TW201841760A - Polarizing plate - Google Patents

Abstract

An object of the present invention is to provide a polarizing plate capable of suppressing color unevenness after being exposed to a wet heat environment. A polarizing plate 1 has a polarizer layer 10, an adhesive layer 15, and a first resin layer 21 in this order. The polarizer layer 10 is a polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented, with a film thickness of 18 [mu]m or more and 25 [mu]m or less. In the first resin layer 21, the atomic concentration ratio (N/C ratio) of nitrogen element and carbon element on the surface in contact with the adhesive layer is 1.0 or more. The adhesive layer 15 is a cured product layer of an active energy ray-curable adhesive composition containing an alicyclic epoxy compound as an active energy ray-curable compound and a cationic polymerization initiator. The content of the alicyclic epoxy compound is 10 to 70 parts by weight based on 100 parts by weight of the active energy ray-curable compound.

Description

   Polarizer   

The present invention relates to a polarizing plate.

A polarizing plate is used as one of optical members constituting a liquid crystal display device and the like. A polarizing plate usually has a laminated structure of a protective film on one side or two areas of a polarizing film, and the laminated structure is incorporated into a liquid crystal display device.

It is known to use an active energy ray hardening adhesive for bonding a polarizing film and a protective film. The active energy ray-curable adhesive is a cationically polymerizable adhesive containing a cationically polymerizable curable component such as an active energy ray-curable epoxy compound as a main component. The cationically polymerizable adhesive has advantages such that it is not easily hindered by oxygen, and is also suitable for bonding a protective film and a polarizing film with low moisture permeability. For example, in Patent Documents 1 and 2, it is described that a photocurable adhesive containing an alicyclic epoxy compound as a photocationic curable component is used for bonding a polarizing film and a protective film.

On the other hand, in order to further improve the adhesion between the protective film and the polarizing film, it is known to use a protective film having a urethane undercoat layer. For example, Patent Document 3 describes that even when a protective film having a urethane undercoat layer is used, a polarizing plate having a cationically polymerizable adhesive having excellent curability is used.

Furthermore, Patent Document 4 discloses an acrylic thermoplastic resin which contains a repeating unit derived from an N-substituted maleimide diimide monomer, and which is excellent as an optical material used for a polarizing plate protective film and the like. A resin with highly controlled birefringence, such as heat resistance.

    [Prior technical literature]         [Patent Literature]    

[Patent Document 1] Japanese Patent Laid-Open No. 2012-208250

[Patent Document 2] Japanese Patent Laid-Open No. 2012-208246

[Patent Document 3] International Publication No. 2014/129260

[Patent Document 4] International Publication No. 2011/149088

A polarizing film is formed by bonding a polarizing film and a protective film having a resin layer containing nitrogen, and using an adhesive containing an alicyclic epoxy compound as an active energy ray-curable adhesive, and may cause color failure when exposed to a hot and humid environment. Both situations. In recent years, with the reduction in weight and thickness of liquid crystal display devices and the like, the requirements for thinning a polarizing plate have gradually increased, and the occurrence of the above-mentioned color unevenness is particularly noticeable on a polarizing plate after being thinned.

The purpose of the present invention is to provide a polarizing plate capable of suppressing color unevenness after exposure in a hot and humid environment.

This invention provides the polarizing plate shown below.

[1] A polarizing plate having a polarizer layer, an adhesive layer, and a first resin layer in this order, wherein the polarizer layer is a polyvinyl alcohol-based resin film that is aligned with iodine; in the first resin layer, The atomic concentration ratio (N / C ratio) of nitrogen and carbon on the surface of the side where the adhesive layer is in contact is 1.0 or more; the adhesive layer system contains active energy ray hardening compounds and active energy of a cationic polymerization initiator. A hardened layer of a wire-curable adhesive composition; the active energy ray-curable compound includes an alicyclic epoxy compound; the film thickness of the polarizer layer is 18 μm or more and 25 μm or less; 100 compared to the active energy ray-curable compound The content of the aforementioned alicyclic epoxy compound is 10 to 70 parts by weight.

[2] A polarizing plate having a polarizer layer, an adhesive layer, and a first resin layer in sequence, wherein the polarizer layer is a polyvinyl alcohol-based resin film that is oriented with iodine; and the first resin layer is The atomic concentration ratio (N / C ratio) of nitrogen and carbon on the surface of the side where the adhesive layer is in contact is 1.0 or more; the adhesive layer system contains active energy ray hardening compounds and active energy of a cationic polymerization initiator. A hardened layer of a wire-curable adhesive composition; the active energy ray-curable compound includes an alicyclic epoxy compound; the film thickness of the polarizer layer is less than 18 μm; and 100 parts by weight relative to the active energy ray-curable compound. The content of the aforementioned alicyclic epoxy compound is 10 to 55 parts by weight.

[3] A polarizing plate having a polarizer layer, an adhesive layer, and a first resin layer in this order, wherein the polarizer layer is a polyvinyl alcohol-based resin film that is oriented with iodine; and the first resin layer, and The atomic concentration ratio (N / C ratio) of nitrogen and carbon on the surface of the side where the adhesive layer is in contact is 1.0 or more; the adhesive layer system contains active energy ray hardening compounds and active energy of a cationic polymerization initiator. A hardened layer of a wire-curable adhesive composition; the active energy ray-curable compound includes an alicyclic epoxy compound; a film thickness of the polarizer layer is 25 μm or less; 100 parts by weight based on the active energy ray-curable compound When the content of the alicyclic epoxy compound is M [parts by weight], and when the amount of iodine per unit area of the polarizer layer is I [g / cm ² ], M is 7 [parts by weight] or more and satisfies the formula (1): I ≧ 2.1M × 10 ^-6 -7.8 × 10 ^-5 (1).

[4] The polarizing plate according to any one of [1] to [3], wherein the film thickness of the adhesive layer is 3.5 μm or less.

[5] The polarizing plate according to any one of [1] to [4], wherein the first resin layer has a moisture permeability of 1500 g / m ² / 24hr or less at a temperature of 40 ° C and a relative humidity of 90% Layers.

[6] The polarizing plate according to any one of [1] to [5], wherein a second resin layer is provided on a surface of the polarizer layer opposite to a side on which the adhesive layer is disposed; second resin layer contains a temperature of 40 ℃, 90% relative humidity in a moisture permeability of 1500g / m ² / 24hr or less layers.

[7] The polarizing plate according to any one of [1] to [6], wherein a single transmittance of the polarizer layer is 40% or more.

[8] The polarizing plate according to any one of [1] to [7], wherein the active energy ray-curable compound further includes an aliphatic epoxy compound; wherein,

The content of the aliphatic epoxy compound is less than 65 parts by weight based on 100 parts by weight of the active energy ray-curable compound.

According to the present invention, it is possible to provide a polarizing plate capable of suppressing color unevenness after exposure to a hot and humid environment.

1‧‧‧ polarizing plate

10‧‧‧Polarizer layer

15‧‧‧The first adhesive layer

21‧‧‧The first resin layer

22‧‧‧ 2nd resin layer

25‧‧‧The second adhesive layer

FIG. 1 is a schematic cross-sectional view showing an example of a layer configuration of a polarizing plate of the present invention.

FIG. 2 is a graph plotting the amount of iodine with respect to the content of the alicyclic epoxy compound for the polarizing plate obtained in the example.

Hereinafter, an embodiment is shown and the polarizing plate of this invention is demonstrated in detail.

The polarizing plate of the present invention includes a polarizer layer and a first resin layer laminated on the surface on one side of the polarizer layer via an adhesive layer. The adhesive layer is an active energy ray-curable adhesive composition. Hardened layer. The polarizer layer is a polyvinyl alcohol-based film containing a polyvinyl alcohol-based resin as a main component that adsorbs and aligns with iodine. In the first resin layer-based resin hardened material layer, the atomic concentration ratio (N / C ratio) of nitrogen element to carbon element on the surface of the side in contact with the adhesive layer is 1.0 or more. The active-energy-ray-curable adhesive composition forming the adhesive layer includes an active-energy-ray-curable compound containing an alicyclic epoxy compound and a cationic polymerization initiator.

When the film thickness of the polarizer layer is 18 μm or more and 25 μm or less, the content of the alicyclic epoxy compound is 10 to 70 parts by weight based on 100 parts by weight of the active energy ray-curable compound; and when the film thickness of the polarizer layer is less than 18 μm The content of the alicyclic epoxy compound is 10 to 55 parts by weight based on 100 parts by weight of the active energy ray-curable compound. In addition, when the film thickness of the polarizer layer is 25 μm or less, the content of the alicyclic epoxy compound is M [parts by weight] with respect to 100 parts by weight of the active energy ray-curable compound, and the iodine per unit area of the polarizer layer is When the amount is I [g / cm ² ], M may be 7 [parts by weight] or more and satisfy the formula (1): I ≧ 2.1M × 10 ^-6 -7.8 × 10 ^-5 (1).

The polarizing plate of the present invention can suppress color unevenness even after being exposed to a hot and humid environment. In addition, the term "color unevenness" in this specification refers to a change in the color of a polarizing plate (reddish, reddish) when the polarizing plate is arranged in a crossed nicols state for observation, as described in the examples described later. (Blue) Part is visually recognized as uneven.

The mechanism of the occurrence of color unevenness in the polarizing plate is estimated as follows. The epoxy compound (monomer), which is an active energy ray-curable compound contained in the active energy ray-curable adhesive composition, forms a cured product layer by cationic polymerization. In the cationic polymerization of an epoxy compound, if a compound having a Lewis basicity or a Bronsted basicity higher than that of the epoxy compound is present, the polymerization reaction of the epoxy compound is hindered. In general, compounds having a nitrogen-containing functional group have higher Lewis basicity or Brinell basicity than epoxy compounds. Therefore, when a compound having a nitrogen-containing functional group is present on the surface in contact with the adhesive layer, the polymerization reaction of the epoxy compound in the active energy ray-curable adhesive composition forming the adhesive layer is hindered. In the case where unreacted epoxy compounds remain in the process. When the polarizing plate is exposed to a hot and humid environment, the epoxy compound remaining in the adhesive moves from the adhesive layer to the polarizer layer.

In the polarizer layer, iodine is adsorbed and aligned on the polyvinyl alcohol-based film. Polarizer layer in addition to iodine I _2, but also the presence of ^{I -, I 3-, I 5-} , such an equilibrium state. Even higher reactive alicyclic epoxy compound of formula in the epoxy compound, member-based polarizing layer I ^- reaction consumes polarizer layer I ^-. As a result, changing the polarization element layer iodine ^{_{(I 2, I -, I}} 3-, I 5-) equilibrium state. At this time, if I ^{3- is} decreased, the blueness of the polarizer layer is increased, and if I ^{5- is} decreased, the redness of the polarizer layer is increased. Therefore, if the amount of the alicyclic epoxy compound remaining in the adhesive layer of the polarizing plate is increased, the amount of iodine reacted with the alicyclic epoxy compound is increased, and the portion where the polarizer layer reacts with iodine tends to become polarized light. The color of the board is uneven.

Such color unevenness tends to occur when the polarizing plate is provided with a polarizer layer, and the iodine is adsorbed and aligned on the polyvinyl alcohol film; the adhesive layer is a cationically polymerizable active energy ray hardening type containing an alicyclic epoxy compound When the cured product layer of the adhesive composition and the first resin layer have an N / C ratio of 1.0 or more on the side in contact with the adhesive layer. In addition, as described later, the color of the polarizing plate is uneven. As described later, the thinner the film thickness of the polarizer layer and the thinner the adhesive layer layer, the more likely it is to occur. The larger the individual transmittance of the polarizer layer, the more likely it is to occur.

Hereinafter, the polarizing plate of the present invention will be described in detail. An example of the layer configuration of the polarizing plate 1 is shown in FIG. 1. The polarizing plate 1 shown in FIG. 1 includes a polarizer layer 10; a first resin layer 21 laminated on one side of the polarizer layer 10 with a first adhesive layer (adhesive layer) 15 interposed therebetween; and a second adhesive layer through the second adhesive layer. A second resin layer 22 is laminated on the other surface of the polarizer layer 10. As shown in FIG. 1, adjacent layers of the polarizing plate 1 are in contact with each other.

