JP2020052425A - Polarization film and manufacturing method thereof - Google Patents

Abstract

To provide a polarization film having a polarizer and an adhesive layer that has excellent water resistance and exhibits a high adhesive force when laminating a transparent protective film and a manufacturing method of the polarization film.SOLUTION: A polarization film includes a transparent protective film laminated at least on one side of a polarizer, interposing an adhesive layer. The adhesive layer is formed of a cured product layer obtained by irradiating an active energy ray to an active energy ray curable adhesive composition. The active energy ray curable adhesive composition includes an A component having a logPow showing an octanol/water partition coefficient of -1 to 1, and a B component having a logPow of 2 to 7. In the adhesive layer, the A component has a higher concentration on a polarizer side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizer via an adhesive layer, and a method for manufacturing the same. The polarizing film can form an image display device such as a liquid crystal display device (LCD), an organic EL display device, a CRT, and a PDP by itself or as an optical film obtained by laminating the polarizing film.

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

  As a polarizer, for example, an iodine-based polarizer having a structure in which iodine is adsorbed on polyvinyl alcohol (hereinafter, also simply referred to as “PVA”) and stretched because it has a high transmittance and a high degree of polarization is the most widely used. in use. Generally, a polarizing film is used in which a transparent protective film is adhered to both sides of a polarizer with a so-called water-based adhesive obtained by dissolving a polyvinyl alcohol-based material in water (see Patent Documents 1 and 2 below). ). As the transparent protective film, triacetyl cellulose having high moisture permeability is used. When the water-based adhesive is used (so-called wet lamination), a drying step is required after bonding the polarizer and the transparent protective film.

  On the other hand, an active energy ray-curable adhesive has been proposed in place 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, the present inventors have proposed a radical polymerization type active energy ray-curable adhesive using an N-substituted amide-based monomer as a curable component (Patent Documents 3 and 4 below).

JP 2006-220732 A JP 2001-296427 A JP 2012-052000 A JP 2012-068593 A

  The adhesive layer formed by using the active energy ray-curable adhesive described in Patent Documents 3 and 4 is, for example, a water resistance test for evaluating the presence or absence of color loss and peeling after immersion in hot water at 60 ° C. for 6 hours. , Can be cleared sufficiently. However, in recent years, the adhesive for polarizing films has been evaluated for the presence or absence of peeling when the end nails are peeled off after being immersed (saturated) in water, for example. Further, further improvement in water resistance is being demanded. Therefore, the adhesives for polarizing films reported to date, including the active energy ray-curable adhesives described in Patent Documents 3 and 4, have room for further improvement in terms of water resistance. there were.

  By the way, in recent years, organic polymer materials are often required to have trade-off characteristics, and it is actually difficult for a single organic polymer material to satisfy such required characteristics. In order to satisfy the trade-off required characteristics, a technique of adding different materials having different properties to an organic polymer material to form a composite has been proposed in many fields. In the bonding technique, for example, when bonding two different types of adherends, it is conceivable to form the adhesive layer into a two-layer structure in order to enhance the adhesiveness with each adherend. However, when the adhesive layer is formed in a two-layer structure, stress concentrates on the interface, and the adhesive strength of the adhesive layer may be reduced. In particular, in recent years, it has been difficult to establish a technique for forming an adhesive layer having a two-layer structure with respect to an adhesive for a polarizing film, which requires a reduction in thickness, and there is no such report as far as the present inventors know.

  As described above, particularly in the field of adhesives for polarizing films that require a reduction in thickness, when bonding two types of adherends having different polarizers and transparent protective films, a technique for improving water resistance while increasing the adhesiveness. It was a fact that it was difficult to develop

  The present invention has been developed to solve the above-mentioned problems, and has a high adhesive strength when laminating a polarizer and a transparent protective film, and a polarizing film having an adhesive layer excellent in water resistance and production thereof. The aim is to provide a method.

  Since the polarizer and the transparent protective film, which are members of the polarizing film, exhibit different properties from the viewpoint of, for example, hydrophilicity, forming an adhesive layer for laminating these adherends in a two-layer structure requires: Although advantageous from the viewpoint of improving the adhesive strength between the two adherends, as described above, there is a possibility that the adhesive strength may be reduced due to interface peeling in the adhesive layer.

  The inventors of the present invention have conducted intensive studies to solve the above-described problems. It has been found that by having a structure, the water resistance of the adhesive layer can be improved while improving the adhesion to the polarizer. The present invention has been completed based on such a discovery, and has the following configuration.

  That is, the present invention is a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizer via an adhesive layer, wherein the adhesive layer is active in an active energy ray-curable adhesive composition. The active energy ray-curable adhesive composition is formed by a cured product layer obtained by irradiating energy rays, and the active energy ray-curable adhesive composition has an A component having a log Pow representing an octanol / water partition coefficient of -1 to 1; And a B component having a logPow of 2 to 7, and wherein the adhesive layer has a high concentration of the A component on the polarizer side.

