KR101921856B1 - Polarizing plate - Google Patents

Abstract

An object of the present invention is to provide a polarizing plate capable of suppressing color unevenness after exposure under a humid (hot) environment.
The polarizing plate 1 has a polarizer layer 10, an adhesive layer 15 and a first resin layer 22 in this order. The polarizer layer 10 is a polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented, and has a film thickness of 18 占 퐉 or more and 25 占 퐉 or less. The first resin layer 15 has an atomic concentration ratio (N / C ratio) of the nitrogen element and the carbon element on the surface in contact with the adhesive layer is 1.0 or more. The adhesive layer 15 is a cured layer of an active energy ray-curable adhesive composition comprising 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

POLARIZING PLATE

The present invention relates to a polarizing plate.

The polarizing plate is used as one of the optical components constituting a liquid crystal display or the like. The polarizing plate usually has a laminated structure in which a protective film is laminated on one side or both sides of a polarizing film, and the laminated structure is incorporated into the liquid crystal display device.

It is known that an active energy ray-curable adhesive is used for bonding the polarizing film and the protective film. As the active energy ray curable adhesive, a cationic polymerizable adhesive containing a cationically polymerizable curable component such as an active energy ray curable epoxy compound as a main component may be used. The cationic polymerizable adhesive has an advantage that it can be applied when bonding a polarizing film with a protective film which is hardly subjected to oxygen inhibition and has a low moisture permeability. For example, Patent Documents 1 and 2 disclose the use of a photo-curing adhesive containing an alicyclic epoxy compound as a photo cationic curable component in order to bond 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 primer layer. For example, Patent Document 3 discloses a polarizing plate using a cationic polymerizable adhesive excellent in curability even when a protective film having a urethane primer layer is used.

Patent Document 4 discloses an acrylic thermoplastic resin which is excellent in heat resistance and is highly controlled in birefringence and used in an optical material such as a polarizing plate protective film and contains an N-substituted maleimide monomer-derived repeating unit Lt; / RTI >

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 20-205050 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2008-208246 [Patent Document 3] International Publication No. 2014/129260 [Patent Document 4] International Publication No. 2011/149088

A polarizing plate obtained by bonding a protective film having a polarizing film and a resin layer containing nitrogen as an active energy ray curable adhesive by using an adhesive containing an alicyclic epoxy compound exhibits color unevenness when exposed under a humid (hot) . The recent trend toward thinner polarizers due to the weight reduction and thinness of liquid crystal display devices and the like, and the above-mentioned occurrence of color unevenness are particularly conspicuous in polarized polarizing plates.

An object of the present invention is to provide a polarizing plate capable of suppressing color unevenness after exposure under a humid environment.

The present invention provides the following polarizing plate.

[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 in which iodine is adsorbed and oriented,

Wherein the first resin layer has an atomic concentration ratio (N / C ratio) of a nitrogen element to a carbon element on the surface in contact with the adhesive layer is 1.0 or more,

Wherein the adhesive layer is a cured layer of an active energy ray curable adhesive composition comprising an active energy ray curable compound and a cationic polymerization initiator,

The active energy ray-curable compound includes an alicyclic epoxy compound,

The film thickness of the polarizer layer is 18 占 퐉 or more and 25 占 퐉 or less,

Wherein 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.

[2] 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 in which iodine is adsorbed and oriented,

Wherein the first resin layer has an atomic concentration ratio (N / C ratio) of a nitrogen element to a carbon element on the surface in contact with the adhesive layer is 1.0 or more,

Wherein the adhesive layer is a cured layer of an active energy ray curable adhesive composition comprising an active energy ray curable compound and a cationic polymerization initiator,

The active energy ray-curable compound includes an alicyclic epoxy compound,

The film thickness of the polarizer layer is less than 18 [mu] m,

Wherein 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.

[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 in which iodine is adsorbed and oriented,

Wherein the first resin layer has an atomic concentration ratio (N / C ratio) of a nitrogen element to a carbon element on the surface in contact with the adhesive layer is 1.0 or more,

Wherein the adhesive layer is a cured layer of an active energy ray curable adhesive composition comprising an active energy ray curable compound and a cationic polymerization initiator,

The active energy ray-curable compound includes an alicyclic epoxy compound,

The film thickness of the polarizer layer is 25 占 퐉 or less,

When the amount 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 amount of iodine per unit area of the polarizer layer is I [g / cm2], M is 7 ] Or more, and the formula (1):

I? 2.1 M × 10 ^-6 -7.8 × 10 ^-5 (1)

.

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

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

[6] The polarizing plate according to any one of [1] to [5], wherein the polarizing layer has a second resin layer on a surface opposite to a side on which the adhesive layer is disposed,

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

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

[8] The active energy ray-curable compound further comprises an aliphatic epoxy compound,

The polarizing plate according to any one of [1] to [7], 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 under a humid environment.

1 is a schematic cross-sectional view showing an example of the layer structure of a polarizing plate according to the present invention.
2 is a graph plotting the amount of iodine with respect to the content of the alicyclic epoxy compound in the polarizing plate obtained in the examples.

Hereinafter, the polarizing plate according to the present invention will be described in detail with reference to embodiments.

The polarizing plate according to the present invention comprises a polarizer layer and a first resin layer laminated on one side thereof with an adhesive layer which is a cured layer of an active energy ray-curable adhesive composition. As the polarizer layer, iodine is adsorbed and oriented on a polyvinyl alcohol-based film containing a polyvinyl alcohol-based resin as a main component. The first resin layer is a resin cured layer, and the atomic concentration ratio (N / C ratio) of the nitrogen element to the carbon element on the surface in contact with the adhesive layer is 1.0 or more. The active energy ray curable adhesive composition constituting the adhesive layer comprises an active energy ray curable compound containing an alicyclic epoxy compound and a cationic polymerization initiator.

The content of the alicyclic epoxy compound is 10 to 70 parts by weight with respect to 100 parts by weight of the active energy ray curable compound when the film thickness of the polarizer layer is 18 占 퐉 or more and 25 占 퐉 or less and when the thickness of the polarizer layer is less than 18 占 퐉, Is 10 to 55 parts by weight based on 100 parts by weight of the active energy ray curable compound. When the content of the alicyclic epoxy compound is M [parts by weight] relative to 100 parts by weight of the active energy ray curable compound and the amount of iodine per unit area of the polarizer layer is I [g / cm < 2 & , M is not less than 7 [parts by weight], and the formula (1):

I? 2.1 M × 10 ^-6 -7.8 × 10 ^-5 (1)

May be satisfied.

The polarizing plate according to the present invention can suppress color unevenness even after being exposed under a humid environment. In the present specification, " color unevenness " means that when a polarizing plate is observed in a cross-Nicol state according to the description of examples described later, the color change (reddish or blue) .

The mechanism of occurrence of color unevenness occurring in the polarizing plate is presumed as follows. The epoxy compound (monomer) as an active energy ray-curable compound contained in the active energy ray-curable adhesive composition becomes a cured layer by cationic polymerization. When a compound having a Lewis basic or Bronsted basicity higher than that of an epoxy compound is present during the cationic polymerization of the epoxy compound, the polymerization reaction of the epoxy compound is inhibited. Generally, a compound having a nitrogen-containing functional group has a higher Lewis basicity or Bronsted basicity than an epoxy compound. 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 inhibited, and an unreacted epoxy compound May remain. The epoxy compound remaining in the adhesive layer may migrate from the adhesive layer to the polarizer layer when the polarizer is exposed under a humid environment.

In the polarizer layer, iodine is adsorbed and oriented on a polyvinyl alcohol-based film. Iodine in the polarizer layer exists in addition to I ₂ , I ^- , I ^{3 -} , I ^{5 -} and they are in an equilibrium state. Aliphatic epoxy compound is high in reactivity is considered among the epoxy compound, I of the polarizer ^layer, reacts with, I of the polarizer ^layer, and consume. As a result, the equilibrium state of iodine (I ₂ , I ^- , I ^3- , I ^5- ) in the polarizer layer changes. At this time, it is considered that when I < ^{3 &gt}; decreases, the blue phase of the polarizer layer increases and when I < ⁵ > decreases, the red phase of the polarizer layer increases. Therefore, when the amount of the alicyclic epoxy compound remaining in the adhesive layer of the polarizing plate is increased, the amount of iodine reacting with the alicyclic epoxy compound increases, and the portion of the polarizer layer reacted with iodine appears as color unevenness of the polarizing plate It seems to be easy.

This color unevenness is caused by the fact that the polarizing plate has a polarizer layer in which iodine is adsorbed and oriented on a polyvinyl alcohol film, an adhesive layer that is a cured layer of a cationic polymerizable active energy ray-curable adhesive composition comprising an alicyclic epoxy compound, And the first resin layer having an N / C ratio of 1.0 or more on the side contacting the first resin layer. As described below, the color unevenness of the polarizing plate tends to occur as the thickness of the polarizer layer and the thickness of the adhesive layer become thinner. As the moisture permeability of the first resin layer formed on the polarizing plate becomes smaller, The larger the mass transmittance of the layer is, the more likely it is to occur.

Hereinafter, the polarizing plate according to the present invention will be described in detail. An example of the layer structure of the polarizing plate 1 is shown in Fig. The polarizing plate 1 shown in Fig. 1 comprises a polarizer layer 10; A first resin layer (21) laminated on one side of the polarizer layer (10) through a first adhesive layer (adhesive layer) (15); And a second resin layer 22 that is laminated on the other side of the polarizer layer 10 through a second adhesive layer 25. As shown in Fig. 1, each adjacent layer of the polarizing plate 1 is in contact with each other.

<Polarizer layer>

The polarizer layer 10 is a film in which iodine is adsorbed and oriented on a polyvinyl alcohol-based film containing a polyvinyl alcohol-based resin as a main component. The polarizer layer 10 is, for example, a polyvinyl alcohol based resin film which is uniaxially stretched and in which iodine is adsorbed and oriented. The polyvinyl alcohol-based resin constituting the polarizer layer 10 may be a polyvinyl alcohol which is a saponified polyvinyl acetate, a polyvinyl alcohol which is a copolymer of vinyl acetate and another monomer copolymerizable therewith (for example, ethylene or an unsaturated carboxylic acid) It may be a vinyl alcohol-based copolymer as a cargo.

