JP6712846B2 - Curable adhesive composition for polarizing film, polarizing film and method for producing the same, optical film and image display device - Google Patents

Description

The present invention relates to a curable adhesive composition for a polarizing film, which forms the adhesive layer in a polarizing film in which a polarizer and a transparent protective film are laminated via an adhesive layer. The present invention also relates to a polarizing film using the adhesive layer. The polarizing film can form an image display device such as a liquid crystal display device (LCD), an organic EL display device, a CRT, or a PDP by itself or as an optical film in which the polarizing film is laminated.

Liquid crystal display devices are rapidly expanding in markets such as watches, mobile phones, PDAs, notebook computers, personal computer monitors, DVD players, and TVs. The liquid crystal display device visualizes a polarization state due to switching of liquid crystal, and a polarizer is used due to its display principle. In particular, in applications such as TVs, higher brightness, higher contrast and wider viewing angle are required, and polarizing films are also required to have higher transmittance, higher polarization degree and higher color reproducibility.

As the polarizer, since it has a high transmittance and a high degree of polarization, for example, an iodine-based polarizer having a structure in which polyvinyl alcohol (hereinafter, also simply referred to as “PVA”) adsorbs iodine and is stretched is most commonly used. It is used. In general, a polarizing film is used in which a transparent protective film is attached to both sides of a polarizer with a so-called water-based adhesive obtained by dissolving a polyvinyl alcohol-based material in water (Patent Document 1 below). As the transparent protective film, triacetyl cellulose having high moisture permeability is used. When the water-based adhesive is used (so-called wet lamination), a drying step is required after the polarizer and the transparent protective film are bonded together.

On the other hand, an active energy ray-curable adhesive has been proposed instead of the water-based adhesive. When a polarizing film is produced using an active energy ray-curable adhesive, a drying step is not required, so that the productivity of the polarizing film can be improved. For example, a radical polymerization type active energy ray-curable adhesive composition using an N-substituted amide-based monomer as a curable component has been proposed (Patent Document 2 below). Such an adhesive composition exhibits excellent durability in a harsh environment under high humidity and high temperature, but in the market, an adhesive composition capable of further improving adhesiveness and/or water resistance It was the actual situation that was being requested.

JP, 2006-220732, A JP, 2008-287207, A

The present invention was developed in view of the above circumstances, an adhesive having good adhesion between a polarizer and a transparent protective film, and an adhesive excellent in water resistance even under severe conditions such as a dew condensation environment. It is an object to provide a curable adhesive composition for a polarizing film that constitutes a layer.

Moreover, the present invention provides a polarizing film in which a transparent protective film is provided on a polarizer by an adhesive layer formed using a curable adhesive composition for a polarizing film, and further, the polarizing film It is an object of the present invention to provide an optical film used, and further to provide an image display device using the polarizing film or the optical film.

As a result of earnest studies to solve the above problems, the present inventors have found that the curable adhesive composition for a polarizing film described below can achieve the above object, and have solved the present invention.

That is, the present invention is a curable adhesive composition for a polarizing film for adhering a transparent protective film to at least one surface of a polarizer,
A curable adhesive composition for a polarizing film, comprising an active energy ray-curable component and at least one organometallic compound selected from the group consisting of metal alkoxides and metal chelates.

In the curable adhesive composition for a polarizing film, the metal of the organometallic compound is preferably titanium.

In the curable adhesive composition for a polarizing film, it is preferable that the metal alkoxide is contained as the organometallic compound, and that the metal group has an organic group having 6 or more carbon atoms, and the organometallic compound is the metal. It is preferable that the metal group containing a chelate has 4 or more carbon atoms in the organic group.

In the curable adhesive composition for a polarizing film, when the total amount of the active energy ray-curable component is 100 parts by weight, the proportion of the organometallic compound is preferably 0.05 to 9 parts by weight.

In the curable adhesive composition for a polarizing film, when a cured product obtained by curing the curable adhesive composition is immersed in pure water at 23° C. for 24 hours,
Formula: {(M2-M1)/M1}×100(%),
However, M1: weight of the cured product before immersion, M2: weight of the cured product after immersion,
The bulk water absorption represented by is preferably 10% by weight or less.

In the curable adhesive composition for a polarizing film, the active energy ray-curable component preferably contains a radical polymerizable compound, and the radical polymerizable compound preferably contains a (meth)acrylamide derivative. It is preferable that the radical-polymerizable compound contains a polyfunctional compound having at least two functional groups having radical-polymerizability.

The curable adhesive composition for a polarizing film preferably further contains a photopolymerization initiator, further preferably contains a compound having a vinyl ether group, and further contains a photoacid generator. preferable.

In the curable adhesive composition for a polarizing film, a cured product obtained by curing the curable adhesive composition preferably has a storage elastic modulus at 25° C. of 1×10 ⁷ Pa or more.

The present invention is also a polarizing film in which a transparent protective film is provided on at least one surface of a polarizer via an adhesive layer, wherein the adhesive layer is any one of claims 1 to 11. And a polarizing film formed by a cured product layer of the curable adhesive composition for polarizing film. The thickness of the adhesive layer is preferably 0.1 to 3 μm. Furthermore, when the adhesive layer is immersed in pure water at 23° C. for 24 hours,
Formula: {(M2-M1)/M1}×100(%),
However, M1: weight of the cured product before immersion, M2: weight of the cured product after immersion,
The bulk water absorption represented by is preferably 10% by weight or less, and the adhesive layer preferably has a storage elastic modulus at 25° C. of 1.0×10 ⁷ Pa or more.

Further, the present invention is the method for producing a polarizing film as described above, wherein a coating step of applying the curable adhesive composition for a polarizing film to at least one surface of the polarizer and the transparent protective film. And a step of laminating the polarizer and the transparent protective film, and irradiating an active energy ray from the polarizer surface side or the transparent protective film surface side to give the active energy ray-curable adhesive composition. And a bonding step of bonding the polarizer and the transparent protective film via the adhesive layer obtained by curing the polarizing film.

Further, the present invention is characterized in that at least one polarizing film described above is laminated, and the polarizing film described above or the optical film described above is used. The present invention relates to an image display device.

When the polarizing film in which the transparent protective film is laminated on the polarizer via the adhesive layer is exposed to a dew condensation environment, the mechanism that causes the peeling of the adhesive between the adhesive layer and the polarizer is as follows. Can be estimated. First, the moisture that has passed through the protective film diffuses into the adhesive layer, and the moisture diffuses to the polarizer interface side. Here, in the conventional polarizing film, the contribution of hydrogen bond and/or ionic bond is large with respect to the adhesive force between the adhesive layer and the polarizer, but due to the moisture diffused on the polarizer interface side, Hydrogen bonds and ionic bonds are dissociated, and as a result, the adhesive force between the adhesive layer and the polarizer is reduced. As a result, in a dew condensation environment, adhesion peeling between the adhesive layer and the polarizer may occur.

On the other hand, the curable adhesive composition for a polarizing film according to the present invention contains at least one organometallic compound selected from the group consisting of metal alkoxides and metal chelates. Such an organometallic compound becomes an active metal species due to the presence of water, and as a result, the organometallic compound strongly interacts with both the polarizer and the active energy ray-curable component constituting the adhesive layer. As a result, even if water is present at the interface between the polarizer and the adhesive layer, since they interact strongly through the organometallic compound, the adhesion water resistance between the polarizer and the adhesive layer is high. Is dramatically improved.

As the curable adhesive composition for a polarizing film of the present invention, it is preferable that the cured product obtained by curing the curable adhesive composition has a bulk water absorption of 10% by weight or less. The bulk water absorption indicates that the water absorption when the adhesive layer is formed by the cured product layer obtained from the curable adhesive composition for a polarizing film of the present invention is very low. Therefore, the polarizing film, in which the transparent protective film is provided on the polarizer via the adhesive layer composed of the cured product layer, has good adhesiveness between the polarizer and the transparent protective film layer, and under high temperature and high humidity. The optical durability under the severe environment can be satisfied at a higher level.

For example, a polarizing film having a cured product layer (adhesive layer) formed using the curable adhesive composition for a polarizing film of the present invention can be used even under a severe humid environment (for example, 85° C.×85% RH). Good optical durability (humidity durability test). Therefore, the polarizing film of the present invention can suppress a decrease (change) in the transmittance and the degree of polarization of the polarizing film even when placed in the severe humid environment. Further, the polarizing film of the present invention can suppress the decrease in adhesive strength even under a harsh environment such as immersion in water, and even under conditions where the contact environment with water is severe, the polarizer and the transparent protective film It is possible to suppress a decrease in the adhesive force between the layers (between the polarizer and the adhesive layer) to be small.

The curable adhesive composition for a polarizing film according to the present invention contains at least one organometallic compound selected from the group consisting of metal alkoxides and metal chelates together with an active energy ray-curable component.

<At least one organometallic compound selected from the group consisting of metal alkoxides and metal chelates>
The metal alkoxide is a compound in which at least one alkoxy group which is an organic group is bonded to the metal, and the metal chelate is a compound in which an organic group is bonded or coordinated to the metal via an oxygen atom. The metal is preferably titanium, aluminum or zirconium. Among these, aluminum and zirconium have a higher reactivity than titanium, the pot life of the adhesive composition may be shortened, and the effect of improving the adhesive water resistance may be reduced. Therefore, from the viewpoint of improving the adhesive water resistance of the adhesive layer, titanium is more preferable as the metal of the organometallic compound.

When the curable adhesive composition for a polarizing film according to the present invention contains a metal alkoxide as an organometallic compound, it is preferable to use an organic group having 4 or more carbon atoms in the metal alkoxide, which is 6 or more. It is more preferable to contain the thing. When the carbon number is 3 or less, the pot life of the adhesive composition may be shortened and the effect of improving the adhesive water resistance may be reduced. Examples of the organic group having 6 or more carbon atoms include an octoxy group, which can be preferably used. Examples of suitable metal alkoxides include, for example, tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetraoctyl titanate, tertiary amyl titanate, tetratertiary butyl titanate, tetrastearyl titanate, zirconium tetraisopropoxide, zirconium. Tetra-normal butoxide, zirconium tetra-octoxide, zirconium tetra-tert-butoxide, zirconium tetrapropoxide, aluminum sec butyrate, aluminum ethylate, aluminum isopropylate, aluminum butyrate, aluminum diisopropylate mono-secondary butyrate, mono sec butoxy aluminum Examples include diisopropylate and the like. Of these, tetraoctyl titanate is preferable.

When the curable adhesive composition for a polarizing film according to the present invention contains a metal chelate as an organometallic compound, it is preferable that the metal chelate contains an organic group having 4 or more carbon atoms. When the carbon number is 3 or less, the pot life of the adhesive composition may be shortened and the effect of improving the adhesive water resistance may be reduced. Examples of the organic group having 4 or more carbon atoms include an acetylacetonate group, an ethylacetoacetate group, an isostearate group, and an octyleneglycolate group. Among these, an acetylacetonate group or an ethylacetoacetate group is preferable as the organic group from the viewpoint of improving the adhesive water resistance of the adhesive layer. Examples of suitable metal chelates include, for example, titanium acetylacetonate, titanium octylene glycolate, titanium tetraacetylacetonate, titanium ethyl acetoacetate, polyhydroxytitanium stearate, dipropoxy-bis(acetylacetonato)titanium, dititanium. Butoxytitanium-bis(octylene glycolate), dipropoxytitanium-bis(ethylacetoacetate), titanium lactate, titanium diethanolaminate, titanium triethanolaminate, dipropoxytitanium-bis(lactate), dipropoxytitanium-bis( Triethanolaminate), di-n-butoxytitanium-bis(triethanolaminate), tri-n-butoxytitanium monostearate, diisopropoxy bis(ethylacetoacetate) titanium, diisopropoxy bis(acetyl). Acetate) titanium, diisopropoxy bis(acetylacetone) titanium, titanium phosphate compound, titanium lactate ammonium salt, titanium-1,3-propanedioxybis(ethylacetoacetate), titanium dodecylbenzenesulfonate compound, titanium aminoethyl Aminoethanolate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium acetylacetonate bisethylacetoacetate, zirconium acetate, tri-n-butoxyethylacetoacetate zirconium, di-n-butoxybis( Ethylacetoacetate) zirconium, n-butoxytris(ethylacetoacetate) zirconium, tetrakis(n-propylacetoacetate) zirconium, tetrakis(acetylacetoacetate) zirconium, tetrakis(ethylacetoacetate) zirconium, aluminum ethylacetoacetate, aluminum acetyl Acetonate, aluminum acetylacetonate bisethylacetoacetate, diisopropoxyethylacetoacetate aluminum, diisopropoxyacetylacetonate aluminum, isopropoxybis(ethylacetoacetate) aluminum, isopropoxybis(acetylacetonate) aluminum, tris( Ethylacetoacetate) aluminum, tris(acetylacetonate) aluminum, monoacetylacetonate/bis(ethylacetoacetate) Aluminum). Of these, titanium acetylacetonate and titanium ethylacetoacetate are preferable.