  The adhesive layer provided in the polarizing film according to the present invention is formed by a cured product layer obtained by irradiating the active energy ray-curable adhesive composition with active energy rays, and the active energy ray-curable adhesive composition Contains an A component having a logPow representing an octanol / water partition coefficient of -1 to 1 and a B component having a logPow of 2 to 7. The polarizer as the adherend of the adhesive layer, particularly a polyvinyl alcohol-based polarizer shows hydrophilicity, but the adhesive layer according to the present invention has a high concentration of the A component on the polarizer side, and the A component is logPow is -1 to 1, indicating high hydrophilicity. For this reason, at the polarizer-side interface of the adhesive layer, a large amount of the hydrophilic component A, which has a particularly strong affinity for the polarizer, is unevenly distributed, so that the adhesive layer and the polarizer are firmly bonded to each other. On the other hand, the adhesive layer included in the polarizing film according to the present invention has a component gradient structure such that the concentration of the A component on the polarizer side is high, so that the concentration of the A component on the polarizer side is high, but the transparent layer is transparent. On the protective film side, logPow is 2 to 7, and the concentration of the component B having high hydrophobicity is high. Since the transparent protective film is more hydrophobic than the polarizer, the adhesive layer included in the polarizing film according to the present invention strongly adheres to the transparent protective film and also has improved water resistance.

  Incidentally, as far as the present inventors can know, in the adhesive layer provided in the polarizing film which is required to be thinner in recent years, an example in which the component gradient structure in which the concentration of the hydrophilic component on the polarizer side is high is adopted. not exist.

In the adhesive layer of the polarizing film according to the present invention, the point where the concentration of the component A on the polarizer side is high, and further the point having a component gradient structure such that the concentration of the component A on the polarizer side is high, For example, it can be confirmed by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). The principle of TOF-SIMS is that when a sample is irradiated with a primary ion beam (for example, 1E12 ions / cm ² or less) under an ultra-high vacuum, secondary ions are emitted only from the outermost surface of the sample (about several Å in depth), By introducing the secondary ions into a time-of-flight (TOF) mass spectrometer, a mass spectrum is obtained. By utilizing this principle, information on the elemental composition and the chemical structure of the compound existing on the outermost surface of the sample can be obtained. Further, in the present invention, it is confirmed that, in the adhesive layer, the concentration of the component A on the polarizer side is increased, and further, the adhesive layer has a component gradient structure such that the concentration of the component A on the polarizer side is increased. Therefore, the cluster ion etching method can be used.

Hereinafter, the “cluster ion etching method” will be described. For example, when the surface of the adhesive layer is etched using a general etching method using a monoatomic ion beam (Ar ⁺ , Cs ^+, etc.) as etching ions, the molecular structure of the adhesive layer surface is destroyed, A damage layer is formed. In this case, even if an attempt is made to obtain a mass spectrum of the surface using TOF-SIMS, an accurate mass spectrum of the surface of the adhesive layer cannot be measured due to the influence of the damaged layer. On the other hand, when the “cluster ion etching method” using “Ar gas cluster ions (Arn ⁺ )” as etching ions is used, damage given to the surface of the adhesive layer after etching is reduced, and a damaged layer is formed. Therefore, the surface of the adhesive layer after etching retains the molecular structure of the surface before etching. Therefore, the mass spectrum of the surface of the adhesive layer can be accurately measured by using TOF-SIMS.

  FIG. 1 is a schematic diagram showing a method for evaluating the point at which the concentration of the component A on the polarizer side increases in the adhesive layer using TOF-SIMS. FIG. 1 (I) shows an example of a polarizing film according to the present invention. In such a polarizing film, a transparent protective film 2 is laminated on both surfaces of a polarizer 1 via an adhesive layer 3. First, the transparent protective film 2 of the polarizing film shown in (I) (the upper transparent protective film 2 in (I) of FIG. 1) is horizontally cut with a microtome to reduce the thickness of the transparent protective film 2 in contact with the adhesive layer 3. ((II)). Next, as shown in (III), the composition of the surface is analyzed by measuring the mass spectrum of the surface of the thinly cut transparent protective film 2 using TOF-SIMS. Next, as shown in (IV), after the surface of the thinly cut transparent protective film 2 is etched using the “cluster ion etching method”, the composition of the surface is analyzed using TOF-SIMS. Further, as shown in (V), the surface of the transparent protective film 2 on the side of the transparent protective film 2 is precipitated by etching the surface of the transparent protective film 2 using the “cluster ion etching method”, and the TOF-SIMS Is used to analyze the composition of the surface. Thereafter, the etching process using the “cluster ion etching method” and the analysis of the composition of the surface of the deposited adhesive layer 3 using TOF-SIMS are repeated, and the etching is performed until the polarizer surface is finally reached. The processing and the analysis of the composition of the surface of the adhesive layer 3 (and the polarizer 1) are continuously performed. According to the method described above, it was confirmed that the concentration of the component A on the polarizer side was increased in the adhesive layer, and that the adhesive layer had a component gradient structure such that the concentration of the component A on the polarizer side was increased. can do.

  In the above-mentioned polarizing film, when the active energy ray-curable adhesive composition contains a (meth) acrylamide derivative as the component A, the active energy ray-curable adhesive composition further contains a multi-component as the component B. It is preferable to contain a functional (meth) acrylate because the adhesiveness of the adhesive layer with the polarizer and the transparent protective film and the water resistance are further increased.

  In the above polarizing film, it is preferable that the active energy ray-curable adhesive composition contains an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer. In the polarizing film, it is preferable that the active energy ray-curable adhesive composition contains a hydroxyl group-containing photopolymerization initiator. When the active energy ray-curable adhesive composition contains an acrylic oligomer obtained by polymerizing a non-polymerizable (meth) acrylic monomer, components of the adhesive composition interposed between the polarizer and the transparent protective film The uneven distribution is likely to proceed, and the concentration of the component A in the adhesive layer is likely to be higher on the polarizer side. When a hydroxyl group-containing photopolymerization initiator is contained as a polymerization initiator, the solubility of the component A on the polarizer side in the adhesive layer having a high concentration increases, and the curability of the adhesive layer increases. As a result, the adhesiveness and the water resistance of the adhesive layer with the polarizer and the transparent protective film are further enhanced, which is preferable.