The polarizer layer 10 may be formed by, for example, a process of uniaxially stretching a polyvinyl alcohol-based resin film, a step of dyeing a polyvinyl alcohol-based resin film with iodine and adsorbing the iodine, a step of iodine-adsorbed polyvinyl alcohol- A step of treating with an aqueous solution of boric acid and a step of washing with water after treatment with an aqueous solution of boric acid. The dyeing by iodine can be carried out by immersing the film in an aqueous solution containing iodine, and the treatment with an aqueous solution of boric acid can be carried out 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, simultaneously with, or after dyeing with iodine. When uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. In addition, uniaxial stretching may be performed in these plural steps.

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 treatment. In this case, the stretched and dyed polyvinyl alcohol-based resin layer becomes a polarizer layer. The laminate can be obtained, for example, by coating a polyvinyl alcohol resin on a base film. The base film laminated on the polarizer layer 10 may be peeled off or used as the first resin layer 21 or the second resin layer 22. The magnification of the stretching is usually 3 to 7 times.

The thickness of the polarizer layer 10 is not particularly limited as long as it is 25 m or less, but it is preferable that the film thickness is thin in order to meet the demand for thinning of the polarizer 1. Specifically, the film thickness of the polarizer layer 10 is preferably 23 占 퐉 or less, more preferably 18 占 퐉 or less, and further preferably 13 占 퐉 or less. The polarizer layer 10 usually has a film thickness of 1 mu m or more, preferably 2 mu m or more, and more preferably 5 mu m or more. The color unevenness that occurs when the polarizing plate is exposed under a humid environment tends to become noticeable in a polarizing plate using a thinned polarizing layer. Therefore, in the polarizing plate 1, especially when the thickness of the polarizer layer 10 is 25 占 퐉 or less, the effect of suppressing color unevenness can be effectively obtained.

The simple transmittance of the polarizer layer 10 is preferably 40% or more, 42.1% or more, and 42.7% or more. The upper limit value of the simple transmittance of the polarizer layer 10 is 50% or less, preferably 45% or less. The color unevenness that occurs when the polarizing plate is exposed under a humid environment is more likely to become noticeable in a polarizing plate using the polarizing layer 10 having a high single transmittance. Therefore, in the polarizing plate 1, the effect of suppressing color unevenness can be effectively obtained particularly when the polarizer layer 10 has a simple transmittance of 40% or more. The above-mentioned simple transmittance is a value measured by a measuring method performed in the following embodiment.

<First Resin Layer>

The first resin layer 21 is formed on one side of the polarizer layer 10 through the first adhesive layer 15. The first resin layer 21 may include, for example, a protective layer, a retardation layer, an optical compensation layer, a brightness enhancement layer, and the like of the polarizer layer 10. The surface of the first resin layer 21 on the side in contact with the first adhesive layer 15 is a surface of the first resin layer 21 and the first adhesive layer 15, The atomic concentration ratio (N / C ratio) of the nitrogen element and the carbon element is 1.0 or more for the purpose of improving optical properties, heat resistance and the like. The N / C ratio can be determined by qualitative and quantitative analysis of the element on the surface of the first resin layer 21 in contact with the first adhesive layer 15 according to the description of the embodiments to be described later, Measured using a spectroscopic (XPS) system.

The color unevenness that occurs when the polarizing plate 1 is exposed under a humid environment tends to become conspicuous as the nitrogen content is high on the surface of the first resin layer 21 in contact with the first adhesive layer 15. Therefore, in the polarizing plate 1, in the case where the N / C ratio in the surface of the first resin layer 21 on the side in contact with the first adhesive layer 15 is 1.0 or more, the effect of suppressing color unevenness Can be effectively obtained. The N / C ratio is not particularly limited as long as it is 1.0 or more, but may be 1.5 or more, and may be 2.0 or more. The upper limit value of the N / C ratio is not particularly limited, but 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 and may be composed of a layer in contact with the first adhesive layer 15 (hereinafter sometimes referred to as an "adhesive layer side surface layer") and a layer other than the adhesive layer side surface layer Layer (hereinafter sometimes referred to as &quot; another layer &quot;). The other layer may be one layer or two or more layers. When the first resin layer 21 is composed of a single layer, the N / C ratio of the first resin layer 21 may be 1.0 or more. When the first resin layer 21 has a plurality of layers, the N / C ratio of at least the adhesive layer side surface layer may be 1.0 or more.

Examples of the other layer include a protective layer, a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, an antifouling layer and a primer layer of the polarizer layer 10. Examples of the adhesive layer side surface layer include a primer layer and a protective layer. When the other layer is a primer layer, the primer layer can enhance the affinity of the first resin layer 21 with the layer formed on the side opposite to the side in contact with the first adhesive layer 15. When the surface layer on the side of the adhesive layer is a primer layer, the primer layer can increase the affinity to the first adhesive layer 15 and increase the adhesive strength. It is preferable that the first resin layer (21) has the other layer as the protective layer and the adhesive layer side surface layer as the primer layer.

The material forming the surface of the first resin layer 21 in contact with the first adhesive layer 15 is not particularly limited as long as the N / C ratio is 1.0 or more. For example, (Meth) acrylic resin, urethane resin, (meth) acrylamide resin, imide resin, melamine resin and the like, and it is preferable to use a (meth) acrylic resin or a urethane resin.

The first resin layer 21, the adhesive layer side surface layer and other layers constituting the first resin layer 21 may have a layer containing a methacrylic resin [A] described later, for example. When the first resin layer 21 is composed of a single layer and is formed using the methacrylic resin [A], the methacrylic resin [A] may be used such that the N / C ratio of the methacrylic resin [A] The content of each constituent unit constituting [A] may be adjusted. The N / C ratio in the case of forming the other layer using the methacrylic resin [A] is not particularly limited.

When the adhesive layer side surface layer constituting the first resin layer 21 is the primer layer, the material may be selected so that the N / C ratio of the primer layer is 1.0 or more. Examples of the material constituting the primer layer include a (meth) acrylic resin, a urethane resin, (meth) acrylic resin having a polar group in the skeleton and having a relatively low molecular weight and a relatively low glass transition temperature and containing a monomer containing N atom as a copolymer component ) Acrylamide resins, melamine resins, and the like.

When the adhesive layer side surface layer constituting the first resin layer 21 is a primer layer, the thickness of the primer layer after drying is usually 0.01 to 5 占 퐉, preferably 0.03 to 0.6 占 퐉. If the thickness is less than 0.01 탆, adhesion with other layers constituting the first resin layer 21 may be inferior. When the thickness exceeds 5 占 퐉, the hydrophilicity of the primer layer becomes excessive, and the water resistance of the polarizing plate may be poor.

The first resin layer 21 preferably includes a low moisture permeable layer having a moisture permeability of 1500 g / m 2/24 hr or less at a temperature of 40 ° C and a relative humidity of 90%. In the case where the first resin layer 21 is two or more layers, the low moisture permeable layer may be at least one of the adhesive layer side surface layer and another layer, and when the other layer is two or more layers, at least one layer . The moisture permeability may be 1000 g / m 2/24 hr or less, and may be 420 g / m 2/24 hr or less. The color unevenness that occurs when the polarizing plate is exposed under a humid environment is more conspicuous in a polarizing plate having a first resin layer having a low moisture permeability. Therefore, in the polarizing plate 1, when the first resin layer 21 includes a low moisture permeable layer having a moisture permeability of 1500 g / m 2/24 hr or less at a temperature of 40 ° C. and a relative humidity of 90% The suppression effect of the stain can be effectively obtained. The moisture permeability is a value measured by a measurement method performed in the following embodiments.

Hereinafter, the material that can form 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 respectively represented by the general formulas (I), (II) and (III), preferably methacrylic resin [A] , Or in the case of containing an additive, the resin component other than the additive may have a layer composed of the methacrylic resin [A].

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

The first structural unit constituting the methacrylic resin [A] is a structural unit represented by the general formula (I), and in the general formula (I), R ¹ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, A halogen atom (F, Cl, Br or I atom), a hydroxyl group, a hydroxyl group, a hydroxyl group, a hydroxyl group, a cyano group, An aryl group having 6 to 14 carbon atoms and at least one substituent selected from the group consisting of a nitro group, an alkoxy group having 1 to 12 carbon atoms, and an alkyl group having 1 to 12 carbon atoms. In the present specification, the alkyl group, the alkyl group in the arylalkyl group, and the alkyl group in the alkoxy group may be linear or branched.

(This is also true for an alkyl group which may be the substituent of the R ^1, which may be an aryl group.) The alkyl group having a carbon number of R ¹ is preferably 1-6, more preferably 1-4. Specific examples of the alkyl group which may be R ¹ include methyl, ethyl, n- or i-propyl, n-, i- or t-butyl, . Of these, a methyl group, an ethyl group, an n- or i-propyl group, a n-, i- or t-butyl group and a 2-ethylhexyl group are preferable from the viewpoints of transparency and weather resistance of the methacrylic resin [A] More preferred is a methyl group.

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

Specific examples of the cycloalkyl group which may be R ¹ include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a tricyclodecyl group, a bicyclooctyl group, a tricyclododecyl group, an isobornyl group, A t-butyl group, and a tetracyclododecyl group. Among them, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a tricyclodecyl group, a bicyclooctyl group, a tricyclododecyl group and an isobornyl group are preferable.

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

The aryl group having the specific substituent which can be R ¹ is preferably a phenyl group having a substituent, and specific examples thereof include a 2,4,6-tribromophenyl group, a 2- or 4-chlorophenyl group, a 2- A 2- or 4-methylphenyl group, a 2- or 4-ethylphenyl group, a 2- or 4-methoxyphenyl group, a 2- or 4-nitrophenyl group, a 2,4,6-trimethylphenyl group, Among them, a 2,4,6-tribromophenyl group is preferable.

The content of the first structural unit is preferably 50 to 95% by weight, more preferably 60 to 92% by weight, more preferably 70 to 90% by weight, more preferably 70 to 90% by weight, based on 100% by weight of the total of the methacrylic resin [A] More preferably 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 constitutional unit, or may contain two or more kinds of the first constitutional unit.