    <Polarizer layer>    

The polarizer layer 10 is a polyvinyl alcohol-based film having a polyvinyl alcohol-based resin as a main component and an orientation of iodine. The polarizer layer 10 is, for example, a uniaxially stretched polyvinyl alcohol-based resin film having iodine aligned thereon. The polyvinyl alcohol-based resin constituting the polarizer layer 10 may be vinyl acetate and other monomers (e.g., ethylene, unsaturated carboxylic acid) that are copolymerizable with the polyvinyl alcohol, in addition to polyvinyl alcohol, which is a saponified product of polyvinyl acetate. Etc.) of vinyl alcohol copolymers of saponified copolymers.

The polarizer layer 10 may be, for example, a step of uniaxially stretching the polyvinyl alcohol-based resin film, a step of dyeing the polyvinyl alcohol-based resin film with iodine to adsorb the iodine, and a polyvinyl alcohol-based resin having iodine absorbed therein. The step of treating the membrane with a boric acid aqueous solution and the step of treating the membrane with a boric acid aqueous solution and then washing with water are produced. The dyeing of iodine can be performed by immersing the film in an aqueous solution containing iodine, and the treatment of the aqueous boric acid solution can be performed by immersing the film in an aqueous solution of boric acid.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before or simultaneously with dyeing of iodine or after dyeing. When uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before or during a boric acid treatment. Furthermore, uniaxial extension may be performed in these plural stages.

The polarizer layer 10 may be obtained by subjecting a laminate of a polyvinyl alcohol-based resin layer and a base film to stretching and dyeing. At this time, the stretched and dyed polyvinyl alcohol-based resin layer becomes a polarizer layer. The laminated body can be obtained, for example, by applying a polyvinyl alcohol-based resin to a base film. The base film laminated on the polarizer layer 10 may be peeled off and removed, and it may be used as the first resin layer 21 or the second resin layer 22. The above-mentioned stretching magnification is usually 3 to 7 times.

The film thickness of the polarizer layer 10 is not particularly limited as long as it is 25 μm or less. In order to meet the requirements of the thinning of the polarizing plate 1, a thin film thickness is preferred. Specifically, the film thickness of the polarizer layer 10 is preferably 23 μm or less, more preferably 18 μm or less, and still more preferably 13 μm or less. The polarizer layer 10 generally has a film thickness of 1 μm or more, preferably 2 μm or more, and more preferably 5 μm or more. The color unevenness generated when the polarizing plate is exposed to a hot and humid environment is likely to become noticeable in a polarizing plate using a thinned polarizer layer. For this reason, when the film thickness of the polarizer layer 10 is 25 μm or less, the effect of effectively suppressing color unevenness of the polarizing plate 1 can be obtained.

The individual transmittance of the polarizer layer 10 is preferably 40% or more, may be 42.1% or more, and may also be 42.7% or more. The upper limit of the single transmittance of the polarizer layer 10 is 50% or less, and preferably 45% or less. The color unevenness generated when the polarizing plate is exposed to a hot and humid environment is likely to be noticeable in a polarizing plate using the polarizer layer 10 having a high unit transmittance. For this reason, the polarizing plate 1 can effectively obtain the effect of suppressing color unevenness, particularly when the unit transmittance of the polarizer layer 10 is 40% or more. The above-mentioned monomer transmittance is a value measured using a measurement method performed in Examples described later.

    〈First resin layer〉    

The first resin layer 21 is provided on one surface of the polarizer layer 10 via the first adhesive layer 15. The first resin layer 21 may include, for example, a protective layer of the polarizer layer 10, a retardation layer, an optical compensation layer, a brightness enhancement layer, and the like. The surface of the first resin layer 21 on the side in contact with the first adhesive layer 15 is to improve the adhesion between the first resin layer 21 and the first adhesive layer 15, the optical characteristics of the first resin layer 21, and heat resistance. For the purpose, the atomic concentration ratio (N / C ratio) of nitrogen and carbon is 1.0 or more. The N / C ratio is measured by qualitative / quantitative analysis of elements on the surface of the first resin layer 21 in contact with the first adhesive layer 15 using an X-ray photoelectron spectroscopy (XPS) system according to the examples described later. Out value.

The color unevenness generated when the polarizing plate is exposed to a hot and humid environment is that the higher the nitrogen content in the surface of the first resin layer 21 on the side in contact with the first adhesive layer 15 is, the more likely it becomes noticeable. For this reason, in the first resin layer 21 of the polarizing plate 1, particularly when the above-mentioned N / C ratio on the surface in contact with the first adhesive layer 15 is 1.0 or more, an effect of effectively suppressing color unevenness can be obtained. The N / C ratio is not particularly limited as long as it is 1.0 or more, and may be 1.5 or more and 2.0 or more. The upper limit of the N / C ratio is also not particularly limited, and is, for example, 10 or less, preferably 8 or less, and more preferably 7 or less.

The first resin layer 21 may be composed of a single layer, or may have a layer (hereinafter referred to as "adhesive agent layer-side surface layer") in contact with the first adhesive agent layer 15 and layers other than the adhesive agent layer-side surface layer (hereinafter Called "other layers"). The other layers may be one layer or two or more layers. When the first resin layer 21 is configured as a single layer, the N / C ratio of the first resin layer 21 may be configured to be 1.0 or more. When the first resin layer 21 has a plurality of layers, it can be configured such that at least the N / C ratio of the surface layer on the adhesive layer side is 1.0 or more.

The other layers include a protective layer, a hard coat layer, an anti-glare layer, an anti-reflection layer, an anti-static layer, an anti-fouling layer, and an undercoat layer of the polarizer layer 10. Examples of the surface layer on the adhesive layer side include an undercoat layer and a protective layer. When the other layer is an undercoat layer, the affinity of the layer provided on the first resin layer 21 on the opposite side to the first adhesive layer 15 can be improved by the undercoat layer. In addition, when the surface layer on the side of the adhesive layer is an undercoat layer, the undercoat layer can increase the affinity for the first adhesive layer 15 and increase the bonding strength. The first resin layer 21 is preferably such that the other layers are protective layers, and the surface layer on the adhesive layer side is an undercoat layer.

The material forming the surface of the first resin layer 21 on the side in contact with the first adhesive layer 15 is not particularly limited as long as it has an N / C ratio of 1.0 or more, and examples thereof include a monomer containing an N atom. The (meth) acrylic resin, urethane resin, (meth) acrylic acid amine resin, fluorene imine resin, melamine resin, etc., which are copolymerized components, (meth) acrylic resin is preferably used. Resin, urethane-based resin.

The first resin layer 21, the adhesive layer-side surface layer, and other layers forming the first resin layer 21 may include, for example, a layer containing a methacrylic resin [A] described later. When the first resin layer 21 is composed of a single layer and is formed using a methacrylic resin [A], it is only necessary to adjust the formation of the formazan so that the N / C ratio of the methacrylic resin [A] is 1.0 or more. The content of each constituent unit of the acrylic resin [A] may be sufficient. The N / C ratio when the other layers are formed using a methacrylic resin [A] is not particularly limited.

When the adhesive layer-side surface layer forming the first resin layer 21 is the above-mentioned undercoat layer, the material may be selected so that the N / C ratio of the undercoat layer becomes 1.0 or more. As a material for forming the undercoat layer, for example, a (meth) acrylic resin containing a monomer having a skeleton having a polar group, a lower molecular weight and a lower glass transition temperature, and a N atom as a copolymerization component can be used. , Urethane resin, (meth) acrylamide resin, melamine resin, etc.

When the adhesive layer-side surface layer forming the first resin layer 21 is an undercoat layer, the thickness of the undercoat layer is usually 0.01 to 5 μm, preferably 0.03 to 0.6 μm in terms of the thickness after drying. When the thickness is less than 0.01 μm, the adhesiveness with other layers forming the first resin layer 21 may be deteriorated. When the thickness exceeds 5 μm, the hydrophilic property of the undercoat layer becomes excessive, and the water resistance of the polarizing plate may be deteriorated.

The first resin layer 21 is preferably contained at a temperature of 40 ℃, 90% relative humidity in a moisture permeability of 1500g / m ² / 24hr or less low moisture-permeable layer. When the first resin layer 21 is two or more layers, the low-moisture-permeability layer may be at least one of the adhesive-layer-side surface layer and other layers. When the other layer is two or more layers, it may be at least one of the other layers. Just fine. The moisture permeability may be 1000 g / m ² / 24hr or less, and may be 420 g / m ² / 24hr or less. The color unevenness generated when the polarizing plate is exposed to a hot and humid environment, and the polarizing plate having the first resin layer having low moisture permeability is likely to become more prominent. For this reason, a polarizing plate particularly when the first resin layer 21 comprises at a temperature of 40 ℃, 90% relative humidity in a moisture permeability of 1500g / m low moisture-permeable layer ² / 24hr or less, the color can be effectively suppressed without Uniform effect.

Hereinafter, materials that can constitute the first resin layer 21 will be described in detail.

    (Methacrylic resin [A])    

The methacrylic resin [A] may have the first, second, and third constituent units represented by the general formulae (I), (II), and (III), respectively, and may preferably include a methacrylic resin [A] ] Or a layer containing a resin component other than the additive when the additive is included is a methacrylic resin [A].

    (First constituent unit of methacrylic resin [A])    

The first structural unit constituting the methacrylic resin [A] is a structural unit represented by the general formula (I). In the general formula (I), R ¹ represents a hydrogen atom, an alkyl group having 1 to 12 carbons, and carbon. A cycloalkylalkyl group having 4 to 12 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, an arylalkyl group having 7 to 14 carbon atoms, an aromatic group having 6 to 14 carbon atoms, or a group selected from halogen atoms (F, Cl , Br or I atom), a hydroxyl group, a nitro group, an alkoxy group having 1 to 12 carbons and an alkyl group having 1 to 12 carbons, at least one of the substituents having an aromatic group having 6 to 14 carbon atoms . In this specification, an alkyl group, an alkyl group of an arylalkyl group, and an alkyl group of an alkoxy group may be linear or branched.

R can be alkyl of ¹ (for the aromatic group R may be ^an alkyl substituent is also the same) of carbon atoms is preferably 1-6, more preferably 1-4. Specific examples of the alkyl group which may be R ¹ include methyl, ethyl, n- or iso-propyl, n-, iso- or 3-butyl, 2-ethylhexyl, nonyl, decyl, Lauryl. Among these, from the viewpoint of transparency and weather resistance of the methacrylic resin [A], methyl, ethyl, n- or iso-propyl, n-, iso-, or 3-butyl is preferred. 2-ethylhexyl, more preferably methyl.

The number of carbon atoms which can be a cycloalkylalkyl group of R ¹ is preferably 5 to 10, and more preferably 6 to 8. Specific examples of the cycloalkylalkyl group that can be R ¹ include cyclopentylmethyl, cyclopentylethyl, cyclohexylmethyl, cyclohexylethyl, and the like.

Specific examples of cycloalkyl groups which may be R ¹ include cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, tricyclodecyl, bicyclooctyl, tricyclododecyl, isofluorenyl, and adamantane. Radical, tetracyclododecyl. Among them, preferred are cyclopentyl, cyclohexyl, cyclooctyl, tricyclodecyl, bicyclooctyl, tricyclododecyl, and isofluorenyl.

Specific examples of the arylalkyl group which may be R ¹ include benzyl, 1- or 2-phenylethyl, 3-phenylpropyl, 6-phenylhexyl, and 8-phenyloctyl. Among them, benzyl, 1- or 2-phenylethyl, and 3-phenylpropyl are preferred. Specific examples of the aromatic group which may be R ¹ include a phenyl group, a naphthyl group, and an anthryl group. Among them, a phenyl group is preferred.

The aromatic group having the above-mentioned specific substituent that can be R ¹ is preferably a phenyl group having a substituent. Specific examples include 2,4,6-tribromophenyl, 2- or 4-chlorophenyl, 2- Or 4-bromophenyl, 2- or 4-methylphenyl, 2- or 4-ethylphenyl, 2- or 4-methoxyphenyl, 2- or 4-nitrophenyl, 2, Of these 4,6-trimethylphenyl groups, preferred is 2,4,6-tribromophenyl.