As the organometallic compound usable in the present invention, in addition to the above, organic carboxylic acid metal salts such as zinc octylate, zinc laurate, zinc stearate and tin octylate, acetylacetone zinc chelate, benzoylacetone zinc chelate, dibenzoylmethane zinc. Examples thereof include chelates and zinc chelate compounds such as ethyl zinc acetoacetate chelates.

In the present invention, the content ratio of the organometallic compound is preferably 0.05 to 9 parts by weight, and preferably 0.1 to 8 parts by weight, based on 100 parts by weight of the total amount of the active energy ray-curable component. It is more preferably 0.15 to 5 parts by weight. When the amount is more than 9 parts by weight, the storage stability of the adhesive composition may be deteriorated, or the ratio of components for adhering to the polarizer or the protective film may be relatively insufficient and the adhesiveness may be deteriorated. .. Also, if the amount is less than 0.05 parts by weight, the effect of the adhesive water resistance cannot be sufficiently exhibited.

In the present invention, from the viewpoint of improving the liquid stability of the organometallic compound in the composition, the composition may contain a polymerizable compound having a polymerizable functional group and a carboxyl group together with the organometallic compound.

<Polymerizable Compound Having Polymerizable Functional Group and Carboxyl Group>
The polymerizable compound having a polymerizable functional group and a carboxyl group has a polymerizable functional group and a carboxyl group. The polymerizable functional group and the carboxyl group contained may be either one or two or more.

The polymerizable functional group is not particularly limited, and examples thereof include a carbon-carbon double bond-containing group, an epoxy group, an oxetanyl group, and a vinyl ether group.

As the polymerizable functional group, in particular, the following general formula (I):
^{_{H 2 C = C (R 1}} ) -COO- (I)
(In the formula, R ¹ represents hydrogen or an organic group having 1 to 20 carbon atoms.) Or the following formula (II):
_{^{H 2 C = C (R 2}} ) -R 3 - (II)
(In the formula, R ¹ represents hydrogen or an organic group having 1 to 20 carbon atoms, and R ³ represents a direct bond or an organic group having 1 to 20 carbon atoms.) A radical-polymerizable functional group represented by the formula is preferable, and R is particularly preferable. Radical polymerizable functional groups in which ¹ or R ² is hydrogen or a methyl group are particularly preferred.

The bonding position of the carboxyl group in the polymerizable compound having a polymerizable functional group and a carboxyl group is not particularly limited, but from the viewpoint of improving the liquid stability of the organometallic compound in the composition, the radical polymerizable functional group and A radical-polymerizable compound in which a radical-polymerizable functional group is bonded to a carboxyl group via an organic group having 1 to 20 carbon atoms which may contain oxygen is preferable to (meth)acrylic acid to which a carboxyl group is directly bonded.

Further, from the viewpoint of improving the liquid stability of the organometallic compound in the composition, the polymerizable compound having a polymerizable functional group and a carboxyl group has a large molecular weight, and when it is bound and/or coordinated with the organometallic compound, it has a large volume. It is preferably high and becomes a steric hindrance when another ligand is coordinated. Therefore, the molecular weight of the polymerizable compound having a polymerizable functional group and a carboxyl group is preferably 100 (g/mol) or more, more preferably 125 (g/mol) or more, and 150 (g/mol). The above is particularly preferable. The upper limit of the molecular weight of the polymerizable compound having a polymerizable functional group and a carboxyl group is not particularly limited, but about 300 (g/mol) can be exemplified.

Further, from the viewpoint of improving the liquid stability of the organometallic compound in the composition, the polymerizable compound having a polymerizable functional group and a carboxyl group, via an organic group having 1 to 20 carbon atoms which may contain oxygen, It is preferably a polymerizable compound having a polymerizable functional group and a carboxyl group. Examples of such organic groups include alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, alicyclic groups, unsaturated alicyclic groups, alkyl ester groups, aromatic ester groups, acyl groups, hydroxyalkyl groups, alkylene oxides. A group may be mentioned, and a single or a plurality of the same organic groups may be bonded, or a plurality of different organic groups may be bonded. Specific examples of the polymerizable compound (B) include β-carboxyethyl acrylate, carboxypentyl acrylate, β-carboxyethyl methacrylate, 2-acryloyloxyethyl-succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2- Acryloyloxyethyl phthalic acid, ω-carboxy-polycaprolactone monoacrylate, 2-acryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxypropyl oxyphthalic acid, 2-acryloyloxypropyl tetrahydrophthalic acid, 2-acryloyloxypropyl hexahydrophthalic acid Acid, methacryloyloxyethyl succinic acid, methacryloyloxyethyl phthalic acid, methacryloyloxyethyl tetrahydrophthalic acid, methacryloyloxyethyl hexahydrophthalic acid, 2-methacryloyloxypropyloxyphthalic acid, 2-metalloyloxypropyl tetrahydrophthalic acid, 2- Examples thereof include metalliloyloxypropylhexahydrophthalic acid.

From the viewpoint of improving the liquid stability of the organometallic compound in the composition, when the total amount of the organometallic compound in the curable adhesive composition for a polarizing film is α (mol), the polymerizable functional group and the carboxyl group are The content of the polymerizable compound contained therein is preferably 0.25α (mol) or more, more preferably 0.35α (mol) or more, and particularly preferably 0.5α (mol) or more. When the content of the polymerizable compound having a polymerizable functional group and a carboxyl group is less than 0.25 α (mol), the organometallic compound is insufficiently stabilized, and the hydrolysis reaction and the self-condensation reaction proceed, resulting in a pot life. May be shortened. The upper limit of the content of the polymerizable compound having a polymerizable functional group and a carboxyl group with respect to the total amount α (mol) of the organometallic compound is not particularly limited, but may be about 4 α (mol), for example.

<Organometallic compound-containing composition>
In the curable adhesive composition for a polarizing film according to the present invention, when a polymerizable compound having a polymerizable functional group and a carboxyl group is used together with an organometallic compound, an active energy ray-curable component, an organometallic compound, and a polymerizable compound It may be obtained by mixing a polymerizable compound having a functional group and a carboxyl group at the same time, but an organometallic compound, and an organometallic compound-containing composition containing a polymerizable compound having a polymerizable functional group and a carboxyl group It may be obtained by preliminarily producing a product and mixing it with an active energy ray-curable component.

In the curable adhesive composition for a polarizing film, the carboxyl group of the polymerizable compound having a polymerizable functional group and a carboxyl group is strongly bonded and/or coordinated with the metal of the organometallic compound to form an organometallic compound. The compound stabilizes. Here, when an organometallic compound and a polymerizable compound having a polymerizable functional group and a carboxyl group are mixed and reacted in the absence of an active energy ray-curable component, the reaction rate and/or coordination rate of these The amount of the organometallic compound-containing composition obtained is significantly increased, and the composition containing the organometallic compound and the reaction product and/or coordination compound of the organometallic compound with the polymerizable compound having a polymerizable functional group and a carboxyl group is highly concentrated. Become. Therefore, the obtained organometallic compound-containing composition has extremely high stability of the organometallic compound, and the curable adhesive composition for a polarizing film containing the same also has high organometallic stability.

<Curable component>
The curable adhesive composition for a polarizing film of the present invention contains an active energy ray-curable component as a curable component.

As the curable component, an active energy ray curable type such as an electron beam curable type, an ultraviolet ray curable type or a visible ray curable type can be preferably used. Furthermore, the ultraviolet curable and visible light curable adhesive compositions can be classified into radical polymerization curable adhesive compositions and cationic polymerization curable adhesive compositions. In the present invention, an active energy ray having a wavelength range of 10 nm to less than 380 nm is referred to as an ultraviolet ray, and an active energy ray having a wavelength range of 380 nm to 800 nm is referred to as a visible ray.

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

<<Monofunctional Radical Polymerizable Compound>>
Examples of the monofunctional radically polymerizable compound include (meth)acrylamide derivatives having a (meth)acrylamide group. The (meth)acrylamide derivative is preferable in terms of ensuring adhesiveness with the polarizer and various transparent protective films, and also because of its high polymerization rate and excellent productivity. Specific examples of the (meth)acrylamide derivative include, for example, N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N. -N-alkyl group-containing (meth)acrylamide derivatives such as -butyl (meth)acrylamide, N-hexyl (meth)acrylamide; N-methylol (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, N-methylol-N- N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as propane (meth)acrylamide; N-aminoalkyl group-containing (meth)acrylamide derivatives such as aminomethyl (meth)acrylamide and aminoethyl (meth)acrylamide; N-methoxymethyl N-alkoxy group-containing (meth)acrylamide derivatives such as acrylamide and N-ethoxymethylacrylamide; N-mercaptoalkyl group-containing (meth)acrylamide derivatives such as mercaptomethyl (meth)acrylamide and mercaptoethyl (meth)acrylamide; To be Examples of the heterocycle-containing (meth)acrylamide derivative in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle include, for example, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. And so on.

Among the (meth)acrylamide derivatives, an N-hydroxyalkyl group-containing (meth)acrylamide derivative is preferable from the viewpoint of adhesiveness to a polarizer and various transparent protective films, and particularly N-hydroxyethyl (meth)acrylamide. Is preferred.

Examples of the monofunctional radically polymerizable compound include various (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Specifically, for example, methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate, isopropyl(meth)acrylate, 2-methyl-2-nitropropyl(meth)acrylate, n-butyl( (Meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t-pentyl (meth)acrylate, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl(meth)acrylate, n-hexyl(meth)acrylate, cetyl(meth)acrylate, n-octyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, 4-methyl-2-propylpentyl( Examples thereof include (meth)acrylic acid (1-20 carbon atoms) alkyl esters such as (meth)acrylate and n-octadecyl (meth)acrylate.

Examples of the (meth)acrylic acid derivative include cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; 2-isobornyl (Meth)acrylate, 2-norbornylmethyl(meth)acrylate, 5-norbornen-2-yl-methyl(meth)acrylate, 3-methyl-2-norbornylmethyl(meth)acrylate, dicyclopentenyl (meth ) Polycyclic (meth)acrylates such as acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, 2-ethoxy Such as ethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethylcarbitol (meth)acrylate, phenoxyethyl (meth)acrylate, alkylphenoxy polyethylene glycol (meth)acrylate Alkoxy group- or phenoxy group-containing (meth)acrylate; and the like.