The first structural unit is a structural unit derived from methacrylic acid or 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 methacrylic acid esters, methyl methacrylate and benzyl methacrylate are preferably used from the viewpoint of transparency and weather resistance of the methacrylic resin [A].

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

The second constituent unit constituting the methacrylic resin [A] is a constitutional unit represented by the general formula (II), and in the general formula (II), R ² is an arylalkyl group having 7 to 14 carbon atoms, 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 an arylalkyl group having 7 to 14 carbon atoms Or an aryl group having 6 to 14 carbon atoms and at least one substituent selected from the group consisting of R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 14 carbon atoms.

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

Specific examples of the aryl group which may be R ² include a phenyl group, a naphthyl group and an anthracenyl group. Among them, a phenyl group is preferable from the viewpoints of heat resistance and low birefringence of the methacrylic resin [A].

The number of carbon atoms of the alkoxy group which may be a substituent of the aryl group which may be R ² is preferably 1 to 10, and more preferably 1 to 8. Specific examples of the alkoxy group include a methoxy group, ethoxy group, n- or i-propyloxy group, n-, i- or t-butyloxy group, 2-ethylhexyloxy group, . Alkyl group and specific examples of the aryl alkyl group having 7 to 14 of 1 to 12 carbon atoms in R ² can be a substituent of the aryl group which may be, an alkyl group and having a carbon number of 7 to 14 of 1 to 12 carbon atoms which may be the R ¹ &Lt; / RTI &gt;

The aryl group having the specific substituent which may be R ² is preferably a phenyl group having a substituent or a naphthyl group having a substituent, and specific examples thereof are the same as the specific examples of the aryl group having a substituent which may be R ¹ Do.

The number of carbon atoms of the alkyl group which may be R ³ or R ⁴ is preferably 1 to 6, more preferably 1 to 4. Specific examples of the alkyl group which may be R ³ and R ⁴ include a methyl group, ethyl group, n- or i-propyl group, n-, i- or t-butyl group, 2- ethylhexyl group, Lauryl group. Of these, a methyl group, an ethyl group, an n- or i-propyl group, a n-, i- or t-butyl group and a 2-ethylhexyl group are preferable from the viewpoints of transparency and weather resistance of the methacrylic resin [A] More preferred is a methyl group.

Specific examples of the aryl group which may be R ³ and R ⁴ include a phenyl group, a naphthyl group and an anthracenyl group, and in particular, from the viewpoints of heat resistance and low birefringence of the methacrylic resin [A] desirable.

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

The content of the second structural unit is 0.1 to 20% by weight, preferably 5 to 20% by weight, and more preferably 7 to 18% by weight, based on 100% by weight of the entire methacrylic resin [A] . When the content of the second structural 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, or may contain two or more kinds of the second constituent unit.

The second structural unit is a structural unit derived from an N-substituted maleimide compound represented by the following general formula (II '). In the formula (II ') R ^2, R ³ and R ⁴ are, the same meaning as R ^2, R ³ and R ⁴ in the formula (II). Among them, N-phenylmaleimide and N-benzylmaleimide are preferably used from the viewpoints of heat resistance and low birefringence of the methacrylic resin [A].

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

The third structural unit constituting the methacrylic resin [A] is the structural unit represented by the general formula (III), and in the general formula (III), R ⁵ represents a hydrogen atom, a cycloalkyl group having 3 to 12 carbon atoms, At least one selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkylalkyl group having 4 to 12 carbon atoms, or a halogen atom (F, Cl, Br or I atom), a hydroxyl group, a nitro group and an alkoxy group having 1 to 12 carbon atoms Represents an alkyl group having 1 to 12 carbon atoms and having one kind of substituent. R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 14 carbon atoms.

Examples of the cycloalkyl group which may be R ⁵ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a tricyclodecyl group, a bicyclooctyl group, A boronyl group, an adamantyl group, and a tetracyclododecyl group. Among them, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group are preferable, and from the viewpoints of transparency, weather resistance and low hygroscopicity of the methacrylic resin [A] Is more preferable.

The number of carbon atoms of the alkyl group which may 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 a methyl group, an ethyl group, an n- or i-propyl group, an n-, i- or t-butyl group, n-dodecyl group, n-octadecyl group, 2-ethylhexyl group, 1-decyl group and 1-dodecyl group. Among them, a methyl group, an ethyl group and an i-propyl group are preferable from the viewpoints of transparency and weather resistance of the methacrylic resin [A].

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

The number of carbon atoms of the alkoxy group which may be a substituent of the aryl group which may be R ⁵ is preferably 1 to 10, and more preferably 1 to 8. Specific examples of the alkoxy group include a methoxy group, ethoxy group, n- or i-propyloxy group, n-, i- or t-butyloxy group, 2-ethylhexyloxy group, .

Specific examples of the alkyl group having the specific substituent which may be R ⁵ include a dichloromethyl group, a trichloromethyl group, a trifluoroethyl group and a hydroxyethyl group, and among them, a trifluoroethyl group is preferable.

The number of carbon atoms of the alkyl group which may be R ⁶ and R ⁷ is preferably 1 to 6, more preferably 1 to 4. Specific examples of the alkyl group which may be R ⁶ and R ⁷ include a methyl group, an ethyl group, an n- or i-propyl group, an n-, i- or t-butyl group, a 2-ethylhexyl group, a nonyl group, Lauryl group. Of these, a methyl group, an ethyl group, an n- or i-propyl group, a n-, i- or t-butyl group and a 2-ethylhexyl group are preferable from the viewpoints of transparency and weather resistance of the methacrylic resin [A] More preferred is a methyl group.

Specific examples of the aryl group which may be R ⁶ and R ⁷ include a phenyl group, a naphthyl group and an anthracenyl group, and in particular, from the viewpoints of heat resistance and low birefringence of the methacrylic resin [A] desirable.

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

The content of the third structural unit is 0.1 to 49.9% by weight, preferably 0.1 to 35% by weight, more preferably 0.1 to 30% by weight, based on 100% by weight of the entire methacrylic resin [A] More preferably 0.1 to 15% by weight. When the content of the third constituent unit is within this range, transparency and low hygroscopicity of the methacrylic resin [A] can be made compatible. The methacrylic resin [A] may contain only one kind of the third constituent unit, or may contain two or more kinds of the third constituent unit.

The third structural unit is a structural unit derived from an N-substituted maleimide compound represented by the following general formula (III '). In the formula (III ') R ^5, R ⁶ and R ⁷ is a R ⁵ meaning, such as R ⁶ and R ⁷ in the formula (III). Among them, N-methylmaleimide, N-ethylmaleimide, Ni-propylmaleimide and N-cyclohexylmaleimide are preferably used from the viewpoint of weatherability of the methacrylic resin [A] N-cyclohexylmaleimide is more preferably used from the viewpoints of low hygroscopicity of the curable resin [A] and higher adhesion with the first adhesive layer 15.

The total content of the second and third constituent units is preferably 5 to 50% by weight, more preferably 5 to 40% by weight, based on 100% by weight of the total of the methacrylic resin [A] Preferably 10 to 35% by weight, more preferably 10 to 30% by weight, and particularly preferably 15 to 30% by weight. When the total content is within this range, the methacrylic resin [A] is advantageous in terms of heat resistance, weather resistance, low hygroscopicity and optical properties.

The molar ratio of the content of the second structural unit to the content of the third structural unit is preferably in the range of more than 0 and 15 or less in view of the optical properties (for example, low birefringence, low photoelasticity coefficient) of the methacrylic resin [A] , And more preferably 10 or less.

From the viewpoint of the optical properties of the methacrylic resin [A], it is preferable that the total content of the first, second and third constituent units is 80% by weight or more when the total amount of the methacrylic resin [A] is 100% desirable.

(Other constituent units of the methacrylic resin [A]),

The methacrylic resin [A] may further contain constituent units other than the first, second and third constituent units. The other constituent unit is not particularly limited as long as it is a constituent unit derived from another monomer copolymerizable with the monomer constituting the first, second and third constituent units.

Specific examples of the other monomer include aromatic vinyl; Unsaturated nitrile; A cyclohexyl group, a benzyl group or an acrylic acid ester having an alkyl group having 1 to 18 carbon atoms; Olefins; Diene; Vinyl ether; Vinyl esters; Vinyl fluoride; Allyl esters or methallyl esters of saturated fatty acid monocarboxylic acids such as allyl propionate; Polyfunctional (meth) acrylates; Polyarylates; Glycidyl compounds; Unsaturated carboxylic acids. The other monomers may be used alone, or two or more of them may be used in combination.

Specific examples of the aromatic vinyl include styrene, -methylstyrene, and divinylbenzene. Specific examples of the unsaturated nitrile include acrylonitrile, methacrylonitrile, ethacrylonitrile, and phenyl acrylonitrile.

Specific examples of the acrylic acid esters include acrylic acid esters such as methyl acrylate, ethyl acrylate, n- or i-propyl acrylate, n- or i-butyl acrylate, n- or i-pentyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, Decyl acrylate, lauryl acrylate, cyclohexyl acrylate, and benzyl acrylate.

Specific examples of olefins include ethylene, propylene, isobutylene, and diisobutylene. Specific examples of dienes include butadiene and isoprene. 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 vinyl fluoride include vinylidene fluoride.

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

Specific examples of the polyvalent arylate include diallyl phthalate and triallyl isocyanurate. Specific examples of the glycidyl compound include glycidyl (meth) acrylate and allyl glycidyl ether. Specific examples of unsaturated carboxylic acids include acrylic acid, itaconic acid, maleic acid, fumaric acid, and their half-esters or anhydrides thereof. Of these, as other monomers, styrene and? -Methylstyrene are preferably used.

From the viewpoint of low hygroscopicity of the methacrylic resin [A], the content of the other constituent units is preferably 0.1 to 20% by weight, more preferably 0.1 to 20% by weight, based on 100% by weight of the entire methacrylic resin [A] 0.1 to 15% by weight, more preferably 0.1 to 10% by weight. From the viewpoint of weatherability, the content of other structural units is preferably 10% by weight or less, more preferably 7% by weight or less.

The methacrylic resin [A] containing the above-mentioned first to third constituent units and optionally containing other constituent units may be composed of one kind of copolymer containing such constituent units, Or may be composed of two or more kinds of copolymers differing in kind and content of units.