  In the polarizing film, it is preferable that the active energy ray-curable adhesive composition contains at least one kind of organometallic compound selected from the group consisting of metal alkoxides and metal chelates.

  When a polarizing film in which a transparent protective film is laminated on a polarizer via an adhesive layer is exposed to a dew condensation environment, in particular, as one of mechanisms by which peeling between the adhesive layer and the polarizer occurs. Can be estimated as follows. First, the water that has passed through the protective film diffuses into the adhesive layer, and the water diffuses toward the polarizer interface. Here, in the conventional polarizing film, the hydrogen bond and / or the ionic bond greatly contribute to the adhesive force between the adhesive layer and the polarizer. Hydrogen bond and ionic bond are dissociated, and as a result, the adhesive strength between the adhesive layer and the polarizer is reduced. As a result, in an environment of dew condensation, the adhesive may peel off between the adhesive layer and the polarizer.

  On the other hand, in the polarizing film according to the present invention, when the active energy ray-curable adhesive composition contains at least one kind of organometallic compound selected from the group consisting of metal alkoxides and metal chelates, Becomes an active metal species through the interposition of moisture. As a result, the organometallic compound strongly interacts with both the polarizer and the active energy ray-curable component constituting the adhesive layer. Thereby, even if moisture is present at the interface between the polarizer and the adhesive layer, since they interact strongly via the organometallic compound, the adhesive water resistance between the polarizer and the adhesive layer is increased. Is dramatically improved.

  In the polarizing film, the metal of the organometallic compound contained in the active energy ray-curable adhesive composition is preferably titanium.

  In the polarizing film, it is preferable that the active energy ray-curable adhesive composition contains the metal alkoxide as the organometallic compound, and the metal group of the metal alkoxide has 6 or more carbon atoms.

  In the polarizing film, it is preferable that the active energy ray-curable adhesive composition contains the metal chelate as the organometallic compound, and the metal group has 4 or more carbon atoms in the organic group.

  The polarizing film preferably contains an alkoxysilane group-containing compound having a viscosity of 15 mPa · s or more. When the active energy ray-curable adhesive composition forming the adhesive layer contains an alkoxysilane group-containing compound having a viscosity of 15 mPa · s or more, the adhesive water resistance between the polarizer and the adhesive layer is reduced. The following points can be considered as reasons for improvement. When moisture permeates through the protective film and diffuses into the adhesive layer, at the interface between the polarizer and the adhesive layer, the alkoxysilane group of the compound becomes a silanol group due to the interposition of moisture and is present on the polarizer surface. A covalent bond is formed with a functional group such as a hydroxyl group or a carboxyl group. Furthermore, when the viscosity of the alkoxysilane group-containing compound is 15 mPa · s or more (high molecular weight), the adhesive composition is being polymerized in the middle of the polymerization while the fluidity is maintained before the polymerization of the adhesive composition. The agent composition and the alkoxysilane group-containing compound have an appropriate incompatibility, and tend to be more unevenly distributed on the adherend interface than a low-viscosity (low molecular weight) alkoxysilane group-containing compound. Therefore, even if the blending amount is set low, the alkoxysilane group-containing compound having a viscosity of 15 mPa · s or more is unevenly distributed on the polarizer surface side. A hydrogen bond and / or an ionic bond and further a covalent bond are formed, and the water resistance of the adhesive between the polarizer and the adhesive layer is dramatically improved.

  In the polarizing film, the main chain of the alkoxysilane group-containing compound preferably has an acrylic polymer structure.

In the above polarizing film, the adhesive layer obtained by curing the active energy ray-curable adhesive composition preferably has a storage elastic modulus at 25 ° C. of 1.0 × 10 ⁷ Pa or more.

The polarizing film according to the present invention includes, for example, a coating step of coating the active energy ray-curable adhesive composition on at least one surface of the polarizer and the transparent protective film, and the polarizer and the transparent film. A laminating step of laminating the protective film and irradiating an active energy ray from the polarizer surface side or the transparent protective film surface side to cure the active energy ray-curable adhesive composition. And a bonding step of bonding the polarizer and the transparent protective film via the adhesive layer. In particular, in the method for producing a polarizing film according to the present invention, when the temperature of the active energy ray-curable adhesive composition is adjusted to 15 to 40 ° C. after the coating step and before the bonding step, the adhesive This is preferable because the concentration of the component A in the layer tends to be higher on the polarizer side. In order to adjust the temperature of the active energy ray-curable adhesive composition to 15 to 40 ° C., for example, the adhesive composition is adjusted by a method such as adjusting the temperature of a room for transporting a film or the temperature of a guide roll. It can also be adjusted by adjusting the temperature of the film to be applied.

The polarizing film according to the present invention is characterized in that the adhesive layer formed after the bonding step has a high concentration of the component A on the polarizer side. The polarizing film according to the present invention is, for example, a production method described below;
A method for producing a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizer via an adhesive layer, wherein the adhesive layer comprises an active energy ray-curable adhesive composition and an active energy ray-curable adhesive composition. And a first active material containing an A component having a logPow representing an octanol / water distribution coefficient of -1 to 1 on the bonding surface of the polarizer. A first application step of applying an energy ray-curable adhesive composition, and a second active energy ray-curable adhesive containing a B component having a logPow of 2 to 7 on the bonding surface of the transparent protective film. A second coating step of coating the composition, a bonding step of bonding the polarizer and the transparent protective film, and irradiating active energy rays from the polarizer surface side or the transparent protective film surface side. , A bonding step of bonding the polarizer and the transparent protective film through the adhesive layer obtained by curing the active energy ray-curable adhesive composition, and formed after the bonding step. The adhesive layer can also be manufactured by a method for manufacturing a polarizing film, wherein the concentration of the component A on the polarizer side is high.