Moreover, as said (meth)acrylic acid derivative, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4- Hydroxyalkyl (meth)acrylates such as hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate and 12-hydroxylauryl (meth)acrylate. Or a hydroxyl group-containing (meth)acrylate such as [4-(hydroxymethyl)cyclohexyl]methyl acrylate, cyclohexanedimethanol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate; glycidyl (meth)acrylate, Epoxy group-containing (meth)acrylate such as 4-hydroxybutyl (meth)acrylate glycidyl ether; 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate, tetra Halogen-containing (meth)acrylates such as fluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, and 3-chloro-2-hydroxypropyl (meth)acrylate. ) Acrylate; alkylaminoalkyl(meth)acrylates such as dimethylaminoethyl(meth)acrylate; 3-oxetanylmethyl(meth)acrylate, 3-methyl-oxetanylmethyl(meth)acrylate, 3-ethyl-oxetanylmethyl(meth)acrylate. , 3-butyl-oxetanylmethyl (meth)acrylate, 3-hexyloxetanylmethyl (meth)acrylate and other oxetane group-containing (meth)acrylates; heterocycles such as tetrahydrofurfuryl (meth)acrylate and butyrolactone (meth)acrylate And (meth)acrylate having hydroxypivalate, neopentyl glycol (meth)acrylic acid adduct, and p-phenylphenol (meth)acrylate.

Further, as the monofunctional radically polymerizable compound, (meth) acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, β-carboxyethyl acrylate, carboxypentyl acrylate, β-carboxyethyl methacrylate, 2-acryloyloxyethyl-succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl phthalic acid, ω-carboxy-polycaprolactone monoacrylate, 2-acryloyloxyethyl tetrahydrophthalic acid 2-acryloyloxypropyl oxyphthalic acid, 2-acryloyloxypropyl tetrahydrophthalic acid, 2-acryloyloxypropyl hexahydrophthalic acid, methacryloyloxyethyl succinic acid, methacryloyloxyethyl phthalic acid, methacryloyloxyethyl tetrahydrophthalic acid, methacryloyloxy Examples thereof include carboxyl group-containing monomers such as ethylhexahydrophthalic acid, 2-methacryloyloxypropyloxyphthalic acid, 2-metallyloyloxypropyltetrahydrophthalic acid, and 2-metallyloyloxypropylhexahydrophthalic acid.

Examples of the monofunctional radically polymerizable compound include lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, Examples thereof include vinyl-based monomers having a nitrogen-containing heterocycle such as vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine.

Further, as the monofunctional radically polymerizable compound, a radically polymerizable compound having an active methylene group can be used. The radical polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acryl group at the terminal or in the molecule and having an active methylene group. Examples of the active methylene group include an acetoacetyl group, an alkoxymalonyl group, a cyanoacetyl group and the like. The active methylene group is preferably an acetoacetyl group. Specific examples of the radically polymerizable compound having an active methylene group include, for example, 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, 2-acetoacetoxy-1-methylethyl (meth)acrylate and the like. Acetoacetoxyalkyl(meth)acrylate; 2-ethoxymalonyloxyethyl(meth)acrylate, 2-cyanoacetoxyethyl(meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl) Examples thereof include acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, N-(2-acetoacetylaminoethyl)acrylamide and the like. The radically polymerizable compound having an active methylene group is preferably acetoacetoxyalkyl(meth)acrylate.

<<Polyfunctional radically polymerizable compound>>
Examples of the bifunctional or higher polyfunctional radically polymerizable compound include N,N'-methylenebis(meth)acrylamide, tripropylene glycol di(meth)acrylate, tetraethylene glycol di, which are polyfunctional (meth)acrylamide derivatives. (Meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth ) Acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl Glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri( (Meth)acrylic acid and polyhydric alcohol such as (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and EO-modified diglycerin tetra(meth)acrylate And an ester compound thereof, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. As specific examples, Aronix M-220 (manufactured by Toagosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DCP-A (Kyoeisha Chemical Co., Ltd.) Preferred), SR-531 (available from Sartomer), CD-536 (available from Sartomer), and the like. If necessary, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, various (meth)acrylate-based monomers and the like can be mentioned. The polyfunctional (meth)acrylamide derivative is preferably contained in the curable resin composition because it has a high polymerization rate and excellent productivity and also has excellent crosslinkability when the resin composition is a cured product.

The radically polymerizable compound contains the polyfunctional radically polymerizable compound, in order to control the water absorption of the cured product, and to satisfy the optical durability of the polarizing film under a severe humid environment. preferable. Among the polyfunctional radically polymerizable compounds, those having a high logPow value described later are preferable.

The curable adhesive composition for a polarizing film of the present invention preferably has a high octanol/water partition coefficient (hereinafter referred to as logPow value). The logPow value is an index showing the lipophilicity of a substance and means the logarithmic value of the partition coefficient of octanol/water. A high log Pow means that it is lipophilic, that is, it has a low water absorption. The logPow value can be measured (flask impregnation method described in JIS-Z-7260), but can also be calculated. In this specification, the logPow value calculated by ChemDraw Ultra manufactured by Cambridge Soft Co. is used. The logPow value of the adhesive composition can be calculated by the following formula.
Adhesive composition logPow=Σ(logPowi×Wi)
logPowi: logPow value of each component of the composition Wi: (number of moles of i component)/(total number of moles of adhesive composition)
The logPow value of the curable adhesive composition of the present invention is preferably 1 or more, more preferably 2 or more, and most preferably 3 or more.

Examples of the radically polymerizable compound having a high logPow value include alicyclic (meth) compounds such as tricyclodecanedimethanol di(meth)acrylate (logPow=3.05) and isobornyl(meth)acrylate (logPow=3.27). Acrylate; long-chain aliphatic (meth)acrylate such as 1,9-nonanediol di(meth)acrylate (logPow=3.68) and 1,10-decanediol diacrylate (logPow=4.10); hydroxypivalic acid Bipentaphenol A, such as neopentyl glycol (meth)acrylic acid adduct (logPow=3.35), 2-ethyl-2-butylpropanediol di(meth)acrylate (logPow=3.92); bisphenol A Di(meth)acrylate (logPow=5.46), bisphenol A ethylene oxide 4 mol adduct di(meth)acrylate (logPow=5.15), bisphenol A propylene oxide 2 mol adduct di(meth)acrylate (logPow= 6.10), bisphenol A propylene oxide 4 mol adduct di(meth)acrylate (logPow=6.43), 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene (logPow= 7.48), (meth)acrylates containing an aromatic ring such as p-phenylphenol (meth)acrylate (logPow=3.98); and the like.

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

<Aspect of radical polymerization curable adhesive composition>
The curable adhesive composition for a polarizing film of the present invention can be used as an active energy ray-curable adhesive composition when a curable component is used as an active energy ray-curable component. The active energy ray-curable adhesive composition, when using an electron beam or the like for the active energy ray, the active energy ray-curable adhesive composition need not contain a photopolymerization initiator, When ultraviolet rays or visible rays are used as the active energy rays, it is preferable to contain a photopolymerization initiator.

<< Photoinitiator >>
The photopolymerization initiator in the case of using a radically polymerizable compound is appropriately selected depending on the active energy ray. In the case of curing with ultraviolet light or visible light, a photopolymerization initiator capable of cleaving ultraviolet light or visible light is used. Examples of the photopolymerization initiator include benzyl, benzophenone, benzoylbenzoic acid, benzophenone compounds such as 3,3′-dimethyl-4-methoxybenzophenone; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2) -Propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenyl ketone, and other aromatic ketone compounds; methoxyacetophenone, 2,2-dimethoxy- Acetophenone compounds such as 2-phenylacetophenone, 2,2-diethoxyacetophenone and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin methyl ether, Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether and anisoin methyl ether; aromatic ketal compounds such as benzyldimethyl ketal; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride Compounds; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, Thioxanthone compounds such as isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxide; acylphosphonate can give. Among the photopolymerization initiators, those having a high logPow value are preferable. The logPow value of the photopolymerization initiator is preferably 2 or more, more preferably 3 or more, and most preferably 4 or more.

The content of the photopolymerization initiator is 20 parts by weight or less based on 100 parts by weight of the total amount of the curable component (radical polymerizable compound). The compounding amount of the photopolymerization initiator is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, and further preferably 0.1 to 5 parts by weight.

Further, when the curable adhesive composition for a polarizing film of the present invention is used in a visible light curable type containing a radically polymerizable compound as a curable component, photopolymerization initiation with high sensitivity particularly to light of 380 nm or more. It is preferable to use an agent. The photopolymerization initiator having high sensitivity to light of 380 nm or more will be described later.

The photopolymerization initiator is a compound represented by the following general formula (1);
(Wherein R ¹ and R ² represent —H, —CH ₂ CH ₃ , —iPr or Cl, and R ¹ and R ² may be the same or different), or they may be used alone or in the general formula ( It is preferable to use the compound represented by 1) in combination with a photopolymerization initiator having high sensitivity to light having a wavelength of 380 nm or more, which will be described later. When the compound represented by the general formula (1) is used, the adhesiveness is excellent as compared with the case where a photopolymerization initiator having high sensitivity to light of 380 nm or more is used alone. Among the compounds represented by the general formula (1), diethylthioxanthone in which R ¹ and R ² are —CH ₂ CH ₃ is particularly preferable. The composition ratio of the compound represented by the general formula (1) in the adhesive composition is preferably 0.1 to 5 parts by weight, and 0.5 to 5 parts by weight based on 100 parts by weight of the total amount of the curable component. It is more preferably 4 parts by weight, further preferably 0.9 to 3 parts by weight.

Moreover, it is preferable to add a polymerization initiation aid as needed. As a polymerization initiation aid, triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, etc. And ethyl 4-dimethylaminobenzoate is particularly preferable. When a polymerization initiation aid is used, its addition amount is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, and most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component. is there.

Further, a known photopolymerization initiator can be used in combination, if necessary. Since the transparent protective film having UV absorbing ability does not transmit light having a wavelength of 380 nm or less, it is preferable to use a photopolymerization initiator having high sensitivity to light having a wavelength of 380 nm or more as the photopolymerization initiator. Specifically, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1. , 2-(Dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine Oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole- 1-yl)-phenyl)titanium and the like.

In particular, as a photopolymerization initiator, a compound represented by the following general formula (2) in addition to the photopolymerization initiator of the general formula (1);
(In the formula, R ³ , R ⁴ and R ⁵ represent —H, —CH ₃ , —CH ₂ CH ₃ , —iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different.) Preference is given to using. As the compound represented by the general formula (2), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: IRGACURE907 maker: BASF), which is also a commercial product, is suitable. Can be used for. In addition, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name: IRGACURE369 manufacturer: BASF), 2-(dimethylamino)-2-[(4-methylphenyl) Methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: IRGACURE379 maker: BASF) is preferable because of its high sensitivity.

<Radical Polymerizable Compound (a1) Having Active Methylene Group and Radical Polymerization Initiator (a2) Having Hydrogen Absorption Action>
In the above active energy ray-curable adhesive composition, when the radical polymerizable compound (a1) having an active methylene group is used as the radical polymerizable compound, it is combined with a radical polymerization initiator (a2) having a hydrogen abstraction action. It is preferable to use. With this configuration, the adhesiveness of the adhesive layer of the polarizing film is significantly improved even immediately after taking out from a high humidity environment or water (non-dried state). The reason for this is not clear, but the following causes are considered. That is, the radical polymerizable compound (a1) having an active methylene group is incorporated into the main chain and/or side chain of the base polymer in the adhesive layer while polymerizing with the other radical polymerizable compound constituting the adhesive layer. To form an adhesive layer. In the polymerization process, when a radical polymerization initiator (a2) having a hydrogen abstraction function is present, hydrogen is released from the radical polymerizable compound (a2) having an active methylene group while the base polymer forming the adhesive layer is formed. It is extracted and a radical is generated in the methylene group. Then, the methylene group in which the radical is generated reacts with the hydroxyl group of the polarizer such as PVA to form a covalent bond between the adhesive layer and the polarizer. As a result, it is speculated that the adhesiveness of the adhesive layer of the polarizing film is significantly improved even in the non-dry state.

In the present invention, examples of the radical polymerization initiator (a2) having a hydrogen abstraction action include thioxanthone radical polymerization initiators and benzophenone radical polymerization initiators. The radical polymerization initiator (a2) is preferably a thioxanthone-based radical polymerization initiator. Examples of the thioxanthone radical polymerization initiator include compounds represented by the above general formula (1). Specific examples of the compound represented by the general formula (1) include thioxanthone, dimethylthioxanthone, diethylthioxanthone, isopropylthioxanthone, chlorothioxanthone and the like. Among the compounds represented by the general formula (1), diethylthioxanthone in which R ¹ and R ² are —CH ₂ CH ₃ is particularly preferable.