(Physical Properties of Methacrylic Resin [A]) [

From the viewpoints of the mechanical strength of the first resin layer 21 and the moldability of the methacrylic resin [A], the weight average molecular weight (Mw) of the methacrylic resin [A] More preferably from 3000 to 1000000, more preferably from 30000 to 800000, and even more preferably from 60000 to 600000. The molecular weight distribution (Mw / Mn) of the methacrylic resin [A] is preferably 1 to 10 in terms of polymethyl methacrylate by GPC measurement in view of moldability of the methacrylic resin [A] 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 占 폚, more preferably 130 to 180 占 폚.

When the first resin layer 21 includes a protective layer, the tensile modulus under a 23 ° C environment is preferably 1,000 to 5,000 MPa, more preferably 1,500 to 5,000 MPa, from the viewpoint of the supporting force as a protective layer. The polarizer layer (10) generated by the heat-resistance durability test after the polarizing plate is formed, the polarizer layer (10) generated by radiation heat from the irradiation source of the active energy ray and the like generated from curing the active energy ray- It is preferable that the first resin layer 21 has a high tensile modulus at high temperature from the viewpoint of preventing shrinkage of the first resin layer 21 due to shrinkage of the first resin layer 21. [ More specifically, the tensile modulus at 80 ° C is preferably 1000 to 4000 MPa, more preferably 1500 to 4000 MPa.

The methacrylic resin [A] and the first resin layer 21 composed of the methacrylic resin [A] can be prepared by the method described in the above-mentioned documents, as described in Japanese Patent Application Laid- photoelastic coefficient is measured by (C _R) absolute value is 3.0 × 10 ^-12 ㎩ ^-1 or less, and further 2.0 × 10 ^-12 ㎩ ^-1 or less, and further may be 1.0 × 10 ^-12 ㎩ ^-1 or less have. Further, according to the definition described in the above document, the in-plane retardation (Re) and the thickness direction retardation (Rth) measured by the method described in the above document are both 8 nm or less, and further, 6 nm or less, 4 nm or less. Further, according to the definition described in the above document, the total light transmittance measured by the method described in the above document can be 85% or more, and more preferably 90% or more.

As described above, the methacrylic resin [A] constituting the first resin layer 21 is a resin having excellent optical properties such as low birefringence (optical isotropy), and the first resin layer 21 containing the methacrylic resin [A] Is suitable as a protective layer of the polarizing plate used for the IPS mode liquid crystal panel. The first resin layer 21 may be a protective layer disposed on the side of the liquid crystal cell in the polarizer layer 10 or a protective layer far from the liquid crystal cell when the liquid crystal panel is used. The mode in which the liquid crystal layer 21 is a protective layer disposed on the liquid crystal cell side in the polarizer layer 10 is formed between the polarizer layer of the polarizing plate disposed on the viewer side of the liquid crystal cell and the polarizer layer of the polarizing plate disposed on the back side The first resin layer 21 having excellent optical properties such as low birefringence (optical isotropy) is disposed in Cross Nicol, which is advantageous for improving the visibility of the liquid crystal display device. In addition, when the first resin layer 21 composed of the methacrylic resin [A] is used as the protective layer disposed on the side of the liquid crystal cell in the polarizer layer 10, as described above, the low tensile modulus Therefore, even in a high temperature environment but under a high temperature and high humidity environment, even in a situation where a bending stress due to bending of the liquid crystal cell or a compressive stress due to heat shrinkage of the polarizer layer 10 is applied, , Which is advantageous in terms of maintaining the visibility of the liquid crystal display device. On the other hand, as will be described later, when the second resin layer 22 is composed of the methacrylic resin [A], the second resin layer 22 is disposed on the liquid crystal cell side of the polarizer layer 10 The same effect as described above can be obtained.

(A material other than the methacrylic resin [A] constituting the first resin layer)

The first resin layer 21 may contain a thermoplastic resin other than the methacrylic resin [A]. Specific examples of other thermoplastic resins include olefin-based polymers such as (meth) acrylic resins other than the methacrylic resin [A], polyethylene, polypropylene and ethylene-propylene copolymer; Halogen-containing polymers such as vinyl chloride and vinyl chloride resin; Styrene-based polymers such as polystyrene, styrene-methyl methacrylate copolymer and styrene-acrylonitrile copolymer; Polyesters such as polyethylene terephthalate; Polyarylates; 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 content of the other thermoplastic resin is, Is preferably 0 to 25% by weight, more preferably 0 to 10% by weight, based on 100% by weight of the methacrylic resin [A].

The first resin layer 21 may contain one or more additives such as 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 formability of the (meth) acrylic resin, the impact resistance of the first resin layer 21, and the slipperiness of the surface of the first resin layer 21 can be improved It is advantageous. The rubber particles include a layer exhibiting rubber elasticity (hereinafter also referred to as a rubber elastic body layer).

The rubber particles may be particles composed only of the rubber elastic body layer or may be particles of a multilayer structure having other layers together with the rubber elastic body layer. Examples of the polymer contained in the rubber elastomer layer include olefin-based elastomer, diene-based elastomer, styrene-diene-based elastic copolymer, and acrylic elastomer. Among them, an acrylic elastomer is preferable from the viewpoint of light resistance and transparency.

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

As the alkyl acrylate constituting the acrylic elastomer, the alkyl group having 4 to 8 carbon atoms is generally used. Examples of the other polymerizable monomer include alkyl methacrylates such as methyl methacrylate and ethyl methacrylate; Styrene monomers such as styrene and alkyl styrene; And unsaturated nitriles such as acrylonitrile and methacrylonitrile; alkenyl esters of unsaturated carboxylic acids such as allyl (meth) acrylate and methallyl (meth) acrylate; Dialkyl esters of dibasic acids such as diallyl maleate; And unsaturated carboxylic acid diesters of glycols such as alkylene glycol di (meth) acrylate.

The rubber particles containing an acrylic elastomer are preferably particles of a multilayer structure having a layer of an acrylic elastomer. Specifically, there are a two-layer structure having a hard polymer layer mainly composed of alkyl methacrylate on the outer side of the acryl-based elastomer layer, and a two-layer structure having a rigid structure composed mainly of alkyl methacrylate Of a polymer layer having a three-layer structure.

As a monomer composition in a polymer mainly composed of alkyl methacrylate which constitutes a hard polymer layer formed on the inside or outside of the acrylic elastomer layer, a monomer composition mainly comprising methyl methacrylate is preferably used . The acrylic rubber particles having such a multi-layer structure can be produced, for example, by the method described in Japanese Patent Publication No. 55-27576.

The rubber particles are preferably contained in the outermost rubber elastic body layer (for example, a rubber elastic body layer (for example, a rubber elastic body layer) contained in the rubber elastic body layer , The acrylic elastomer 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, further preferably 50 nm or more, still more preferably 300 nm or less, further preferably 280 nm or less.

From the viewpoints of the film formability of the methacrylic resin [A], the impact resistance of the first resin layer 21, and the slipperiness of the surface of the first resin layer 21, the rubber particles constitute the first resin layer 21 Is preferably incorporated in a proportion of 3 to 60% by weight, more preferably 45% by weight or less, and still more preferably 35% by weight or less, based on the total amount of the methacrylic resin [A] When the rubber particle content is more than 60% by weight, the dimensional change of the first resin layer 21 becomes large, and the heat resistance thereof is lowered. On the other hand, if the amount of the rubber particles is less than 3% by weight, the heat resistance of the first resin layer 21 is good, but the winding property at the time of film formation is poor and the productivity may be lowered.

In the case where the first resin layer 21 contains rubber particles, the methacrylic resin [A] and the resin composition containing the rubber particles used for the production of the first resin layer 21 are preferably a methacrylic resin [A] and rubber particles by melt-kneading or the like, but also by a method in which rubber particles are first prepared, and a monomer composition to be a raw material of the methacrylic resin [A] is polymerized in the presence of the rubber particles have.

(Urethane resin)

The resin containing the urethane-based resin can be suitably used when the surface layer on the adhesive layer side of the first resin layer 21 is a primer layer. Based resin composition containing urethane-based resin in an amount of 40% by weight or more. The urethane resin can be obtained, for example, by polymerization reaction of a diisocyanate compound or a polyisocyanate compound with polyols, polyesters, polyamines and the like. The urethane resin may be a block copolymer or a graft copolymer with another polymer (such as a polyester resin or an acrylic resin). For example, a resin (or a resin mixture in some cases) obtained by polymerizing an acrylic resin in a urethane resin solution or dispersion may be used. The resin (or resin mixture in some cases) obtained by polymerizing an urethane-based resin in an acrylic resin solution or dispersion or another polymer solution or dispersion may also be used.

Examples of the diisocyanate compound or polyisocyanate compound include tolylene diisocyanate, phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 4,4'-dicyclohexylmethane di Isocyanate, isophorone diisocyanate, and the like.

Examples of polyols include polyether polyols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; Polyethylene adipate in which the polymer terminal is hydroxyl group, polyester polyols such as polyethylene-butylene adipate and polycaprolactone; Acrylic polyol, polycarbonate-based polyol, and castor oil.

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

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

As the polyesters or polyols, those having a weight average molecular weight of 300 to 2,000 are generally used. In the production of the urethane-based resin, a chain length-extending agent or a crosslinking agent may be used to adjust the weight-average molecular weight. Examples of the chain length extenders or crosslinking agents include ethylene glycol, propylene glycol, butanediol, diethylene glycol, trimethylol propane, hydrazine, piperazine, ethylenediamine, diethylenetriamine, 4,4'- , 4'-diaminodicyclohexylmethane, and water.

The urethane-based resin is preferably water-soluble or water-dispersible in order to obtain a coating solution of a urethane-based resin composition containing the urethane-based resin. It is preferable to use the coating liquid as the aqueous system because its handling property is good and there is no fear of erosion into the first resin layer 21.

Examples of a method for imparting water solubility or water dispersibility to the urethane resin include a method of introducing a repeating unit containing a hydrophilic substituent into a urethane resin or a method of introducing a repeating unit containing an ether bond into a urethane resin Is adopted.

The polymerization reaction system of the urethane-based resin can be appropriately selected according to the monomer (or oligomer, polymer) to be used and the polymer property to be polymerized. For example, the polymerization reaction may be carried out in the presence of a small amount of tin, bismuth, Emulsion polymerization, or dispersion polymerization.