When the total amount of the methacrylic resin [A] is 100% by weight, the content of the first constituent unit is 50 to 95% by weight, preferably 60 to 92% by weight, more preferably 70 to 90% by weight, and even more preferably It is 79 to 90% by weight. When the content of the first constituent unit is less than 50% by weight, it is disadvantageous in terms of the total light transmittance and weather resistance of the methacrylic resin [A]. The methacrylic resin [A] may contain only one kind of the first constituent unit, or may contain two or more kinds.

The first constitutional unit is a constitutional unit derived from methacrylic acid or a methacrylic acid ester represented by the following general formula (I '). R ¹ in the general formula (I ′) has the same meaning as R ^{1 in the} general formula (I). Among the methacrylates, methyl methacrylate and benzyl methacrylate are preferably used from the viewpoint of the transparency and weather resistance of the methacrylic resin [A].

    (Second constituent unit of methacrylic resin [A])    

The second constitutional unit constituting the methacrylic resin [A] is a constitutional unit represented by the general formula (II). In the general formula (II), R ² represents an arylalkyl group having 7 to 14 carbon atoms, and 6 carbon atoms. Aromatic groups from 14 to 14 or having a group selected from a halogen atom (F, Cl, Br or I atom), a hydroxyl group, a nitro group, an alkoxy group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms, and 7 to 7 carbon atoms An aryl group having 14 to 14 aryl groups having 6 to 14 carbon atoms in at least one substituent. R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aromatic group having 6 to 14 carbon atoms.

Specific examples of the arylalkyl group which may be R ² include benzyl, 1- or 2-phenylethyl, 3-phenylpropyl, 6-phenylhexyl, and 8-phenyloctyl. Among them, benzyl is preferred from the viewpoints of heat resistance and low birefringence of the methacrylic resin [A].

Specific examples of the aromatic group that can be R ² include a phenyl group, a naphthyl group, and an anthryl group. Among them, a phenyl group is preferred from the viewpoints of heat resistance and low birefringence of the methacrylic resin [A].

The number of carbon atoms of the alkoxy group which can be substituted as the aromatic group of R ² is preferably from 1 to 10, more preferably from 1 to 8. Specific examples of the alkoxy group include methoxy, ethoxy, n- or iso-propoxy, n-, iso- or 3-butoxy, 2-ethylhexyloxy, and 1-decyloxy base. Specific examples of the alkyl group having 1 to 12 carbon atoms and the aromatic alkyl group having 7 to 14 carbon atoms which can be substituted for the aromatic group of R ^{2 are} the alkyl group having 1 to 12 carbon atoms and R ¹ Specific examples of the arylalkyl group having 7 to 14 carbon atoms are the same.

The aromatic group having the above-mentioned specific substituent that can be R ² is preferably a phenyl group having a substituent or a naphthyl group having a substituent. Specific examples are the same as those of the aromatic group having the above-mentioned specific substituent that can be R ¹ . Specific examples are the same.

The number of carbon atoms which can be an alkyl group of R ³ and R ⁴ is preferably 1 to 6, and more preferably 1 to 4. Specific examples of the alkyl group which can be R ³ and R ⁴ include methyl, ethyl, n- or iso-propyl, n-, iso-, or 3-butyl, 2-ethylhexyl, nonyl, and decyl. Base, lauryl. Among these, from the viewpoint of transparency and weather resistance of the methacrylic resin [A], methyl, ethyl, n- or iso-propyl, n-, iso-, or 3-butyl is preferred. 2-ethylhexyl, more preferably methyl.

Specific examples of the aromatic group that can be R ³ and R ⁴ include phenyl, naphthyl, and anthracenyl. Among them, from the viewpoint of the heat resistance and low birefringence of the methacrylic resin [A], it is preferable. Is phenyl.

R ³ and R ^{4 are} preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, and more preferably a hydrogen atom.

When the total amount of the methacrylic resin [A] is 100% by weight, the content of the second constituent unit is 0.1 to 20% by weight, preferably 5 to 20% by weight, and more preferably 7 to 18% by weight. When the content of the second constituent unit is within this range, the heat resistance of the methacrylic resin [A] can be improved while maintaining transparency. The methacrylic resin [A] may contain only one kind of the second constituent unit, and may also contain two or more kinds.

The second constitutional unit is a constitutional unit derived from an N-substituted maleimide diimide compound represented by the following general formula (II ′). In the general formula ^{(II ') R 2, R} 3 and R ⁴ and R lines of general formula (II) of, R ³ and R ²⁴ have the same meaning. Among these, from the viewpoints of heat resistance, low birefringence, and the like of the methacrylic resin [A], it is preferable to use N-phenyl maleimide and N-benzyl maleimide.醯 imine.

    (The third constituent unit of the methacrylic resin [A])    

The third constitutional unit constituting the methacrylic resin [A] is a constitutional unit represented by the general formula (III). In the general formula (III), R ⁵ represents a hydrogen atom, a cycloalkyl group having 3 to 12 carbon atoms, and carbon. Alkyl group of 1 to 12, cycloalkylalkyl group of 4 to 12 carbons or a group having a halogen atom (F, Cl, Br or I atom), a hydroxyl group, a nitro group, and an alkoxy group of 1 to 12 carbon atoms An alkyl group having 1 to 12 carbons in at least one of the substituents formed. R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aromatic group having 6 to 14 carbon atoms.

As far as the cycloalkyl group which can be R ⁵ is concerned, including cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, tricyclodecyl, bicyclooctyl, tricyclododecane Group, isofluorenyl, adamantyl, tetracyclododecyl. Among these, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl are preferred, and from the viewpoints of transparency, weather resistance, and low hygroscopicity of the methacrylic resin [A] In particular, cyclohexyl is more preferred.

The carbon number of the alkyl group which can be R ⁵ is preferably from 1 to 10, more preferably from 1 to 8. Specific examples of the alkyl group which may be R ⁵ include methyl, ethyl, n- or iso-propyl, n-, iso- or 3-butyl, n-pentyl, n-hexyl, n-octyl , N-dodecyl, n-octadecyl, 2-ethylhexyl, 1-decyl, 1-dodecyl. Among these, from the viewpoints of transparency and weather resistance of the methacrylic resin [A], methyl, ethyl, and iso-propyl are preferred.

The carbon number of the cycloalkylalkyl group which can be R ⁵ is preferably 5 to 10, more preferably 6 to 8. Specific examples of the cycloalkylalkyl group which may be R ⁵ include cyclopentylmethyl, cyclopentylethyl, cyclohexylmethyl, and cyclohexylethyl.

The carbon number of the alkoxy group which can be a substituent of the alkyl group which can be R ⁵ is preferably 1 to 10, more preferably 1 to 8. Specific examples of the alkoxy group include methoxy, ethoxy, n- or iso-propoxy, n-, iso- or 3-butoxy, 2-ethylhexyloxy, and 1-decyloxy base.

Specific examples of the alkyl group having the above-mentioned specific substituent that can be R ⁵ include dichloromethyl, trichloromethyl, trifluoroethyl, and hydroxyethyl. Among these, trifluoroethyl is preferred.

The number of carbon atoms which can be an alkyl group of R ⁶ and R ⁷ is preferably 1 to 6, more preferably 1 to 4. Specific examples of the alkyl group which can be R ⁶ and R ⁷ include methyl, ethyl, n- or iso-propyl, n-, iso-, or 3-butyl, 2-ethylhexyl, nonyl, and decyl. Base, lauryl. Among these, from the viewpoint of transparency and weather resistance of the methacrylic resin [A], methyl, ethyl, n- or iso-propyl, n-, iso-, or 3-butyl is preferred. 2-ethylhexyl, more preferably methyl.

Specific examples of the aromatic group that can be R ⁶ and R ⁷ include a phenyl group, a naphthyl group, and an anthryl group. Among them, from the viewpoint of the heat resistance and low birefringence of the methacrylic resin [A], it is preferably Phenyl.

R ⁶ and R ^{7 are} preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, and more preferably a hydrogen atom.

When the total amount of the methacrylic resin [A] is 100% by weight, the content of the third constituent unit is 0.1 to 49.9% by weight, preferably 0.1 to 35% by weight, more preferably 0.1 to 30% by weight, and even more preferably It is 0.1 to 15% by weight. When the content of the third constituent unit is within this range, the methacrylic resin [A] can have both transparency and low hygroscopicity. The methacrylic resin [A] may contain only one kind of the third constituent unit, and may also contain two or more kinds.

The third constitutional unit is a constitutional unit derived from an N-substituted maleimide diimide compound represented by the following general formula (III ′). R of general formula (III ') of the ^5, R ⁶ and R ⁷ and R lines of general formula (II) of ^5, the same meanings as R ⁶ and R ^7. Among these, from the viewpoint of the weather resistance of the methacrylic resin [A], it is preferable to use N-methylcis butylenediimide, N-ethylcis butylenediimide, N-iso Propyl cis-butene diimide and N-cyclohexyl cis-butene diimide, among these, have low hygroscopicity of the methacrylic resin [A] and are higher than the first adhesive layer. From the viewpoint of adhesiveness, it is more preferable to use N-cyclohexylcis-butenediamidine.

When the total amount of the methacrylic resin [A] is 100% by weight, the total content of the second and third constituent units is 5 to 50% by weight, preferably 5 to 40% by weight, and more preferably 10 to 35% by weight. , And more preferably 10 to 30% by weight, and particularly preferably 15 to 30% by weight. When the total content is within this range, it is advantageous in terms of heat resistance, weather resistance, low moisture absorption, optical characteristics, and the like of the methacrylic resin [A].

From the viewpoint of the optical characteristics (for example, low birefringence and low photoelastic modulus) of the methacrylic resin [A], the molar ratio of the content of the second constituent unit to the content of the third constituent unit is preferred. It is more than 0 and 15 or less, and more preferably 10 or less.

From the viewpoint of the optical characteristics of the methacrylic resin [A], when the total amount of the methacrylic resin [A] is 100% by weight, the total content of the first, second, and third constituent units is preferably 80. More than% by weight.

    (Other constituent units of methacrylic resin [A])    

The methacrylic resin [A] may further contain other constituent units than the first, second, and third constituent units. The other constitutional unit is not particularly limited as long as it is a constitutional unit derived from another monomer that can be copolymerized with the monomers forming the first, second, and third constitutional units.

Specific examples of the above other monomers include: aromatic ethylene; unsaturated nitriles; acrylates having cyclohexyl, benzyl, or alkyl groups having 1 to 18 carbons; olefins; dienes; vinyl ethers; vinyl esters; fluorine Allyl or methallyl esters of saturated fatty acid monocarboxylic acids such as allyl propionate; polyvalent (meth) acrylates; polyvalent aryl esters; epoxypropyl compounds; unsaturated carboxylic acids. Other monomers may be used alone or in combination of two or more.

Specific examples of the aromatic ethylene include styrene, α-methylstyrene, and divinylbenzene. Specific examples of the unsaturated nitrile include acrylonitrile, methacrylonitrile, ethacrylonitrile, and phenylacrylonitrile.

Specific examples of the acrylate include methyl acrylate, ethyl acrylate, n- or iso-propyl acrylate, n-, iso-, or 3-butyl acrylate, n- or iso-amyl acrylate, octyl acrylate, and acrylic acid 2-ethylhexyl, decyl acrylate, lauryl acrylate, cyclohexyl acrylate, benzyl acrylate.

Specific examples of the olefin include ethylene, propylene, isobutylene, and diisobutylene. Specific examples of the diene include butadiene and isoprene. Specific examples of the vinyl ether include methyl vinyl ether and butyl vinyl ether. Specific examples of the vinyl ester include vinyl acetate and vinyl propionate. Specific examples of the fluorinated ethylene include vinylidene fluoride.

Specific examples of the polyvalent (meth) acrylate include ethylene glycol (meth) acrylate, diethylene glycol (meth) acrylate, trimethylolpropane tri (meth) acrylate, and hexanediol di (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, bisphenol A ethylene oxide or propylene oxide adduct di (meth) acrylate, Di (meth) acrylate of ethylene oxide or propylene oxide adduct of halogenated bisphenol A, di or tri (methyl) of ethylene oxide or propylene oxide adduct of isocyanurate Acrylate.

