JP2020034898A - Polarizer, polarizing film, optical film and image display device - Google Patents

Abstract

To provide a polarizer and a polarizing film suppressing degradation in optical characteristics even in a humidified environment.SOLUTION: The polarizer includes a durability-improving layer on at least one surface thereof. The durability-improving layer contains at least a copolymer of a compound (A) having a carbon-carbon double bond and a cyclic skeleton and a compound (B) copolymerizable with the compound (A). The cyclic skeleton of the compound (A) is preferably a heterocyclic skeleton and is preferably a lactone skeleton. Furthermore, the compound (A) is preferably a γ-butyrolactone (meth)acrylate.SELECTED DRAWING: None

Description

  The present invention relates to a polarizer having a durability improving 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, and a PDP by itself or as an optical film obtained by laminating the polarizing film.

  Liquid crystal display devices are rapidly developing in markets such as watches, mobile phones, PDAs, notebook computers, monitors for personal computers, DVD players, and TVs. The liquid crystal display device visualizes a polarization state by switching of liquid crystal, and a polarizer is used from the display principle. In particular, for applications such as TVs, higher brightness, higher contrast, and wider viewing angles are required, and even higher polarizing films are required to have higher transmittance, higher degree of polarization, higher color reproducibility, and the like.

  As a polarizer, 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 because it has a high transmittance and a high degree of polarization is the most widely used. It is used. Generally, a polarizing film is used in which a transparent protective film is attached to both surfaces of a polarizer with a so-called aqueous adhesive obtained by dissolving a polyvinyl alcohol-based material in water (Patent Document 1 below). As the transparent protective film, triacetyl cellulose 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, an active energy ray-curable adhesive has been proposed instead of the water-based adhesive. When a polarizing film is produced using an active energy ray-curable adhesive, a drying step is not required, so that the productivity of the polarizing film can be improved. 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 Literature 2 has a sufficient water resistance test for evaluating the presence or absence of color loss and peeling after immersion in, for example, 60 ° C. hot water for 6 hours. Can be cleared. However, in recent years, the adhesive for polarizing films has been evaluated for the presence or absence of peeling when the end nails are peeled off after being immersed (saturated) in water, for example. Further, further improvement in water resistance is being demanded.

  Patent Document 3 listed below reports a technique of forming a resin layer on the surface of a polarizer for the purpose of suppressing the deterioration of the polarizer. However, under severe humidification conditions, the deterioration of the polarizer is sufficiently suppressed. It turns out there is more room for it.

JP 2001-296427 A JP 2012-052000 A JP 2000-199819 A

  The present invention has been developed in view of the above circumstances, and has as its object to provide a polarizer and a polarizing film in which deterioration of optical characteristics is suppressed even in a humid environment.

Still another object 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.

  The present inventors have conducted intensive studies to solve the above problems, and as a result, by forming a durability improving layer containing a copolymer of a specific compound on at least one surface of the polarizer, the humidification environment Even below, the inventors have found that the deterioration of the optical properties of the polarizer and the polarizing film provided with the polarizer can be suppressed, and the present invention has been achieved.

That is, the present invention is a polarizer including a durability improving layer on at least one surface, wherein the durability improving layer has a compound (A) having a carbon-carbon double bond and a cyclic skeleton; A polarizer comprising at least a copolymer of (A) and a compound (B) copolymerizable with the compound (A).

In the above polarizer, the durability improving layer is a copolymer of a compound (A) having a carbon-carbon double bond and a cyclic skeleton, and a compound (B) copolymerizable with the compound (A). It is preferable that the composition is formed by at least the curable composition contained therein.

で表される化合物（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）であることが好ましい。 In the above polarizer, the compound (B) is represented by the following general formula (1):

Wherein X is a functional group containing a reactive group, and R ¹ and R ² are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group or an aryl group. Or a heterocyclic group).

  In the above polarizer, the cyclic skeleton of the compound (A) is preferably a heterocyclic skeleton.

  In the above polarizer, the cyclic skeleton of the compound (A) is preferably a lactone skeleton (cyclic lactone skeleton).

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

  In the above polarizer, it is preferable that the curable composition further contains a polymerization initiator.

  In the above 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 including the polarizer according to any one of the 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.

  It is preferable that the polarizing film further includes an adhesive layer between the durability improving layer and the transparent protective film.

Furthermore, the present invention provides an optical film, wherein at least one polarizing film described above is laminated, or an image using the polarizing film described above, or the optical film described above is used. It relates to a display device.

  The present invention also relates to a copolymer of a compound (A) having a carbon-carbon double bond and a cyclic skeleton, and a compound (B) copolymerizable with the compound (A).

で表される化合物（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）であることが好ましい。 In the above copolymer, the compound (B) is represented by the following general formula (1):

Wherein X is a functional group containing a reactive group, and R ¹ and R ² are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group or an aryl group. Or a heterocyclic group).

  In the above copolymer, the cyclic skeleton of the compound (A) is preferably a heterocyclic skeleton.

  In the above copolymer, the cyclic skeleton of the compound (A) is preferably a lactone skeleton (cyclic lactone skeleton).

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

  Further, the present invention relates to a curable composition containing at least the copolymer described in any of the above, and it is preferable that the curable composition contains a polymerization initiator in addition to the copolymer.

  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 includes a durability improving layer on at least one surface thereof, and the durability improving layer has a compound (A) having a carbon-carbon double bond and a cyclic skeleton, and the compound (A) And at least a copolymer of the compound (B) and a copolymerizable compound (B). For this reason, the optical characteristics of the polarizer can be prevented from deteriorating even in a humid environment. Although the reason why such an effect is obtained is not clear, since the polarizer includes the durability improving layer containing the compound (A) on at least one surface, the iodine complex present on the polarizer surface even in a humid environment is removed. Stabilization is one of the reasons. In the present invention, since at least a part of the compound (A) is copolymerized with the compound (B), the compound (A) is easily fixed near the polarizer. As a result, the effect of stabilizing the iodine complex existing on the polarizer surface even in a humid environment is enhanced.

  In particular, in the present invention, when the compound (B) is the compound represented by the general formula (1), the compound (B) is a copolymer of the compound (A) and the compound (B) contained in the durability improving layer. ) Reacts with a functional group such as a hydroxyl group of the polarizer, and the compound (A) is more likely to be fixed near the polarizer. As a result, the adhesion between the polarizer and the durability improving layer can be further improved, and the deterioration of the optical properties of the polarizer in a humid environment can be further suppressed.

  Further, in a polarizing film in which a transparent protective film is laminated on at least one surface of the polarizer according to the present invention, for example, when an adhesive layer is interposed between the polarizer and the transparent protective film, in a humid environment. Also, the deterioration of the optical characteristics of the polarizing film can be suppressed. The reason why such an effect is obtained is not clear, but a covalent bond or a hydrogen bond formed between a functional group such as a hydroxyl group present on the polarizer surface and a functional group of the adhesive layer by the durability improving layer. Is considered as one of the reasons that the iodine complex existing on the surface of the polarizer can be stabilized because hydrolysis of the iodine complex can be suppressed.

  Note that 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 the polarizing film includes the polarizer provided with the specific durability improving layer on at least one surface. Good. In such a polarizing film, the durability improving layer suppresses the deterioration of the optical properties of the polarizer in a humid environment, and the durability improving layer also exhibits a protective function instead of the transparent protective film.

  Copolymer of compound (A) having a carbon-carbon double bond and a cyclic skeleton, and compound (B) copolymerizable with compound (A), and curable composition containing at least the copolymer Can form a durability-improving layer, for example, by applying it to the surface of a polarizer. As described above, in the polarizer including the durability improving layer, deterioration of the optical characteristics of the polarizer is suppressed even in a humid environment. Therefore, such a copolymer and a curable composition containing at least the copolymer can be particularly suitably used for a polarizer and a polarizing film having at least the polarizer.

  The present invention relates to a polarizer having a durability improving layer on at least one surface. Hereinafter, each configuration will be described.

<Durability improving layer>
The durability improving layer contains at least a copolymer of a compound (A) having a carbon-carbon double bond and a cyclic skeleton, and a compound (B) copolymerizable with the compound (A). The durability improving layer is, for example, a cured product containing at least a copolymer of a compound (A) having a carbon-carbon double bond and a cyclic skeleton and a compound (B) copolymerizable with the compound (A). It can be formed by a hydrophilic composition.

  The compound (A) contains at least one carbon-carbon double bond such as a vinyl group and a (meth) acryloyl group, and further has a cyclic skeleton. The cyclic skeleton may be composed of only carbon atoms, but is preferably a heterocyclic skeleton having carbon atoms and hetero atoms.

  Examples of the hetero atom having a heterocyclic skeleton include a nitrogen atom, an oxygen atom and a sulfur atom, and specific examples of the heterocyclic skeleton include ethyleneimine, azacyclobutane, pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, piperidine, and pyridine. , Morpholine, hexamethyleneimine, azatopyroline and other nitrogen-containing heterocyclic skeletons; ethylene oxide, α-acetolactone, propylene oxide, β-propiolactone, tetrahydrofuran, furan, γ-butyrolactone, tetrahydropyran, dioxane, σ-valerolactone And heteroatoms containing oxygen atoms such as hexamylene oxide; ethylene sulfide, trimethylene sulfide, tetrahydrothiophene, thiophene, thiazole, tetrahydrothiopyran And sulfur atom-containing hetero ring structure, such as azine and hexamethylene sulfide and the like. Among the heterocyclic skeletons, lactone skeletons such as α-acetolactone, β-propiolactone, γ-butyrolactone, and σ-valerolactone (cyclic lactone skeleton) from the viewpoint of suppressing optical property deterioration of the durability improving layer provided in the polarizer. ) Is preferred, and γ-butyrolactone is preferred.