When the active energy ray-curable adhesive composition contains a radical polymerizable compound (a1) having an active methylene group and a radical polymerization initiator (a2) having a hydrogen abstraction action, the total amount of curable components Is 100% by weight, the radical polymerizable compound (a1) having the active methylene group is 1 to 50% by weight, and the radical polymerization initiator (a2) is 0 based on 100 parts by weight of the total amount of the curable component. It is preferable to contain 1 to 10 parts by weight.

As described above, in the present invention, in the presence of the radical polymerization initiator (a2) having a hydrogen abstraction action, a radical is generated in the methylene group of the radically polymerizable compound (a1) having an active methylene group, and the methylene group is generated. Reacts with the hydroxyl group of the polarizer such as PVA to form a covalent bond. Therefore, in order to generate a radical in the methylene group of the radically polymerizable compound (a1) having an active methylene group and sufficiently form such a covalent bond, when the total amount of the curable component is 100% by weight, the active methylene group is The radically polymerizable compound (a1) having 1 to 50% by weight is preferably contained, and more preferably 3 to 30% by weight. The radically polymerizable compound (a1) having an active methylene group is preferably 1% by weight or more in order to sufficiently improve the water resistance and the adhesiveness in a non-dried state. On the other hand, if it exceeds 50% by weight, curing failure of the adhesive layer may occur. Further, the radical polymerization initiator (a2) having a hydrogen abstraction function is preferably contained in an amount of 0.1 to 10 parts by weight, and more preferably 0.3 to 9 parts by weight, based on 100 parts by weight of the total amount of the curable component. More preferably. In order for the hydrogen abstraction reaction to proceed sufficiently, it is preferable to use 0.1 part by weight or more of the radical polymerization initiator (a2). On the other hand, in some cases, if it exceeds 10 parts by weight, it may not be completely dissolved in the composition.

<2: Cationic polymerization-curable adhesive composition>
The cationically polymerizable compound used in the cationically polymerizable curable resin composition includes a monofunctional cationically polymerizable compound having one cationically polymerizable functional group in the molecule and two or more cationically polymerizable functional groups in the molecule. It is classified as a polyfunctional cationic polymerizable compound having. Since the monofunctional cationically polymerizable compound has a relatively low liquid viscosity, the liquid viscosity of the resin composition can be reduced by including it in the resin composition. In addition, monofunctional cationically polymerizable compounds often have functional groups that exert various functions, and when incorporated into the resin composition, various functions are exhibited in the resin composition and/or the cured product of the resin composition. Can be made. Since the polyfunctional cationically polymerizable compound can three-dimensionally crosslink the cured product of the resin composition, it is preferably contained in the resin composition. The ratio of the monofunctional cationically polymerizable compound and the polyfunctional cationically polymerizable compound is such that the polyfunctional cationically polymerizable compound is mixed in the range of 10 parts by weight to 1000 parts by weight with respect to 100 parts by weight of the monofunctional cationically polymerizable compound. Is preferred. Examples of the cationically polymerizable functional group include an epoxy group, an oxetanyl group, and a vinyl ether group. Examples of the compound having an epoxy group include an aliphatic epoxy compound, an alicyclic epoxy compound, and an aromatic epoxy compound, and the cationic polymerization curable resin composition of the present invention has excellent curability and adhesiveness, It is particularly preferable to contain an alicyclic epoxy compound. Examples of the alicyclic epoxy compound include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate modified with caprolactone or modified with trimethylcaprolactone. And valerolactone modified products, and specific examples thereof include celoxide 2021, celoxide 2021A, celoxide 2021P, celoxide 2081, celoxide 2083, celoxide 2085 (above, Daicel Chemical Industries, Ltd., Cylacure UVR-6105, Cylacure UVR). -6107, Syracure 30, R-6110 (all manufactured by Dow Chemical Japan Co., Ltd.), etc. The compound having an oxetanyl group improves the curability of the cationic polymerization curable resin composition of the present invention. The compound having an oxetanyl group is preferably contained because it has the effect of lowering the liquid viscosity of the composition.As the compound having an oxetanyl group, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl- 3-Oxetanyl)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, di[(3-ethyl-3-oxetanyl)methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl) Examples include oxetane and phenol novolac oxetane, and Aron oxetane OXT-101, Aron oxetane OXT-121, Aron oxetane OXT-211, Aron oxetane OXT-221, Aron oxetane OXT-212 (above, manufactured by Toagosei Co., Ltd.) and the like are commercially available. The compound having a vinyl ether group is preferably contained because it has the effects of improving the curability of the cationically polymerizable curable resin composition of the present invention and reducing the liquid viscosity of the composition. Examples of the compound having a group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, vinyl ether of diethylene glycol, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, cyclohexanedimethanol monovinyl ether, tricyclodecane vinyl ether, Examples thereof include cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, pentaerythritol type tetravinyl ether and the like.

<Cationic photoinitiator>
The cationic polymerization curable resin composition contains as the curable component at least one compound selected from the compound having an epoxy group, the compound having an oxetanyl group, and the compound having a vinyl ether group, all of which are cationically polymerized. The photo-cationic polymerization initiator is blended because it is cured by. This cationic photopolymerization initiator generates a cationic species or a Lewis acid upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates a polymerization reaction of epoxy groups and oxetanyl groups. As the photocationic polymerization initiator, the photoacid generator described below is preferably used. When the curable resin composition used in the present invention is curable with visible light, it is preferable to use a cationic photopolymerization initiator that is highly sensitive to light of 380 nm or more. Is generally a compound that exhibits maximum absorption in the wavelength range of around 300 nm or shorter, so it is necessary to add a photosensitizer that exhibits maximum absorption in light of longer wavelength range, specifically, longer than 380 nm. Thus, it is possible to be sensitive to light having a wavelength in the vicinity of this, and to promote generation of a cationic species or an acid from the cationic photopolymerization initiator. Examples of the photosensitizer include anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, and the like. You may use it in mixture of 2 or more types. In particular, the anthracene compound is preferable because it has an excellent photosensitizing effect, and specific examples thereof include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Kasei). The content of the photosensitizer is preferably 0.1% by weight to 5% by weight, and more preferably 0.5% by weight to 3% by weight.

<Other ingredients>
The curable adhesive composition according to the present invention preferably contains the following components.

<Acrylic oligomer (A)>
The active energy ray-curable adhesive composition according to the present invention may contain an acrylic oligomer (A) obtained by polymerizing a (meth)acrylic monomer, in addition to the curable component related to the radically polymerizable compound. it can. By containing the component (A) in the active energy ray-curable adhesive composition, curing shrinkage when the composition is irradiated with active energy rays and cured is reduced, and the adhesive, the polarizer and the transparent protection are provided. Interface stress with an adherend such as a film can be reduced. As a result, it is possible to suppress a decrease in the adhesiveness between the adhesive layer and the adherend. In order to sufficiently suppress the curing shrinkage of the cured product layer (adhesive layer), the content of the acrylic oligomer (A) should be 20 parts by weight or less based on 100 parts by weight of the total amount of the curable component. Is preferred, and more preferably 15 parts by weight or less. When the content of the acrylic oligomer (A) in the adhesive composition is too large, the reaction rate when the composition is irradiated with an active energy ray is drastically reduced, which may result in poor curing. On the other hand, the acrylic oligomer (A) is preferably contained in an amount of 3 parts by weight or more, more preferably 5 parts by weight or more, based on 100 parts by weight of the total amount of the curable component.

The active energy ray-curable adhesive composition preferably has a low viscosity in view of workability and uniformity at the time of coating, and therefore an acrylic oligomer (A) obtained by polymerizing a (meth)acrylic monomer. Also, it is preferable that the viscosity is low. The acrylic oligomer having a low viscosity and capable of preventing curing shrinkage of the adhesive layer preferably has a weight average molecular weight (Mw) of 15,000 or less, more preferably 10,000 or less, and particularly preferably 5,000 or less. preferable. On the other hand, in order to sufficiently suppress the curing shrinkage of the cured product layer (adhesive layer), the weight average molecular weight (Mw) of the acrylic oligomer (A) is preferably 500 or more, and preferably 1000 or more. More preferably, it is 1500 or more, and particularly preferably. Specific examples of the (meth)acrylic monomer that constitutes the acrylic oligomer (A) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and 2 -Methyl-2-nitropropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, S-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t-pentyl(meth)acrylate, 3-pentyl(meth)acrylate, 2,2-dimethylbutyl(meth)acrylate, n-hexyl(meth)acrylate, cetyl(meth)acrylate, n-octyl(meth)acrylate, 2 -(Meth)acrylic acid (C 1-20) alkyl esters such as -ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, N-octadecyl (meth)acrylate, and further, for example, cyclo Alkyl (meth)acrylate (for example, cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate), aralkyl (meth)acrylate (for example, benzyl (meth)acrylate), polycyclic (meth)acrylate (for example, 2- Isobornyl (meth)acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, etc., hydroxyl group Containing (meth)acrylic acid esters (for example, hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate), alkoxy group or phenoxy group-containing ( (Meth)acrylic acid esters (2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethylcarbitol (meth) Acrylate, phenoxyethyl (meth)acrylate, etc., epoxy group-containing (meth)acrylic acid esters (eg, glycidyl (meth)acrylate), halogen-containing (meth)acrylic acid esters (eg, 2,2,2-) Trifluoroethyl (meth)acrylate, 2,2 , 2-trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, etc.), alkylaminoalkyl (Meth)acrylate (for example, dimethylaminoethyl (meth)acrylate etc.) etc. are mentioned. These (meth)acrylates can be used alone or in combination of two or more kinds. Specific examples of the acrylic oligomer (A) include "ARUFON" manufactured by Toagosei Co., Ltd., "Actflow" manufactured by Soken Kagaku Co., Ltd., and "JONCRYL" manufactured by BASF Japan. Among the acrylic oligomers (A) formed by polymerizing a (meth)acrylic monomer, those having a high logPow value are preferable. The acrylic oligomer (A) obtained by polymerizing a (meth)acrylic monomer has a logPow value of preferably 2 or more, more preferably 3 or more, and most preferably 4 or more.

<Photoacid generator (B)>
The active energy ray-curable adhesive composition may contain a photoacid generator (B). When the active energy ray-curable resin composition contains a photo-acid generator, the water resistance and durability of the adhesive layer can be dramatically improved as compared with the case where the photo-acid generator is not contained. .. The photoacid generator (B) can be represented by the following general formula (3).

General formula (3)

(However, L ⁺ represents an arbitrary onium cation. Further, X ⁻ represents PF6 ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , SbCl ₆ ⁻ , BiCl ₅ ⁻ , SnCl ₆ ⁻ , ClO ₄ ⁻ , dithiocarbamate. Represents a counter anion selected from the group consisting of anion and SCN-.)

Among the above-exemplified anions, PF ₆ ⁻ , SbF ₆ ⁻ and AsF ₆ ⁻ are particularly preferable as the counter anion X ⁻ in the general formula (3), and particularly preferable are PF ₆ ⁻ and SbF. ₆ ^- and the like.

Therefore, specific examples of preferable onium salts constituting the photo-acid generator (B) of the present invention include "Syracure UVI-6992" and "Syracure UVI-6974" (all manufactured by Dow Chemical Japan Co., Ltd.). , "Adeka Optimer SP150", "Adeka Optimer SP152", "Adeka Optimer SP170", "Adeka Optimer SP172" (above, manufactured by ADEKA Corporation), "IRGACURE250" (manufactured by Ciba Specialty Chemicals), " CI-5102", "CI-2855" (above, Nippon Soda Co., Ltd.), "Sun-Aid SI-60L", "Sun-Aid SI-80L", "Sun-Aid SI-100L", "Sun-Aid SI-110L", "Sun-Aid SI". -180L" (above, Sanshin Chemical Co., Ltd.), "CPI-100P", "CPI-100A" (above, San Apro Co., Ltd.), "WPI-069", "WPI-113", "WPI-116". , "WPI-041", "WPI-044", "WPI-054", "WPI-055", "WPAG-281", "WPAG-567", "WPAG-596" (above, Wako Pure Chemical Industries, Ltd. ) Are mentioned as preferable specific examples of the photo-acid generator (B) of the present invention.