Specific examples of the polyvalent aromatic ester include diallyl phthalate and triallyl isocyanurate. Specific examples of the glycidyl compound include glycidyl (meth) acrylate and allyl glycidyl ether. Specific examples of the unsaturated carboxylic acids include acrylic acid, itaconic acid, maleic acid, fumaric acid, and half-esters or acid anhydrides thereof. Among the above, styrene and α-methylstyrene are preferably used for other monomers.

From the viewpoint of the low hygroscopicity of the methacrylic resin [A], when the entire methacrylic resin [A] is 100% by weight, the content of other constituent units is preferably 0.1 to 20% by weight, more preferably It is preferably 0.1 to 15% by weight, and still more preferably 0.1 to 10% by weight. From the viewpoint of weather resistance, the content of other constituent units is preferably 10% by weight or less, and more preferably 7% by weight or less.

The methacrylic resin [A] containing the first to third constituent units as described above and other constituent units arbitrarily contained may be composed of one type of copolymer including such constituent units, or may be, for example, any one or more types. The structural unit is composed of two or more copolymers of different kinds and contents.

    (Physical properties of methacrylic resin [A])    

From the viewpoint of the mechanical strength of the first resin layer 21 and the moldability of the methacrylic resin [A], the weight average of the methacrylic resin [A] measured by GPC and calculated in terms of polymethyl methacrylate The molecular weight Mw is preferably 3,000 to 1,000,000, more preferably 30,000 to 800,000, and still more preferably 60,000 to 600,000. From the viewpoint of moldability of the methacrylic resin [A], the molecular weight distribution (Mw / Mn) of the methacrylic resin [A] measured by GPC and converted into polymethyl methacrylate is preferably 1 to 10, more preferably 1.1 to 7, and still more preferably 1.2 to 5.

From the viewpoint of the heat resistance of the first resin layer 21, the glass transition temperature Tg of the methacrylic resin [A] is preferably 120 to 180 ° C, and more preferably 130 to 180 ° C.

When the first resin layer 21 includes a protective layer, the tensile elastic modulus in a 23 ° C. environment is preferably 1,000 to 5000 MPa, and more preferably 1500 to 5000 MPa from the viewpoint of the supporting force of the protective layer. In addition, from the viewpoint of protecting the polarizer layer 10 during a heat-resistant endurance test after forming a polarizing plate, from preventing heat generated when the active energy ray-curable adhesive composition is cured and radiant heat from an irradiation source of the active energy ray From the viewpoint of the shrinkage of the first resin layer 21 caused by the shrinkage of the polarizer layer 10 and the like, the first resin layer 21 preferably has a high high-temperature tensile elastic modulus. Specifically, the tensile elastic modulus in an 80 ° C. environment is preferably 1000 to 4000 MPa, and more preferably 1500 to 4000 MPa.

The methacrylic resin [A] and the first resin layer 21 composed of the methacrylic resin [A] are described in Japanese Patent Application Laid-Open No. 2013-033237. According to the definition described in the document, the photoelasticity measured by the method described in the document. The absolute value of the coefficient C _R is 3.0 × 10 ^-12 Pa ^-1 or less, and 2.0 × 10 ^-12 Pa ^-1 or less, or 1.0 × 10 ^-12 Pa ^-1 or less. Furthermore, according to the definitions described in this document, the phase difference Re and the phase difference Rth in the thickness direction measured by the method described in this document are both 8 nm or less, 6 nm or less, and 4 nm or less. . Furthermore, according to the definition described in this document, the total light transmittance measured by the method described in this document is 85% or more, and may be 90% or more.

The methacrylic resin [A] constituting the first resin layer 21 in this manner is a resin excellent in optical characteristics such as low birefringence (optical isotropy). The first resin layer 21 containing the resin is suitable as a polarizing plate 1 is a protective layer, in particular, a protective layer of a polarizing plate 1 used in an IPS mode liquid crystal panel. When forming a liquid crystal panel, the first resin layer 21 may be a protective layer disposed on the liquid crystal cell side of the polarizer layer 10 or may be a protective layer remote from the liquid crystal cell side. However, the first resin layer 21 is particularly disposed. In the aspect of the protective layer on the liquid crystal cell side of the polarizer layer 10, it is formed between the polarizer layer of the polarizer disposed on the viewing side of the liquid crystal cell and the polarizer layer of the polarizer disposed on the back side. The first resin layer 21 having excellent optical characteristics such as low birefringence (optical isotropy) is disposed in the cross nicol, and therefore it is advantageous in improving the visibility of the liquid crystal display device. In addition, when the first resin layer 21 made of a methacrylic resin [A] is used as a protective layer disposed on the liquid crystal cell side of the polarizer layer 10, it exhibits a low tensile elastic modulus as described above. In a high-temperature environment and a high-temperature and high-humidity environment, low birefringence continues to be displayed even when a bending stress due to the bending of the liquid crystal cell and a compressive stress accompanying the thermal contraction of the polarizer layer 10 are applied. The visibility of a liquid crystal display device is advantageous. When the second resin layer 22 is composed of the methacrylic resin [A] as described later, the same effect as described above can be obtained by disposing the second resin layer 22 on the liquid crystal cell side of the polarizer layer 10.

    (Material other than methacrylic resin [A] forming the first resin layer)    

The first resin layer 21 may include a thermoplastic resin other than the methacrylic resin [A]. Specific examples of other thermoplastic resins include (meth) acrylic resins other than methacrylic resins [A], olefin polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers; Halogen polymers; styrene polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer; polyesters such as polyethylene terephthalate; polyarylate; Polycarbonate; Polyamide; Polyacetal. However, in order to ensure the heat resistance, moisture resistance, scratch resistance, mechanical strength, optical isotropy, etc. of the first resin layer 21 derived from the methacrylic resin [A], the methacrylic resin [A] is generally set to At 100% by weight, the content of the other thermoplastic resin is preferably 0 to 25% by weight, and more preferably 0 to 10% by weight.

The first resin layer 21 may contain additives such as one or more rubber particles, lubricants, dispersants, heat stabilizers, ultraviolet absorbers, infrared absorbers, antistatic agents, and antioxidants.

The blending of the rubber particles is advantageous in that the film forming properties of the (meth) acrylic resin, the impact resistance of the first resin layer 21, and the smoothness of the surface of the first resin layer 21 can be improved. The rubber particles include a layer showing rubber elasticity (hereinafter also referred to as a rubber elastic body layer).

The rubber particles may be particles composed of only a rubber elastomer layer, or particles having a multilayer structure of a rubber elastomer layer and other layers. Examples of the polymer contained in the rubber elastomer layer include olefin-based elastic polymers, diene-based elastic polymers, styrene-diene-based elastic polymers, and acrylic-based elastic polymers. Among these, from the viewpoints of light resistance and transparency, an acrylic elastic polymer is preferred.

The acrylic elastic polymer may be mainly composed of an alkyl acrylate, that is, a polymer containing 50% by weight or more of a constituent unit derived from an alkyl acrylate based on the total amount of monomers. The acrylic elastic polymer may be a homopolymer of an alkyl acrylate, or a copolymer containing 50% by weight or more of a structural unit derived from an alkyl acrylate and 50% by weight or less of a structural unit derived from another polymerizable monomer. .

The alkyl acrylate constituting the acrylic elastic polymer is usually one having 4 to 8 carbon atoms in the alkyl group. Examples of the other polymerizable monomers include alkyl methacrylates such as methyl methacrylate and ethyl methacrylate; styrene-based monomers such as styrene and alkylstyrene; and acrylonitrile and methyl Monofunctional monomers such as unsaturated nitriles, such as acrylonitrile, and allyl esters of unsaturated carboxylic acids, such as allyl (meth) acrylate and methallyl (meth) acrylate; maleic acid di Difunctional esters of dibasic acids such as allyl esters; and polyfunctional monomers such as diol unsaturated unsaturated carboxylic acid diesters such as alkanediol di (meth) acrylate.

The rubber particles containing an acrylic elastic polymer are preferably particles having a multilayer structure of an acrylic elastic polymer layer. Specific examples include a two-layer structure having a hard polymer layer mainly composed of an alkyl methacrylate on the outside of the acrylic elastic polymer layer, or a methyl group on the inside of the acrylic elastic polymer layer. A three-layer structure of a hard polymer layer mainly composed of alkyl acrylate.

In terms of the monomer composition of the polymer mainly composed of the alkyl methacrylate constituting the hard polymer layer formed on the outer or inner side of the acrylic elastic polymer layer, it is preferable to use methyl methacrylate as the main component. Of monomer composition. Such a multilayered acrylic rubber particle can be produced, for example, by the method described in Japanese Patent Publication No. 55-27576.

The rubber particles include the outermost rubber elastomer layer from the viewpoint of the film-forming properties of the (meth) acrylic resin, the impact resistance of the first resin layer 21, and the smoothness of the surface of the first resin layer 21. The average particle diameter of the particles (for example, an acrylic elastic polymer layer) is preferably in the range of 10 to 500 nm, and more preferably in the range of 10 to 350 nm. The average particle diameter is more preferably 30 nm or more and 50 nm or more, and more preferably 300 nm or less and 280 nm or less.

From the viewpoint of the film-forming properties of the methacrylic resin [A], the impact resistance of the first resin layer 21, and the smoothness of the surface of the first resin layer 21, the methacrylic resin constituting the first resin layer 21 The total amount of the resin [A] is used as a reference, and the rubber particles are preferably blended at a ratio of 3 to 60% by weight, more preferably 45% by weight or less, and still more preferably 35% by weight or less. When the rubber particles are more than 60% by weight, the dimensional change of the first resin layer 21 becomes large, and the heat resistance thereof decreases. On the other hand, when the rubber particles are less than 3% by weight, although the heat resistance of the first resin layer 21 is good, the winding property at the time of film formation is not good, and the productivity may be reduced.

When the first resin layer 21 contains rubber particles, the resin composition containing the methacrylic resin [A] and the rubber particles used for the production of the first resin layer 21 can be used in addition to the methacrylic resin [A] and the rubber. In addition to the particles obtained by melt-kneading, etc., it can also be obtained by a method of first preparing rubber particles and polymerizing a monomer composition that will form a methacrylic resin [A] as a raw material in the presence of the rubber particles.

    (Urethane resin)    

The resin containing a urethane-based resin can be suitably used when the surface layer on the adhesive layer side of the first resin layer 21 is an undercoat layer. A urethane-based resin composition containing a urethane-based resin in an amount of 40% by weight or more is preferred. The urethane resin can be obtained by, for example, polymerizing a diisocyanate compound or a polyisocyanate compound with a polyol, a polyester, or a polyamide. The urethane resin may be a copolymer such as a block copolymer or a graft copolymer with another polymer (for example, a polyester resin, an acrylic resin, or the like). For example, it may be a resin (in some cases, a resin mixture) obtained by polymerizing a urethane-based resin in a urethane-based resin solution or dispersion. Furthermore, it may be a resin (in some cases, a resin mixture) obtained by polymerizing a urethane resin in an acrylic resin solution or dispersion or other polymer solution or dispersion.

Examples of the diisocyanate compound or polyisocyanate compound include tolyl diisocyanate, phenylene diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, dimethylbenzene diisocyanate, and 4 , 4'-dicyclohexyl methane diisocyanate and isophorone diisocyanate.

Polyols include polyether polyols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol; polyethylene adipate and polyethylene adipate with hydroxyl groups at the polymer ends- Polyester polyols such as succinate and polycaprolactone; acrylic polyols, polycarbonate polyols, and castor oil.

Examples of the polyesters include ethylene glycol, 1,4-butanediol, diethylene glycol, and triethylene glycol having a carboxyl group at the polymer terminal, and adipic acid, suberic acid, sebacic acid, and the like. Condensation reactants such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid.

Examples of the polyamines include 4,4'-diaminodiphenylmethane, o-toluenediamine, and m-toluenediamine. In addition, a resin obtained by the reaction of a polyamine and a diisocyanate is also called a polyurea resin.

For polyesters or polyols, those having a weight average molecular weight of 300 to 2000 are generally used. In the production of the urethane-based resin, a chain extender or a cross-linking agent may be used in order to adjust the weight average molecular weight. Examples of the chain extender or cross-linking agent include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, trimethylolpropane, hydrazine, and piperazine. , Diethylenediamine, diethylenetriamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodicyclohexylmethane and water.