  As the compound (A), a compound containing at least one carbon-carbon double bond such as a vinyl group and a (meth) acryloyl group and having the cyclic skeleton can be used. In the present invention, particularly, as the compound (A), (meth) acryloylmorpholine, α-acetolactone (meth) acrylate, β-propiolactone (meth) acrylate, γ-butyrolactone (meth) acrylate and σ-valerolactone (meth) ) Acrylates and the like are preferred.

  If the content of the compound (A) in the durability improving layer is too small, the deterioration of the optical properties of the polarizer in a humid environment may not be sufficiently suppressed. Therefore, the content of the compound (A) in the durability improving layer is preferably at least 50 parts by mass, more preferably at least 80 parts by mass, and even more preferably at least 95 parts by mass.

で表される化合物（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）を使用した場合、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、さらに化合物（Ａ）とも反応する。これにより、偏光子と耐久性向上層との密着性がさらに向上するとともに、加湿環境下での偏光子の光学特性劣化をさらに抑制することができる。 The compound (B) is a compound copolymerizable with the compound (A), for example, a compound containing at least one carbon-carbon double bond such as a vinyl group and a (meth) acryloyl group like the compound (A). If there is, it can be used without particular limitation. As the compound (B), in particular, the following general formula (1):

Wherein X is a functional group containing a reactive group, and R ¹ and R ² are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group or an aryl group. Or a heterocyclic group), the boric acid group and / or boric acid ester group of the compound (B) reacts with a functional group such as a hydroxyl group of the polarizer, and the compound (A) react. Thereby, the adhesion between the polarizer and the durability improving layer is further improved, and the deterioration of the optical properties of the polarizer in a humid environment can be further suppressed.

Examples of the aliphatic hydrocarbon group include a linear or branched alkyl group which may have a substituent having 1 to 20 carbon atoms, a cyclic alkyl group which may have a substituent having 3 to 20 carbon atoms, Examples thereof include an alkenyl group having 2 to 20 carbon atoms, and examples of the aryl group include a phenyl group which may have a substituent having 6 to 20 carbon atoms and a naphthyl group which may have a substituent having 10 to 20 carbon atoms. Examples of the heterocyclic group include a 5-membered or 6-membered ring group having at least one heteroatom and which may have a substituent. These may be connected to each other to form a ring. In the general formula (1), R ¹ and R ² are preferably a hydrogen atom, a linear or branched alkyl group having 1 to 3 carbon atoms, and most preferably a hydrogen atom.

  X of the compound (B) represented by the general formula (1) is a functional group containing a reactive group. Examples of the reactive group included in X include a hydroxyl group, an amino group, an aldehyde group, a carboxyl group, a vinyl group, a (meth) acryl group, a styryl group, a (meth) acrylamide group, a vinyl ether group, an epoxy group, an 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 is 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) acryl 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 described above). More preferably, the following compounds (1a) to (1d) are mentioned.

  In the present invention, the compound (B) represented by the general formula (1) may be one in which a reactive group and a boron atom are directly bonded, but as shown in the specific examples, The compound (B) represented by the general formula (1 ′), in which the compound (B) represented by (1) is a compound in which a reactive group and a boron atom are bonded via an organic group. It is preferable that When the compound (B) represented by the general formula (1) is bonded to a reactive group via, for example, an oxygen atom bonded to a boron atom, the optical characteristics 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 has a boron-carbon bond due to a bond between a boron atom and an organic group. A group containing a group (in the case of general formula (1 ′)) is preferable because deterioration of the optical characteristics of the polarizing element can be suppressed. The organic group specifically means an organic group having 1 to 20 carbon atoms, which may have a substituent, and more specifically, for example, has a substituent having 1 to 20 carbon atoms. A linear or branched alkylene group which may be substituted, a cyclic alkylene group which may have a substituent having 3 to 20 carbon atoms, a phenylene group which may have a substituent having 6 to 20 carbon atoms, 10 to 10 carbon atoms And a naphthylene group which may have 20 substituents.

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

  If the content of the compound (B) in the durability improving layer is too small, the effect of fixing the compound (A) in the vicinity of the polarizer is reduced, and deterioration of the optical properties of the polarizer in a humid environment cannot be sufficiently suppressed. There are cases. Therefore, the content of the compound (B) in the durability improving layer is preferably 0.5 parts by mass or more, more preferably 3.0 parts by mass or more, and more preferably 10 parts by mass or more. More preferred.

  The method of copolymerizing the compound (A) and the compound (B) includes, for example, radical polymerization in a solution containing the compound (A) and the compound (B). When performing radical polymerization, thermal initiators known to those skilled in the art as initiators, for example, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2,2 ′ -Azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, benzoyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-butyl peroxide, 2,2′-azobis (2-methylpropion Acid) dimethyl, dicumyl peroxide and the like can be used. As the solvent, a solvent known to those skilled in the art, for example, an organic solvent, water, or a mixed solvent thereof can be used. 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 and cyclohexanol. Aliphatic or alicyclic alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and diethylene glycol monoethyl ether; Chi glycol monomethyl ether acetate, glycol ether acetates such as diethylene glycol monoethyl ether acetate; can be selected from such.

  The copolymer of compound (A) and compound (B) may be a random copolymer or a block copolymer. The copolymerization ratio of the compound (A) and the compound (B) is expressed by a mass ratio of (compound (A)) from the viewpoint of the effect of suppressing the deterioration of the optical properties of the polarizer of the finally obtained durability improving layer. : (Compound (B)) is preferably 60:40 to 99.5: 0.5, more preferably 80:20 to 99: 1.

  As a method for forming a durability-improving layer using a curable composition containing at least a copolymer of compound (A) and compound (B), for example, a coating method described below is applied to at least one surface of a polarizer. For example, a coating layer made of a curable composition containing such a copolymer may be provided using, for example, and dried as necessary to form a durability improving layer.

  The curable composition serving as a raw material for forming the durability-improving layer may be composed of only a copolymer of the compound (A) and the compound (B). Solvents and additives may be included.

  In the case where the curable composition contains a polymerization initiator in addition to the copolymer of the compound (A) and the compound (B), the durability improving layer is formed by the cured product layer of the curable composition. In the case where the copolymer is used, the copolymer and the polymer thereof are fixed in the vicinity of the polarizer, whereby the durability of the polarizer is further improved. As a result, deterioration of the optical characteristics of the polarizer can be preferably suppressed, which is preferable. For a method of forming a durability improving layer by a cured product layer, for example, a curable composition containing at least a copolymer and a polymerization initiator is applied to a polarizer, and cured by irradiating an active energy ray described below. A method of curing the conductive composition to form a cured product layer (durability improving layer). The usable active energy rays will be described later.

  In the present invention, it is preferable to use a photopolymerization initiator as the polymerization initiator. The photopolymerization initiator is appropriately selected depending on the active energy ray. When curing with ultraviolet light or visible light, a photopolymerization initiator that cleaves ultraviolet light or visible light is used. Examples of the photopolymerization initiator include benzophenone-based compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3′-dimethyl-4-methoxybenzophenone; and 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2). -Propyl) ketone, aromatic ketone compounds such as α-hydroxy-α, α′-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenyl ketone; methoxyacetophenone, 2,2-dimethoxy- Acetophenone-based compounds such as 2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2-morpholinopropane-1, benzoin methyl ether, Benzoin ethyl ether, Benzoi Benzoin ether compounds such as isopropyl ether, benzoin butyl ether and anisoin methyl ether; aromatic ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalene sulfonyl chloride; 1-phenone-1 Photoactive oxime compounds such as 1,1-propanedione-2- (o-ethoxycarbonyl) oxime; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichloro Thioxanthone compounds such as thioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone and dodecylthioxanthone; camphorquinone; halogenated ketones; acylphos Finoxide; acylphosphonate and the like.

（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）と化合物（Ｂ）との共重合体に対して、０．５〜４．０質量％であることが好ましく、１．０〜２．５質量％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 are used alone or in the general formula ( It is preferable to use the compound represented by 3) in combination with a photopolymerization initiator having high sensitivity to light of 380 nm or more, 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 having high sensitivity to light of 380 nm or more is used alone. Among the compounds represented by the general formula (3), diethylthioxanthone in which R ⁶ and R ⁷ are —CH ₂ CH ₃ is particularly preferable. The composition ratio of the compound represented by the general formula (3) in the curable composition is 0.5 to 4.0% by mass based on the copolymer of the compound (A) and the compound (B). And more preferably 1.0 to 2.5% by mass.

  In addition, it is preferable to add a polymerization initiation aid as needed. Examples of the polymerization initiator 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, its addition amount is usually 0 to 5% by mass, preferably 0 to 4% by mass, based on the total amount of the copolymer of compound (A) and compound (B). Preferably it is 0-3 mass%.