  As described above, when the adhesive layer is formed in a two-layer structure, stress is concentrated on the interface, and the adhesive strength of the adhesive layer may be reduced as described above. On the other hand, according to the manufacturing method, the first active energy ray-curable adhesive composition and the second active energy ray-curable adhesive composition are bonded in a fluid state, so that a certain degree of fluidity between the two layers is obtained. Since the compatibilization proceeds, a two-layer structure is not formed, and a component gradient structure in which the concentration of the component A having high hydrophilicity is increased on the polarizer side is formed. Therefore, the interface separation between the first active energy ray-curable adhesive composition and the second active energy ray-curable adhesive composition does not occur, and the polarizer and the transparent protective film have good adhesion, And the polarizing film has good water resistance.

  In the method for producing a polarizing film, it is preferable that the active energy ray-curable adhesive composition contains at least one kind of organometallic compound selected from the group consisting of metal alkoxides and metal chelates.

  In the method for producing a polarizing film, the first active energy ray-curable adhesive composition preferably contains the organometallic compound.

  In the above method for producing a polarizing film, the metal of the organometallic compound contained in the active energy ray-curable adhesive composition is preferably titanium.

  In the method for producing a polarizing film, the active energy ray-curable adhesive composition preferably contains the metal alkoxide as the organometallic compound, and the organic group of the metal alkoxide has 6 or more carbon atoms. .

  In the method for producing a polarizing film, the active energy ray-curable adhesive composition preferably contains the metal chelate as the organometallic compound, and the organic group of the metal chelate preferably has 4 or more carbon atoms. .

  In the above-mentioned method for producing a polarizing film, it is preferable to contain an alkoxysilane group-containing compound having a viscosity of 15 mPa · s or more.

  In the above method for producing a polarizing film, the main chain of the compound containing an alkoxysilane group preferably has an acrylic polymer structure.

In the method for producing a polarizing film, the storage elastic modulus at 25 ° C. of the adhesive layer obtained by curing the active energy ray-curable adhesive composition is preferably 1.0 × 10 ⁷ Pa or more.

Schematic showing an evaluation method of a component gradient structure in an adhesive layer using TOF-SIMS

  The polarizing film according to the present invention is obtained by laminating a transparent protective film on at least one surface of a polarizer via an adhesive layer, and the adhesive layer is activated by an active energy ray-curable adhesive composition. It is formed by a cured product layer obtained by irradiating energy rays.

  Active energy ray-curable adhesive compositions can be broadly classified into electron beam-curable, ultraviolet ray-curable, and visible ray-curable adhesive compositions. Further, the ultraviolet-curable and visible-light-curable adhesives can be classified into radical polymerization-curable adhesives and cationic polymerization-type adhesives. In the present invention, active energy rays having a wavelength range of 10 nm to less than 380 nm are represented by ultraviolet rays, and active energy rays having a wavelength range of 380 nm to 800 nm are represented by visible light rays.

  Examples of the compound constituting the radical polymerization-curable adhesive include a radical polymerizable compound. Examples of the radical polymerizable compound include compounds having a radical polymerizable functional group having a carbon-carbon double bond such as a (meth) acryloyl group and a vinyl group. As these curable components, either a monofunctional radical polymerizable compound or a bifunctional or higher polyfunctional radical polymerizable compound can be used. These radically polymerizable compounds can be used alone or in combination of two or more. As these radically polymerizable compounds, for example, compounds having a (meth) acryloyl group are suitable. The active energy ray-curable adhesive composition used in the present invention preferably contains a compound having a (meth) acryloyl group as a main component. Specifically, the total amount of the active energy ray-curable adhesive composition is When the content is 100% by weight, the content of the compound having a (meth) acryloyl group is preferably 50% by weight or more, more preferably 80% by weight or more. In the present invention, (meth) acryloyl means an acryloyl group and / or a methacryloyl group, and “(meth)” has the same meaning hereinafter.

<Monofunctional radical polymerizable compound>
Examples of the monofunctional radical polymerizable compound include (meth) acrylamide derivatives having a (meth) acrylamide group. The (meth) acrylamide derivative is preferable in terms of securing adhesion to a polarizer and various transparent protective films, and also because the polymerization rate is high and the productivity is excellent. 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-alkyl group-containing (meth) acrylamide derivatives such as -butyl (meth) acrylamide and 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; Can be Examples of the heterocycle-containing (meth) acrylamide derivative in which the nitrogen atom of the (meth) acrylamide group forms a heterocycle include N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. And the like.

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

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

  The (meth) acrylic acid derivative includes 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, Hydroxyalkyl (meth) acrylates such as hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, and 12-hydroxylauryl (meth) acrylate And hydroxyl groups such as [4- (hydroxymethyl) cyclohexyl] methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate. (Meth) acrylates; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate glycidyl ether; 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2- Trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, 3-chloro-2-hydroxypropyl Halogen-containing (meth) acrylates such as (meth) acrylate; alkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate; 3-oxetanylmethyl (meth) acrylate; Oxetane group-containing (meth) acrylates such as methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth) acrylate, 3-butyl-oxetanylmethyl (meth) acrylate, and 3-hexyloxetanylmethyl (meth) acrylate A (meth) acrylate having a heterocyclic ring such as tetrahydrofurfuryl (meth) acrylate or butyrolactone (meth) acrylate, neopentyl glycol (meth) acrylic acid hydroxypivalate adduct, p-phenylphenol (meth) acrylate, or the like. Is mentioned.