The urethane-based resin is preferably water-soluble or water-dispersible in order to prepare a coating liquid containing the urethane-based resin composition. The coating liquid is water-based, has good handleability, and is not preferable because it does not erode toward the first resin layer 21.

As a method for imparting water solubility or water dispersibility to a urethane-based resin, for example, a method of introducing a repeating unit containing a hydrophilic substituent into a urethane-based resin is used, and in a urethane-based resin A method for introducing a repeating unit including an ether bond.

The polymerization reaction system of the urethane-based resin can be appropriately selected according to the nature of the monomer (or oligomer, polymer) used and the polymerized resin. Examples of the polymerization reaction system include a small amount of tin, bismuth, or titanium-based catalysts. Solution polymerization, block polymerization, emulsification polymerization, or dispersion polymerization in the presence of a polymer.

The urethane-based resin composition may contain a polyester-based resin. When the primer layer contains a polyester-based resin, the adhesion to the first adhesive layer 15 and the water resistance can be improved.

The polyester resin used herein means that the total of terephthalic acid component, 2,6-naphthalenedicarboxylic acid component and ethylene glycol component accounts for 40 to 80 mol% of the repeating unit and 20 to 60 mol of the repeating unit. % Is a resin composed of another polyvalent carboxylic acid, a polyvalent hydroxy compound component, and / or a hydroxycarboxylic acid component.

The urethane-based resin composition may contain an acrylic resin. When the undercoat layer contains an acrylic resin, the adhesion to the first adhesive layer 15 can be improved. The acrylic resin refers to a homopolymer or copolymer containing a monomer unit composed of a polymerizable monomer having a (meth) acrylfluorene group as a main component.

The blending amount of the urethane-based resin composition of the polyester-based resin and the acrylic-based resin is, for example, 1% by weight or more and less than 40% by weight, and preferably 5% by weight or more and 35% by weight %the following. When the blending amount is 40% by weight, the blending amount of the urethane-based resin may be relatively reduced, which may impair the advantages such as the good adhesion of the urethane-based resin.

The urethane-based resin composition may contain a crosslinking agent resin compound. Examples of the crosslinking agent resin compound include a melamine-based resin and an epoxy-based resin. Among these, a melamine-based resin compound is preferred in terms of coating properties and adhesion durability.

The urethane-based resin composition may contain inorganic particles or organic particles. By containing the inorganic particles or organic particles in an appropriate amount in the undercoat layer, agglomeration of the first resin layer 21 having the undercoat layer can be prevented, and the adhesiveness with the first adhesive layer 15 can be improved.

The urethane-based resin composition may contain an organic compound having a metal element. By making the undercoating layer contain an organic compound having a metal element, the refractive index of the undercoating layer can be increased to the same degree as the other layers forming the first resin layer 21 or the functional layer laminated thereon. The interface reflection is reduced, so that the light transmittance of the other layers of the first resin layer 21 formed by the undercoat layer can be increased.

The urethane-based resin composition may contain a wax. By including a wax in the undercoat layer, the lubricity and the blocking resistance of the other layers forming the first resin layer 21 laminated on the undercoat layer can be improved.

    (Manufacturing method of the first resin layer)    

The first resin layer 21 may be the entirety of the first resin layer 21 or at least one of the adhesive layer-side surface layer and other layers forming the first resin layer 21 being a film containing the above-mentioned methacrylic resin [A]. A film containing a methacrylic resin [A], or a film containing a resin component other than the additive when the additive is included is preferably a methacrylic resin [A]. The film can be formed by a conventionally known method such as a melt extrusion method, a hot press molding method, an injection molding method, or a solvent cast film method.

The first resin layer 21 may be an extended film extended in at least one direction. The mechanical strength of the first resin layer 21 can be improved by stretching. The stretched film made of methacrylic resin [A] generally reduces the adhesiveness with the adhesive when the stretched process is performed. However, according to the present invention, even when the first resin layer 21 is a stretched film, excellent results can be obtained. Adhesiveness.

Examples of the stretching treatment include uniaxial stretching and biaxial stretching. Examples of the stretching direction include a mechanical moving direction (MD) of the unstretched film, a direction (TD) perpendicular thereto, and a direction oblique to the mechanical moving direction. The two-axis extension can be a two-axis extension that simultaneously extends in two extension directions, or a sequential two-axis extension that extends in other directions after extending in a specified direction. For the stretching process, for example, two or more pairs of clamping rollers with a large rotation speed on the exit side are used to extend in the longitudinal direction (machine moving direction: MD). Both sides of the unstretched film are held by chucks. Direction (TD) is unfolded.

The stretching ratio by the stretching treatment is usually 1.1 times or more, and even if the stretching ratio is 1.2 times or more, according to the present invention, excellent adhesion to the adhesive layer can be obtained. The stretching ratio is usually 5 times or less, and preferably 3.5 times or less. In addition, the stretch magnification of the biaxial stretching refers to the stretch magnification in a direction in which the stretch magnification is large.

The thickness of the first resin layer 21 is, for example, about 1 to 200 μm. From the viewpoint of thinning the polarizing plate and the strength and operability of the first resin layer 21, it is preferably 5 to 150 μm, and more preferably 10 to 120 μm.

The adhesive layer-side surface layer of the first resin layer 21 can be formed by, for example, applying a coating solution containing a precursor of a material constituting the adhesive layer-side surface layer to another layer forming the first resin layer 21. The adhesive layer-side surface layer can be formed by applying a coating solution on one side of another layer forming the first resin layer 21 and then drying or drying / hardening the coating solution. The surface layer on the adhesive layer side may be formed immediately after the other layers forming the first resin layer 21 are formed, or may be formed before bonding to the polarizer layer 10.

As a method for applying the coating liquid, for example, a slit coater, a comma coater, a reverse roll coater, a gravure coater, a bar coater, and a wire bar coater are used. Machine, blade coater and air knife coater. The method and conditions for drying the applied coating liquid are not particularly limited, and for example, a method of drying using a hot air dryer or an infrared dryer can be adopted.

In order to adjust the affinity of the adhesive for forming the first adhesive layer 15 on the surface layer of the adhesive layer, and to improve the adhesion between the adhesive layer-side surface layer and the first adhesive layer 15, it can be applied to the adhesive layer-side surface. The layer is subjected to, for example, a corona discharge treatment, a plasma treatment, an ozone blowing, an ultraviolet irradiation, a flame treatment, a chemical treatment, and other previously known surface treatments.

    <First Adhesive Layer>    

The first adhesive layer 15 is a layer for bonding the polarizer layer 10 and the first resin layer 21 together. The first adhesive layer 15 is a cured product layer of an active energy ray-curable adhesive composition containing an active energy ray-curable compound containing an alicyclic epoxy compound and a cationic polymerization initiator. The content of the alicyclic epoxy compound in the active energy ray-curable adhesive composition is 10 to 70 parts by weight based on 100 parts by weight of the active energy ray-curable compound. The active energy ray-curable adhesive composition is hardened by irradiation with active energy rays such as ultraviolet rays, visible light, electron rays, and X-rays.

The active energy ray-curable adhesive composition is preferably a solvent-free type, so that the adhesion between the polarizer layer 10 and the first resin layer 21 can be improved. In contrast, when the active energy ray-curable adhesive composition contains a solvent (especially an organic solvent), even if the active energy ray-curable compound contained in the adhesive is the same, the adhesiveness tends to be lower than that of the solvent-free type. When the polarizing plate 1 is cut to a predetermined size, defects such as peeling of the first resin layer 21 from the polarizer layer 10 easily occur at the ends thereof.

The “solvent-free type” in the present specification means positively that no solvent is added, specifically, when the total amount of the solvent-free active energy ray-curable compound is 100% by weight, the content of the inorganic and organic solvents is 5 % By weight or less.

The film thickness of the first adhesive layer 15 is preferably 3.5 μm or less, may be 3 μm or less, and may be 2 μm or less. The film thickness of the first adhesive layer 15 is usually 0.01 μm or more. The color unevenness generated when the polarizing plate is exposed to a hot and humid environment, and the polarizing plate having a smaller thickness in the first adhesive layer 15 becomes more prominent. For this reason, especially when the film thickness of the first adhesive layer 15 is 3.5 μm or less for the polarizing plate 1, the effect of suppressing color unevenness can be effectively obtained.

Hereinafter, the active energy ray-curable adhesive composition forming the first adhesive layer 15 and the material included in the active energy ray-curable adhesive composition will be described in detail.

    (Active energy ray hardening type adhesive composition)    

The active-energy-ray-curable adhesive composition includes an alicyclic epoxy compound as an active-energy-ray-curable compound, and may include an epoxy compound other than the alicyclic epoxy compound, and may also contain an epoxy compound other than the epoxy compound. Compound. Here, the epoxy compound refers to a compound having one or more epoxy groups in the molecule, and preferably two or more epoxy groups. Examples of the epoxy compound other than the alicyclic epoxy compound include aliphatic epoxy compounds. Compounds, hydrogenated epoxy compounds (glycidyl ethers of polyalcohols having alicyclic rings), and the like. The active energy ray-curable compound preferably contains an alicyclic epoxy compound and an aliphatic epoxy compound.

From the viewpoint of adhesion between the polarizer layer 10 and the first resin layer 21, the content of the epoxy compound is preferably 40% by weight or more, more preferably 50% by weight based on 100% by weight of the active energy ray-curable compound. More than 60% by weight, and more preferably 60% by weight or more. The upper limit of the content of the epoxy compound relative to 100% by weight of the active energy ray-curable compound may be 100% by weight or less, may be 90% by weight or less, and may be 80% by weight or less, and may not reach 75%. weight%.

The epoxy equivalent of the epoxy compound as the active energy ray-curable compound is usually in the range of 30 to 3000 g / equivalent, preferably 50 to 1500 g / equivalent. When the epoxy equivalent is less than 30 g / equivalent, the adhesion between the polarizer layer 10 and the first resin layer 21 may be reduced, and the flexibility of the first adhesive layer 15 after curing may be reduced. On the other hand, if it exceeds 3000 g / equivalent, the compatibility with other components contained in the adhesive may decrease.

    (Alicyclic epoxy compound)    

When the film thickness of the polarizer layer is 18 μm or more and 25 μm or less, the active energy ray-curable adhesive composition contains 10 to 70 parts by weight of an alicyclic epoxy compound based on 100 parts by weight of the active energy ray-curable compound. The content of the alicyclic epoxy compound is 10 parts by weight or more, preferably 20 parts by weight or more, and more preferably 50 parts by weight or more based on 100 parts by weight of the active energy ray-curable compound. The content of the alicyclic epoxy compound is 70 parts by weight or less, preferably 68 parts by weight or less, and more preferably 65 parts by weight or less based on 100 parts by weight of the active energy ray-curable compound. When the film thickness of the polarizer layer is 18 μm or more and 25 μm or less, the content of the alicyclic epoxy compound is within the above range, even if the thickness of the polarizer layer 10 is as thin as 25 μm or less, and the thickness of the first resin layer 21 is the same as that of the first resin layer 21. When the N / C ratio of the surface on the contact side of the adhesive layer 15 is 1.0 or more, the color unevenness that may occur after the polarizing plate is exposed to a hot and humid environment can be suppressed.

When the thickness of the polarizer layer is less than 18 μm, the active energy ray-curable adhesive composition contains 10 to 55 parts by weight of an alicyclic epoxy compound based on 100 parts by weight of the active energy ray-curable compound. The content of the alicyclic epoxy compound is 10 parts by weight or more, preferably 20 parts by weight or more, and more preferably 40 parts by weight or more based on 100 parts by weight of the active energy ray-curable compound. The content of the alicyclic epoxy compound is 55 parts by weight or less, preferably 53 parts by weight or less, and more preferably 51 parts by weight or less based on 100 parts by weight of the active energy ray-curable compound. When the film thickness of the polarizer layer is less than 18 μm, the content of the alicyclic epoxy compound is within the above range, even if the thickness of the polarizer layer 10 is less than 18 μm, and the thickness of the first resin layer 21 and the first When the N / C ratio of the surface on the contact side of the adhesive layer 15 is 1.0 or more, the color unevenness that may be generated after the polarizing plate is exposed to a hot and humid environment can be suppressed.