  Further, a known photopolymerization initiator can be used in combination as needed. Since a transparent protective film having UV absorbing ability does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator having high sensitivity to light of 380 nm or more as a photopolymerization initiator. 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）と化合物（Ｂ）との共重合体に対して、０．５〜４．０質量％であることが好ましく、１．０〜２．５質量％であることがより好ましい。 In particular, as the photopolymerization initiator, in addition to the photopolymerization initiator of the 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), commercially available 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (trade name: IRGACURE907, manufacturer: BASF) is preferable. It can be used for In addition, 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 the general formula (4) in the curable composition is 0.5 to 4.0% by mass based on the copolymer of the compound (A) and the compound (B). And more preferably 1.0 to 2.5% by mass.

  As the solvent which the curable composition may contain, a solvent which can stabilize a copolymer of the compound (A) and the compound (B), furthermore, a polymerization initiator and the like, and which can be dissolved or dispersed is preferable. As the solvent, the same solvents as those which can be used when copolymerizing the compound (A) and the compound (B) can be used. For example, using the solvents exemplified above, the compound (A) and the compound (B) can be used. Alternatively, a solution obtained by copolymerizing the above may be used as it is, and if necessary, a polymerization initiator or an additive may be added to use as a curable composition.

  Additives that the curable composition may include, for example, surfactants, plasticizers, tackifiers, low molecular weight polymers, polymerizable monomers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light Examples include a stabilizer, an ultraviolet absorber, a polymerization inhibitor, a silane coupling agent, a titanium coupling agent, an inorganic or organic filler, a metal powder, particles, and a foil.

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

  When the curable composition contains a polymerization initiator, by curing the curable composition on at least one surface of the polarizer to form a cured layer, a durability improving layer may be formed, Forming a durability improving layer made of an uncured curable composition on at least one surface of the polarizer, and laminating the transparent protective film, and then curing the curable composition, thereby improving the durability made of the cured material layer. A layer may be formed.

<Polarizer>
The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include, for example, a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, and two colors such as iodine and a dichroic dye. And uniaxially stretched by adsorbing a hydrophilic material, or a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Among these, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is generally 1 to 30 μm.

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

  By the way, in mobile applications such as mobile phones, there has been an increasing demand for a thin polarizer having a thickness of 10 μm or less from the viewpoint of design and compactness. However, when the thickness of the polarizer is reduced, the optical characteristics are increased, especially in a humid environment. Tends to be remarkable. However, even when the polarizer according to the present invention is a thin polarizer having a thickness of 10 μm or less, since the optical polarizer is provided with an optical enhancement layer on at least one surface, deterioration of optical characteristics is suppressed even in a humid environment. I have. The thickness of the polarizer is preferably 1 to 7 μm from the viewpoint of thinning. It is preferable that such a thin polarizer has little unevenness in thickness, is excellent in visibility, has little dimensional change, and can further reduce the thickness as a polarizing film.

  Representative examples of the thin polarizer include Japanese Patent Application Laid-Open Nos. 51-069644 and 2000-338329, WO2010 / 100917, pamphlet of PCT / JP2010 / 001460, and Japanese Patent Application No. 2010-001460. The thin polarizing films described in Japanese Patent Application No. 269002 and Japanese Patent Application No. 2010-263692 can be exemplified. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as a PVA-based resin) layer and a stretching resin substrate in a laminated state, and a step of dyeing. According to this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without any trouble such as breakage due to stretching because it is supported by the stretching resin base material.

  WO 2010/100917 pamphlet, PCT / JP-A-2009, which can be stretched at a high magnification to improve the polarization performance among the production methods including a stretching step and a dyeing step in the state of a laminate, as the thin polarizing film. JP 2010/001460, or those obtained by a production method including a step of stretching in a boric acid aqueous solution as described in Japanese Patent Application No. 2010-269002 or Japanese Patent Application No. 2010-263892 are preferable, and particularly preferable. What is obtained by the manufacturing method including the process of auxiliary | assistant air stretching before extending | stretching in a boric acid aqueous solution as described in Japanese Patent Application No. 2010-269002 or Japanese Patent Application No. 2010-263692 is preferable.

  Before the formation of the durability improving layer, a surface modification treatment of the polarizer may be performed. Examples of the surface modification treatment include a treatment such as a corona treatment, a plasma treatment, and an itro treatment, and a corona treatment is particularly preferable. By performing the corona treatment, a reactive functional group such as a carbonyl group or an amino group is generated on the polarizer surface, and the adhesion to the durability improving layer is improved. In addition, a foreign substance on the surface is removed by the ashing effect, and unevenness on the surface is reduced, so that a polarizing film having excellent appearance characteristics can be produced.

  The polarizing film according to the present invention includes a polarizer provided on at least one surface with a durability improving layer formed of a curable composition containing a compound (A) having a carbon-carbon double bond and a cyclic skeleton. Further, the polarizing film according to the present invention may be one in which a transparent protective film is laminated 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 of the polarizer and the transparent protective film may be further laminated via an adhesive layer. Hereinafter, the adhesive layer will be described.

<Adhesive layer>
The thickness of the adhesive layer is preferably from 0.01 to 3.0 μm. If the thickness of the adhesive layer is too thin, the cohesive force of the adhesive layer is insufficient, and the peeling force is undesirably reduced. If the thickness of the adhesive layer is too large, peeling is likely to occur when stress is applied to the cross section of the polarizing film, and peeling failure due to impact occurs, which is not preferable. The thickness of the adhesive layer is more preferably 0.1 to 2.5 μm, and most preferably 0.5 to 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 thermal curing and active energy ray curing. Examples of the thermosetting resin include a polyvinyl alcohol resin, an epoxy resin, an unsaturated polyester, a urethane resin, an acrylic resin, a urea resin, a melamine resin, a phenol resin, and the like. If necessary, a curing agent is used in combination. As the thermosetting resin, a polyvinyl alcohol resin or an epoxy resin can be more preferably used. Active energy ray-curable resins can be broadly classified into electron beam curable, ultraviolet ray curable, and visible ray curable as classifications based on active energy rays. In addition, the form of curing can be classified into a radical polymerizable curable adhesive composition and a cationic polymerizable resin composition. In the present invention, active energy rays having a wavelength range of 10 nm to less than 380 nm are represented by ultraviolet rays, and active energy rays having a wavelength range of 380 nm to 800 nm are represented by visible light rays.

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

  The curable component contained in the radically polymerizable adhesive composition includes, for example, a radically polymerizable compound used in the radically polymerizable adhesive composition. Examples of the radical polymerizable compound include compounds having a radical polymerizable functional group of a carbon-carbon double bond such as a (meth) acryloyl group and a vinyl group. As these curable components, either a monofunctional radical polymerizable compound or a bifunctional or higher polyfunctional radical polymerizable compound can be used. These radically polymerizable compounds can be used alone or in combination of two or more. 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 hereinafter.

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。 As the monofunctional radical polymerizable compound, for example, the following general formula (2):

Wherein R ³ is a hydrogen atom or a methyl group, and 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 heterocyclic ring). The number of carbon atoms in the alkyl portion of the alkyl group, the hydroxyalkyl group, and / or the alkoxyalkyl group is not particularly limited, but is, for example, one to four. Examples of the cyclic heterocyclic ring which may be formed by R ⁴ and R ⁵ include N-acryloylmorpholine.

  Specific examples of the compound represented by the general formula (2) include, for example, 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; It is. Examples of the cyclic ether group-containing (meth) acrylamide derivative include a heterocycle-containing (meth) acrylamide derivative in which a nitrogen atom of the (meth) acrylamide group forms a heterocyclic ring, and examples thereof include N-acryloylmorpholine and N-acryloylmorpholine. -Acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine and the like. Among these, N-hydroxyethylacrylamide and N-acryloylmorpholine are preferably used in terms of excellent reactivity, obtaining a cured product having a high elastic modulus, and excellent adhesion to a polarizer. it can.

  From the viewpoint of improving the adhesiveness and the water resistance when the polarizer and the transparent protective film are adhered through the adhesive layer, the content of the compound represented by the general formula (2) in the adhesive composition is 0.1%. It is preferably from 01 to 80% by mass, more preferably from 5 to 40% by mass.

  Further, the adhesive composition used in the present invention may contain another monofunctional radically polymerizable compound as a curable component in addition to the compound represented by the general formula (2). Examples of the monofunctional radical polymerizable compound 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 ( Meth) acrylate, n-o Tadeshiru (meth) (meth) acrylic acid (1-20 carbon atoms) such as acrylates alkyl esters.

  Examples of the (meth) acrylic acid derivative include, for example, 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) aclay Alkoxy or phenoxy groups such as, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, and alkylphenoxy polyethylene glycol (meth) acrylate (Meth) acrylate; and the like. Of these, dicyclopentenyloxyethyl acrylate and phenoxyethyl acrylate are preferred because of their excellent adhesion to various protective films.