The content of the photoacid generator (B) is 10 parts by weight or less, preferably 0.01 to 10 parts by weight, and 0.05 to 5 parts by weight, based on 100 parts by weight of the total amount of the curable component. More preferably, it is 0.1 to 3 parts by weight.

<Compound (C) containing either an alkoxy group or an epoxy group>
In the above active energy ray-curable adhesive composition, the photoacid generator (B) and the compound (C) containing either an alkoxy group or an epoxy group can be used in combination in the active energy ray curable adhesive composition. ..

(Compounds and polymers having epoxy groups) (C)
When a compound having one or more epoxy groups in the molecule or a polymer (epoxy resin) having two or more epoxy groups in the molecule is used, a functional group having reactivity with the epoxy group is used in the molecule. You may use together the compound which has three or more. Examples of the functional group having reactivity with an epoxy group include a carboxyl group, a phenolic hydroxyl group, a mercapto group, a primary or secondary aromatic amino group, and the like. It is particularly preferable to have two or more of these functional groups in one molecule in consideration of three-dimensional curability.

Examples of the polymer having one or more epoxy groups in the molecule include an epoxy resin, and a bisphenol A type epoxy resin derived from bisphenol A and epichlorohydrin, a bisphenol F type epoxy derived from bisphenol F and epichlorohydrin. Resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, diphenyl ether type epoxy resin, hydroquinone type epoxy resin, Naphthalene type epoxy resin, biphenyl type epoxy resin, fluorene type epoxy resin, multifunctional type epoxy resin such as trifunctional type epoxy resin and tetrafunctional type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, hydantoin type epoxy resin , Isocyanurate type epoxy resin, aliphatic chain epoxy resin and the like, and these epoxy resins may be halogenated or hydrogenated. Examples of commercially available epoxy resin products include, for example, JER Coat 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, YX4000, manufactured by Japan Epoxy Resin Co., Ltd., Epiclon. 830, EXA835LV, HP4032D, HP820, EP4100 series, EP4000 series, EPU series manufactured by ADEKA Corporation, Celoxide side series (2021, 2021P, 2083, 2085, 3000, etc.) manufactured by Daicel Chemical Co., Ltd., Epolide series, EHPE. Series, Nippon Steel Chemical Co., Ltd.'s YD series, YDF series, YDCN series, YDB series, phenoxy resin (polyhydroxy polyether synthesized from bisphenols and epichlorohydrin having epoxy groups at both ends; YP series, etc.), Examples include, but are not limited to, Denacol series manufactured by Nagase Chemtex and Epolite series manufactured by Kyoeisha Kagaku. Two or more of these epoxy resins may be used in combination. When calculating the glass transition temperature Tg of the adhesive layer, the compound having an epoxy group and the polymer (C) are not included in the calculation.

(Compound and Polymer Having Alkoxyl Group) (C) The compound having an alkoxyl group in the molecule is not particularly limited as long as it has one or more alkoxyl groups in the molecule, and known compounds can be used. Representative examples of such a compound include a melamine compound, an amino resin, and a silane coupling agent. When calculating the glass transition temperature Tg of the adhesive layer, the compound having an alkoxyl group and the polymer (C) are not included in the calculation.

The compounding amount of the compound (C) containing either an alkoxy group or an epoxy group is usually 30 parts by weight or less based on 100 parts by weight of the total amount of the curable component, and the content of the compound (C) in the composition. If the amount is too large, the adhesiveness may be lowered and the impact resistance in the drop test may be deteriorated. The content of the compound (C) in the composition is more preferably 20 parts by weight or less. On the other hand, from the viewpoint of water resistance, the composition preferably contains 2 parts by weight or more of the compound (C), more preferably 5 parts by weight or more.

<Silane coupling agent (D)>
When the curable adhesive composition for a polarizing film of the present invention is an active energy ray curable curable type, it is preferable to use an active energy ray curable compound as the silane coupling agent (D). Similar water resistance can be imparted even if it is not energy ray curable.

Specific examples of the silane coupling agent (D) include vinyl trichlorosilane, vinyl trimethoxysilane, vinyl triethoxysilane, 2-(3,4 epoxycyclohexyl)ethyl trimethoxysilane, and 3 as active energy ray-curable compounds. -Glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxy Examples thereof include propyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane and 3-acryloxypropyltrimethoxysilane.

Preferred are 3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane.

As a specific example of the silane coupling agent which is not curable with active energy rays, a silane coupling agent (D1) having an amino group is preferable. Specific examples of the silane coupling agent having an amino group (D1) include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane , Γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltriisopropoxysilane, γ-(2-(2-aminoethyl)aminoethyl)aminopropyltrimethoxysilane , Γ-(6-aminohexyl)aminopropyltrimethoxysilane, 3-(N-ethylamino)-2-methylpropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N- Phenyl-γ-aminopropyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldi Amino group-containing silanes such as ethoxymethylsilane, N-phenylaminomethyltrimethoxysilane, (2-aminoethyl)aminomethyltrimethoxysilane, N,N′-bis[3-(trimethoxysilyl)propyl]ethylenediamine; Ketimine type silanes such as N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine may be mentioned.

As the silane coupling agent (D1) having an amino group, only one type may be used, or a plurality of types may be used in combination. Of these, γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane and γ-(2-aminoethyl)aminopropylmethyldimethoxysilane are used to ensure good adhesion. , Γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)- 1-propanamine is preferred.

The content of the silane coupling agent (D) is preferably 0.01 to 20 parts by weight, and more preferably 0.05 to 15 parts by weight, based on 100 parts by weight of the total amount of the curable component. It is more preferably from 1 to 10 parts by weight. This is because if the amount is more than 20 parts by weight, the storage stability of the adhesive composition is deteriorated, and if it is less than 0.1 parts by weight, the effect of adhesive water resistance is not sufficiently exhibited. When calculating the glass transition temperature Tg of the adhesive layer, the silane coupling agent (D) is not included in the calculation.

Specific examples of silane coupling agents other than the above which are not curable by active energy rays include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane. Examples thereof include silane, bis(triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane, and imidazolesilane.

<Compound (E) having vinyl ether group>
It is preferable that the curable adhesive composition for a polarizing film of the present invention contains the compound (E) having a vinyl ether group because the adhesive water resistance between the polarizer and the adhesive layer is improved. The reason why such an effect is obtained is not clear, but it is one of the reasons that the adhesive force between the polarizer and the adhesive layer is increased by the interaction of the vinyl ether group contained in the compound (E) with the polarizer. Presumed to be. In order to further enhance the adhesive water resistance between the polarizer and the adhesive layer, the compound (E) is preferably a radical polymerizable compound having a vinyl ether group. Further, the content of the compound (E) is preferably 0.1 to 19 parts by weight based on 100 parts by weight of the total amount of the curable component.

<Compound (F) that produces keto-enol tautomerism>
The curable adhesive composition for a polarizing film of the present invention may contain a compound that causes keto-enol tautomerism. For example, in an adhesive composition containing a cross-linking agent or an adhesive composition that can be used by blending the cross-linking agent, an embodiment containing a compound that produces the keto-enol tautomerism can be preferably adopted. As a result, it is possible to achieve an effect of suppressing an excessive increase in viscosity and gelation of the adhesive composition after compounding with the organometallic compound, and generation of a microgel product, and prolonging the pot life of the composition.

As the compound (F) that produces the keto-enol tautomerism, various β-dicarbonyl compounds can be used. Specific examples include acetylacetone, 2,4-hexanedione, 3,5-heptanedione, 2-methylhexane-3,5-dione, 6-methylheptane-2,4-dione and 2,6-dimethylheptane-. Β-diketones such as 3,5-dione; acetoacetic acid esters such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate and tert-butyl acetoacetate; ethyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, propionyl acetic acid Propionyl acetates such as tert-butyl; isobutyryl acetates such as ethyl isobutyryl acetate, ethyl isobutyryl acetate, isopropyl isobutyryl acetate, tert-butyl isobutyryl acetate; malonates such as methyl malonate and ethyl malonate; Can be mentioned. Among them, preferable compounds include acetylacetone and acetoacetic acid esters. The compound (F) that produces such keto-enol tautomerism may be used alone or in combination of two or more kinds.

The amount of the compound that causes keto-enol tautomerism is, for example, 0.05 part by weight to 10 parts by weight, preferably 0.2 part by weight to 3 parts by weight (for example, 0.3 part by weight, relative to 1 part by weight of the organometallic compound). Parts by weight to 2 parts by weight). If the amount of the above compound used is less than 0.05 parts by weight with respect to 1 part by weight of the organometallic compound, it may be difficult to exert a sufficient use effect. On the other hand, when the amount of the compound used exceeds 10 parts by weight with respect to 1 part by weight of the organometallic compound, it may interact too much with the organometallic compound and the desired water resistance may be difficult to be exhibited.

<Additives other than the above>
Further, the curable adhesive composition for a polarizing film of the present invention may contain various additives as other optional components within a range not impairing the objects and effects of the present invention. Such additives include epoxy resin, polyamide, polyamideimide, polyurethane, polybutadiene, polychloroprene, polyether, polyester, styrene-butadiene block copolymer, petroleum resin, xylene resin, ketone resin, cellulose resin, fluorine-based oligomer, Polymers or oligomers such as silicone-based oligomers and polysulfide-based oligomers; polymerization inhibitors such as phenothiazine and 2,6-di-t-butyl-4-methylphenol; polymerization initiation aids; leveling agents; wettability improvers; surfactants Agents; plasticizers; ultraviolet absorbers; inorganic fillers; pigments; dyes and the like. Among various additives, those having a high logPow value are preferable. The logPow value of various additives is preferably 2 or more, more preferably 3 or more, and most preferably 4 or more.

The above-mentioned additive is usually 0 to 10 parts by weight, preferably 0 to 5 parts by weight, and most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component.

<Viscosity of adhesive composition>
The curable adhesive composition for a polarizing film of the present invention contains the curable component, and the viscosity of the adhesive composition is preferably 100 cp or less at 25°C from the viewpoint of coatability. On the other hand, when the curable adhesive composition for a polarizing film of the present invention exceeds 100 cp at 25° C., the temperature of the adhesive composition during coating may be controlled to be 100 cp or less for use. The viscosity is more preferably in the range of 1 to 80 cp, most preferably 10 to 50 cp. The viscosity can be measured using an E-type viscometer TVE22LT manufactured by Toki Sangyo Co., Ltd.

Further, in the curable adhesive composition for a polarizing film of the present invention, from the viewpoint of safety, it is preferable to use a material having low skin irritation as the curable component. Skin irritation is described in P. I. It can be judged by the index I. P. I. I is widely used as an indicator of the degree of skin damage and is measured by the Draize method. The measured value is displayed in the range of 0 to 8, and the smaller the value is, the lower the irritation is judged to be. However, since the error of the measured value is large, it is preferable to regard it as a reference value. P. I. I is preferably 4 or less, more preferably 3 or less, and most preferably 2 or less.