The urethane-based resin composition may contain a polyester-based resin. By including a polyester-based resin in the primer layer, adhesion with the first adhesive layer 15 and water resistance can be improved.

The polyester resin used herein is a resin in which the sum of the terephthalic acid component, the 2,6-naphthalenedicarboxylic acid component and the ethylene glycol component accounts for 40 to 80 mol% of the repeating units and the 20 to 60 mol% Refers to a resin composed of a polyvalent carboxylic acid component, another polyhydric hydroxy compound component, and / or a hydroxycarboxylic acid component.

The urethane resin composition may contain an acrylic resin. By containing the acrylic resin in the primer layer, adhesion with the first adhesive layer 15 can be improved. The acrylic resin refers to a homopolymer or a copolymer containing as a main component a monomer unit comprising a polymerizable monomer having a (meth) acryloyl group.

The blending amount of the polyester resin and the acrylic resin in the urethane resin composition is preferably 1% by weight or more and less than 40% by weight, more preferably 5% by weight or more and 35% by weight or less, When the blending amount is 40 wt% or more, the amount of the urethane-based resin to be blended is relatively reduced, which may adversely affect the advantages such as good adhesiveness of the urethane-based resin.

The urethane resin composition may contain a crosslinking resin compound. Examples of the crosslinking resin compound include a melamine-based resin and an epoxy-based resin, among which a melamine-based resin compound is preferable from the viewpoint of coatability and adhesion durability.

The urethane resin composition may contain inorganic particles or organic particles. By containing appropriate amounts of inorganic particles or organic particles in the primer layer, blocking of the first resin layer 21 having the primer layer is prevented, and adhesion with the first adhesive layer 15 is improved.

The urethane resin composition may contain an organic compound having a metal element. By containing an organic compound having a metal element in the primer layer, the refractive index of the primer layer can be increased to the same level as the other layers constituting the first resin layer 21 or the functional layers laminated thereon, It is possible to improve the light transmittance of the other layer constituting the first resin layer 21 in which the primer layer is laminated.

The urethane resin composition may contain wax. By containing the wax in the primer layer, slipperiness and blocking resistance of the other layer constituting the first resin layer 21 in which the primer layer is laminated are improved.

(Manufacturing Method of First Resin Layer)

The first resin layer 21 is formed such that at least one of the entire first resin layer 21 or the adhesive layer side surface layer and the other layer constituting the first resin layer 21 contains the methacrylic resin [A] , Preferably a methacrylic resin [A], or a film comprising a methacrylic resin [A] as a resin component other than an additive in the case of containing an additive. Molding into a film can be carried out by conventionally known methods such as melt extrusion, hot press molding, injection molding, solvent casting and the like.

The first resin layer 21 may be a stretched film stretched in at least one direction. The mechanical strength of the first resin layer 21 can be improved by stretching. In general, the stretched film composed of the methacrylic resin [A] generally has poor adhesiveness to the adhesive layer by the stretching treatment. However, according to the present invention, even if the first resin layer 21 is a stretched film, Adhesion can be obtained.

Examples of the stretching treatment include uniaxial stretching and biaxial stretching. Examples of the stretching direction include a direction in which the unstretched film is obliquely crossed in the machine direction (MD), the direction (TD) perpendicular to the machine direction, and the machine direction (MD). The biaxial stretching may be simultaneous biaxial stretching in which two stretching directions are simultaneously performed, or may be sequential biaxial stretching after stretching in a predetermined direction and then stretching in other directions. The stretching treatment may be carried out by stretching in the longitudinal direction (machine direction: MD) using two or more pairs of nip rolls having a larger peripheral speed on the exit side, or grasping both side ends of the unstretched film with a chuck ) And widening it in a direction (TD) orthogonal to the machine flow direction.

According to the present invention, excellent adhesion to the adhesive layer can be obtained even if the draw ratio by the draw treatment is usually 1.1 times or more and the draw ratio is 1.2 times or more. The draw ratio is usually 5 times or less, preferably 3.5 times or less. On the other hand, the stretching magnification in the biaxial stretching refers to the stretching magnification in the direction in which the stretching ratio is larger.

The thickness of the first resin layer 21 is, for example, about 1 to 200 占 퐉, preferably 5 to 150 占 퐉, more preferably 5 to 100 占 퐉, from the viewpoint of thinning of the polarizing plate and strength and handleability of the first resin layer 21 10 to 120 占 퐉.

The adhesive layer side surface layer constituting the first resin layer 21 is formed, for example, by applying a coating solution containing a precursor of a material constituting the adhesive layer side surface layer to another layer constituting the first resin layer 21 . The adhesive layer side surface layer can be formed by applying a coating liquid to one side of the other layer constituting the first resin layer 21, followed by drying or drying and curing. The adhesive layer side surface layer may be formed immediately after the formation of the other layer constituting the first resin layer 21 or may be formed immediately before bonding to the polarizer layer 10.

As a method of applying the coating liquid, for example, a die coater, a comma coater, a reverse roll coater, a gravure coater, a rod coater, a wire bar coater, a doctor blade coater and an air doctor coater are employed. The method and conditions for drying the applied coating liquid are not particularly limited, and for example, a drying method using a hot air dryer or an infrared ray dryer may be adopted.

In order to improve the adhesion between the adhesive layer side surface layer and the first adhesive layer 15 by adjusting the affinity for the adhesive constituting the first adhesive layer 15 of the adhesive layer side surface layer, for example, corona discharge treatment, Plasma treatment, ozone spraying, ultraviolet ray irradiation, flame treatment, chemical treatment, and other conventionally known surface treatment may be performed.

&Lt; First adhesive layer >

The first adhesive layer 15 is a layer for bonding the polarizer layer 10 and the first resin layer 21. The first adhesive layer 15 is a cured layer of an active energy ray-curable adhesive composition comprising 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 cured by irradiation of active energy rays such as ultraviolet rays, visible rays, electron rays, and X-rays.

The active energy ray-curable adhesive composition is desirably solvent-free, whereby the adhesion between the polarizer layer 10 and the first resin layer 21 can be improved. On the other hand, if the active energy ray-curable adhesive composition contains a solvent (especially organic solvent), the adhesion of the active energy ray-curable compound contained in the adhesive is the same as that of the solventless type, The first resin layer 21 is liable to be peeled off from the polarizer layer 10 at the end portion thereof.

In the present specification, &quot; no-solvent formulation &quot; means that no solvent is actively added. More specifically, when the total amount of the active energy ray-curable compound of the solventless formulation is 100 wt% The content is 5% by weight or less.

The film thickness of the first adhesive layer 15 is preferably not more than 3.5 占 퐉, not more than 3 占 퐉, or not more than 2 占 퐉. The film thickness of the first adhesive layer is usually 0.01 m or more. The color unevenness that occurs when the polarizing plate is exposed under a humid environment becomes more remarkable in a polarizing plate having a smaller thickness of the first adhesive layer 15. [ Therefore, in the polarizing plate 1, especially when the thickness of the first adhesive layer 15 is 3.5 占 퐉 or less, the color unevenness suppressing effect can be effectively obtained.

Hereinafter, the active energy ray-curable adhesive composition constituting the first adhesive layer 15 and the materials contained in the active energy ray-curable adhesive composition will be described in detail.

(Active energy ray-curable adhesive composition)

The active energy ray-curable adhesive composition may contain an alicyclic epoxy compound as an active energy ray-curable compound, and may contain an epoxy compound other than the alicyclic epoxy compound, and may contain a compound other than an epoxy compound. Here, the epoxy compound is a compound having one or more, preferably two or more, epoxy groups in the molecule, and examples of the epoxy compounds other than alicyclic epoxy compounds include aliphatic epoxy compounds, hydrogenated epoxy compounds (glycidyl Cidyl ether), 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 or more based on 100% by weight of the active energy ray- And more preferably at least 60% by weight. The upper limit of the content of the epoxy compound may be 100% by weight or less, 90% by weight or less, more preferably 80% by weight or less, and less than 75% by weight based on 100% by weight of the active energy ray curable compound.

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. If the epoxy equivalent is less than 30 g / equivalent, there is a possibility that the adhesion between the polarizer layer 10 and the first resin layer 21 is lowered or the flexibility of the first adhesive layer 15 after curing is lowered . On the other hand, if it exceeds 3000 g / equivalent, compatibility with other components contained in the adhesive may be lowered.

(Alicyclic epoxy compound)

The active energy ray curable adhesive composition contains 10 to 70 parts by weight of an alicyclic epoxy compound per 100 parts by weight of the active energy ray curable compound when the film thickness of the polarizer layer is 18 占 퐉 or more and 25 占 퐉 or less. The content of the alicyclic epoxy compound is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, and still 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 preferably 70 parts by weight or less, more preferably 68 parts by weight or less, and even more preferably 65 parts by weight or less, based on 100 parts by weight of the active energy ray curable compound. The content of the alicyclic epoxy compound is in the above range when the film thickness of the polarizer layer is 18 탆 or more and 25 탆 or less so that the thickness of the polarizer layer 10 is as thin as 25 탆 or less, Even when the N / C ratio of the surface on the side in contact with the first adhesive layer 15 is 1.0 or more, it is possible to suppress the color unevenness that may occur after the polarizing plate is exposed under the humid environment.

The active energy ray curable adhesive composition contains 10 to 55 parts by weight of an alicyclic epoxy compound per 100 parts by weight of the active energy ray curable compound when the thickness of the polarizer layer is less than 18 m. The content of the alicyclic epoxy compound is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, and even 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 thickness of the polarizer layer is less than 18 占 퐉, the content of the alicyclic epoxy compound is within the above range, so that the thickness of the polarizer layer 10 is thinner than 18 占 퐉 and the first adhesive of the first resin layer 21 Even when the N / C ratio on the surface in contact with the layer 15 is 1.0 or more, it is possible to suppress color unevenness that may occur after the polarizing plate is exposed under a humid environment.