  The (meth) acrylic acid derivatives include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 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 groups such as [4- (hydroxymethyl) cyclohexyl] methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate (Meth) acrylates; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate glycidyl ether; 2,2,2-trifluoroethyl (meth) acrylate; 2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, 3-chloro-2- Halogen-containing (meth) acrylates such as hydroxypropyl (meth) acrylate; alkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate; 3-oxetanylmethyl (meth) acrylate Oxetane groups such as methacrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth) acrylate, 3-butyl-oxetanylmethyl (meth) acrylate, and 3-hexyloxetanylmethyl (meth) acrylate Containing (meth) acrylate; (meth) acrylate having a heterocycle such as tetrahydrofurfuryl (meth) acrylate, butyrolactone (meth) acrylate, neopentyl glycol hydroxypivalate (meth) acrylic acid adduct, 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 the monofunctional radical polymerizable compound 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 the monofunctional radical polymerizable compound include, for example, lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, Examples include vinyl monomers having a nitrogen-containing heterocycle such as vinyl pyrrole, vinyl imidazole, vinyl oxazole, and vinyl morpholine.

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

  Further, as the monofunctional radical polymerizable compound, a radical polymerizable compound having an active methylene group can be used. The radical polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth) acryl group at a terminal or in a molecule and having an active methylene group. Examples of the active methylene group include an acetoacetyl group, an alkoxymalonyl group, and a cyanoacetyl group. Preferably, the active methylene group is an acetoacetyl group. Specific examples of the radical polymerizable compound having an active methylene group include, for example, 2-acetoacetoxyethyl (meth) acrylate, 2-acetoacetoxypropyl (meth) acrylate, 2-acetoacetoxy-1-methylethyl (meth) acrylate, and the like. Acetoacetoxyalkyl (meth) acrylate; 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 can be mentioned. The radical polymerizable compound having an active methylene group is preferably acetoacetoxyalkyl (meth) acrylate.

  Examples of the bifunctional or higher polyfunctional radical polymerizable compound include polyfunctional (meth) acrylamide derivatives such as N, N′-methylenebis (meth) acrylamide, tripropylene glycol di (meth) acrylate, and tetraethylene glycol diamine. (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di (meth) A) 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, tricyclodecane dimethanol di (meth) acrylate, cyclic trimethylolpropane formal (meth) acrylate, dioxane glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate (Meth) acryl such as pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, EO-modified diglycerin tetra (meth) acrylate Examples of the esterified product of an acid and a polyhydric alcohol include 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.), and light acrylate DCP-A (manufactured by Kyoeisha Chemical.) And SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer) and the like. If necessary, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, and various (meth) acrylate monomers can be used. The polyfunctional (meth) acrylamide derivative has a high polymerization rate and is excellent in productivity, and is excellent in cross-linkability when a resin composition is a cured product.

  The radical polymerizable compound is a combination of a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound, from the viewpoint of achieving both the adhesiveness with a polarizer and various transparent protective films and the optical durability in a severe environment. Is preferred. Usually, it is preferable to use 3 to 80% by mass of the monofunctional radically polymerizable compound and 20 to 97% by mass of the polyfunctional radically polymerizable compound in combination with 100% by mass of the radically polymerizable compound.

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

  When a radical polymerizable compound having an active methylene group is used as the radical polymerizable compound in the active energy ray-curable adhesive composition, it is preferably used in combination with a radical polymerization initiator having a hydrogen abstracting action. According to such a configuration, the adhesiveness of the adhesive layer of the polarizing film is significantly improved, especially even immediately after being taken out of a high humidity environment or water (non-dry state). Although the reason is not clear, the following causes are considered. That is, the radical 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 polymerizing together with the other radical polymerizable compounds constituting the adhesive layer, and Form an agent layer. In the polymerization process, when a radical polymerization initiator having a hydrogen abstracting action is present, hydrogen is abstracted from the radical polymerizable compound having an active methylene group while the base polymer constituting the adhesive layer is formed, and the hydrogen is extracted to the methylene group. Radicals are generated. Then, the methylene group in which the radical has been generated reacts with the hydroxyl group of the polarizer such as PVA, and a covalent bond is formed 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 significantly improved even in a non-dried state.

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

  When the active energy ray-curable adhesive composition contains a radical polymerizable compound having an active methylene group and a radical polymerization initiator having a hydrogen abstracting action, the total amount of the curable component is set to 100% by mass. At this time, it is preferable that the radical polymerizable compound having an active methylene group is contained in an amount of 1 to 50% by mass and a radical polymerization initiator in an amount of 0.1 to 10% by mass based on the total amount of the adhesive composition.

  As described above, in the present invention, a radical is generated in a methylene group of a radical polymerizable compound having an active methylene group in the presence of a radical polymerization initiator having a hydrogen abstracting action, and the methylene group is combined with a polarizer such as PVA. Reacts 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 mass, the radical having an active methylene group is used. The polymerizable compound is preferably contained in an amount of 1 to 50% by mass, more preferably 3 to 30% by mass. In order to sufficiently improve the water resistance and the adhesiveness in a non-dried state, the content of the radical polymerizable compound having an active methylene group is preferably 1% by mass or more. On the other hand, if it exceeds 50% by mass, poor curing of the adhesive layer may occur. Further, the radical polymerization initiator having a hydrogen extracting effect is preferably contained in an amount of 0.1 to 10% by mass, more preferably 0.3 to 9% by mass, based on the total amount of the adhesive composition. . In order for the hydrogen abstraction reaction to proceed sufficiently, it is preferable to use a radical polymerization initiator of 0.1% by mass or more. In some cases, when the content exceeds 10% by mass, the composition may not be completely dissolved.

  The cationically polymerizable compound used in the cationically polymerizable curable adhesive composition includes a monofunctional cationically polymerizable compound having one cationically polymerizable functional group in the molecule and two cationically polymerizable functional groups in the molecule. It is classified into a polyfunctional cationic polymerizable compound having the above. Since the monofunctional cation polymerizable compound has a relatively low liquid viscosity, the liquid viscosity of the resin composition can be reduced by including it in the resin composition. In addition, the monofunctional cationically polymerizable compound often has a functional group that exerts various functions, and the various functions are expressed in the resin composition and / or the cured product of the resin composition by being contained in the resin composition. Can be done. The polyfunctional cation polymerizable compound is preferably contained in the resin composition because the cured product of the resin composition can be three-dimensionally crosslinked. The ratio of the monofunctional cation polymerizable compound to the polyfunctional cation polymerizable compound is such that the polyfunctional cation polymerizable compound is mixed in the range of 10 parts by mass to 1000 parts by mass with respect to 100 parts by mass of the monofunctional cation polymerizable compound. Is preferred. Examples of the cationically polymerizable functional group include an epoxy group, an oxetanyl group, and a vinyl ether group. Examples of the compound having an epoxy group include an aliphatic epoxy compound, an alicyclic epoxy compound, and an aromatic epoxy compound, and the cationically polymerizable curable adhesive composition of the present invention has excellent curability and adhesiveness. And an alicyclic epoxy compound. Examples of the alicyclic epoxy compound include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate modified with caprolactone and trimethylcaprolactone. And valerolactone modified products. Specific examples thereof include celloxide 2021, celloxide 2021A, celloxide 2021P, celloxide 2081, celloxide 2083, celloxide 2085 (all manufactured by Daicel Chemical Industries, Ltd., Cyracure UVR-6105, Cyracure UVR). -6107, Cyracure 30, R-6110 (both manufactured by Dow Chemical Japan Co., Ltd.), etc. The compound having an oxetanyl group is a cationically polymerizable compound of the present invention. The compound having an oxetanyl group is preferably contained because it has an effect of improving the curability of the adhesive composition and lowering the liquid viscosity of the composition. , 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 novolak oxetane, and the like, and Alonoxetane OXT-101, Alonoxetane OXT-121, Alonoxetane OXT-211, Alonoxetane OXT-221, Alonoxetane OXT- 212 (all manufactured by Toagosei Co., Ltd.) and the like are commercially available. The compound having a vinyl ether group is preferably contained because it has an effect of improving the curability of the cationically polymerizable curable adhesive composition of the present invention or lowering the liquid viscosity of the composition. Examples of the compound having 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, vinyl ether of diethylene glycol, triethylene glycol divinyl ether, cyclohexane dimethanol divinyl ether, cyclohexane dimethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether Methoxyethyl vinyl ether, ethoxyethyl vinyl ether, pentaerythritol-type tetravinyl ether and the like. .

  The cationically polymerizable curable adhesive composition contains at least one compound selected from the above-described compounds having an epoxy group, compounds having an oxetanyl group, and compounds having a vinyl ether group as a curable component. Since it is cured by polymerization, a cationic photopolymerization initiator is blended. The cationic photopolymerization initiator generates a cationic species or Lewis acid upon irradiation with an active energy ray such as visible light, ultraviolet light, X-ray, or electron beam, and initiates a polymerization reaction of an epoxy group or an oxetanyl group. As the photocationic polymerization initiator, a photoacid generator described below is suitably used. In addition, when the adhesive composition used in the present invention is used with visible light curability, it is particularly preferable to use a photocationic polymerization initiator that is highly sensitive to light of 380 nm or more. In general, since the compound exhibits a maximum absorption in a wavelength region around 300 nm or shorter, a photosensitizer which exhibits a maximum absorption in light having a longer wavelength region, specifically, light having a wavelength longer than 380 nm can be used. In response to light having a wavelength in the vicinity of this, the generation of cationic species or acids from the photocationic polymerization initiator can be promoted. Examples of the photosensitizer include anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, and the like. Two or more kinds may be used as a mixture. In particular, an anthracene compound is preferable because of its 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% by mass to 5% by mass, and more preferably 0.5% by mass to 3% by mass.