  In addition, examples of the monofunctional radical polymerizable compound include carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

  Examples of the monofunctional radical polymerizable compound include lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, Vinyl monomers having a nitrogen-containing heterocycle such as vinyl pyrrole, vinyl imidazole, vinyl oxazole, and vinyl morpholine are exemplified.

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

<Polyfunctional radical polymerizable compound>
Examples of the bifunctional or higher polyfunctional radical polymerizable compound include, for example, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (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) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta Esterified products of (meth) acrylic acid and polyhydric alcohol such as (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and EO-modified diglycerin tetra (meth) acrylate, and 9,9-bis [4- (2- (Meth) acryloyloxyethoxy) phenyl] fluorene. Specific examples include Aronix M-220 (manufactured by Toagosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), and light acrylate DCP-A (manufactured by Kyoeisha Chemical.) ), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer) and the like. If necessary, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, and various (meth) acrylate monomers can be used.

  In the adhesive layer according to the present invention, the concentration of the component A on the polarizer side is high. In the adhesive layer, in order to realize a component gradient structure with respect to the A component, the active energy ray-curable adhesive composition comprises an A component having a log Pow representing an octanol / water distribution coefficient of -1 to 1, and a log Pow. And B component which is 2-7.

  Octanol / water partition coefficient (logPow) is an index indicating the lipophilicity of a substance, and means the logarithmic value of the octanol / water partition coefficient. High logPow means lipophilic, that is, low water absorption. The logPow value can be measured (flask immersion method described in JIS-Z-7260), but can also be calculated. In this specification, a logPow value calculated by Chem Draw Ultra manufactured by Cambridge Software Inc. is used.

  As the component A having a log Pow of -1 to 1, of the radically polymerizable compounds described above, a compound having a log Pow of -1 to 1 can be arbitrarily used. Specifically, for example, hydroxyethylacrylamide ( Trade name "HEAA", LogPow; -0.56, manufactured by Kojin Co., N-vinylformamide (trade name "Beamset 770", LogPow, -0.25, manufactured by Arakawa Chemical Co., Ltd.), acryloylmorpholine (trade name) "ACMO", LogPow; -0.20 manufactured by Kojin Co., Ltd., γ-butyrolactone acrylate (trade name "GBLA", LogPow; 0.19 manufactured by Osaka Organic Chemical Industry Co., Ltd.), acrylic acid dimer (trade name) “Β-CEA”, manufactured by Daicel, LogPow; 0.2), N-vinylpyrrolidone (trade name “NVP”, manufactured by Nippon Shokubai Co., Ltd., LogPo w; 0.24), acetoacetoxyethyl methacrylate (trade name “AAEM”, manufactured by Nippon Gohsei, LogPow; 0.27), 2-hydroxyethyl acrylate (trade name “HEA”, manufactured by Osaka Organic Chemical Industry Co., Ltd.) LogPow; 0.28), glycidyl methacrylate (trade name "Light Ester G", manufactured by Kyoeisha Chemical, LogPow; 0.57), dimethylacrylamide (tradename "DMAA", manufactured by Kojin Co., LogPow; 0.58), Tetrahydrofurfuryl alcohol acrylic acid multimer ester (trade name “Biscoat # 150D”, manufactured by Osaka Organic Chemical Industry, LogPow; 0.60), 4-hydroxybutyl acrylate (trade name “4-HBA”, Osaka Organic Chemical Industry) (LogPow; 0.68), acrylic acid (trade name "acrylic acid") Manufactured by Mitsubishi Chemical Corporation, LogPow; 0.69), triethylene glycol diacrylate (trade name "LIGHT ACRYLATE 3EG-A" manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 0.72), and the like. Among them, in the present invention, it is preferable to use a (meth) acrylamide derivative as the component A having a log Pow of -1 to 1, and it is more preferable to use hydroxyethylacrylamide, acryloylmorpholine, or dimethylacrylamide. Other than the (meth) acrylamide derivative, 4-hydroxybutyl acrylate is preferably used.

  In order to improve the adhesive strength and water resistance of the adhesive layer, when the total amount of the active energy ray-curable adhesive composition is 100% by weight, the content of the component A whose log Pow is -1 to 1 is , Preferably 5 to 50% by weight, more preferably 10 to 45% by weight.