<Bulk water absorption rate>
The curable adhesive composition for a polarizing film of the present invention is the bulk water absorption described above, which is measured when the cured product obtained by curing the curable adhesive composition is immersed in pure water at 23° C. for 24 hours. The ratio is preferably 10% by weight or less. When the polarizing film is placed in a harsh environment of high temperature and high humidity (85°C/85%RH, etc.), the moisture that has permeated the transparent protective film and the adhesive layer enters the polarizer to hydrolyze the crosslinked structure. As a result, the orientation of the dichroic dye is disturbed, and the optical durability is deteriorated by increasing the transmittance and decreasing the polarization degree. By setting the bulk water absorption of the adhesive layer to 10% by weight or less, the movement of water to the polarizer is suppressed when the polarizing film is placed in a severe environment of high temperature and high humidity, and the transmittance of the polarizer increases. It is possible to suppress a decrease in the degree of polarization. The bulk water absorption rate of the adhesive layer of the polarizing film is preferably 5% by weight or less, more preferably 3% by weight or less, from the viewpoint of further improving the optical durability in a severe environment at high temperature. Most preferably, it is 1% by weight or less. On the other hand, when the polarizer and the transparent protective film are bonded together, the polarizer holds a certain amount of water, and when the curable adhesive composition and the water contained in the polarizer are repelled, bubbles are generated. A defective appearance may occur. In order to suppress poor appearance, it is preferable that the curable adhesive composition can absorb a certain amount of water. More specifically, the bulk water absorption is preferably 0.01% by weight or more, and more preferably 0.05% by weight or more. The bulk water absorption is specifically measured by the water absorption test method described in JISK 7209.

<Curing shrinkage rate>
Moreover, since the curable adhesive composition for a polarizing film of the present invention has a curable component, when the curable adhesive composition is cured, curing shrinkage usually occurs. The cure shrinkage is an index showing the rate of cure shrinkage when forming an adhesive layer from a curable adhesive composition for a polarizing film. When the curing shrinkage rate of the adhesive layer is large, it is preferable to suppress the occurrence of interface failure due to interface strain when the curable adhesive composition for a polarizing film is cured to form the adhesive layer. From the above viewpoint, the curing shrinkage rate of the cured product obtained by curing the curable adhesive composition for a polarizing film of the present invention is preferably 10% or less. The curing shrinkage is preferably small, and the curing shrinkage is preferably 8% or less, more preferably 5% or less. The curing shrinkage ratio is measured by the method described in JP2013-104869A, specifically by a method using a curing shrinkage sensor manufactured by Sentec.

<Polarizing film>
In the polarizing film of the present invention, a transparent protective film is attached to at least one surface of a polarizer via an adhesive layer formed of a cured product layer of the curable adhesive composition for polarizing film. As described above, the adhesive layer, which is the cured product layer, preferably has a bulk water absorption of 10% by weight or less.

<Adhesive layer>
The thickness of the adhesive layer formed of the curable adhesive composition is preferably controlled to 0.1 to 3 μm. The thickness of the adhesive layer is more preferably 0.3 to 2 μm, further preferably 0.5 to 1.5 μm. It is preferable that the thickness of the adhesive layer is 0.1 μm or more in order to suppress the occurrence of adhesion failure due to the cohesive force of the adhesive layer and the appearance failure (air bubbles) during lamination. On the other hand, if the adhesive layer is thicker than 3 μm, the polarizing film may not satisfy the durability.

The curable adhesive composition is preferably selected so that the Tg of the adhesive layer formed thereby is 60° C. or higher, more preferably 70° C. or higher, and further 75° C. As described above, it is preferably 100° C. or higher, and more preferably 120° C. or higher. On the other hand, if the Tg of the adhesive layer is too high, the flexibility of the polarizing film is lowered. Therefore, the Tg of the adhesive layer is preferably 300° C. or lower, further 240° C. or lower, further 180° C. or lower. Tg <glass transition temperature> is measured under the following measurement conditions using a dynamic viscoelasticity measuring device RSAIII manufactured by TA Instruments.
Sample size: width 10 mm, length 30 mm,
Clamp distance 20mm,
Measurement mode: tensile, frequency: 1 Hz, temperature rising rate: 5° C./min. Dynamic viscoelasticity was measured and adopted as the temperature Tg at the peak top of tan δ.

Further, in the curable adhesive composition, the storage elastic modulus of the adhesive layer formed thereby is preferably 1.0×10 ⁷ Pa or more at 25° C., and 1.0×10 ⁸ Pa or more. Is more preferable. The storage elastic modulus of the pressure-sensitive adhesive layer is 1.0×10 ³ Pa to 1.0×10 ⁶ Pa, which is different from the storage elastic modulus of the adhesive layer. The storage elastic modulus of the adhesive layer affects the polarizer crack when the polarizing film is subjected to a heat cycle (-40°C to 80°C, etc.), and when the storage elastic modulus is low, a defect of the polarizer crack occurs. Cheap. The temperature range having a high storage elastic modulus is more preferably 80°C or lower, most preferably 90°C or lower. The storage elastic modulus is measured at the same time as Tg <glass transition temperature> under the same measurement conditions using TA Instruments dynamic viscoelasticity measuring apparatus RSAIII. The dynamic viscoelasticity was measured and the value of storage elastic modulus (E') was adopted.

The polarizing film according to the present invention has the following manufacturing method;
At least one surface of the polarizer and the transparent protective film, a coating step of applying a curable adhesive composition for a polarizing film, a bonding step of bonding the polarizer and the transparent protective film, the polarizer surface side or Irradiation with active energy rays from the transparent protective film surface side, through an adhesive layer obtained by curing the active energy ray-curable adhesive composition, a bonding step of bonding the polarizer and the transparent protective film. Can be manufactured by a manufacturing method including. In such a manufacturing method, the water content of the polarizer in the bonding step is preferably 8 to 19%.

The polarizer and the transparent protective film may be subjected to a surface modification treatment before being coated with the curable adhesive composition. Specific treatments include corona treatment, plasma treatment, and saponification treatment.

The coating method of the curable adhesive composition is appropriately selected depending on the viscosity of the composition and the desired thickness. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater, and the like. In addition, a method such as a dipping method can be appropriately used for coating.

The polarizer and the transparent protective film are bonded together via the curable adhesive composition coated as described above. The lamination of the polarizer and the transparent protective film can be performed with a roll laminator or the like.

<Curing of adhesive composition>
The curable adhesive composition for a polarizing film according to the present invention is used as an active energy ray-curable adhesive composition. The active energy ray curable adhesive composition can be used in an electron beam curable type, an ultraviolet ray curable type and a visible ray curable type. From the viewpoint of productivity, the embodiment of the curable adhesive composition is preferably a visible light curable adhesive composition.

≪Active energy ray curing type≫
In the active energy ray-curable adhesive composition, the active energy ray-curable adhesive composition is irradiated with active energy rays (electron beam, ultraviolet ray, visible light, etc.) after bonding the polarizer and the transparent protective film. Cure to form the adhesive layer. The active energy ray (electron beam, ultraviolet ray, visible ray, etc.) can be emitted from any appropriate direction. Irradiation is preferably performed from the transparent protective film side. When irradiated from the polarizer side, the polarizer may be deteriorated by active energy rays (electron rays, ultraviolet rays, visible rays, etc.).

<<Electron beam curing type>>
In the electron beam curable type, any appropriate condition can be adopted as the electron beam irradiation condition as long as it can cure the active energy ray curable adhesive composition. For example, the electron beam irradiation has an acceleration voltage of preferably 5 kV to 300 kV, more preferably 10 kV to 250 kV. If the accelerating voltage is less than 5 kV, the electron beam may not reach the adhesive and the curing may be insufficient. If the accelerating voltage exceeds 300 kV, the penetrating force through the sample is too strong and damages the transparent protective film and the polarizer. May be given. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. If the irradiation dose is less than 5 kGy, the adhesive will be insufficiently cured, and if it exceeds 100 kGy, it will damage the transparent protective film and the polarizer, causing a decrease in mechanical strength and yellowing, and obtaining the desired optical characteristics. I can't.

The electron beam irradiation is usually carried out in an inert gas, but if necessary, it may be carried out in the air or under the condition that a small amount of oxygen is introduced. Depending on the material of the transparent protective film, by appropriately introducing oxygen, oxygen can be intentionally inhibited on the surface of the transparent protective film where the electron beam hits first, and it is possible to prevent damage to the transparent protective film. The electron beam can be efficiently irradiated.

<<UV curing type, visible light curing type>>
In the method for producing a polarizing film according to the present invention, as the active energy rays, those containing visible light in the wavelength range of 380 nm to 450 nm, particularly active energy rays having the largest irradiation dose of visible light in the wavelength range of 380 nm to 450 nm are used. It is preferable. When using a transparent protective film (ultraviolet-impermeable transparent protective film) having an ultraviolet absorbing ability in the ultraviolet curable type or the visible light curable type, it absorbs light having a wavelength shorter than approximately 380 nm and thus has a wavelength shorter than 380 nm. Light does not reach the active energy ray-curable adhesive composition and does not contribute to its polymerization reaction. Further, the light having a wavelength shorter than 380 nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, which causes defects such as curling and wrinkling of the polarizing film. Therefore, when the ultraviolet curable type or the visible ray curable type is adopted in the present invention, it is preferable to use a device that does not emit light having a wavelength shorter than 380 nm as the active energy ray generator, and more specifically, the wavelength range 380. The ratio of the integrated illuminance of ˜440 nm to the integrated illuminance of the wavelength range of 250 to 370 nm is preferably 100:0 to 100:50, and more preferably 100:0 to 100:40. The active energy ray according to the present invention is preferably a gallium-encapsulated metal halide lamp or an LED light source emitting light in the wavelength range of 380 to 440 nm. Or ultraviolet light such as low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, incandescent lamp, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excimer laser or sunlight. A light source containing visible light can be used, and a bandpass filter can be used to block ultraviolet rays having a wavelength shorter than 380 nm. In order to prevent curling of the polarizing film while improving the adhesive performance of the adhesive layer between the polarizer and the transparent protective film, a gallium-encapsulated metal halide lamp is used, and light with a wavelength shorter than 380 nm can be blocked. It is preferable to use an active energy ray obtained through a bandpass filter or an active energy ray having a wavelength of 405 nm obtained by using an LED light source.

In the ultraviolet curable type or the visible ray curable type, it is preferable to heat the active energy ray curable adhesive composition (pre-irradiation heating) before irradiating with the ultraviolet ray or the visible light, in which case it is heated to 40° C. or higher. Is preferable, and it is more preferable to heat to 50° C. or higher. It is also preferable to heat the active energy ray-curable adhesive composition after irradiation with ultraviolet rays or visible light (heating after irradiation). In that case, it is preferable to heat to 40°C or higher, and to 50°C or higher. It is more preferable to warm.

The active energy ray-curable adhesive composition according to the present invention can be suitably used particularly when forming an adhesive layer for adhering a polarizer and a transparent protective film having a light transmittance at a wavelength of 365 nm of less than 5%. Is. Here, the active energy ray-curable adhesive composition according to the present invention, by containing the photopolymerization initiator of the general formula (1) described above, irradiates ultraviolet rays through the transparent protective film having UV absorption ability. Thus, the adhesive layer can be cured and formed. Therefore, the adhesive layer can be cured even in a polarizing film in which transparent protective films having UV absorbing ability are laminated on both sides of the polarizer. However, as a matter of course, the adhesive layer can be cured also in the polarizing film in which the transparent protective film having no UV absorption ability is laminated. The transparent protective film having UV absorbing ability means a transparent protective film having a transmittance of 380 nm light of less than 10%.

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

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

After the polarizer and the transparent protective film are bonded together, an active energy ray (electron beam, ultraviolet ray, visible light, etc.) is irradiated to cure the active energy ray-curable adhesive composition to form an adhesive layer. The active energy ray (electron beam, ultraviolet ray, visible ray, etc.) can be emitted from any appropriate direction. Irradiation is preferably performed from the transparent protective film side. When irradiated from the polarizer side, the polarizer may be deteriorated by active energy rays (electron rays, ultraviolet rays, visible rays, etc.).

When the polarizing film according to the present invention is manufactured in a continuous line, the line speed depends on the curing time of the adhesive composition, but is preferably 1 to 500 m/min, more preferably 5 to 300 m/min, and further preferably 10 It is 100 m/min. If the line speed is too low, the productivity is poor, or the transparent protective film is damaged too much, so that a polarizing film that can withstand a durability test or the like cannot be produced. If the line speed is too high, the adhesive composition may be insufficiently cured and the desired adhesiveness may not be obtained.