  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 relating to the radically polymerizable compound. By containing the components in the active energy ray-curable adhesive composition, curing shrinkage when irradiating and curing the composition with the active energy ray is reduced, and the adhesive and the polarizer and the transparent protective film are used. Interfacial stress with the adherend can be reduced. As a result, it is possible to suppress a decrease in the adhesiveness between the adhesive layer and the adherend. In order to sufficiently suppress the curing shrinkage of the cured product layer (adhesive layer), the content of the acrylic oligomer is preferably 20% by mass or less, and more preferably 15% by mass, based on the total amount of the adhesive composition. % Is more preferable. If the content of the acrylic oligomer in the adhesive composition is too large, the reaction rate when irradiating the composition with active energy rays is drastically reduced, which may result in poor curing. On the other hand, based on the total amount of the adhesive composition, the acrylic oligomer is preferably contained in an amount of 3% by mass or more, more preferably 5% by mass or more.

  The active energy ray-curable adhesive composition preferably has a low viscosity in consideration of workability and uniformity at the time of coating. Therefore, an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer also has a low viscosity. It is preferable that The acrylic oligomer having a low viscosity and capable of preventing curing shrinkage of the adhesive layer is preferably one having a weight average molecular weight (Mw) of 15,000 or less, more preferably 10,000 or less, and particularly preferably 5,000 or less. preferable. On the other hand, in order to sufficiently suppress the 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 1,000 or more, It is particularly preferred that it is 1500 or more. Specific examples of the (meth) acrylic monomer constituting the acrylic oligomer include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and 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 (Meth) acrylic acid (C1-20) alkyl esters such as 4-methyl-2-propylpentyl (meth) acrylate and N-octadecyl (meth) acrylate, and further, for example, cycloalkyl (meth) acrylate (e.g., , Cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), aralkyl (meth) acrylate (eg, benzyl (meth) acrylate, etc.), polycyclic (meth) acrylate (eg, 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) acrylate (Eg, hydro Siethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (meth) methacrylate, etc., and alkoxy or phenoxy group-containing (meth) acrylates (2-methoxyethyl ( (Meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, etc.), epoxy Group-containing (meth) acrylates (eg, glycidyl (meth) acrylate), halogen-containing (meth) acrylates (eg, 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) Acrylates (for example, dimethylaminoethyl (meth) acrylate and the like) and the like can be mentioned. These (meth) acrylates can be used alone or in combination of two or more. Specific examples of the acrylic oligomer include "ARUFON" manufactured by Toagosei Co., Ltd., "ACTFLOW" 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 as compared with the case where the photoacid generator is not contained. it 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、ＰＦ６_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)

(However, ^{L +} represents any onium cation addition, X ^{-. _{Is, PF6 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 the general formula (5) will be described.

The counter anion X ⁻ in the 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, a nucleophilic reaction in a cation coexisting in the molecule or various materials used in combination is unlikely to occur, and as a result, the photoacid generator itself represented by the general formula (4) results. And the stability over time of the composition using the same. The non-nucleophilic anion as used herein refers to an anion having a low ability to cause a nucleophilic reaction. Examples of such anions include PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , SbCl ₆ ⁻ , BiCl ₅ ⁻ , SnCl ₆ ⁻ , ClO ₄ ⁻ , dithiocarbamate anion, SCN ^{− and the} like.

  Specifically, “SILACURE UVI-6992”, “SYRACURE UVI-6974” (both manufactured by Dow Chemical Japan Co., Ltd.), “ADEKA OPTOMER SP150”, “ADEKA OPTOMER SP152”, “ADEKA OPTOMER” SP170 "," ADEKA OPTOMER SP172 "(all manufactured by ADEKA CORPORATION)," IRGACURE250 "(manufactured by Ciba Specialty Chemicals)," CI-5102 "," CI-2855 "(all manufactured by Nippon Soda), "Sun-Aid SI-60L", "Sun-Aid SI-80L", "Sun-Aid SI-100L", "Sun-Aid SI-110L", "Sun-Aid SI-180L" (all manufactured by Sanshin Chemical Co., Ltd.), "CPI-100P", “CPI-100A” (above, manufactured by Sun Apro Co., Ltd.), “WPI-069” , “WPI-113”, “WPI-116”, “WPI-041”, “WPI-044”, “WPI-054”, “WPI-055”, “WPAG-281”, “WPAG-567”, “ WPAG-596 "(all manufactured by Wako Pure Chemical Industries, Ltd.) is a preferred specific example of the photoacid generator of the present invention.

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

  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 the active energy ray-curable adhesive composition.

  When a compound having one or more epoxy groups in the molecule or a polymer having two or more epoxy groups in the molecule (epoxy resin) is used, a functional group having reactivity with the epoxy group is used in the molecule. Two or more compounds may be used in combination. Here, the functional group having reactivity with the epoxy group includes, for example, a carboxyl group, a phenolic hydroxyl group, a mercapto group, a primary or secondary aromatic amino group, and the like. It is particularly preferable to have two or more of these functional groups in one molecule in consideration of three-dimensional curability.

  Examples of the polymer having one or more epoxy groups in a molecule include an epoxy resin, a bisphenol A epoxy resin derived from bisphenol A and epichlorohydrin, and a bisphenol F epoxy resin 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, Polyfunctional epoxy resins such as naphthalene epoxy resin, biphenyl epoxy resin, fluorene epoxy resin, trifunctional epoxy resin and tetrafunctional epoxy resin There are glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, aliphatic chain epoxy resin, etc., and these epoxy resins may be halogenated or hydrogenated. You may. 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 Epicron manufactured by DIC Corporation. 830, EXA835LV, HP4032D, HP820, EP4100 series, EP4000 series, EPU series manufactured by ADEKA Corporation, celoxide side series (2021, 2021P, 2083, 2085, 3000, etc.) manufactured by Daicel Chemical Industries, Ltd., Epolide series, EHPE Series, Nippon Steel Chemical's YD series, YDF series, YDCN series, YDB series, phenoxy resin (polysynthesis from bisphenols and epichlorohydrin Mud carboxymethyl at both ends with polyether having an epoxy group; and YP series), Nagase ChemteX Corporation of Denacol series manufactured by Kyoeisha although chemical Co. Epo light series are exemplified but not limited thereto. 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 a compound include a melamine compound, an amino resin, and a silane coupling agent.

  The compounding amount of the compound containing any one of an alkoxy group and an epoxy group is usually 30% by mass or less based on the total amount of the adhesive composition. And the impact resistance to the drop test may be deteriorated. The content of the compound in the composition is more preferably 20% by mass or less. On the other hand, from the viewpoint of water resistance, the composition preferably contains 2% by mass or more of the compound, more preferably 5% by mass or more.

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

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

  The compounding amount of the silane coupling agent is preferably in the range of 0.01 to 20% by mass, more preferably 0.05 to 15% by mass, and preferably 0.1 to 10% by mass based on the total amount of the adhesive composition. % Is more preferable. When the amount is more than 20% by mass, the storage stability of the adhesive composition is deteriorated. When the amount is less than 0.1% by mass, the effect of adhesive water resistance is not sufficiently exhibited.

  It is preferable that the adhesive composition used in the present invention contains a compound having a vinyl ether group, since the water resistance of the adhesive between the polarizer and the adhesive layer is improved. The reason why such an effect is obtained is not clear, but it is speculated that one of the reasons is that the vinyl ether group of the compound interacts with the polarizer, thereby increasing the adhesive strength between the polarizer and the adhesive layer. You. In order to further increase the adhesion water resistance between the polarizer and the adhesive layer, the compound is preferably a radical polymerizable compound having a vinyl ether group. The content of the compound is preferably 0.1 to 19% by mass based on the total amount of the adhesive composition.

  The adhesive composition used in the present invention may contain a compound that causes 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 embodiment containing the compound that causes keto-enol tautomerism can be preferably adopted. Thereby, an effect of suppressing an excessive increase in viscosity and gelation of the adhesive composition after the formation of the organometallic compound and a generation of a microgel substance, and extending a pot life of the composition can be realized.

  As the compound causing keto-enol tautomerism, various β-dicarbonyl compounds can be used. Specific examples include acetylacetone, 2,4-hexanedione, 3,5-heptanedione, 2-methylhexane-3,5-dione, 6-methylheptane-2,4-dione, and 2,6-dimethylheptane- Β-diketones such as 3,5-dione; acetoacetates such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate and tert-butyl acetoacetate; ethyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, and propionyl acetate propionyl acetates such as tert-butyl; ethyl isobutyryl acetate, ethyl isobutyryl acetate, isopropyl isobutyryl acetate, isobutyryl acetates such as tert-butyl isobutyryl acetate; malonic acid esters such as methyl malonate and ethyl malonate Le acids; and the like. Among them, preferred compounds include acetylacetone and acetoacetates. Such compounds that cause keto-enol tautomerism may be used alone or in combination of two or more.