  As the component B having a logPow of 2 to 7, of the radically polymerizable compounds described above, a compound having a logPow of 2 to 7 can be arbitrarily used. Specifically, for example, dicyclopentenyl acrylate (Trade name “Fancryl FA-511AS”, manufactured by Hitachi Chemical Co., Ltd., LogPow; 2.26), butyl acrylate (trade name “butyl acrylate”, manufactured by Mitsubishi Chemical Corporation, LogPow; 2.35), 1, 6-hexanediol diacrylate (trade name “light acrylate 1.6HX-A”, manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 2.43), dicyclopentanyl acrylate (trade name “Fancryl FA-513AS”), Hitachi Chemical Co., Ltd., LogPow; 2.58), dimethylol-tricyclodecane diacrylate (trade name "Light Acrylate DC") -A ", manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 3.05), isobornyl acrylate (trade name" Light Acrylate IB-XA ", manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 3.27), neopentyl glycol acrylic hydroxypivalate Acid adduct (trade name “Light Acrylate HPP-A”, manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 3.35), 1,9-nonanediol diacrylate (trade name “Light Acrylate 1,9ND-A”, Kyoeisha Chemical Co., Ltd.) Manufactured by LogPow; 3.68), o-phenylphenol EO-modified acrylate (trade name “Fancryl FA-301A”, manufactured by Hitachi Chemical Co., Ltd., LogPow; 3.98), 2-ethylhexyloxetane (trade name: “Alonoxetane OXT”) -212 ", manufactured by Toagosei Co., Ltd., LogPow; 4.24), bisuf Knol-A-diglycidyl ether (trade name "JER828", LogPow; 4.76, manufactured by Mitsubishi Chemical Corporation), bisphenol A EO 6 mol-modified diacrylate (trade name "FA-326A", manufactured by Hitachi Chemical Co., Ltd., LogPow; 4) .84), bisphenol A EO4 mol-modified diacrylate (trade name “FA-324A”, manufactured by Hitachi Chemical Co., Ltd., LogPow; 5.15), bisphenol A PO2 mol-modified diacrylate (trade name “FA-P320A”, Hitachi Chemical) , LogPow; 6.10), bisphenol A PO3 mol-modified diacrylate (trade name “FA-P323A”, Hitachi Chemical, LogPow; 6.26), bisphenol A PO4 mol-modified diacrylate (trade name “FA”) -P324A ", LogPow; 6.4, manufactured by Hitachi Chemical Co., Ltd. ), And the like. Among these, in the present invention, it is preferable to use a polyfunctional (meth) acrylate as the B component having a log Pow of 2 to 7, and furthermore, 1,6-hexanediol diacrylate), dimethylol-tricyclodecane diacrylate. Acrylate, neopentyl glycol hydroxypivalate acrylic acid adduct, 1,9-nonanediol diacrylate, 2-ethylhexyloxetane, bisphenol-A-diglycidyl ether, bisphenol A EO 6 mol modified diacrylate, bisphenol A EO 4 mol modified diacrylate It is preferred to use bisphenol A PO2 mol modified diacrylate, bisphenol A PO3 mol modified diacrylate, or bisphenol A PO4 mol modified diacrylate.

  In order to improve the adhesive strength and water resistance of the adhesive layer, when the total amount of the active energy ray-curable adhesive composition is 100% by weight, the content of the component B having a logPow of 2 to 7 is as follows: It is preferably from 30 to 95% by weight, more preferably from 40 to 80% by weight.

  When the active energy ray-curable adhesive composition uses an electron beam or the like as the active energy ray, the active energy ray-curable adhesive composition does not need to contain a photopolymerization initiator. When an ultraviolet ray or a visible light ray is used as the energy ray, it preferably contains a photopolymerization initiator.

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

  The compounding amount of the photopolymerization initiator is 20% by weight or less when the total amount of the active energy ray-curable adhesive composition is 100% by weight. The compounding amount of the photopolymerization initiator is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, and further preferably 0.1 to 5% by weight.

  When the curable adhesive for a polarizing film of the present invention is used in a visible light curable type containing a radical polymerizable compound as a curable component, a photopolymerization initiator highly sensitive to light of 380 nm or more is used. Preferably, it is used. The photopolymerization initiator highly sensitive to light of 380 nm or more will be described later.

  As the photopolymerization initiator, a compound represented by the following general formula (1);

（式中、Ｒ^１およびＲ^２は−Ｈ、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^１およびＲ^２は同一または異なっても良い）を単独で使用するか、あるいは一般式（１）で表される化合物と後述する３８０ｎｍ以上の光に対して高感度な光重合開始剤とを併用することが好ましい。一般式（１）で表される化合物を使用した場合、３８０ｎｍ以上の光に対して高感度な光重合開始剤を単独で使用した場合に比べて接着性に優れる。一般式（１）で表される化合物の中でも、Ｒ^１およびＲ^２が−ＣＨ_２ＣＨ_３であるジエチルチオキサントンが特に好ましい。接着剤組成物中の一般式（１）で表される化合物の組成比率は、硬化性成分の全量１００重量部に対して、０．１〜５重量部であることが好ましく、０．５〜４重量部であることがより好ましく、０．９〜３重量部であることがさらに好ましい。

(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 may be a compound represented by the general formula ( It is preferable to use the compound represented by 1) in combination with a photopolymerization initiator having high sensitivity to light of 380 nm or more, which will be described later. When the compound represented by the general formula (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 from 0.1 to 5 parts by weight, preferably from 0.5 to 5 parts by weight, based on 100 parts by weight of the total amount of the curable component. The amount is more preferably 4 parts by weight, and even more preferably 0.9 to 3 parts by weight.

  In addition, it is preferable to add a polymerization initiation aid as needed. Examples of the polymerization initiator include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate. And ethyl 4-dimethylaminobenzoate is particularly preferred. When a polymerization initiator is used, its addition amount is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, 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 as needed. Since a transparent protective film having UV absorbing ability does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator having high sensitivity to light of 380 nm or more as a photopolymerization initiator. Specifically, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 , 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine Oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole) 1-yl) -phenyl) titanium and the like.