The active energy ray curable adhesive composition contains an alicyclic epoxy compound of M (parts by weight) per 100 parts by weight of the active energy ray-curable compound when the thickness of the polarizer layer is 25 m or less and the amount of iodine per unit area of the polarizer layer M is 7 [parts by weight] or more in the case of I (g / cm &lt; 2 &gt;),

I? 2.1 M × 10 ^-6 -7.8 × 10 ^-5 (1)

May be satisfied. The content M of the alicyclic epoxy compound is preferably not less than 7 parts by weight and not less than 10 parts by weight, more preferably not less than 20 parts by weight, and even more preferably not less than 40 parts by weight, [Part by weight], but it is preferably 90 [parts by weight] or less, more preferably 80 [parts by weight] or less. 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 be hard to cure. When the content M of the alicyclic epoxy compound is in the above range, the thickness of the polarizer layer 10 is as small as 25 m or less and the surface of the first resin layer 21 on the side in contact with the first adhesive layer 15 Even when the N / C ratio in the polarizing plate is 1.0 or more, it is possible to suppress the color unevenness that may occur after the polarizing plate is exposed under the humid environment.

When the thickness of the polarizer layer is in the range of 18 탆 or more and 25 탆 or less and 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 when the thickness of the polarizer layer is less than 18 탆 It is expected that the color unevenness of the polarizing plate can be further suppressed by containing 10 to 55 parts by weight of the alicyclic epoxy compound per 100 parts by weight of the active energy ray curable compound and satisfying the above formula (1).

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

The compound in which one or more hydrogen atoms of the (CH ₂ ) _m in the above formula are removed from other groups in the chemical structure may be an alicyclic epoxy compound. (CH ₂ ) _m may be appropriately substituted with a straight chain alkyl group such as methyl group or ethyl group. Among the alicyclic epoxy compounds, an epoxy compound having an oxabicyclohexane ring (m = 3 in the above formula) or an oxabicycloheptane ring (m = 4 in the above formula) is used as the polarizer layer 10 ) And the first resin layer 21, and is therefore preferably used. Hereinafter, the alicyclic epoxy compounds which are preferably used are specifically exemplified, but the compounds are not limited thereto

(a) epoxycyclohexylmethyl epoxycyclohexanecarboxylates represented by the following formula (IV):

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

(b) epoxycyclohexanecarboxylates of alkanediol represented by the following formula (V):

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

(c) epoxycyclohexylmethyl esters of dicarboxylic acids represented by the following formula (VI):

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

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

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

(e) epoxycyclohexyl methyl ethers of alkane diols represented by the following formula (VIII):

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

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

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

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

In the formula (X), R ²⁰ and R ²¹ independently represent a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms.

(h) vinylcyclohexene epoxides represented by the following formula (XI):

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

(i) epoxycyclopentyl ethers represented by the following formula (XII):

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

Among the above-exemplified alicyclic epoxy compounds, the following alicyclic epoxy compounds are more preferably used from the viewpoint of adhesion between the polarizer layer 10 and the first resin layer 21 and from the viewpoint of availability.

(IV-a) The esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (7-oxa-bicyclo [4.1.0] hept- , Wherein R ⁸ = R ⁹ = H, compound: 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexene carboxylate]

(IV-b) To a solution of 4-methyl-7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (4-methyl-7-oxa-bicyclo [4.1.0] hept- Ester compound [in the formula (IV), a compound of R ⁸ = R ⁹ = 4-CH ₃ ]

(Va) The esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and 1,2-ethanediol [compound of formula (V) wherein R ¹⁰ = R ¹¹ = H, n = 2 ],

(VI-a) (7-oxabicyclo [4.1.0] hept-3-yl) methanol and an adipic acid [wherein R ¹² = R ¹³ = H, p = 4 compound],

(Ⅵ-b) (4- methyl-7-oxabicyclo [4.1.0] hept-3-yl) according to the formula esterified methanol and adipic acid ^{(VI), R 12 = R} 13 = 4- CH ₃ , p = 4]

(VIII-a) (7-oxabicyclo [4.1.0] hept-3-yl) methanol and an ether of 1,2-ethanediol [In 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 an 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 even more preferably 50 parts by weight or less, based on 100 parts by weight of the active energy ray curable compound. (0 parts by weight), and more preferably 10 parts by weight or more, and more preferably 20 parts by weight or more, based on 100 parts by weight of the active energy ray curable compound.

The reactivity of the aliphatic epoxy compound is lower than that of the alicyclic epoxy compound. When the content of the aliphatic epoxy compound exceeds 65 parts by weight, the polymerization reaction of the active energy ray-curable compound tends not to proceed sufficiently, 15, the unreacted portion is likely to occur in a spot shape. In the polarizer layer in contact with the unreacted portion formed in the first adhesive layer 15, moisture is likely to permeate during the heat test, iodine escapes by the permeating moisture, and as a result, Bright portion), and discoloration occurs in the polarizing plate 1. In the present specification, &quot; decolorization &quot; means that when the polarizing plate is irradiated with illumination light from the side opposite to the side on the viewer side and observed with naked eyes, coloration due to iodine in the polarizing plate is lost, It is said that it is admitted as list.

Specific examples of the aliphatic epoxy compound include a polyglycidyl ether 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 glycerin; Triglycidyl ether of trimethylolpropane; Diglycidyl ether of polyethylene glycol; Diglycidyl ether of propylene glycol; And polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol or glycerin.

(Hydrogenated epoxy compound (glycidyl ether of polyol having alicyclic ring))

The hydrogenated epoxy compound is obtained by reacting epichlorohydrin with an alicyclic polyol obtained by subjecting an aromatic ring of an aromatic polyol to a hydrogenation reaction. Specific examples of the aromatic polyol include bisphenol-type compounds such as bisphenol A, bisphenol F, and bisphenol S; Novolak type resins such as phenol novolac resin, cresol novolak resin and hydroxybenzaldehyde phenol novolac resin; Tetrahydroxydiphenylmethane, tetrahydroxydiphenylmethane, tetrahydroxybenzophenone, polyvinylphenol and the like. Of the hydrogenated epoxy compounds, diglycidyl ethers of hydrogenated bisphenol A can be mentioned.

(An active energy ray-curable compound other than an epoxy compound)

The active energy ray curable adhesive composition may contain a (meth) acrylic compound or the like together with an active energy ray curable compound such as an epoxy compound. (Meth) acrylic compound is used in combination, the effect of increasing the adhesion between the polarizer layer 10 and the first resin layer 21, the hardness of the adhesive layer 15 and the mechanical strength can be expected. Further, And the hardening speed can be more easily adjusted.

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. If the blending amount of the (meth) acrylic compound is excessively large, the adhesion between the polarizer layer 10 and the first resin layer 21 tends to be lowered inversely.

(Cationic polymerization initiator)

The active energy ray curable adhesive composition contains a cationic polymerization initiator, preferably a photocationic polymerization initiator. The photocationic polymerization initiator generates a cationic species or a Lewis acid by irradiation with an active energy ray such as visible light, ultraviolet ray, X-ray or electron ray to initiate polymerization reaction of the epoxy group.

The method of curing the adhesive by irradiation of an active energy ray using a photocationic polymerization initiator enables curing at room temperature and reduces the need to consider deformation due to heat resistance or expansion of the polarizer layer 10, It is advantageous in that it can adhere well between layers. In addition, since the photocationic polymerization initiator acts catalytically with light, it is excellent in storage stability and workability even when mixed with an epoxy compound.

Examples of the photocationic polymerization initiator include aromatic diazonium salts; Onium salts such as aromatic iodonium salts and aromatic sulfonium salts; Iron-allene complexes and the like.

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

Specific examples of the aromatic iodonium salt include diphenyl iodonium tetrakis (pentafluorophenyl) borate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoroantimonate, di (4- Nonylphenyl) iodonium hexafluorophosphate.

Specific examples of the aromatic sulfonium salts include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4,4'-bis (di (Phenylsulfonyl) diphenyl sulfide bis (hexafluorophosphate), 4,4'-bis [di (? - hydroxyethoxy) phenylsulfonio] diphenyl sulfide bis (hexafluoroantimonate ), 7- [di (p-toluyl) sulfonio] - diphenylsulfide bis (hexafluorophosphate), 4,4'- 2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbamoylcarbamate, 4-phenylcarbamoylcarbodiimide, Diphenylsulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfone-diphenylsulfide hexafluorophosphate, 4- (P-tert-butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) borate.

Specific examples of the iron-allene complexes include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, xylene-cyclopentadienyl iron (II) -Tris (trifluoromethylsulfonyl) methanide. &Lt; / RTI &gt;

The cationic polymerization initiator may be used alone, or two or more of them may be used in combination. Among them, an aromatic sulfonium salt is preferably used because it has ultraviolet ray absorbing property even in a wavelength range of 300 nm or more and is therefore excellent in curability and can provide a cured product having good mechanical strength and adhesive strength.

The mixing amount of the cationic polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 to 15 parts by weight, per 100 parts by weight of the active energy ray curable compound. If the blending amount of the cationic polymerization initiator is less than 0.5 part by weight, the curing becomes insufficient and the mechanical strength of the adhesive layer or the adhesion between the polarizer layer 10 and the first resin layer 21 tends to be lowered. If the blending amount of the cationic polymerization initiator is more than 20 parts by weight, the amount of ionic substances in the cured product increases, so that the hygroscopicity of the cured product increases, and the durability of the polarizing plate may be lowered.

(Photosensitizer)

The active energy ray-curable adhesive composition may further contain a photosensitizer, if necessary. The use of the photosensitizer improves the reactivity of the active energy ray curable compound and improves the mechanical strength of the first adhesive layer 15 and the adhesion between the polarizer layer 10 and the first resin layer 21 There is a case. Examples of the photosensitizer include a carbonyl compound, an organic sulfur compound, a persulfate, a redox compound, an azo and diazo compound, a halogen compound, a photoreducible dye, and the like.

(Cation polymerization accelerator)

The active energy ray-curable compound of the cationic polymerizable non-solvent type may further contain a compound that promotes cationic polymerization such as oxetanes and polyols.