  The amount of the compound that produces keto-enol tautomerism is, for example, 0.05 to 10 parts by mass, preferably 0.2 to 3 parts by mass (for example, 0.3 to 3 parts by mass) based on 1 part by mass of the organometallic compound. Parts by mass to 2 parts by mass). When the use amount of the compound is less than 0.05 part by mass with respect to 1 part by mass of the organometallic compound, a sufficient use effect may be hardly exhibited. On the other hand, when the use amount of the compound exceeds 10 parts by mass with respect to 1 part by mass of the organometallic compound, the compound excessively interacts with the organometallic compound, and it may be difficult to develop the desired water resistance.

  The adhesive composition used in the present invention may contain various additives as other optional components as long as the objects and effects of the present invention are not impaired. Such additives include epoxy resins, polyamides, polyamideimides, polyurethanes, polybutadienes, polychloroprenes, polyethers, polyesters, styrene-butadiene block copolymers, petroleum resins, xylene resins, ketone resins, cellulose resins, fluorine oligomers, Polymers or oligomers such as silicone oligomers and polysulfide oligomers; polymerization inhibitors such as phenothiazine and 2,6-di-t-butyl-4-methylphenol; polymerization initiators; leveling agents; wettability improvers; Agents; plasticizers; ultraviolet absorbers; inorganic fillers; pigments;

  The above-mentioned additives are usually 0 to 10% by mass, preferably 0 to 5% by mass, and most preferably 0 to 3% by mass based on the total amount of the adhesive composition.

  The viscosity of the adhesive composition used in the present invention is preferably 100 cp or less at 25 ° C. from the viewpoint of coatability. 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 be adjusted to 100 cp or less. A more preferred range of viscosity is 1 to 80 cp, most preferably 10 to 50 cp. The viscosity can be measured using an E-type viscometer TVE22LT manufactured by Toki Sangyo Co., Ltd.

  In the adhesive composition used in the present invention, it is preferable to use a material having low skin irritation as the curable component from the viewpoint of safety. Skin irritation is determined by I. It can be determined by the index I. P. I. I is widely used to indicate the degree of skin disorder, and is measured by the Draize method. The measured value is displayed in the range of 0 to 8, and it is determined that the smaller the value is, the lower the irritation is. However, since the error of the measured value is large, it is good to catch it as a reference value. P. I. I is preferably 4 or less, more preferably 3 or less, and most preferably 2 or less.

<Polarizing film>
The polarizing film according to the present invention includes a polarizer provided on at least one surface with a durability improving layer formed of a curable composition containing a compound (A) having a carbon-carbon double bond and a cyclic skeleton. Further, the polarizing film according to the present invention may be one in which a transparent protective film is laminated on at least one surface of the polarizer. Preferably, an adhesive layer is further provided between the durability improving layer and the transparent protective film. Hereinafter, a polarizing film further provided with an adhesive layer between the durability improving layer and the transparent protective film will be described as an example.

The polarizing film according to the present invention is, for example, a production method described below;
A first application step of applying a curable composition containing at least a copolymer of a compound (A) and a compound (B) to a bonding surface of a polarizer to form a durability improving layer; A second coating step of applying the adhesive composition to the bonding surface, a bonding step of bonding the surface on which the durability improving layer of the polarizer is formed and the adhesive composition coating surface of the transparent protective film, and a polarizer surface side Or production of a polarizing film including a bonding step of bonding a polarizer and a transparent protective film through an adhesive layer obtained by irradiating active energy rays from the transparent protective film side and curing the adhesive composition. It can be manufactured by a method.

  The surface modification treatment may be performed not only on the polarizer but also on the transparent protective film. Examples of the surface modification treatment include a treatment such as a corona treatment, a plasma treatment, and an itro treatment, and a corona treatment is particularly preferable.

  The method for applying the adhesive composition to the transparent protective film is appropriately selected depending on the viscosity and the intended thickness of the adhesive composition. Examples thereof include a roll coater, a die coater, a bar coater, and a rod coater. The viscosity of the adhesive composition used in the present invention is preferably from 3 to 100 mPa · s, more preferably from 5 to 50 mPa · s, and most preferably from 10 to 30 mPa · s. If the viscosity of the adhesive composition is high, the surface smoothness after application is poor and poor appearance occurs, which is not preferable. The adhesive composition used in the present invention can be applied by adjusting the viscosity of the composition to a preferable range by heating or cooling the composition.

  The polarizer and the transparent protective film are bonded together via the adhesive composition applied as described above. The bonding of the polarizer and the transparent protective film can be performed using a roll laminator or the like.

  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 an electron beam-curable, ultraviolet-curable, or visible light-curable mode. The aspect of the adhesive composition is preferably a visible light curable adhesive composition from the viewpoint of productivity.

  In the active energy ray-curable adhesive composition, after bonding the polarizer and the transparent protective film, the active energy ray (electron beam, ultraviolet ray, visible light, etc.) is irradiated, and the active energy ray-curable adhesive composition is cured. Curs to form an adhesive layer. The irradiation direction of the active energy ray (electron beam, ultraviolet ray, visible light, etc.) can be applied from any appropriate direction. Preferably, irradiation is performed from the transparent protective film side. When irradiated from the side of the polarizer, the polarizer may be degraded by active energy rays (such as electron beams, ultraviolet rays, and visible rays).

  Regarding the electron beam curability, any appropriate condition can be adopted as the irradiation condition of the electron beam as long as the active energy beam curable adhesive composition can be cured. For example, the electron beam irradiation preferably has an acceleration voltage of 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the accelerating voltage is less than 5 kV, the electron beam may not reach the adhesive and curing may be insufficient. If the accelerating voltage exceeds 300 kV, the penetrating power through the sample is too strong, and the transparent protective film and the polarizer are damaged. May be given. 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 the polarizer will be damaged, resulting in a decrease in mechanical strength and yellowing, and obtaining predetermined optical characteristics. Can not.

  The electron beam irradiation is usually performed in an inert gas, but may be performed in the air or under a condition in which oxygen is slightly introduced, if necessary. Depending on the material of the transparent protective film, by properly introducing oxygen, it is possible to prevent oxygen from being applied to the surface of the transparent protective film to which the electron beam first strikes, thereby preventing damage to the transparent protective film, and using only the adhesive. An electron beam can be efficiently irradiated.

  In the method for producing a polarizing film according to the present invention, as the active energy rays, those containing visible light having a wavelength range of 380 nm to 450 nm, particularly those having the largest irradiation amount of visible light having a wavelength range of 380 nm to 450 nm are used. Is preferred. In the case of using a transparent protective film provided with an ultraviolet absorbing ability (ultraviolet transparent transparent protective film) in ultraviolet curability and visible light curability, it absorbs light having a wavelength shorter than about 380 nm, so that light having a wavelength shorter than 380 nm is used. Light does not reach the active energy ray-curable adhesive composition and does not contribute to its polymerization reaction. Further, light having a wavelength shorter than 380 nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, which causes defects such as curling and wrinkling of the polarizing film. Therefore, when ultraviolet curability and visible light curability are employed in the present invention, it is preferable to use a device that does not emit light having a wavelength shorter than 380 nm as an active energy ray generator, and more specifically, a wavelength range of 380. The ratio between 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, and 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 that emits light in a wavelength range of 380 to 440 nm are preferable. Or UV light such as low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, incandescent lamp, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excimer laser or sunlight A light source containing visible light can be used, and ultraviolet light having a wavelength shorter than 380 nm can be cut off using a bandpass filter. In order to prevent the curling of the polarizing film while improving the adhesive performance of the adhesive layer between the polarizer and the transparent protective film, a gallium-sealed metal halide lamp can be used, and light having a wavelength shorter than 380 nm can be blocked. It is preferable to use an active energy ray obtained through a band-pass filter or an active energy ray having a wavelength of 405 nm obtained using an LED light source.

  In the case of ultraviolet curing or visible light curing, it is preferable to heat the active energy ray-curable adhesive composition before irradiation with ultraviolet light or visible light (heating before irradiation). It is preferable to heat to 50 ° C. or more. It is also preferable to heat the active energy ray-curable adhesive composition after irradiation with ultraviolet light or visible light (heating after irradiation). It is more preferable to warm.

  The active energy ray-curable adhesive composition used in the present invention is suitably used particularly when 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 is less than 5%. It is possible. Here, the active energy ray-curable adhesive composition according to the present invention contains the photopolymerization initiator represented by the general formula (3), and is irradiated with ultraviolet light through a transparent protective film having UV absorbing ability. Thus, the adhesive layer can be formed by curing. Therefore, even in a polarizing film in which a transparent protective film having UV absorbing ability is laminated on both surfaces of the polarizer, the adhesive layer can be cured. However, as a matter of course, the adhesive layer can be cured even in a polarizing film in which a transparent protective film having no UV absorbing ability is laminated. In addition, the transparent protective film having UV absorption ability means a transparent protective film having a transmittance of less than 10% for light of 380 nm.

  Examples of the method of imparting the UV absorbing ability to the transparent protective film include a method of including an ultraviolet absorbent in the transparent protective film, and a method of laminating a surface treatment layer containing the ultraviolet absorbent on the surface of the transparent protective film.

  Specific examples of the ultraviolet absorber include, for example, conventionally known oxybenzophenone-based compounds, benzotriazole-based compounds, salicylic acid ester-based compounds, benzophenone-based compounds, cyanoacrylate-based compounds, nickel complex salt-based compounds, and triazine-based compounds. .