In the polarizing film of the present invention, a polarizer and a transparent protective film are bonded together via an adhesive layer formed by a cured product layer of the active energy ray-curable adhesive composition, but the transparent protective film An easy-adhesion layer can be provided between the adhesive layer and the adhesive layer. The easy-adhesion layer can be formed of various resins having, for example, a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, or the like. These polymer resins can be used alone or in combination of two or more. Further, other additives may be added to form the easily adhesive layer. Specifically, a tackifier, a UV absorber, an antioxidant, a stabilizer such as a heat stabilizer, and the like may be used.

The easy-adhesion layer is usually provided in advance on the transparent protective film, and the easy-adhesion layer side of the transparent protective film and the polarizer are bonded together by an adhesive layer. The easy-adhesion layer is formed by applying a material for forming the easy-adhesion layer onto the transparent protective film by a known technique and drying. The material for forming the easily adhesive layer is usually prepared as a solution diluted to an appropriate concentration in consideration of the thickness after drying and the smoothness of coating. The thickness of the easily adhesive layer after drying is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and further preferably 0.05 to 1 μm. A plurality of easy-adhesion layers can be provided, but in this case as well, it is preferable that the total thickness of the easy-adhesion layers be within the above range.

<Polarizer>
The polarizer is not particularly limited, and various kinds can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene/vinyl acetate copolymer partially saponified film, and dichroic dye such as iodine or dichroic dye. Examples include polyene oriented films such as those obtained by adsorbing a volatile material and uniaxially stretched, polyvinyl alcohol dehydrated products, polyvinyl chloride dehydrochlorinated products, and the like. Among these, a polarizer made of a polyvinyl alcohol film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 80 μm or less.

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

Further, the curable adhesive composition of the present invention exhibits its effect (satisfying the optical durability in a severe environment under high temperature and high humidity) when a thin polarizer having a thickness of 10 μm or less is used as the polarizer. It can be remarkably expressed. The above-mentioned polarizer having a thickness of 10 μm or less has a relatively large influence of moisture as compared with a polarizer having a thickness of more than 10 μm, and does not have sufficient optical durability in an environment of high temperature and high humidity, resulting in an increase in transmittance and a degree of polarization. Degradation is likely to occur. Therefore, from the cured product of the curable adhesive composition for a polarizing film according to the present invention, the above-mentioned polarizer having a thickness of 10 μm or less containing at least one organometallic compound selected from the group consisting of metal alkoxides and metal chelates. When laminated with an adhesive layer having a bulk water absorption rate of 10% by weight or less, the movement of water to the polarizer is suppressed in a severe environment of high temperature and high humidity, and It is possible to remarkably suppress deterioration of optical durability such as increase in transmittance and decrease in polarization degree. From the viewpoint of thinning, the thickness of the polarizer is preferably 1 to 7 μm. It is preferable that such a thin polarizer has less unevenness in thickness, excellent visibility, less dimensional change, and a thinner polarizing film.

As a thin polarizer, typically, JP-A-51-096644, JP-A-2000-338329, WO2010/100917, the specification of PCT/JP2010/001460, or Japanese Patent Application No. 2010- Examples thereof include thin polarizing films described in Japanese Patent No. 269002 and Japanese Patent Application No. 2010-263692. These thin polarizing films can be obtained by a production method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a stretching resin base material in a laminate state and a dyeing step. According to this production method, even if the PVA-based resin layer is thin, it can be stretched without trouble such as breakage due to stretching because it is supported by the stretching resin base material.

As the thin polarizing film, among manufacturing methods including a step of stretching in a laminate state and a step of dyeing, WO 2010/100917 pamphlet, PCT/PCT/ Those obtained by a method including a step of stretching in an aqueous solution of boric acid as described in JP 2010/001460, or Japanese Patent Application Nos. 2010-269002 and 2010-263692 are preferable, and particularly preferable. Those obtained by a production method including a step of auxiliary stretching in air before stretching in a boric acid aqueous solution described in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692 are preferable.

<Transparent protective film>
As a material for forming the transparent protective film provided on one side or both sides of the above-mentioned polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, etc. is preferable. For example, polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose, acrylic-based polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples thereof include a polymer and a polycarbonate polymer. Further, polyethylene, polypropylene, polyolefin having a cyclo or norbornene structure, polyolefin polymer such as ethylene/propylene copolymer, vinyl chloride polymer, amide polymer such as nylon or aromatic polyamide, imide polymer, sulfone polymer. , Polyethersulfone-based polymer, polyetheretherketone-based polymer, polyphenylene sulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, epoxy-based polymer, or the above Blends of polymers and the like are also mentioned as examples of the polymer forming the transparent protective film. One or more kinds of any appropriate additive may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, an anti-coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment and a coloring agent. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. .. When the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency originally possessed by the thermoplastic resin may not be sufficiently exhibited.

In addition, as the transparent protective film, a polymer film described in JP 2001-343529 A (WO01/37007), for example, (A) a thermoplastic resin having a substituted and/or unsubstituted imide group in a side chain, B) A resin composition containing a thermoplastic resin having a substituted and/or unsubstituted phenyl and a nitrile group in the side chain is mentioned. A specific example thereof is a film of a resin composition containing an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile/styrene copolymer. As the film, a film made of a mixed extruded product of a resin composition or the like can be used. Since these films have a small retardation and a small photoelastic coefficient, problems such as unevenness due to distortion of the polarizing film can be eliminated, and since the moisture permeability is small, they have excellent humidification durability.

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

As a material for forming the transparent protective film provided on one side or both sides of the above-mentioned polarizer, those having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, and the like are preferable, and particularly moisture permeability is 150 g. /M ² /24h or less is more preferable, 140 g/m ² /24h or less is particularly preferable, and 120 g/m ² /24h or less is further preferable. The water vapor permeability is determined by the method described in the examples.

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

The thickness of the transparent protective film can be appropriately determined, but is generally about 1 to 100 μm in view of workability such as strength and handleability, and thin layer property. Particularly, 1 to 80 μm is preferable, and 3 to 60 μm is more preferable.

When the transparent protective films are provided on both sides of the polarizer, the transparent protective films made of the same polymer material may be used on the front and back sides, or the transparent protective films made of different polymer materials may be used.

A functional layer such as a hard coat layer, an antireflection layer, an antisticking layer, a diffusion layer or an antiglare layer can be provided on the surface of the transparent protective film to which the polarizer is not adhered. The functional layers such as the hard coat layer, the antireflection layer, the sticking prevention layer, the diffusion layer and the antiglare layer can be provided on the transparent protective film itself, or separately, separately from the transparent protective film. You can also

<Optical film>
In practical use, the polarizing film of the present invention can be used as an optical film laminated with another optical layer. Although the optical layer is not particularly limited, for example, for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including a wave plate such as 1/2 or 1/4), and a viewing angle compensation film. One or two or more optical layers that may be used can be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film obtained by further laminating a reflective plate or a semi-transmissive reflective plate on the polarizing film of the present invention, an elliptical polarizing film or a circularly polarized light obtained by further laminating a retardation plate on the polarizing film A wide viewing angle polarizing film obtained by further laminating a viewing angle compensation film on a film or a polarizing film, or a polarizing film obtained by further laminating a brightness improving film on a polarizing film is preferable.

An optical film obtained by laminating the above optical layer on a polarizing film can be formed by a method of laminating sequentially in the manufacturing process of a liquid crystal display device, etc. Has an advantage in that it is excellent in quality stability and assembling work and can improve the manufacturing process of liquid crystal display devices and the like. Appropriate adhesion means such as an adhesive layer may be used for lamination. When adhering the above-mentioned polarizing film and other optical films, the optical axes thereof can be set at an appropriate arrangement angle according to the intended retardation characteristics and the like.

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

The pressure-sensitive adhesive layer can be provided on one side or both sides of the polarizing film or the optical film as a layer in which different compositions or types are laminated. Further, when it is provided on both surfaces, an adhesive layer having different composition, type and thickness may be provided on the front and back of the polarizing film or the optical film. The thickness of the pressure-sensitive adhesive layer can be appropriately determined depending on the purpose of use, adhesive strength, etc., and is generally 1 to 500 μm, preferably 1 to 200 μm, and particularly preferably 1 to 100 μm.

The exposed surface of the pressure-sensitive adhesive layer is temporarily covered with a separator until it is put to practical use for the purpose of preventing its contamination. As a result, it is possible to prevent contact with the adhesive layer in the usual handling state. As the separator, excluding the above thickness conditions, for example, a plastic film, a rubber sheet, a paper, a cloth, a non-woven fabric, a net, a foam sheet or a metal foil, an appropriate thin sheet such as a laminated body thereof, and a silicone-based or long Appropriate conventional ones such as those coated with an appropriate release agent such as chain alkyl type, fluorine type or molybdenum sulfide may be used.

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

It is possible to form an appropriate liquid crystal display device such as a liquid crystal display device in which a polarizing film or an optical film is arranged on one side or both sides of a liquid crystal cell, or a device using a backlight or a reflector in an illumination system. In that case, the polarizing film or the optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When a polarizing film or an optical film is provided on both sides, they may be the same or different. Furthermore, when forming a liquid crystal display device, for example, a diffusion plate, an anti-glare layer, an antireflection film, a protection plate, a prism array, a lens array sheet, a light diffusion plate, a back light, and other appropriate parts are provided in a single layer or at appropriate positions. Two or more layers can be arranged.

Examples of the present invention will be described below, but the embodiments of the present invention are not limited thereto.

<Production of polarizer>
A polyvinyl alcohol film having a mean polymerization degree of 2400 and a saponification degree of 99.9 mol% and a thickness of 75 μm was immersed in warm water at 30° C. for 60 seconds to be swollen. Then, the film was immersed in an aqueous solution of iodine/potassium iodide (weight ratio=0.5/8) with a concentration of 0.3% and stretched to 3.5 times to dye the film. Then, stretching was performed in a boric acid ester aqueous solution at 65° C. so that the total stretching ratio was 6 times. After stretching, it was dried in an oven at 40° C. for 3 minutes to obtain a PVA-based polarizer X (thickness 23 μm).

<Transparent protective film>
Transparent protective film 1: A triacetyl cellulose film having a thickness of 60 μm (moisture permeability 530 g/m ² /24 h) was used without saponification and corona treatment (referred to as TAC in Table 1).
Transparent protective film 2: 100 parts by weight of the imidized MS resin described in Production Example 1 of JP 2010-284840 A and 0.62 parts by weight of a triazine-based ultraviolet absorber (manufactured by ADEKA CORPORATION, trade name: T-712). Resin pellets were prepared by mixing at 220° C. with a biaxial kneader. The resin pellets thus obtained were dried at 100.5 kPa and 100° C. for 12 hours, and then extruded from a T die at a die temperature of 270° C. with a single-screw extruder to form a film (thickness 160 μm). Further, the film is stretched in the conveying direction in an atmosphere of 150° C. (thickness: 80 μm), then an easy adhesive containing an aqueous urethane resin is applied, and then stretched in an atmosphere of 150° C. in a direction orthogonal to the film conveying direction. Then, a transparent protective film 2 having a thickness of 40 μm (moisture permeability 58 g/m ² /24 h) was obtained (indicated as acrylic in Table 1).

<Water vapor permeability of transparent protective film>
The moisture permeability was measured according to the moisture permeability test (cup method) of JIS Z0208. The sample cut into a diameter of 60 mm was set in a moisture permeable cup containing about 15 g of calcium chloride, and the temperature was 40° C. and the humidity was 90% R.V. H. The moisture permeability (g/m ² /24 h) was determined by measuring the weight increase of calcium chloride before and after leaving it in the incubator for 24 hours.