(Other additives)

The active energy ray curable adhesive composition may contain additives such as an ion trap agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, a defoamer, an antistatic agent, a leveling agent, &Lt; / RTI &gt;

&Lt; Second adhesive layer >

The second adhesive layer 25 is a layer for bonding the polarizer layer 10 and the second resin layer 22. The second adhesive layer 25 may 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 and may be formed of a radically polymerizable curable component such as a (meth) Or a radically polymerizable adhesive containing, as a main component, a different adhesive composition. The second resin layer 22 may be directly laminated on the surface of the polarizer layer 10 without passing through the second adhesive layer 25. [

Wherein the second adhesive layer (25) is a cured layer of an active energy ray curable adhesive composition comprising an active energy ray curable compound and a cationic polymerization initiator, wherein the active energy ray curable compound contains an alicyclic epoxy compound, When the atomic concentration ratio (N / C ratio) of the nitrogen element and the carbon element on the surface in contact with the resin layer 22 is 1.0 or more, the active energy ray-curable adhesive composition constituting the first adhesive layer 15 , It is preferable to adjust the content of the alicyclic epoxy compound in the active energy ray curable adhesive composition. Specifically, when the thickness of the polarizer layer is 18 占 퐉 or more and 25 占 퐉 or less, it is preferable that 10 to 70 parts by weight of the alicyclic epoxy compound is contained relative to 100 parts by weight of the active energy ray curable compound, Is less than 18 탆, it is preferable that 10 to 55 parts by weight of the alicyclic epoxy compound is contained relative to 100 parts by weight of the active energy ray-curable compound. When the content of the alicyclic epoxy compound is M [parts by weight] relative to 100 parts by weight of the active energy ray curable compound and the amount of iodine per unit area of the polarizer layer is I [g / cm &lt; 2 & , M is not less than 7 [parts by weight], and the formula (1):

I? 2.1 M × 10 ^-6 -7.8 × 10 ^-5 (1)

May be satisfied. By setting the content of the alicyclic epoxy compound within the above-mentioned range, it is possible to suppress color unevenness that may occur after the polarizing plate is exposed under a humid environment. Each component contained in the active energy ray-curable adhesive composition constituting the second adhesive layer 25 in this case is the same as the component described in the first adhesive layer 15.

&Lt; Second resin layer 22 >

The second resin layer 22 is formed on the side opposite to the side where the first resin layer 21 of the polarizer layer 10 is formed. The polarizing plate 1 is not limited to the example shown in Fig. 1, and may or may not include the second resin layer 22 laminated on the polarizer layer 10. In the case where the polarizing plate 1 includes the second resin layer 22, the second resin layer 22 may be formed in a single layer or in a multi-layer structure like the first resin layer 21 . The resin constituting the second resin layer 22 may be composed of the same resin as the first resin layer 21 or may be composed of different thermoplastic resins. The second resin layer 22 has an atomic concentration ratio (N / C ratio) of the nitrogen element to the carbon element on the surface in contact with the second adhesive layer 25, similarly to the first resin layer 21, May be 1.0 or more. For example, the N / C ratio of the primer layer constituting the second resin layer 22 may be 1.0 or more.

The second resin layer 22 preferably includes a low moisture permeable layer having a moisture permeability of 1500 g / m 2/24 hr or less at a temperature of 40 ° C and a relative humidity of 90%, as in the case of the first resin layer 21. 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 2/24 hr or less, and may be 420 g / m 2/24 hr or less. The color unevenness that occurs when the polarizing plate is exposed under a humid environment is more conspicuous in the polarizing plate having the moisture-permeable second resin layer 22. Therefore, in the polarizing plate 1, when the second resin layer 22 includes a low moisture permeable layer having a moisture permeability of 1500 g / m 2/24 hr or less at a temperature of 40 ° C. and a relative humidity of 90% The suppression effect of the stain can be effectively obtained.

[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 percentages and parts representing the content and amount of the examples and comparative examples are by weight unless otherwise specified.

[Examples 1 to 13, Reference Examples 1 and 2, Comparative Examples 1 to 5]

(Fabrication of Polarizer Layer x)

A polyvinyl alcohol resin film having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more and a thickness of 60 mu m is immersed in pure water at 30 DEG C and then the weight ratio of iodine / potassium iodide / water is 0.02 / 2/100 Lt; RTI ID = 0.0 &gt; 30 C. &lt; / RTI &gt; 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. Subsequently, the film was washed with pure water at 8 占 폚 and then dried at 65 占 폚 to obtain a polarizer layer x in which iodine was adsorbed and oriented on a polyvinyl alcohol-based resin film. The stretching was performed mainly in a step of iodine dyeing and boric acid treatment. The total stretching magnification was 5.3 times, the thickness of the obtained polarizer layer x was 23 mu m, and the single transmittance was 42.7%. The amount of iodine in the polarizer layer x was measured in the order of [amount of iodine] described later, and found to be 6.3 x 10 ^-5 g / cm 2.

(Fabrication of first resin layer)

A first resin layer comprising methacrylic resin films a to c shown below was prepared and prepared. (Coating side) coated with an ultraviolet-curing type urethane-based resin and a side (film side) on which this coating is not formed are formed on the methacrylic resin films a to c in accordance with the order of [amount of surface element amount] Table 1 shows the atomic concentration ratio (N / C ratio) of the nitrogen element / carbon element measured for each.

[Methacrylic resin film a]

The methacrylic resin (a) was stretched to prepare a biaxially stretched film having a thickness of 40 占 퐉. 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 prepare a biaxially stretched film having a thickness of 40 占 퐉. Further, a methacrylic resin film b was obtained by coating an ultraviolet curing type urethane resin on one side thereof.

[Methacrylic resin film c]

The methacrylic resin c was stretched to prepare a biaxially stretched film having a thickness of 40 占 퐉. Further, a methacrylic resin film c was obtained by coating an ultraviolet curing type urethane resin on one side thereof.

(Fabrication of second resin layer)

A second resin layer made of the following methacrylic resin film d was produced in the following procedure. The second resin layer in this embodiment or the like is a protective layer of the polarizer layer.

[Methacrylic resin film d]

As the methacrylic resin d, a copolymer of methyl methacrylate / methyl acrylate = 96% / 4% was prepared. Further, it is preferable that, as the rubber particles, the innermost layer is made of a hard polymer obtained by polymerizing methyl methacrylate with a small amount of allyl methacrylate, and the intermediate layer is composed mainly of butyl acrylate and further contains styrene and a small amount of allyl methacrylate Layered structure composed of a soft polymer polymerized using a soft polymer polymerized in the outermost layer and a hard polymer polymerized by using a small amount of ethyl acrylate in methyl methacrylate and having an average particle diameter 240 nm. On the other hand, in this rubber particle, the total weight of the innermost layer and the intermediate layer was 70% of the whole particles.

70% of the methacrylic resin d and 30% of the rubber particles were mixed with a super mixer and melt-kneaded by a twin-screw extruder to obtain pellets. This pellet was poured into a 65 mm single screw extruder and extruded through a T-die having a set temperature of 275 DEG C and cooled by inserting a film between two polishing rolls having a mirror surface to obtain a sheet having a thickness of 80 mu m and a moisture permeability of 60 g / M &lt; 2 &gt; / 24 hr.

(Preparation of active energy ray-curable adhesive composition)

The following alicyclic epoxy compounds (A1), aliphatic epoxy compounds (A2) and photocationic polymerization initiators (B1) were mixed in the amounts shown in Table 2 to prepare an active energy ray curable adhesive composition of a UV curable adhesive Hereinafter simply referred to as &quot; adhesive &quot;).

[Alicyclic epoxy compound (A1)]

3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexene carboxylate ("Celloxide 2021P" manufactured by Daicel Chemical Industries, Ltd.)

[Aliphatic epoxy compound (A2)]

Neopentyl glycol glycidyl ether

[Gwangyang Ionic Polymerization Initiator (B1)]

Triarylsulfonium hexafluorophosphate

(Production of polarizing plate)

A laminate having a layer structure of the first resin layer / first adhesive layer / polarizer layer x / second adhesive layer / second resin layer was obtained in the following procedure. On the other hand, in the present embodiment, the comparative example and the reference example, the methacrylic resin film d was used as the second resin layer, and the adhesive f was used as the adhesive constituting the second adhesive 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 with the polarizer layer. Adhesives shown in Tables 3 and 4 were applied to the corona discharge treated surface of the first resin layer (bonding surface to the polarizer layer x), and an adhesive f was applied to the bonding surface of the second resin layer to the polarizer layer x. Subsequently, the first resin layer is laminated on one side of the polarizer layer x through the adhesive coated in the above, and the second resin layer is laminated on the other side of the polarizer layer x through the adhesive f coated thereon , And passed through a bonding roll to obtain the laminate. When the laminate 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 占 퐉.

Ultraviolet rays were irradiated from the side of the resin layer of the obtained laminate to cure the adhesive on both sides to obtain a polarizing plate. The ultraviolet ray irradiation was conducted under the conditions of an illuminance of 200 mW / cm 2 in a wavelength range of 260 to 320 nm and an accumulated light quantity of 200 mJ / cm 2 by a "D bulb" manufactured by Fusion UV Systems Inc. using an ultraviolet irradiator having a belt conveyor .

[Reference Example 3]

(Production of Polarizer Layer y)

A polyvinyl alcohol resin film having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more and a thickness of 75 탆 was immersed in pure water at 30 캜 and then immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.02 / Lt; 0 &gt; C. 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. Subsequently, the film was washed with pure water at 8 캜 and dried at 65 캜 to obtain a polarizer layer y in which iodine was adsorbed and oriented on a polyvinyl alcohol-based resin film. The stretching was carried out mainly in the steps of iodine dyeing and boric acid treatment. The thickness of the obtained polarizer layer y was 28 mu m and the single transmittance was 42.7%. The amount of iodine in the polarizer layer y was measured in the order of [amount of iodine] described later, and found to be 7.5 x ^10-5 g / cm2.

(Production of polarizing plate)

A polarizing plate was obtained in the same manner as in Example 1 except that the 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]

(Production of polarizer layer z)

A polyvinyl alcohol resin film having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more and a thickness of 30 탆 was immersed in pure water at 30 캜 and then immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.02 / Lt; 0 &gt; C. 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. Subsequently, the film was washed with pure water at 8 占 폚 and then dried at 65 占 폚 to obtain a polarizer layer z in which iodine was adsorbed and oriented on a polyvinyl alcohol-based resin film. The stretching was carried out mainly in a step of iodine dyeing and boric acid treatment. The thickness of the obtained polarizer layer z was 13 占 퐉 and the single transmittance was 42.7%. The amount of iodine in the polarizer layer y was measured in the order of [amount of iodine] described later, and found to be 2.4 x 10 ^-5 g / cm 2.

