honeycomb, number of gravure roll lines: 1000 lines/inch, rotation speed: 140%/relative to line speed) was used on the easy-adhesion layer side of the polarizer with an easy-adhesion layer. , the curable composition was applied to a thickness of 0.7 µm to form a durability-improving layer. Then, using a roll machine, a transparent protective film was attached from the durability improving layer side of the polarizer. After that, from the side of the laminated transparent protective film, the visible light is irradiated by an active energy ray irradiation device to cure the curable composition constituting the durability improving layer, and the polarizer and the transparent protective film are adhered. After drying with hot air at 70° C. for 3 minutes, the amorphous PET substrate laminated on the other side of the polarizer was peeled off to obtain a polarizing film having a transparent protective film on one side of the polarizer. rice field. The lamination line speed was 25 m/min.

Example 2
An MCD coater (manufactured by Fuji Machine Co., Ltd.) (cell shape: honeycomb, number of gravure roll lines: 1000 lines/inch, rotation speed: 140%/relative to line speed) was used on the easy-adhesion layer side of the polarizer with an easy-adhesion layer. , the curable composition was applied to a thickness of 0.7 µm to form a durability-improving layer. Next, using a roll machine, a polyester film (Diafoil S-100, 38 μm, manufactured by Mitsubishi Chemical Co., Ltd.) was laminated from the durability improving layer side of the polarizer. After that, the visible light was irradiated from the bonded polyester film side with an active energy ray irradiation device to cure the curable composition constituting the durability improving layer. Subsequently, the polyester film was peeled off.
MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, number of gravure roll lines: 1000 lines/inch, rotation speed: 140%/relative to line speed) was applied to the bonding surface of the transparent protective film, and the above adhesive composition was applied. The material was applied so as to have a thickness of 0.7 μm, and the durability-improving layer-forming surface of the polarizer and the adhesive composition-coated surface of the transparent protective film were bonded together using a rolling machine. After that, from the side of the laminated transparent protective film, the above visible light is irradiated with an active energy ray irradiation device to cure the adhesive composition constituting the adhesive layer, and then dried with hot air at 70 ° C. for 3 minutes, By peeling and removing the amorphous PET substrate laminated on the other side of the polarizer, a polarizing film having a transparent protective film on one side of the polarizer was obtained. The lamination line speed was 25 m/min.

Example 3
An MCD coater (manufactured by Fuji Machine Co., Ltd.) (cell shape: honeycomb, number of gravure roll lines: 1000 lines/inch, rotation speed: 140%/relative to line speed) was used on the easy-adhesion layer side of the polarizer with an easy-adhesion layer. , the curable composition was applied to a thickness of 0.7 µm to form a durability-improving layer. Next, using a roll machine, a polyester film (Diafoil S-100, 38 μm, manufactured by Mitsubishi Chemical Co., Ltd.) was laminated from the durability improving layer side of the polarizer. After that, the visible light was irradiated from the bonded polyester film side with an active energy ray irradiation device to cure the curable composition constituting the durability improving layer. Subsequently, by peeling off the polyester film, a polarizing film composed of a polarizer having a durability improving layer on one surface was obtained.

Comparative example 1
A polarizing film was produced in the same manner as in Example 2, except that a polarizer without a durability-enhancing layer was used as the polarizer.

Comparative example 2
A polarizing film comprising a polarizer having an adhesive layer on one surface was obtained in the same manner as in Example 3, except that an adhesive composition was applied instead of the curable composition.

The polarizing films obtained in the above examples and comparative examples were evaluated as follows. Table 1 shows the evaluation results.

(Humidification durability test)
The transmittance and degree of polarization of the produced polarizing film were measured using a spectral transmittance meter with an integrating sphere (Dot-3c, Murakami Color Research Laboratory). The degree of polarization P is the transmittance (parallel transmittance: Tp) when two identical polarizing films are superimposed so that their transmission axes are parallel, and It is obtained by applying the combined transmittance (orthogonal transmittance: Tc) to the following equation.
Degree of polarization P (%) = {(Tp-Tc)/(Tp+Tc)} 1/2 x 100
Each transmittance is indicated by the Y value corrected for luminous efficiency by a 2-degree field of view (C light source) of JIS Z8701, with the fully polarized light obtained through the Glan-Teller prism polarizer being 100%. The polarizer surface of this polarizing film is subjected to corona treatment and a 20 μm-thick acrylic adhesive is attached, and the other surface of the acrylic adhesive is attached to non-alkali glass. The initial value of the modulus was measured. Then, this polarizing film with glass was placed in an environment of 60° C. and 95% RH for 48 hours, and the degree of polarization of the polarizing film with glass was measured after aging. A value obtained by subtracting the initial degree of polarization P from the degree of polarization P after the lapse of time was taken as the change in the degree of polarization. It means that the smaller the absolute value of the change in the degree of polarization, the better the humidification durability.

Claims (9)

A polarizer comprising a durability-enhancing layer on at least one surface,
The durability-improving layer was formed of a curable composition containing a compound (A) that showed a pH increase of 3.0 or less even when 0.5 equivalent of a basic component was added in a titration test at 60°C. is a
The compound (A) is γ-butyrolactone (meth)acrylate,
The polarizer is a polarizer with an easy-adhesion layer, and the easy-adhesion layer has the following general formula (1):

Compound (B) represented by (wherein X is a functional group containing a reactive group, R ¹ and R ² are each independently a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent , an aryl group, or a heterocyclic group),
A polarizer, wherein the durability-improving layer is formed directly on the easy-adhesion layer side of the polarizer. 2. The polarizer according to claim 1, wherein at least part of said compound (A) contained in said curable composition is polymerized. 3. The polarizer according to claim 1, wherein the curable composition further contains a polymerization initiator. 4. The polarizer according to claim 3 , wherein the durability-improving layer is formed from a cured product layer of the curable composition. A polarizing film comprising the polarizer according to any one of claims 1 to 4 . A transparent protective film is laminated on at least one surface of the polarizer,
6. The polarizing film according to claim 5 , wherein the transparent protective film is laminated on the durability improving layer side of the polarizer. The polarizing film according to claim 6 , further comprising an adhesive layer between the durability improving layer and the transparent protective film. An optical film comprising a laminate of at least one polarizing film according to any one of claims 5 to 7 . An image display device using the polarizing film according to any one of claims 5 to 7 or the optical film according to claim 8.