  In particular, as a photopolymerization initiator, in addition to the photopolymerization initiator of the general formula (1), a compound represented by the following general formula (2);

（式中、Ｒ^３、Ｒ^４およびＲ^５は−Ｈ、−ＣＨ_３、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^３、Ｒ^４およびＲ^５は同一または異なっても良い）を使用することが好ましい。一般式（２）で表される化合物としては、市販品でもある２−メチル−１−（４−メチルチオフェニル）−２−モルフォリノプロパン−１−オン（商品名：ＩＲＧＡＣＵＲＥ９０７ メーカー：ＢＡＳＦ）が好適に使用可能である。その他、２−ベンジル−２−ジメチルアミノ−１−（４−モルフォリノフェニル）−ブタノン−１（商品名：ＩＲＧＡＣＵＲＥ３６９ メーカー：ＢＡＳＦ）、２−（ジメチルアミノ）−２−［（４−メチルフェニル）メチル］−１−［４−（４−モルホリニル）フェニル］−１−ブタノン（商品名：ＩＲＧＡＣＵＲＥ３７９ メーカー：ＢＡＳＦ）が感度が高いため好ましい。

Wherein 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. It is preferred to use. As the compound represented by the general formula (2), commercially available 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (trade name: IRGACURE907 maker: BASF) is suitable. It can be used for In addition, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (trade name: IRGACURE369 Manufacturer: BASF), 2- (dimethylamino) -2-[(4-methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (trade name: IRGACURE379 Manufacturer: BASF) is preferred because of its high sensitivity.

  In the present invention, among the above photopolymerization initiators, it is preferable to use a hydroxyl group-containing photopolymerization initiator. When the active energy ray-curable adhesive composition contains a hydroxyl group-containing photopolymerization initiator as a polymerization initiator, the solubility of the component A on the polarizer side in the high-concentration adhesive layer is increased, and the adhesive layer is Hardens. Examples of the photopolymerization initiator having a hydroxyl group include 2-methyl-2-hydroxypropiophenone (trade name “DARCOCUR 1173”, manufactured by BASF), 1-hydroxycyclohexyl phenyl ketone (trade name “IRGACURE 184”, manufactured by BASF) ), 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name “IRGACURE2959”, manufactured by BASF), 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one (trade name “IRGACURE127”, manufactured by BASF) and the like. In particular, 1-hydroxycyclohexyl phenyl ketone is more preferable because it has particularly high solubility in the adhesive layer having a high concentration of the component A.

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

In the present invention, examples of the radical polymerization initiator having a hydrogen abstracting action include a thioxanthone-based radical polymerization initiator and a benzophenone-based radical polymerization initiator. The radical polymerization initiator is preferably a thioxanthone-based radical polymerization initiator. Examples of the thioxanthone radical polymerization initiator include a compound represented by the above general formula (1). Specific examples of the compound represented by the general formula (1) include thioxanthone, dimethylthioxanthone, diethylthioxanthone, isopropylthioxanthone, and chlorothioxanthone. 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.

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

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

<Cationically curable adhesive>
Examples of the curable component of the cationic polymerization curable adhesive include a compound having an epoxy group or an oxetanyl group. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in a molecule, and various curable epoxy compounds generally known can be used. Preferred epoxy compounds include compounds having at least two epoxy groups and at least one aromatic ring in the molecule (aromatic epoxy compounds), and compounds having at least two epoxy groups in the molecule and at least one of them. Examples of the compound include a compound formed between two adjacent carbon atoms constituting an alicyclic ring (alicyclic epoxy compound) and the like. However, even when a cationic polymerization curable adhesive is used in the adhesive layer to realize a component gradient structure with respect to the component A, the active energy ray-curable adhesive composition has an octanol / water partition coefficient. It is necessary to contain an A component having a log Pow of -1 to 1 and a B component having a log Pow of 2 to 7.

<Photocationic polymerization initiator>
The cationic polymerization-curable adhesive contains the above-described epoxy compound and oxetane compound as curable components, and both of them are cured by cationic polymerization. Therefore, a cationic photopolymerization initiator is blended. The cationic photopolymerization initiator generates a cationic species or a Lewis acid upon irradiation with an active energy ray such as visible light, ultraviolet light, X-ray, or electron beam, and initiates a polymerization reaction of an epoxy group or an oxetanyl group.

<At least one organometallic compound selected from the group consisting of metal alkoxides and metal chelates>
A metal alkoxide is a compound in which at least one or more alkoxy group which is an organic group is bonded to a metal, and a metal chelate is a compound in which an organic group is bonded or coordinated to a metal via an oxygen atom. As the metal, titanium, aluminum and zirconium are preferable. Among them, aluminum and zirconium have higher reactivity than titanium, and the pot life of the adhesive composition is 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 one having 4 or more carbon atoms in an organic group of the metal alkoxide, and 6 or more. It is more preferable to contain these. When the carbon number is 3 or less, the pot life of the adhesive composition is shortened, and the effect of improving the adhesive water resistance may be reduced. The organic group having 6 or more carbon atoms includes, for example, an octoxy group, and can be suitably used. Examples of suitable metal alkoxides include, for example, tetraisopropyl titanate, tetra normal butyl titanate, butyl titanate dimer, tetraoctyl titanate, tertiary amyl titanate, tetratertiary butyl titanate, tetrastearyl titanate, zirconium tetraisopropoxide, zirconium Tetra normal butoxide, zirconium tetraoctoxide, zirconium tetratertiary butoxide, zirconium tetrapropoxide, aluminum sec butyrate, aluminum ethylate, aluminum isopropylate, aluminum butyrate, aluminum diisopropylate monosecondary butyrate, monosec butoxy aluminum Diisopropylate, and the like. Among them, tetraoctyl titanate is preferred.