When the film thickness of the polarizer layer is 25 μm or less, the active energy ray-curable adhesive composition contains 100 parts by weight of the active energy ray-curable compound, and the alicyclic epoxy compound contains M [parts by weight] of the polarizer. When the amount of iodine per unit area of the layer is I [g / cm ² ], M may be 7 [parts by weight] and satisfy the formula (1): I ≧ 2.1M × 10 ^-6 -7.8 × 10 ^-5 (1). The content M of the alicyclic epoxy compound is 7 [parts by weight] or more, preferably 10 [parts by weight] or more, more preferably 20 [parts by weight] or more, and still more preferably 40 [parts by weight] or more, and may be 100 [parts by weight], preferably 90 [parts by weight] or less, and more preferably 80 [parts by weight]. When the content M of the alicyclic epoxy compound is less than 7 [parts by weight], the active energy ray-curable adhesive composition tends to become hard to harden. When the content M of the alicyclic epoxy compound is within the above range, even if the thickness of the polarizer layer 10 is as thin as 25 μm or less, and the N / C of the surface of the first resin layer 21 in contact with the first adhesive layer 15 When the ratio is 1.0 or more, the color unevenness that may occur after the polarizing plate is exposed to a hot and humid environment can be suppressed.

In addition, when the film thickness of the polarizer layer is 18 μm or more and 25 μm or less, when the alicyclic epoxy compound is contained in an amount of 10 to 70 parts by weight based on 100 parts by weight of the active energy ray-curable compound, or the film thickness of the polarizer layer is not When it reaches 18 μm and contains 10 to 55 parts by weight of the alicyclic epoxy compound with respect to 100 parts by weight of the active energy ray-curable compound, by further satisfying the above formula (1), it is expected that the color of the polarizing plate can be further suppressed. Both.

An alicyclic epoxy compound is an epoxy compound having one or more epoxy groups bonded to an alicyclic ring in the molecule. The "epoxy group bonded to the alicyclic ring" means an oxygen atom -O- bridged in a structure represented by the following formula. In the following formula, m is an integer of 2 to 5.

A compound in which a group in which one or a plurality of hydrogen atoms in the formula (CH ₂ ) _m is bonded to another chemical structure can be alicyclic epoxy compounds. One or more hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. Among the alicyclic epoxy compounds, epoxy compounds having oxabicyclohexane (the one with the formula m = 3) and oxabicycloheptane (the one with the formula m = 4) are provided with the polarizer layer 10 and the first Since the resin layers 21 have excellent adhesiveness, they are preferably used. Hereinafter, alicyclic epoxy compounds which are preferably used are specifically exemplified, but are not limited to these compounds.

(a) epoxy cyclohexyl carboxylic acid epoxy cyclohexyl methyl esters represented by the following formula (IV):

In formula (IV), R ⁸ and R ⁹ independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.

(b) an epoxy cyclohexane carboxylic acid ester of an alkanediol represented by the following formula (V):

In the formula (V), R ¹⁰ and R ¹¹ independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and n represents an integer of 2 to 20.

(c) epoxy cyclohexyl methyl esters of dicarboxylic acids represented by the following formula (VI):

In formula (VI), R ¹² and R ¹³ independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and p represents an integer of 2 to 20.

(d) epoxy cyclohexyl methyl ethers of polyethylene glycol represented by the following formula (VII):

In formula (VII), R ¹⁴ and R ¹⁵ independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and q represents an integer of 2 to 10.

(e) an epoxy cyclohexyl methyl ether of an alkanediol represented by the following formula (VIII):

In the formula (VIII), R ¹⁶ and R ¹⁷ independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and r represents an integer of 2 to 20.

(f) a diepoxytrispirocyclic compound represented by the following formula (IX):

In formula (IX), R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.

(g) a diepoxy monospirocyclic compound represented by the following formula (X):

In formula (X), R ²⁰ and R ²¹ independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.

(h) Vinylcyclohexene diepoxides represented by the following formula (XI):

In the formula (XI), R ²² represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.

(i) epoxy cyclopentyl ethers represented by the following formula (XII):

In the formula (XII), R ²³ and R ²⁴ independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.

(j) Diepoxytricyclodecanes represented by the following formula (XIII):

In the formula (XIII), R ²⁵ represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.

Among the alicyclic epoxy compounds exemplified above, it is more preferable to use the following alicyclic epoxy compounds from the viewpoint of adhesion between the polarizer layer 10 and the first resin layer 21 and in terms of ease of acquisition. .

Esters of (IV-a) 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (7-oxabicyclo [4.1.0] hept-3-yl) methanol [in formula (IV) , R ⁸ = R ⁹ = H, compound name: 3 ', 4'-epoxycyclohexenylcarboxylic acid 3,4-epoxycyclohexenyl methyl ester], (IV-b) 4 -Methyl-7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (4-methyl-7-oxabicyclo [4.1.0] hept-3-yl) methanol [ester Compound of formula (IV), R ⁸ = R ⁹ = 4-CH ₃ ], (Va) 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and 1,2-ethylene glycol ester [In the compound of formula (V), R ¹⁰ = R ¹¹ = H, n = 2], (VI-a) (7-oxabicyclo [4.1.0] hept-3-yl) methanol and adipic acid Esters [compounds of formula (VI), R ¹² = R ¹³ = H, p = 4], (VI-b) (4-methyl-7-oxabicyclo [4.1.0] hept-3-yl ) Ester of methanol and adipic acid [in the compound of formula (VI), R ¹² = R ¹³ = 4-CH ₃ , p = 4], (VIII-a) (7-oxabicyclo [4.1.0] Hept-3-yl) etherate of methanol with 1,2-ethylene glycol [compound of formula (VIII), R ¹⁶ = R ¹⁷ = H, r = 2].

    (Aliphatic epoxy compound)    

The active energy ray-curable adhesive composition may contain an aliphatic epoxy compound as the active energy ray-curable compound. The content of the aliphatic epoxy compound is preferably less than 65 parts by weight, more preferably 60 parts by weight or less, and still more preferably 50 parts by weight or less with respect to 100 parts by weight of the active energy ray-curable compound. It may not contain an aliphatic epoxy compound, and it is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, based on 100 parts by weight of the active energy ray-curable compound.

Compared with alicyclic epoxy compounds, aliphatic epoxy compounds have lower reactivity, and when the content of the aliphatic epoxy compound is 65 parts by weight or more, the polymerization reaction of the active energy ray-curable compound tends to be insufficient, A spot-shaped unreacted portion is easily generated in the first adhesive layer 15. The polarizer layer in contact with the unreacted portion formed in the first adhesive layer 15 is susceptible to moisture transmission during the moist-heat test, and the transmitted moisture causes iodine deficiency. As a result, iodine-free light absorbs and becomes a bright portion. Polarized light Plate 1 is discolored. In this specification, the term "bleaching" means that the polarizing plate alone is irradiated with illumination light from a surface opposite to the surface on the viewing side according to the description of the embodiment described later. When viewed with the naked eye, the lack of the polarizing plate is visually recognized. The bright part is caused by the color caused by iodine.

Specific examples of the aliphatic epoxy compound include a polyhydric alcohol of an aliphatic polyhydric alcohol or an alkylene oxide adduct thereof. More specifically, diglycidyl ether of 1,4-butanediol; diglycidyl ether of 1,6-hexanediol; triglycidyl ether of glycerol; trihydroxyl Triglycidyl ether of methylpropane; Diglycidyl ether of polyethylene glycol; Glycidyl ether of propylene glycol; By adding aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol or glycerol Polyepoxy ether of a polyether polyalcohol obtained from one or two or more kinds of alkylene oxides (ethylene oxide, propylene oxide).

    (Hydrogenated epoxy compound (glycidyl ether of a polyalcohol having an alicyclic ring))    

The hydrogenated epoxy compound is an alicyclic polyalcohol obtained by hydrogenating an aromatic ring of an aromatic polyalcohol, and the alicyclic polyalcohol is reacted with epichlorohydrin. Specific examples of the aromatic polyols include bisphenol compounds such as bisphenol A, bisphenol F, and bisphenol S; phenol resins such as phenol novolac resin, cresol novolac resin, and hydroxybenzaldehyde phenol novolac resin; tetrahydroxydibenzene Polyfunctional compounds such as methyl methane, tetrahydroxybenzophenone, and polyvinyl alcohol. Preferred hydrogenated epoxy compounds are, for example, the diglycidyl ethers of hydrogenated bisphenol A.

    (Active energy ray hardening compound other than epoxy compound)    

The active energy ray-curable adhesive composition may contain an active energy ray-curable compound such as an epoxy compound, and may include a (meth) acrylic compound. By using a (meth) acrylic compound in combination, the effects of improving the adhesion between the polarizer layer 10 and the first resin layer 21, the hardness and mechanical strength of the adhesive layer can be expected, and the adhesive can be more easily carried out. Adjustment of viscosity and curing speed.

When the active energy ray-curable adhesive composition contains a (meth) acrylic compound, its content is preferably 30% by weight or less, more preferably 20% by weight or less, based on 100 parts by weight of the active energy ray-curable compound. When the amount of the (meth) acrylic compound is too large, the adhesiveness between the polarizer layer 10 and the first resin layer 21 tends to decrease.

    (Cationic polymerization initiator)    

The active energy ray-curable adhesive composition contains a cationic polymerization initiator, and preferably contains a photocationic polymerization initiator. A photocationic polymerization initiator is a polymerization initiator that generates a cationic substance or a Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron rays.

The photocationic polymerization initiator is used to harden the adhesive by irradiating the active energy ray. The hardening is possible at room temperature. The reduction of the heat resistance of the polarizer layer 10 or the bending due to swelling must be considered. The points between layers are then advantageous. In addition, since the photocationic polymerization initiator is catalyzed by light, it has excellent storage stability and workability even when mixed with an epoxy compound.

Examples of the photocationic polymerization initiator include an aromatic diazonium salt; an onium salt such as an aromatic sulfonium salt and an aromatic sulfonium salt; an iron-aromatic hydrocarbon complex; and the like.

Specific examples of the aromatic diazonium salt include benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate.

Specific examples of the aromatic phosphonium salt include diphenylphosphonium tetrakis (pentafluorophenyl) borate, diphenylphosphonium hexafluorophosphate, diphenylphosphonium hexafluoroantimonate, and bis (4-nonylphenyl ) Hexafluorophosphate.

Specific examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4,4 ' -Bis (diphenylsulfonium) diphenylsulfide bis (hexafluorophosphate), 4,4'-bis [bis (β-hydroxyethoxy) phenylsulfonium)] diphenylsulfide bis (hexa Fluoroantimonate), 4,4'-bis [bis (β-hydroxyethoxy) phenylsulfonium)] diphenylsulfide bis (hexafluorophosphate), 7- [bis (p-tolyl) Thio] -2-isopropylthiaxanthone hexafluoroantimonate, 7- [bis (p-tolyl) thionium] -2-isopropylthiaxanthone tetra (pentafluorophenyl) boric acid Salt, 4-phenylcarbonyl-4'-diphenylsulfonium diphenylsulfide hexafluorophosphate, 4- (p-third-butylphenylcarbonyl) -4'-diphenylsulfonium diphenylsulfide Ether hexafluoroantimonate, 4- (p-third-butylphenylcarbonyl) -4'-bis (p-tolyl) sulfonium diphenylsulfide tetrakis (pentafluorophenyl) borate.

Specific examples of the iron-arene complex include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, Xylene-cyclopentadienyl iron (II) tris (trifluoromethylsulfonium) methane.

A cationic polymerization initiator may be used individually by 1 type, and may use 2 or more types together. Among them, the aromatic sulfonium salt is preferably used because it has ultraviolet absorption characteristics in a wavelength region of 300 nm or more, and can provide a cured product having excellent hardenability, good mechanical strength, and adhesive strength.

The blending amount of the cationic polymerization initiator is usually 0.5 to 20 parts by weight, and preferably 1 to 15 parts by weight based on 100 parts by weight of the active energy ray-curable compound. When the amount of the cationic polymerization initiator is less than 0.5 parts by weight, curing becomes insufficient, and the mechanical strength of the adhesive layer or the adhesiveness between the polarizer layer 10 and the first resin layer 21 tends to decrease. Moreover, when the compounding quantity of a cationic polymerization initiator exceeds 20 weight part, the ionic substance in a hardened | cured material may increase, the hygroscopicity of a hardened | cured material may increase, and the durability of a polarizing plate may fall.