  After laminating the polarizer and the transparent protective film, the active energy ray-curable adhesive composition is irradiated with an active energy ray (electron beam, ultraviolet ray, visible light, etc.) to form an adhesive layer. The irradiation direction of the active energy ray (electron beam, ultraviolet ray, visible light, etc.) can be applied from any appropriate direction. Preferably, irradiation is performed from the transparent protective film side. When irradiated from the side of the polarizer, the polarizer may be degraded by active energy rays (such as electron beams, ultraviolet rays, and visible rays).

  When the polarizing film according to the present invention is manufactured in a continuous line, the line speed depends on the curing time of the adhesive composition, but is preferably 1 to 500 m / min, more preferably 5 to 300 m / min, and still more preferably 10 to 10 m / min. 100 m / min. If the line speed is too low, the productivity is poor, or the damage to the transparent protective film is too large, 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 desired adhesiveness may not be obtained.

  Incidentally, the polarizing film of the present invention, preferably, a polarizer and a transparent protective film are bonded via an adhesive layer formed by a cured 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, for example, various resins having a polyester skeleton, polyether skeleton, polycarbonate skeleton, polyurethane skeleton, silicone, polyamide skeleton, polyimide skeleton, polyvinyl alcohol skeleton, and the like. These polymer resins can be used alone or in combination of two or more. Further, other additives may be added to the formation of the second easy adhesion layer. Specifically, stabilizers such as tackifiers, ultraviolet absorbers, antioxidants, and heat stabilizers may be used.

  Usually, the second easy-adhesion layer is 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 with an adhesive layer. The formation of the second easy-adhesion layer is performed by applying and drying the material for forming the second easy-adhesion layer on the transparent protective film by a known technique. 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, more preferably 0.02 to 2 μm, and still more preferably 0.05 to 1 μm. In addition, a plurality of second easy-adhesion layers can be provided, but in this case, it is preferable that the total thickness of the second easy-adhesion layers be in the above range.

<Transparent protective film>
As the transparent protective film, those having excellent transparency, mechanical strength, heat stability, moisture barrier properties, isotropy, and the like are 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; styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) Polymers, polycarbonate polymers, and the like. In addition, polyethylene, polypropylene, polyolefin having a cyclo- or norbornene structure, polyolefin polymers such as ethylene-propylene copolymer, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, and sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Blends of polymers and the like are also mentioned as examples of the polymer forming the transparent protective film. The transparent protective film may contain one or more optional appropriate additives. Examples of the additives include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by mass, more preferably 50 to 99% by mass, further preferably 60 to 98% by mass, and particularly preferably 70 to 97% by mass. . When the content of the thermoplastic resin in the transparent protective film is 50% by mass or less, high transparency or the like inherent to the thermoplastic resin may not be sufficiently exhibited.

  Examples of the transparent protective film include polymer films described in JP-A-2001-343529 (WO 01/37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in a side chain; A resin composition containing a thermoplastic resin having a substituted and / or unsubstituted phenyl and a nitrile group in a chain is exemplified. A specific example is a film of a resin composition containing an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film composed of a mixed extruded product of a resin composition or the like can be used. These films have a small retardation and a small photoelastic coefficient, so that problems such as unevenness due to distortion of the polarizing film can be eliminated, and since the moisture permeability is small, the humidification durability is excellent.

In the polarizing film, it is preferable moisture permeability of the transparent protective film is not more than 150g ^/ m 2 ^/ 24h. According to such a configuration, it is difficult for moisture in the air to enter the polarizing film, and the change in the moisture content of the polarizing film itself can be suppressed. As a result, curling and dimensional change of the polarizing film caused by the storage environment can be suppressed.

As the transparent protective film provided on one or both surfaces of the polarizer, those having excellent transparency, mechanical strength, heat stability, moisture barrier properties, isotropy, and the like are preferable, and particularly, the moisture permeability is 150 g / m ² /. more preferably not more 24h or less, particularly preferably the following 120 g ^/ m 2 / 24h, more preferably the following 5~70g ^/ m 2 ^/ 24h. The moisture permeability is determined by the method described in the examples.

  Examples of the material for forming the transparent protective film satisfying the low moisture permeability include polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate resins; arylate resins; amide resins such as nylon and aromatic polyamides; , A polyolefin-based polymer such as an ethylene-propylene copolymer, a cyclic olefin-based resin having a cyclo- or norbornene structure, a (meth) acryl-based resin, or a mixture thereof. Among the above resins, a polycarbonate resin, a cyclic polyolefin resin, and a (meth) acrylic resin are preferable, and a cyclic polyolefin resin and a (meth) acrylic resin are particularly preferable.

  Although the thickness of the transparent protective film can be determined as appropriate, it is generally preferably from 5 to 100 μm from the viewpoint of workability such as strength and handleability and thinness. In particular, 10 to 60 μm is preferable, and 13 to 40 μm is more preferable.

  The method of attaching the polarizer and the protective film can be performed by a roll laminator. The method of laminating the protective films on both sides of the polarizer is 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. It is selected from the methods to be combined. Entrapment bubbles generated when bonding are significantly reduced by adopting the former method, that is, a method of bonding a polarizer and one protective film and then bonding another protective film. Is preferred because

<Optical film>
The polarizing film of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited. For example, liquid crystal such as a retardation film (including a wavelength plate such as や or ４), a visual compensation film, a brightness enhancement film, a reflection plate or an anti-transmission plate, etc. An optical layer that can be used for forming a display device or the like can be given. These optical layers can be used as a base film of the base film with an easy-adhesion layer in the present invention. It has a functional group. Therefore, an easily-adhesion-treated retardation film comprising the compound represented by the general formula (1) on at least one surface of the retardation film containing at least a reactive functional group on the surface, particularly the general formula (1) For example, a retardation film with an easy-adhesion layer formed with an easy-adhesion layer containing the compound represented by the formula (1) improves the adhesion between the phase difference 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 phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm.

  Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a film in which a liquid crystal polymer alignment layer is supported by a film. 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 in-plane retardation values of the retardation film measured at 23 ° C. with light having wavelengths of 450 nm and 550 nm, respectively, and Δn is the retardation of the retardation film. The axial direction, the refractive index in the fast axis direction, nx, is the in-plane birefringence which is nx-ny when ny, and NZ, when nz is the refractive index in the thickness direction of the retardation film, (A ratio of nx-nz which is birefringence in the thickness direction to nx-ny which is in-plane birefringence) may be used.

  The above-mentioned polarizing film or an optical film in which at least one polarizing film is laminated may be provided with an adhesive layer for bonding to another member such as a liquid crystal cell. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited, and for example, an acrylic polymer, a silicone-based polymer, a polyester, a polyurethane, a polyamide, a polyether, and a polymer having a fluorine-based or rubber-based polymer as a base polymer are appropriately selected. Can be used. In particular, those having excellent optical transparency, such as an acrylic pressure-sensitive adhesive, exhibiting appropriate wettability, cohesiveness and adhesive pressure-sensitive adhesive properties, and having excellent weather resistance and heat resistance can be preferably used.

  The adhesive layer may be provided on one side or both sides of a polarizing film or an optical film as a superposed layer of different compositions or types. When provided on both sides, it is also possible to form an adhesive layer having a different composition, type and thickness on the front and back of the polarizing film or optical film. The thickness of the pressure-sensitive adhesive layer can be appropriately determined depending on the purpose of use, adhesive strength, and the like.

  A separator is temporarily attached to the exposed surface of the pressure-sensitive adhesive layer for the purpose of preventing contamination and the like until the pressure-sensitive adhesive layer is put to practical use. As a result, it is possible to prevent the contact with the adhesive layer in the usual handling state. Except for the above thickness conditions, for example, a suitable thin leaf such as a plastic film, a rubber sheet, paper, cloth, nonwoven fabric, a net, a foamed sheet or a metal foil, or a laminate thereof may be used as a separator. Appropriate conventional ones, such as those coated with an appropriate release agent such as a chain alkyl type, fluorine type or molybdenum sulfide, may 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 a liquid crystal display device. The formation of the liquid crystal display device can be performed according to a conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell and a polarizing film or an optical film and, if necessary, an illumination system and incorporating a drive circuit. There is no particular limitation except that a polarizing film or an optical film according to the present invention is used, and conventional methods can be followed. As for the liquid crystal cell, any type such as TN type, STN type and π type can be used.

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

  Hereinafter, examples of the present invention will be described, but embodiments of the present invention are not limited thereto.

<Polarizer>
First, a laminate in which a 9 μm-thick PVA layer is formed on an amorphous PET substrate 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 obtain a colored laminate. And a 5 μm-thick PVA layer stretched integrally with the amorphous PET substrate so that the total stretch ratio becomes 5.94 times by boric acid aqueous stretching at a stretching temperature of 65 ° C. An optical film laminate was produced. By such two-stage stretching, the PVA molecules of the PVA layer formed on the amorphous PET base material are highly oriented, and the iodine adsorbed by the dyeing is highly unidirectionally oriented as a polyiodide ion complex. An optical film laminate including a PVA layer having a thickness of 5 μm and constituting a thin polarizer was obtained.