(Production of polarizing plate)

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

[Measurement of film thickness]

The film thickness of the polarizer layer, the first adhesive layer, and the second adhesive layer was measured using a digital side (MH-15, Nikon Corporation).

[Quantity of surface element amount]

Qualitative and quantitative analysis of the element on the surface of the resin layer on the side in contact with the first adhesive layer was performed using a K-Alpha ( ^TM) + X-ray photoelectron spectroscopy (XPS) system manufactured by Thermo Fisher Scientific Corporation. A monochrome Al-K alpha was used as the X-ray light source, and a measurement range of 400 탆 phi, an output of 72 W, a neutralization condition of 0.15 mA / 0.2 V, a pass energy of 50 eV and a scan frequency of 5 times (step: 0.1 eV) Was measured at 90 DEG with respect to the surface of the sample.

[Measurement of mass transmittance]

(V light source) of JIS Z 8701 with respect to the transmittance obtained by using a spectrophotometer ("V7100" manufactured by Nihon Bunko Co., Ltd.) having an integrating sphere, Corrected corrected transmittance Ty was measured.

[Quantity of iodine amount]

The amount of iodine I (g / cm &lt; 2 &gt;) of the polarizer layer was determined by the following procedure using oxygen combustion ion chromatography. The polarizer layer was weighed, wrapped in filter paper, and set in a platinum basket. (A mixed solution of an alkali solution and a reducing agent (hydrazine, etc.) as an example) was charged into a flask, and the flask was filled with oxygen. Thereafter, the filter paper set in the platinum basket in a state of being polished with the polarizer layer was lighted and immediately put into the flask together with the platinum basket, and the polarizer layer in the flask was burned in the filter paper. After the combustion was finished, the solution was allowed to stand for 30 minutes to absorb the iodine component into the absorption liquid, and thereafter the amount of iodine absorbed in the absorption liquid was quantitatively measured using ICS-1000 (manufactured by Nippon Dionex) (mass fraction) . The amount of iodine was converted into the amount of iodine per unit area I [g / cm 2] from the mass fraction using the density and thickness of the polarizer layer.

[Measurement of water vapor permeability]

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

[Evaluation of Appearance after Durability of Polarizer Plate]

The polarizing plate prepared in the order of producing the polarizing plate was cut into a square of 100 mm x 100 mm and cut out. The cut surface was covered with a capton tape and its vicinity, and then put into an oven at 80 캜 and 90% RH. Respectively. When the polarizing plate immediately after being taken out was observed in a crossed Nicols state or the polarizing plate alone was irradiated with illumination light from the side opposite to the viewer side and observed in a crossed Nicol state, And whether or not it was made by the naked eye was evaluated as follows.

[Evaluation of color unevenness]

When the polarizing plate was observed in a cross-Nicol state, the problem that the color change (reddish or blue) portion of the polarizing plate was visually recognized as a stain was evaluated as color unevenness and evaluated according to the following criteria.

A: Color spots are not recognized at all.

B: Color spots are partially observed very slightly.

C: The color unevenness is partially recognized.

D: Color unevenness is observed on the entire surface of the polarizing plate.

E: Color unevenness is strongly recognized on the entire surface of the polarizing plate.

[Evaluation of discoloration]

The problem that the part of the polarizing plate lacking coloration due to iodine was visually recognized as a list part when the polarizing plate was observed by illuminating the illumination light from the side opposite to the viewer side was evaluated as the following criteria.

a: Decolorization is not recognized at all.

b: Decolorization is partially acknowledged.

c: Decolorization is observed on the entire surface of the polarizing plate.

[Preparation of graph shown in Fig. 2]

Examples 1, 5, 8, 11, and 14 (in which the methacrylic resin film a was used as the first resin layer and the bonding surface was a coating surface (N / C ratio: 5.8) Of the polarizer layer and the amount [I / g] of iodine in the polarizer layer as the abscissa axis, with respect to the content M [parts by weight] of the alicyclic epoxy compound as the vertical axis, for Comparative Examples 1, 6 and 7 and Reference Example 3 Respectively. This graph is shown in Fig. In the graph shown in Fig. 2, the evaluation of color unevenness is "A", "B", "C", and "D" And &quot; E &quot;, respectively. The graph shown in Fig. 2 also shows a straight line represented by the right side of equation (1) (2.1M x 10 ^-6 -7.8 x 10 ^-5 ).

[Review of results]

As shown in Examples 1 to 13 in Table 3, when the thickness of the polarizer layer was 18 占 퐉 or more and 25 占 퐉 or less and the N / A ratio at the bonding surface of the first resin layer (the surface on the side in contact with the first adhesive layer) C ratio is 1.0 or more, when the content of the alicyclic epoxy compound in the active energy ray-curable adhesive composition constituting the first adhesive layer is in the range of 10 to 70 parts by weight based on 100 parts by weight of the active energy ray curable compound, It was not admitted.

On the other hand, as shown in Reference Examples 1 and 2 in Table 4, when the N / C ratio in the bonding surface of the first resin layer is 0.6 or 0.8, even when the content of the alicyclic epoxy compound is 75 weight, Was not admitted. Further, as shown in Reference Example 3 in Table 4, when the thickness of the polarizer layer was 28 占 퐉, the content of the alicyclic epoxy compound was 75 parts by weight, and the occurrence of color unevenness was extremely slight.

As shown in Comparative Examples 1 to 4 in Table 4, when the thickness of the polarizer layer was 23 占 퐉 and the N / C ratio in the bonding surface of the first resin layer was 1.0 or more, the content of the alicyclic epoxy compound was 75 When it is in the amount by weight, color unevenness was visually observed on the entire polarizing plate. Further, as shown in Comparative Example 5 of Table 4, when the content of the alicyclic epoxy compound was 5 parts by weight, the active energy ray-curable adhesive composition did not cure.

As shown in Example 14 of Table 3, when the thickness of the polarizer layer is less than 18 占 퐉 and the N / C ratio at the bonding surface of the first resin layer (the surface in contact with the first adhesive layer) is 1.0 or more , If the content of the alicyclic epoxy compound in the active energy ray-curable adhesive composition constituting the first adhesive layer was 50 parts by weight per 100 parts by weight of the active energy ray curable compound, the occurrence of color unevenness was very slightly observed.

On the other hand, as shown in Comparative Examples 6 and 7 in Table 4, when the thickness of the polarizer layer was 13 占 퐉 and the N / C ratio at the bonding surface of the first resin layer (the surface in contact with the first adhesive layer) 1.0 or more, if the content of the alicyclic epoxy compound in the active energy ray-curable adhesive composition constituting the first adhesive layer is 75 parts by weight or 65 parts by weight based on 100 parts by weight of the active energy ray-curable compound, the entire polarizing plate is color- .

2, when the content of the alicyclic epoxy compound relative to 100 parts by weight of the active energy ray-curable compound is M [parts by weight] and the amount of iodine in the polarizer layer is I [g / cm 2] Equation (1):

I? 2.1 M × 10 ^-6 -7.8 × 10 ^-5 (1)

In the graph shown in Fig. 2, the occurrence of color unevenness was not observed at all in the embodiment above the straight line indicated by the right side of the equation (1).

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 was less than 65 parts by weight, discoloration of the polarizing plate was suppressed.

1: polarizer 10: polarizer layer
15: first adhesive layer 21: first resin layer
22: second resin layer 25: second adhesive layer

Claims (8)

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 in which iodine is adsorbed and oriented,
Wherein the first resin layer has an atomic concentration ratio (N / C ratio) of a nitrogen element to a carbon element on the surface in contact with the adhesive layer is 1.0 or more,
Wherein the adhesive layer is a cured layer of an active energy ray curable adhesive composition comprising an active energy ray curable compound and a cationic polymerization initiator,
The active energy ray-curable compound includes an alicyclic epoxy compound,
The thickness of the polarizer layer is not less than 18 占 퐉 and not more than 25 占 퐉,
Wherein 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. 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 in which iodine is adsorbed and oriented,
Wherein the first resin layer has an atomic concentration ratio (N / C ratio) of a nitrogen element to a carbon element on the surface in contact with the adhesive layer is 1.0 or more,
Wherein the adhesive layer is a cured layer of an active energy ray curable adhesive composition comprising an active energy ray curable compound and a cationic polymerization initiator,
The active energy ray-curable compound includes an alicyclic epoxy compound,
The thickness of the polarizer layer is less than 18 [micro] m,
Wherein 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. 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 in which iodine is adsorbed and oriented,
Wherein the first resin layer has an atomic concentration ratio (N / C ratio) of a nitrogen element to a carbon element on the surface in contact with the adhesive layer is 1.0 or more,
Wherein the adhesive layer is a cured layer of an active energy ray curable adhesive composition comprising an active energy ray curable compound and a cationic polymerization initiator,
The active energy ray-curable compound includes an alicyclic epoxy compound,
The thickness of the polarizer layer is 25 占 퐉 or less,
When the amount 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 amount of iodine per unit area of the polarizer layer is I [g / cm2], M is 7 ] Or more, and the formula (1):
I? 2.1 M × 10 ^-6 -7.8 × 10 ^-5 (1)
/ RTI &gt; The polarizing plate according to any one of claims 1 to 3, wherein the thickness of the adhesive layer is 3.5 占 퐉 or less. The polarizing plate according to any one of claims 1 to 3, wherein the first resin layer comprises a layer having a moisture permeability of 1500 g / m 2/24 hr or less at a temperature of 40 ° C and a relative humidity of 90%. The polarizing plate according to any one of claims 1 to 3, further comprising a second resin layer on a surface of the polarizer layer opposite to the side on which the adhesive layer is disposed,
Wherein the second resin layer comprises a layer having a moisture permeability of 1500 g / m &lt; 2 &gt; / 24 hr or less at a temperature of 40 DEG C and a relative humidity of 90%. 4. The polarizer according to any one of claims 1 to 3, wherein the polarizer layer has a simple transmittance of 40% or more. The positive active radiation-sensitive composition according to any one of claims 1 to 3, wherein the active energy ray-curable compound further comprises 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.

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