<Bulk water absorption rate>
The curable adhesive for polarizing film used in each example was sandwiched between two sheets of glass provided with a 100 μm spacer, and cured under the same active energy conditions as in the example to obtain an adhesive layer (cured with a thickness of 100 μm). Was prepared. This was used as a sample. The weight of the sample was (M1) g. Sample M1g was immersed in pure water at 23° C. for 24 hours. Then, the weight (M2) g of the sample was measured again within 1 minute after being taken out from pure water and wiped with a dry cloth. From these results,
Formula: {(M2-M1)/M1}×100(%),
The bulk water absorption was calculated by

<Storage elastic modulus>
The storage elastic modulus was measured under the following measurement conditions using a dynamic viscoelasticity measuring device RSAIII manufactured by TA Instruments.
Sample size: width 10 mm, length 30 mm,
Clamp distance 20mm,
Measurement mode: pulling, frequency: 1 Hz, heating rate: 5°C/min

The dynamic viscoelasticity was measured, and the storage elastic modulus was used as the measured value at 25°C.

<Active energy ray>
As the active energy ray, visible light (gallium sealed metal halide lamp) irradiation apparatus: Fusion UV Systems, Inc, Inc. Light HAMMER10 Valve: V Valve peak irradiance: 1600 mW / cm @ 2, integrated dose 1000 / mJ / cm ² (wavelength 380~440nm )It was used. The illuminance of visible light was measured using a Sola-Check system manufactured by Solatell.

Examples 1-12 and Comparative Examples 1-3
(Preparation of active energy ray curable adhesive)
According to the formulation table shown in Table 1, each component was mixed, and further KAYACURE-DETX-S (2,4-diethylthioxanthone; manufactured by Nippon Kayaku Co., Ltd.), and Irgacure 907 (2-methyl-1-(4-methylthio). (Phenyl)-2-morpholinopropan-1-one (manufactured by BASF) was added to 1.5 g and 3 g of the radical-polymerizable compound in total of 100 g, respectively, and the mixture was stirred to give Examples 1 to 9 and Comparative Example 1. The active energy ray-curable adhesive composition was obtained.

(Production of polarizing film)
On the transparent protective film, the active energy ray-curable adhesive according to Examples 1 to 12 or Comparative Examples 1 to 3 was applied by MCD coater (manufactured by Fuji Kikai Co., Ltd.) (cell shape: honeycomb, gravure roll wire number: 1000 pieces) /Inch, rotation speed 140%/against line speed), coating was performed so as to have a thickness of 0.7 μm, and the both sides of the above-mentioned polarizer X were laminated by a roll machine. After that, the active energy ray-curable adhesives according to Example 1 and Comparative Example 1 were cured by irradiating both sides with the visible light from the laminated transparent protective film side (both sides) with an active energy ray irradiation device. It was dried with hot air at 70° C. for 3 minutes to obtain a polarizing film having transparent protective films on both sides of the polarizer. The line speed for bonding was 25 m/min.

The following evaluations were performed on the polarizing films obtained in the above Examples and Comparative Examples. The evaluation results are shown in Table 1.

<Adhesive strength after water immersion (water resistance evaluation)>
The polarizing film is cut into a size of 200 mm parallel to the stretching direction of the polarizer and 15 mm in the orthogonal direction, and the polarizing film is immersed in water at 23° C. for 3 hours, and then taken out within 30 minutes (in a non-dried state). ) A polarizing film was attached to a glass plate. Then, a cut is made with a cutter knife between the transparent protective film (acrylic or TAC) and the polarizer, and the protective film and the polarizer are peeled off at a peeling speed of 300 mm/min in the 90° direction by a tensilon, and the peeling strength ( N/15 mm) was measured. When the peel strength was 0.5 N/15 mm or more, it was marked with ⊚, when it was 0.1 N/15 mm or more, it was marked with ◯, and when it was less than 0.1 N/15 mm, it was marked with x.

In Table 1, the radical polymerizable monomer is
HEAA: hydroxyethyl acrylamide, manufactured by Kojinsha;
4HBA; 4-hydroxybutyl acrylate, manufactured by Osaka Organic Chemical Company;
ACMO: Acryloylmorpholine, manufactured by Kojinsha;
TPGDA: tripropylene glycol diacrylate, manufactured by Toagosei (Aronix M-220),
1,9-NDA:1,9 nonadiacrylate, manufactured by Kyoeisha Chemical Co., Ltd.;
Indicates
The metal alkoxide and metal chelate are
TC-750: ethyl acetoacetate chelate (carbon number of organic group is 6), manufactured by Matsumoto Fine Chemicals;
TC-100: titanium acetylacetonate (carbon number of organic group is 5), manufactured by Matsumoto Fine Chemical Co.;
TA-30: Titanium octoxide (organic group having 8 carbon atoms), manufactured by Matsumoto Fine Chemical Co.;
D-20: Titanium butoxide (carbon number of organic group is 4), manufactured by Shin-Etsu Silicone Co., Ltd.;
ZA-65: Zirconium butoxide (carbon number of organic group is 4), manufactured by Matsumoto Fine Chemical Co.;
Aluminum chelate M: alkyl acetoacetate diisopropylate (organic group having 4 or more carbon atoms), manufactured by Kawaken Fine Chemicals;
Indicates
Vinyl ether compound,
VEEA: 2-(2-vinyloxyethoxy)ethyl acrylate, manufactured by Nippon Shokubai Co., Ltd.
The photo-acid generator is
CPI-100P, manufactured by San Apro;
Indicates.

Examples 13-15
(Preparation of active energy ray curable adhesive)
According to the formulation table shown in Table 2, the components were mixed, and further KAYACURE-DETX-S (2,4-diethylthioxanthone; manufactured by Nippon Kayaku Co., Ltd.), and Irgacure 907 (2-methyl-1-(4-methylthio). Phenyl)-2-morpholinopropan-1-one (manufactured by BASF) is added to 1.5 g and 3 g of the radical-polymerizable compound in total of 100 g, respectively, and stirred, and the active energy rays according to Examples 13 to 15 are added. A curable adhesive composition was obtained.

(Production of polarizing film)
On the transparent protective film, the active energy ray-curable adhesives according to Examples 13 to 15 were applied with an MCD coater (manufactured by Fuji Machine Co., Ltd.) (cell shape: honeycomb, gravure roll wire number: 1000/inch, rotation speed 140). %/Vs. line speed) to have a thickness of 0.7 μm, and the both sides of the above-mentioned polarizer X were laminated with a roll machine. After that, the active energy ray-curable adhesives according to Example 1 and Comparative Example 1 were cured by irradiating both sides with the visible light from the laminated transparent protective film side (both sides) with an active energy ray irradiation device. It was dried with hot air at 70° C. for 3 minutes to obtain a polarizing film having transparent protective films on both sides of the polarizer. The line speed for bonding was 25 m/min.

In Table 2, the radical polymerizable monomer is
HEAA: hydroxyethyl acrylamide, manufactured by Kojinsha;
ACMO: Acryloylmorpholine, manufactured by Kojinsha;
1,9-NDA:1,9 nonadiacrylate, manufactured by Kyoeisha Chemical Co., Ltd.;
M-5300: ω-carboxy-polycaprolactone (n≈2) monoacrylate (polymerizable compound having a polymerizable functional group and a carboxyl group), manufactured by Toagosei Co., Ltd.;
The metal alkoxide and metal chelate are
TA-21: titanium butoxide (carbon number of organic group is 4), manufactured by Matsumoto Fine Chemicals;
TC-750: ethyl acetoacetate chelate (carbon number of organic group is 6), manufactured by Matsumoto Fine Chemicals;
TC-100: titanium acetylacetonate (carbon number of organic group is 5), manufactured by Matsumoto Fine Chemical Co.;
As other components of the adhesive composition,
UP-1190: Toagosei Co., Ltd.

The following evaluations were performed on the polarizing films obtained in the above Examples and Comparative Examples. The evaluation results are shown in Table 2.

<Adhesive strength after water immersion (water resistance evaluation)>
The polarizing film is cut into a size of 200 mm parallel to the stretching direction of the polarizer and 15 mm in the orthogonal direction, and the polarizing film is immersed in water at 23° C. for 3 hours, and then taken out within 30 minutes (in a non-dried state). ) A polarizing film was attached to a glass plate. Then, a cut is made with a cutter knife between the transparent protective film (acrylic or TAC) and the polarizer, and the protective film and the polarizer are peeled off at a peeling speed of 300 mm/min in the 90° direction by a tensilon, and the peeling strength ( N/15 mm) was measured. When the peel strength was 0.5 N/15 mm or more, it was marked with ⊚, when it was 0.1 N/15 mm or more, it was marked with ◯, and when it was less than 0.1 N/15 mm, it was marked with x.

Claims (17)

At least one surface of the polarizer, a curable adhesive composition for a polarizing film for adhering a transparent protective film,
An active energy ray-curable component, and at least one organometallic compound selected from the group consisting of metal alkoxides and metal chelates ,
The active energy ray-curable component contains a radically polymerizable compound,
A curable adhesive composition for a polarizing film, wherein the organic group contained in the organometallic compound has 6 or more carbon atoms . The curable adhesive composition for a polarizing film according to claim 1, wherein the metal of the organometallic compound is titanium. The curable adhesive composition for a polarizing film according to claim 1 or 2 , wherein the ratio of the organometallic compound is 0.05 to 9 parts by weight when the total amount of the active energy ray-curable component is 100 parts by weight. .. When the cured product obtained by curing the curable adhesive composition is immersed in pure water at 23° C. for 24 hours,
Formula: {(M2-M1)/M1}×100(%),
However, M1: weight of the cured product before immersion, M2: weight of the cured product after immersion,
In polarizing film for curable adhesive composition according to any one of claims 1-3 bulk water absorption is 10 wt% or less represented. The radical polymerizable compound, (meth) polarizing film for curable adhesive composition according to any one of claims 1 to 4 containing acrylamide derivative. The curable adhesive composition for a polarizing film according to claim 1, wherein the radical-polymerizable compound contains a polyfunctional compound having at least two functional groups having radical-polymerizability. Further, the polarizing film for curable adhesive composition according to any one of claims 1 to 6 containing a photopolymerization initiator. Further, according to claim 1-7 polarizing film for curable adhesive composition according to any one containing a compound having a vinyl ether group. Further, the polarizing film for curable adhesive composition according to any one of claims 1 to 8 containing a photoacid generator. Of the cured product obtained by curing the curable adhesive composition, the storage elastic modulus at 25 ° C. is 1.0 × 10 7 ^Pa or more at which claims 1-9 polarizing film for curing adhesive according to any one of Composition. At least one surface of the polarizer, a polarizing film provided with a transparent protective film through an adhesive layer,
Polarizing film, wherein the adhesive layer, characterized in that it is one that is formed with a cured product layer of the polarizing film for curable adhesive composition according to any one of claims 1-10. The polarizing film according to claim 11, wherein the adhesive layer has a thickness of 0.1 to 3 µm. When the adhesive layer is immersed in pure water at 23° C. for 24 hours,
Formula: {(M2-M1)/M1}×100(%),
However, M1: weight of the cured product before immersion, M2: weight of the cured product after immersion,
The polarizing film according to claim 11 or 12 , which has a bulk water absorption of 10% by weight or less. Polarizing film according to any one of the adhesive layer, 25 storage modulus is 1.0 × ¹⁰ 7 Pa or more at ℃ claims 11 to 13. A method for producing a polarizing film according to any one of claims 11 to 14,
At least one surface of the polarizer and the transparent protective film, a coating step of applying the curable adhesive composition for the polarizing film,
A laminating step of laminating the polarizer and the transparent protective film,
The polarizer is irradiated with an active energy ray from the polarizer surface side or the transparent protective film surface side, and the polarizer is obtained through the adhesive layer obtained by curing the active energy ray-curable adhesive composition. And a step of adhering the transparent protective film to each other, the method for producing a polarizing film. Optical film polarizing film according to any one of claims 11 to 14, characterized in that it is laminated at least one. An image display device comprising the optical film is used according to the polarizing film or claim 16, according to any of claims 11 to 14.