<Transparent protective film>
100 parts by mass of the imidized MS resin described in Production Example 1 of JP-A-2010-284840 and 0.62 parts by mass of a triazine-based ultraviolet absorber (trade name: T-712, manufactured by ADEKA CORPORATION) are biaxially kneaded. At 220 ° C. to produce resin pellets. The obtained resin pellet was dried at 100.5 kPa and 100 ° C. for 12 hours, and extruded from a T-die at a die temperature of 270 ° C. with a single screw extruder to form a film (thickness: 160 μm). Further, the film is stretched in the transport direction in an atmosphere of 150 ° C. (thickness: 80 μm), and then an easy adhesive containing an aqueous urethane resin is applied, and then stretched in an atmosphere of 150 ° C. in a direction orthogonal to the film transport direction. to obtain a transparent protective film having a thickness of 40 [mu] m (moisture permeability ^58g / m 2 / 24h).

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

(Production of copolymer of compound (A) having a carbon-carbon double bond and a cyclic skeleton and compound (B) copolymerizable with compound (A))
Ethyl acetate is charged into a vessel purged with nitrogen, and γ-butyrolactone acrylate (compound (A)) 90 is stirred at 60 to 80 ° C. in the presence of 0.4 parts by mass of 2,2′-azobisisobutyronitrile. Curable composition 1 containing a copolymer 1 of γ-butyrolactone acrylate and 4-vinylphenylboronic acid by solution polymerization of 10 parts by mass and 10 parts by mass of 4-vinylphenylboronic acid (compound (B)). (Polymerization rate 99.2%, solid content 30.0% by mass). Also, except that the copolymer component and the solvent used were changed to those described in Table 1, the curable compositions 2 to 4 containing the copolymers 2 to 4 were produced under the same conditions as for the copolymer 1. Manufactured. In Table 1;

“ΓBL” means “gamma-butyrolactone”, “FA513AS” means “dicyclopentanyl acrylate (manufactured by Hitachi Chemical), and“ ACMO ”means“ acroylmorpholine (manufactured by KJ Chemicals).

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

(Preparation of polarizing film)
Example 1
The curable composition 1 is applied to the PVA surface of the optical film laminate including the PVA layer having a thickness of 5 μm, which constitutes the thin polarizer, and is air-dried at 60 ° C. for 2 minutes to form a durability improving layer on one surface. Was produced. Next, the MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, number of gravure roll lines: 1000 / inch, rotation speed 140% / line speed) was used on the bonding surface of the transparent protective film. The adhesive composition was applied so as to have a thickness of 0.7 μm, and a transparent protective film was bonded from the side of the durability improving layer of the polarizer using a roll machine. Then, from the side of the bonded transparent protective film, the visible light is irradiated by an active energy ray irradiator, and the polarizer and the transparent protective film are adhered by curing the adhesive composition. By drying with hot air for 3 minutes 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 bonding line speed was 25 m / min.

(Adjustment of easy adhesion composition)
To 6.9 parts by mass of an isopropyl alcohol solution of 4-vinylphenylboronic acid adjusted to 15% by mass, 5.1 parts by mass of acryloylmorpholine, 0.2 parts by mass of Olfin EXP4200 (manufactured by Nissin Chemical Co., Ltd.), and 87 parts of pure water An easy-adhesion composition containing 0.9 parts by mass was prepared.

<Polarizer with easy adhesion layer>
Using a wire bar (manufactured by Daiichi Rika Co., No. 2), the above-mentioned easy-adhesion composition was applied to the PVA surface of the optical film laminate including the PVA layer having a thickness of 5 μm of the polarizer, and heated at 60 ° C. The solvent was removed by air drying for 2 minutes to prepare a polarizer with an easily adhesive layer.

Example 2
An MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, number of gravure rolls: 1000 lines / inch, rotation speed 140% / line speed) was used on the easy adhesion layer side of the polarizer with the easy adhesion layer. The curable composition was applied to a thickness of 0.7 μm to form a durability improving layer. Next, a polyester film (Diafoil S-100 38 μm, manufactured by Mitsubishi Chemical Corporation) was bonded from the side of the durability improving layer of the polarizer using a roll machine. Thereafter, the visible light was irradiated from the side of the laminated polyester film by an active energy ray irradiation device to cure the curable composition constituting the durability improving layer. Subsequently, the polyester film was peeled off to obtain a polarizing film comprising a polarizer having a durability improving layer on one surface.

Comparative Example 1
An MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, number of gravure roll lines: 1000 / inch, rotation speed 140) was formed on the surface of the polarizer having the easy-adhesion layer on which the easy-adhesion layer was formed and the bonding surface of the transparent protective film. % / With respect to line speed), applying the adhesive composition to a thickness of 0.7 μm, and attaching the adhesive composition-coated surfaces of the polarizer and the transparent protective film to each other using a roll machine. I combined. Thereafter, from the side of the bonded transparent protective film, the visible light is irradiated by an active energy ray irradiation device to cure the adhesive composition constituting the adhesive layer, followed by hot-air drying 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. The bonding line speed was 25 m / min.

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 2 except that an adhesive composition was applied instead of the curable composition.

Examples 3 to 5
A polarizing film is produced in the same manner as in Example 1 except that curable compositions 2 to 4 containing copolymers 2 to 4 are used instead of the curable composition 1 containing the copolymer 1. I got

  The following evaluation was performed about the polarizing film obtained by the said Example and the comparative example. Table 2 shows the evaluation results.

(Humidification durability test)
The transmittance and the degree of polarization of the manufactured polarizing film were measured using a spectral transmittance meter with an integrating sphere (Dot-3c of Murakami Color Research Laboratory). The degree of polarization P is such that the transmittance (parallel transmittance: Tp) when two identical polarizing films are overlapped so that their transmission axes are parallel and that the two transmission films are orthogonal to each other. It is determined by applying the combined transmittance (orthogonal transmittance: Tc) to the following equation.
Degree of polarization P (%) = {(Tp−Tc) / (Tp + Tc)} 1/2 × 100
Each transmittance is represented by a Y value obtained by adjusting luminosity by a 2-degree field of view (C light source) according to JIS Z8701, with 100% of completely polarized light obtained through a Glan-Teller prism polarizer. The polarizer surface of this polarizing film is subjected to a corona treatment, and an acrylic pressure-sensitive adhesive having a thickness of 20 μm is bonded thereto, and the other surface of the acrylic pressure-sensitive adhesive is bonded to non-alkali glass. The initial value of the rate was measured. Next, this polarizing film with glass was put in an environment of 60 ° C. and 95% RH for 48 hours, and the degree of polarization of the polarizing film with glass after aging was measured. The value obtained by subtracting the initial degree of polarization P from the degree of polarization P after aging was defined as the degree of polarization change. The smaller the absolute value of the change in the degree of polarization, the better the humidification durability.

Claims (20)

A polarizer having a durability improving layer on at least one surface,
The durability improving layer contains at least a copolymer of a compound (A) having a carbon-carbon double bond and a cyclic skeleton, and a compound (B) copolymerizable with the compound (A). Characteristic polarizer.   The curability in which the durability improving layer contains at least a copolymer of a compound (A) having a carbon-carbon double bond and a cyclic skeleton, and a compound (B) copolymerizable with the compound (A). The polarizer according to claim 1, wherein the polarizer is formed of a composition. The compound (B) has the following general formula (1):

Wherein X is a functional group containing a reactive group, and R ¹ and R ² are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group or an aryl group. Or a heterocyclic group).   The polarizer according to any one of claims 1 to 3, wherein the cyclic skeleton of the compound (A) is a heterocyclic skeleton.   The polarizer according to any one of claims 1 to 4, wherein the cyclic skeleton of the compound (A) is a lactone skeleton.   The polarizer according to claim 1, wherein the compound (A) is γ-butyrolactone (meth) acrylate.   The polarizer according to any one of claims 1 to 6, wherein the curable composition further contains a polymerization initiator.   The polarizer according to any one of claims 2 to 7, wherein the durability improving layer is formed by a cured product layer of the curable composition.   A polarizing film comprising the polarizer according to claim 1. A transparent protective film is laminated on at least one surface of the polarizer,
The polarizing film according to claim 9, wherein the transparent protective film is laminated on the durability improving layer side of the polarizer.   The polarizing film according to claim 10, further comprising an adhesive layer between the durability improving layer and the transparent protective film.   An optical film, wherein at least one polarizing film according to any one of claims 9 to 11 is laminated.   An image display device, comprising the polarizing film according to claim 9 or the optical film according to claim 12.   A copolymer of a compound (A) having a carbon-carbon double bond and a cyclic skeleton, and a compound (B) copolymerizable with the compound (A). The compound (B) has the following general formula (1):

Wherein X is a functional group containing a reactive group, and R ¹ and R ² are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group or an aryl group. Or a heterocyclic group).   The copolymer according to claim 14 or 15, wherein the cyclic skeleton of the compound (A) is a heterocyclic skeleton.   The copolymer according to any one of claims 14 to 16, wherein the cyclic skeleton of the compound (A) is a lactone skeleton.   The copolymer according to any one of claims 14 to 17, wherein the compound (A) is γ-butyrolactone (meth) acrylate.   A curable composition containing at least the copolymer according to claim 14.   The curable composition according to claim 19, further comprising a polymerization initiator in addition to the copolymer.