    (Photosensitizer)    

The active-energy-ray-curable adhesive composition may further contain a photosensitizer if necessary. By using a photosensitizer, the reactivity of the active energy ray-curable compound, the mechanical strength of the first adhesive layer 15 and the adhesion between the polarizer layer 10 and the first resin layer 21 may be improved. Examples of the photosensitizer include a carbonyl compound, an organic sulfur compound, a persulfide, a redox compound, an azo and diazo compound, a halide, and a photoreducible dye.

    (Cationic polymerization accelerator)    

The cationically polymerizable solventless active energy ray-curable compound may further contain a compound that promotes cation polymerization such as oxetane and polyalcohol.

    (Other additives)    

The active energy ray hardening type adhesive composition may further contain an ion trapping agent, an antioxidant, a chain transfer agent, an adhesion-imparting agent, a thermoplastic resin, a filler, a flow rate adjusting agent, a plasticizer, an antifoaming agent, and an antistatic agent as required. Additives, leveling agents, radical polymerization initiators and other additives.

    <Second Adhesive Layer>    

The second adhesive layer 25 is a layer for bonding the polarizer layer 10 and the second resin layer 22 together. The second adhesive layer 25 can be formed of the same active energy ray-curable adhesive composition as the active energy ray-curable adhesive composition forming the first adhesive layer 15, or it can be formed freely by containing a (meth) acrylic compound or the like. The base polymerizable curable component is formed of a different adhesive composition such as a radical polymerizable adhesive as a main component. The surface of the polarizer layer 10 may be directly laminated with the second resin layer 22 without the second adhesive layer 25 therebetween.

The second adhesive layer 25 is a cured product layer of an active energy ray-curable adhesive composition containing an active energy ray-curable compound and a cationic polymerization initiator. The active energy ray-curable compound contains an alicyclic epoxy compound, and When the atomic concentration ratio (N / C ratio) of the nitrogen element to the carbon element on the surface in contact with the second resin layer 22 is 1.0 or more, the active energy ray-curable adhesive composition that becomes the first adhesive layer 15 as described above Similarly, it is preferable to adjust the content of the alicyclic epoxy compound in the active energy ray-curable adhesive composition. Specifically, when the film thickness of the polarizer layer is 18 μm or more and 25 μm or less, the polarizer layer preferably contains 10 to 70 parts by weight of the alicyclic epoxy compound with respect to 100 parts by weight of the active energy ray-curable compound; When the film thickness is less than 18 μm, the alicyclic epoxy compound is preferably contained in an amount of 10 to 55 parts by weight based on 100 parts by weight of the active energy ray-curable compound. In addition, when the film thickness of the polarizer layer is 25 μm or less, the content of the alicyclic epoxy compound is M [parts by weight] with respect to 100 parts by weight of the active energy ray-curable compound, and the iodine per unit area of the polarizer layer is When the amount is I [g / cm ² ], M may be 7 [parts by weight] or more and satisfy the formula (1): I ≧ 2.1M × 10 ^-6 -7.8 × 10 ^-5 (1). When the content of the alicyclic epoxy compound is within the above range, it is possible to suppress color unevenness that may occur after the polarizing plate is exposed to a hot and humid environment. The components contained in the active energy ray-curable adhesive composition forming the second adhesive layer 25 at this time are the same as those described in the first adhesive layer 15 described above.

    <Second resin layer 22>    

The second resin layer 22 is provided on the opposite side of the polarizer layer 10 from the side on which the first resin layer 21 is provided. The polarizing plate 1 is not limited to the example shown in FIG. 1, and may include or may not include the second resin layer 22 laminated on the polarizer layer 10. When the polarizing plate 1 includes the second resin layer 22, the second resin layer 22 may be formed in a single layer in the same manner as the first resin layer 21, or may be formed in a plurality of layers. The resin forming the second resin layer 22 may be composed of the same resin as the first resin layer 21 or may be composed of a different thermoplastic resin. In addition, the second resin layer 22 may have the same atomic concentration ratio (N / C ratio) of nitrogen element to carbon element (N / C ratio) of the surface on the side in contact with the second adhesive layer 25 as the first resin layer 21, for example, for example, The N / C ratio of the undercoat layer forming the second resin layer 22 may be 1.0 or more.

Second resin layer 22 and the first resin layer 21 in the same manner, comprising preferably at a temperature of 40 ℃, relative humidity of 90% moisture permeability of 1500g / m ² / 24hr or less low moisture-permeable layer. When the second resin layer 22 is two or more layers, at least one of the two or more layers may be a low moisture-permeable layer. The moisture permeability may be 1000 g / m ² / 24hr or less, and may be 420 g / m ² / 24hr or less. The color unevenness generated when the polarizing plate is exposed to a hot and humid environment, and the polarizing plate of the second resin layer 22 having moisture permeability is liable to be noticeable. For this reason, a polarizing plate especially when the second layer 22 contains the resin at a temperature of 40 ℃, 90% relative humidity in a moisture permeability of 1500g / m low moisture-permeable layer ² / 24hr or less, the color can be effectively suppressed without Uniform effect.

    [Example]    

Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to these examples. The content and% used in the examples and comparative examples are shown in% and parts. Unless otherwise specified, they are based on weight.

    [Examples 1 to 13, Reference Examples 1 and 2, Comparative Examples 1 to 5]         (Production of polarizer layer x)    

A polyvinyl alcohol-based resin film having an average polymerization degree of about 2,400, a degree of saponification of 99.9 mol% or more, and a thickness of 60 μm is immersed in pure water at 30 ° C and then immersed in iodine / potassium iodide / water at a temperature of 0.02 / 2. / 100 of water solution. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. Next, it was washed with pure water at 8 ° C for 20 seconds, and then dried at 65 ° C to obtain a polarizer layer x having a polyvinyl alcohol-based resin film adsorbed and aligned with iodine. The stretching is mainly performed in the steps of iodine dyeing and boric acid treatment, and the total stretching ratio is 5.3 times. The obtained film thickness of the polarizer layer x is 23 μm, and the monomer transmittance is 42.7%. The amount of iodine in the polarizer layer x was 6.3 × 10 ^-5 g / cm ² when measured according to a procedure of [quantification of iodine amount] described later.

    (Production of the first resin layer)    

First resin layers including methacrylic resin films a to c shown below were prepared and prepared. For the methacrylic resin films a to c, the surface (coated surface) coated with the UV-curable urethane resin and the uncoated surface are respectively determined according to the procedure of [quantification of the amount of surface elements] described later. (Film surface) The measured atomic concentration ratio (N / C ratio) of the nitrogen element / carbon element is shown in Table 1.

    [Methacrylic resin film a]    

The methacrylic resin a was stretched to produce a biaxially stretched film having a thickness of 40 μm. Further, a methacrylic resin film a was obtained by coating an ultraviolet curable urethane resin on one side thereof.

    [Methacrylic resin film b]    

The methacrylic resin b was stretched to produce a biaxially stretched film having a thickness of 40 μm. Furthermore, a methacrylic resin film b was obtained by coating an ultraviolet curable urethane resin on one side thereof.

    [Methacrylic resin film c]    

The methacrylic resin c was stretched to produce a biaxially stretched film having a thickness of 40 μm. Furthermore, a methacrylic resin film c was obtained by coating an ultraviolet curable urethane resin on one side thereof.

    (Production of the second resin layer)    

A second resin layer including the following methacrylic resin film d was produced by the following procedure. The second resin layer in this example and the like is a layer forming a protective layer of the polarizer layer.

    [Methacrylic resin film d]    

A copolymer of methyl methacrylate / methyl acrylate = 96% / 4% was prepared as a methacrylic resin d. In addition, as the rubber particles, the innermost layer is composed of a hard polymer polymerized with a small amount of allyl methacrylate in methyl methacrylate, and the intermediate layer is mainly composed of butyl acrylate. It is composed of a soft elastomer obtained by polymerizing styrene and a small amount of allyl methacrylate. The outermost layer is a hard polymer obtained by polymerizing a small amount of allyl methacrylate with methyl methacrylate. The elastomer particles constituting the three-layer structure have an average particle diameter up to the elastomer of the intermediate layer of 240 nm. In addition, in this rubber particle, the total weight of the innermost layer and the intermediate layer is 70% of the entire particle.

70% of the methacrylic resin d and 30% of the rubber particles were mixed using a super mixer, and melt-kneaded with a biaxial extruder to obtain pellets. The particles are put into 65mm The single-screw extruder was extruded through a T-die at a set temperature of 275 ° C. The film was clamped and cooled by two polishing rollers with a mirror surface to obtain a thickness of 80 μm and a moisture permeability of 60 g / m ² / 24hr. Methacrylic resin film d.

    (Preparation of active energy ray hardening type adhesive composition)    

The alicyclic epoxy compound (A1), alicyclic epoxy compound (A2), and photocationic polymerization initiator (B1) shown below were mixed in the amounts shown in Table 2 to obtain an active energy ray-curable adhesive. Solventless UV-curable adhesives (hereinafter referred to simply as "adhesives") of the agent composition e to j.

    [Alicyclic epoxy compound (A1)]    

3 ’, 4’-epoxycyclohexenyl carboxylic acid 3,4-epoxycyclohexenyl methyl ester (" Celloxide 2021P "manufactured by DAICEL Chemical Industries, Ltd.)

    [Alicyclic epoxy compound (A2)]    

Neopentyl glycol epoxy propyl ether

    [Photocationic polymerization initiator (B1)]    

Triarylthionium hexafluorophosphate

    (Production of polarizing plate)    

A laminated body having a layer structure of a first resin layer / a first adhesive layer / a polarizer layer x / a second adhesive layer / a second resin layer was obtained by the procedure shown below. In this example, the comparative example, and the reference example, the methacrylic resin film d is used as the second resin layer, and the above-mentioned adhesive agent f is used as the adhesive agent constituting the second adhesive agent layer.

Corona discharge treatment was performed on the bonding surfaces of the first resin layer and the second resin layer shown in Tables 3 and 4 and the polarizer layer x. The corona discharge treatment surface (the bonding surface with the polarizer layer x) of the first resin layer was coated with the adhesive on the bonding surface of the second resin layer and the polarizer layer x as shown in Tables 3 and 4. f. Then, a first resin layer is laminated on one side of the polarizer layer x with the above-mentioned applied adhesive, and a second resin layer is laminated on the other side of the polarizer layer x with the above-mentioned applied adhesive f. The roller is combined to obtain the above-mentioned laminated body. When the laminated body was obtained, the coating amount and the bonding speed of the adhesive were adjusted so that the film thickness after curing of the adhesive became 2.0 μm.

Ultraviolet rays were irradiated from the resin layer side of the obtained laminated body, thereby curing the adhesive on both sides to obtain a polarizing plate. Ultraviolet irradiation is performed by using a "D bulb" manufactured by Fusion UV system of a UV irradiation device with a belt conveyor so that the illuminance in the wavelength range of 260 to 320 nm is 200 mW / cm ² and the cumulative light amount is 200 mJ / cm ² way.

    [Reference Example 3]         (Fabrication of Polarizer Layer y)    

A polyvinyl alcohol-based resin film having an average degree of polymerization of about 2,400, a degree of saponification of 99.9 mol% or more, and a thickness of 75 μm was immersed in pure water at 30 ° C., and the weight ratio of iodine / potassium iodide / water was 0.02 / 2 / 100 of water solution. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. Next, it was washed with pure water at 8 ° C for 20 seconds, and then dried at 65 ° C to obtain a polarizer layer y in which a polyvinyl alcohol-based resin film adsorbed and aligned iodine. The stretching is mainly performed in the steps of iodine dyeing and boric acid treatment. The film thickness of the obtained polarizer layer y is 28 μm, and the monomer transmittance is 42.7%. The amount of iodine in this polarizer layer y was 7.5 × 10 ^-5 g / cm ² when measured according to a procedure of [quantification of iodine amount] described later.

    (Production of polarizing plate)    

A polarizing plate was obtained in the same manner as in Example 1 except that the above-mentioned adhesive j was used as the adhesive constituting the first adhesive layer and the polarizer layer y was used as the polarizer layer.

    [Example 14, Comparative Examples 6 and 7]         (Fabrication of Polarizer Layer y)    

A polyvinyl alcohol-based resin film having an average degree of polymerization of about 2,400, a degree of saponification of 99.9 mol% or more, and a thickness of 30 μm was immersed in pure water at 30 ° C., and the weight ratio of iodine / potassium iodide / water was 0.02 / 2 at 30 ° C. / 100 of water solution. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. Then, it was washed with pure water at 8 ° C for 20 seconds, and then dried at 65 ° C to obtain a polarizer layer z in which a polyvinyl alcohol-based resin film adsorbed and aligned iodine. The stretching is mainly performed in the steps of iodine dyeing and boric acid treatment. The film thickness of the obtained polarizer layer z is 13 μm, and the monomer transmittance is 42.7%. The amount of iodine in this polarizer layer z was 2.4 × 10 ^-5 g / cm ² when measured according to a procedure of [quantification of iodine amount] described later.

    (Production of polarizing plate)    

A polarizing plate was obtained in the same manner as in Example 1 except that the adhesives shown in Tables 3 and 4 were used as the adhesive constituting the first adhesive layer, and the polarizer layer z was used as the polarizer layer.

    [Measurement of film thickness]    

Using a digital length measuring machine (MH-15, manufactured by Nikon), the film thickness of the first adhesive layer and the second adhesive layer was measured.

    [Quantification of surface element amount]    

The K-Alpha ^TM + X-ray photoelectron spectroscopy (XPS) system manufactured by ThermoFisher Scientific was used to perform qualitative / quantitative analysis of elements on the surface of the resin layer in contact with the first adhesive layer. As an X-ray light source, use single-light Al-Kα with a measurement range of 400 μm The output is 72W, the neutralization condition is 0.15mA / 0.2V, the energy is 50eV, and the number of scans is 5 times (Step: 0.1eV). The photoelectron emission angle is 90 ° to the sample surface, and the measurement is performed.

    [Determination of monomer transmittance]    

An absorbance spectrometer with an integrating sphere ("V7100" manufactured by JASCO Corporation) was used for the polarizer alone, and the obtained transmittance was corrected for visual sensitivity through a 2 degree viewing angle (C light source) of JIS Z 8701. The visual acuity correction unit transmittance Ty was measured.

    [Quantitative amount of iodine]    

The amount of iodine I [g / cm ² ] in the polarizer layer was quantified by the following procedure using oxygen combustion ion chromatography. Weigh the polarizer layer, wrap it with filter paper, and place it in a platinum cage. An absorption liquid [a composition solution using a mixed solution of an alkali solution and a reducing agent (such as hydrazine) as an example] was put into a flask, and the flask was filled with oxygen. Then, the filter paper was ignited after being placed in a platinum cage with the polarizer layer wrapped, and immediately put into the flask together with the platinum cage, and the polarizer layer wrapped in the filter paper was burned in the flask. After the combustion was completed, the mixture was left to stand for 30 minutes to absorb the iodine component by the absorption liquid, and then the amount of iodine absorbed by the absorption liquid was quantified (mass ratio) using ICS-1000 (manufactured by Japan Dionex). The iodine amount was converted from the mass fraction to the iodine amount I [g / cm ² ] by using the density and thickness of the polarizer layer.

    [Measurement of moisture permeability]    

The moisture permeability of the second resin layer at a temperature of 40 ° C and a relative humidity of 90% was measured by the cup method specified in JIS Z 0208.

    [Appearance evaluation after polarizing plate's damp heat endurance]    

A 100 mm × 100 mm square was cut out of the polarizing plate produced by the above-mentioned polarizing plate manufacturing procedure, and the cut surface and its vicinity were covered with Kapton tape, and then put into an oven at 80 ° C. and 90% RH and taken out after 12 hours. When observing the polarizing plate immediately after being taken out to observe the state of crossed Nicols, or arranging the polarizing plate alone to illuminate the illumination light from a surface opposite to the surface on the viewing side and placing it in the form of crossed Nicols for observation It was evaluated by visual observation as described below whether color unevenness or discoloration of the polarizing plate was observed.

    [Evaluation of color unevenness]    

When the polarizing plate is placed in a crossed Nicols state and observed, the color change (red or blue) of the polarizing plate is regarded as uneven color defects, and the following criteria are evaluated.

A: Color unevenness is not recognized at all

B: Very slight color unevenness is recognized

C: Partial color unevenness is recognized

D: Uneven overall color of the polarizing plate is recognized

E: Strongly recognize uneven color across the polarizer

    [Discolored evaluation]    

When the polarizing plate is irradiated with illuminating light from a surface opposite to the viewing side, the defect in which the portion lacking the coloring caused by iodine in the polarizing plate becomes a bright portion is regarded as discoloration, and the following is taken as Benchmarking.

a: Discoloration is not recognized at all

b: Partial discoloration is recognized

c: The overall discoloration of the polarizer is recognized

    [Creation of Figure 2]    

From Examples, Reference Examples, and Comparative Examples, Examples 1, 5, 8, and 4 using a methacrylic resin film a as the first resin layer and a bonding surface being a coating surface (N / C ratio of 5.8) 11, 14, Comparative Examples 1, 6, 7, and Reference Example 3 Let the content M [parts by weight] of the alicyclic epoxy compound be the vertical axis, and the amount of iodine I [g / cm ² ] in the polarizer layer be set Plot for horizontal axis. This diagram is shown in FIG. 2. In the graph shown in Fig. 2, the color unevenness is evaluated as "A" by "○", B by "●", C by "△", D by "▲", and E Those are indicated by "×". In the graph shown in FIG. 2, a straight line represented by the right side (2.1M × 10 ^-6 -7.8 × 10 ^-5 ) of the formula (1) is also displayed.

    [Exploration of results]    

As shown in Examples 1 to 13 in Table 3, the film thickness of the polarizer layer is 18 μm or more and 25 μm or less, and the N / C ratio on the bonding surface (the surface in contact with the first adhesive layer) of the first resin layer When it is 1.0 or more, the content of the alicyclic epoxy compound in the active energy ray-curable adhesive composition forming the first adhesive layer is 10 to 70 parts by weight based on 100 parts by weight of the active energy ray-curable compound. In the range, no color unevenness was seen at all.

On the other hand, as shown in Reference Examples 1 and 2 of Table 4, when the N / C ratio on the bonding surface of the first resin layer is 0.6 or 0.8, even if the content of the alicyclic epoxy compound is 75 parts by weight No color unevenness was recognized. Furthermore, as shown in Reference Example 3 of Table 4, when the film thickness of the polarizer layer was 28 μm, even if the content of the alicyclic epoxy compound was 75 parts by weight, the occurrence of color unevenness was very slight.

As shown in Comparative Examples 1 to 4 in Table 4, when the film thickness of the polarizer layer is 23 μm and the N / C ratio on the bonding surface of the first resin layer is 1.0 or more, if the content of the alicyclic epoxy compound is At 75 parts by weight, uneven coloring of the entire polarizing plate was recognized. As shown in Comparative Example 5 in Table 4, when the content of the alicyclic epoxy compound is 5 parts by weight, the active energy ray-curable adhesive composition does not harden.

As shown in Example 14 of Table 3, when the film thickness of the polarizer layer is less than 18 μm, and the N / C ratio on the bonding surface (the surface contacting the first adhesive layer side) of the first resin layer is 1.0 or more, With respect to 100 parts by weight of the active energy ray-curable compound, if the content of the alicyclic epoxy compound in the active energy ray-curable adhesive composition forming the first adhesive layer is 50 parts by weight, a very slight Color unevenness occurs.

On the other hand, as shown in Comparative Examples 6 and 7 in Table 4, the film thickness of the polarizer layer was 13 μm, and the N / C ratio on the bonding surface (the surface contacting the first adhesive layer side) of the first resin layer When it is 1.0 or more, the content of the alicyclic epoxy compound in the active-energy-ray-curable adhesive composition forming the first adhesive layer is 75 parts by weight, 65 with respect to 100 parts by weight of the active-energy-ray-curable compound. At parts by weight, uneven color is noticed across the polarizer.

From the graph shown in FIG. 2, the content of the alicyclic epoxy compound was set to M [parts by weight] and the amount of iodine in the polarizer layer was set to I [g / cm ² ], by satisfying the formula (1): I ≧ 2.1M × 10 ^-6 -7.8 × 10 ^-5 (1); that is, the graph shown in FIG. 2 is expressed by the right side of the formula (1) In the example where the straight line is on the upper side, the occurrence of color unevenness is not recognized at all.

As shown in Examples 8 to 13 in Table 3, when the content of the aliphatic epoxy compound in the active energy ray-curable adhesive composition is less than 65 parts by weight, discoloration of the polarizing plate is suppressed.

Claims (8)

    A polarizing plate has a polarizer layer, an adhesive layer, and a first resin layer in this order, wherein the polarizer layer is a polyvinyl alcohol resin film that is oriented with iodine; the first resin layer and the adhesive are The atomic concentration ratio (N / C ratio) of nitrogen and carbon on the surface of the layer in contact with the layer is 1.0 or more; the adhesive layer system includes an active energy ray hardening compound and an active energy ray hardening type of a cationic polymerization initiator. The hardened material layer of the adhesive composition; the active energy ray-curable compound includes an alicyclic epoxy compound; the film thickness of the polarizer layer is 18 μm or more and 25 μm or less; and 100 parts by weight of the active energy ray-curable compound, The content of the aforementioned alicyclic epoxy compound is 10 to 70 parts by weight.         A polarizing plate has a polarizer layer, an adhesive layer, and a first resin layer in this order, wherein the polarizer layer is a polyvinyl alcohol resin film that is oriented with iodine; the first resin layer and the adhesive are The atomic concentration ratio (N / C ratio) of nitrogen and carbon on the surface of the layer in contact with the layer is 1.0 or more; the adhesive layer system includes an active energy ray hardening compound and an active energy ray hardening type of a cationic polymerization initiator. The hardened material layer of the adhesive composition; the active energy ray-curable compound contains an alicyclic epoxy compound; the film thickness of the polarizer layer is less than 18 μm; The content of the cyclic epoxy compound is 10 to 55 parts by weight.     A polarizing plate has a polarizer layer, an adhesive layer, and a first resin layer in this order, wherein the polarizer layer is a polyvinyl alcohol resin film that is oriented with iodine; the first resin layer and the adhesive are The atomic concentration ratio (N / C ratio) of nitrogen and carbon on the surface of the layer in contact with the layer is 1.0 or more; the adhesive layer system includes an active energy ray hardening compound and an active energy ray hardening type of a cationic polymerization initiator. The hardened material layer of the adhesive composition; the active energy ray-curable compound includes an alicyclic epoxy compound; the film thickness of the polarizer layer is 25 μm or less; the weight of the fat is 100 parts by weight relative to 100 parts by weight of the active energy ray-curable compound. When the content of the cyclic epoxy compound is M [parts by weight], and when the amount of iodine per unit area of the polarizer layer is I [g / cm ² ], M is 7 [parts by weight] or more and satisfies the formula (1) : I ≧ 2.1M × 10 ^-6 -7.8 × 10 ^-5 (1).     The polarizing plate according to any one of claims 1 to 3 in the scope of patent application, wherein the film thickness of the adhesive layer is 3.5 μm or less.     The polarizing plate according to any one of claims 1 to 4 in the scope of patent application, wherein the first resin layer has a moisture permeability of 1500 g / m ² / 24hr or less at a temperature of 40 ° C and a relative humidity of 90%. Layers. According to the polarizing plate described in any one of claims 1 to 5, the second resin layer is provided on the surface of the polarizer layer opposite to the side on which the adhesive layer is arranged; 2 The resin layer includes a layer having a temperature of 40 ° C. and a relative humidity of 90% and a moisture permeability of 1500 g / m ² / 24hr or less.     The polarizing plate according to any one of claims 1 to 6 in the scope of patent application, wherein the single-layer transmittance of the polarizer layer is 40% or more.         The polarizing plate according to any one of claims 1 to 7, wherein the active energy ray-curable compound further includes an aliphatic epoxy compound; wherein the active energy ray-curable compound is 100% of the active energy ray-curable compound. The content of the aforementioned aliphatic epoxy compound is less than 65 parts by weight.