  When the curable adhesive composition for a polarizing film according to the present invention contains a metal chelate as an organometallic compound, it preferably contains an organic group of the metal chelate having 4 or more carbon atoms. When the carbon number is 3 or less, the pot life of the adhesive composition is 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 octylene glycolate 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, Butoxytitanium-bis (octylene glycolate), dipropoxytitanium-bis (ethylacetoacetate), titanium lactate, titanium diethanolaminate, titanium triethanolaminate, dipropoxytitanium-bis (lactate), dipropoxytitanium-bis ( Triethanol aminate), di-n-butoxy titanium-bis (triethanol aminate), tri-n-butoxy titanium monostearate, diisopropoxy bis (ethyl acetoacetate) Titanium, diisopropoxy bis (acetylacetate) titanium, diisopropoxy bis (acetylacetone) titanium, titanium phosphate compound, titanium lactate ammonium salt, titanium-1,3-propanedioxybis (ethylacetoacetate), dodecyl Titanium benzenesulfonate compound, titanium aminoethylaminoethanolate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium acetylacetonate bisethylacetoacetate, zirconium acetate, tri-n-butoxyethylacetate Acetate zirconium, di-n-butoxybis (ethylacetoacetate) zirconium, n-butoxytris (ethylacetoacetate) Tetrate) zirconium, tetrakis (n-propylacetoacetate) zirconium, tetrakis (acetylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium, aluminum ethylacetoacetate, aluminum acetylacetonate, aluminum acetylacetonate bisethylacetoacetate, di Aluminum isopropoxyethyl acetoacetate, aluminum diisopropoxyacetylacetonate, aluminum isopropoxybis (ethylacetoacetate), aluminum isopropoxybis (acetylacetonate), aluminum tris (ethylacetoacetate), aluminum tris (acetylacetonate) , Monoacetylacetonate bis (ethylacetoacete G) aluminum. Among them, titanium acetylacetonate and titanium ethyl acetoacetate are preferable.

  As the organic metal compound usable in the present invention, other than the above, zinc octylate, zinc laurate, zinc stearate, tin octylate, and other organic carboxylic acid metal salts, acetylacetone zinc chelate, benzoylacetone zinc chelate, dibenzoylmethane zinc Chelates and zinc chelate compounds such as ethyl zinc acetoacetate chelate.

<Other ingredients>
The active energy ray-curable adhesive composition according to the present invention may contain the following components.

<Alkoxysilane group-containing compound having a viscosity of 15 mPa · s or more>
As the alkoxysilane group-containing compound having a viscosity of 15 mPa · s or more, a compound having a higher molecular weight than a low molecular weight compound containing an alkoxysilane group is used. In particular, a compound having an alkoxysilane group at a side chain and / or a molecular terminal is used. A polymer or an oligomer type alkoxysilane group-containing compound can be suitably used.

As the polymer containing an alkoxysilane group at a side chain and / or a molecular terminal, a polymer having a (meth) acryl-based polymer main chain can be suitably used. Examples of the (meth) acrylic monomer constituting the acrylic polymer include (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. Isopropyl acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, (meth) acryl Cyclohexyl acid, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate , Decyl (meth) acrylate, isodecyl (meth) acrylate, (meth) acrylic acid Sobornyl, dicyclopentanyl (meth) acrylate, dodecyl (meth) acrylate, phenyl (meth) acrylate, toluyl (meth) acrylate, benzyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, (Meth) acrylic such as 3-methoxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, stearyl (meth) acrylate, and isostearyl (meth) acrylate Acid esters and the like. In the present invention, (meth) acryl means acryl and / or methacryl, and “(meth)” has the same meaning hereinafter.

  The viscosity of the polymer containing an alkoxysilane group at a side chain and / or a molecular terminal is 15 mPa · s or more, more preferably 10,000 mPa · s or more, and further preferably 100000 mPa · s or more. The upper limit of the viscosity is not particularly limited, but is preferably 2,000,000 mPa · s or less in consideration of workability and the like.

  Examples of the oligomer type alkoxysilane group-containing compound include a hydrolytic condensate of a low molecular weight alkoxysilane group-containing compound. As the hydrolysis-condensation product of the low-molecular-weight alkoxysilane group-containing compound, commercially available products can also be suitably used. For example, X-41-1059A, X-24-9590, KR-516, X -41-1805, KR513, X-40-9296, KR-511, KR-500, X-40-9225, X-40-9246, X-40-9250, KR-401N, X-40-9227, KR -510, KR-9218, KR-213 and the like.

  The viscosity of the oligomer type alkoxysilane group-containing compound is 15 mPa · s or more, more preferably 20 mPa · s or more, and further preferably 25 mPa · s or more. The upper limit of the viscosity is not particularly limited, but is preferably 100000 mPa · s or less in consideration of workability and the like.

  In the present invention, the content of the alkoxysilane group-containing compound having a viscosity of 15 mPa · s or more is preferably in the range of 0.2 to 15 parts by weight based on 100 parts by weight of the total amount of the active energy ray-curable component. It is preferably from 0.5 to 10 parts by weight, more preferably from 0.8 to 5 parts by weight. When the amount is more than 15 parts by weight, the storage stability of the adhesive composition may be deteriorated, or the ratio of components for bonding to the polarizer or the protective film may be relatively insufficient, and the adhesiveness may be reduced. . On the other hand, if the amount is less than 0.2 parts by weight, the effect of adhesive water resistance cannot be sufficiently exhibited.

<Acrylic oligomer>
The active energy ray-curable adhesive composition used in the present invention is an acrylic resin obtained by polymerizing a (meth) acrylic monomer in addition to the curable component relating to the radically polymerizable compound or the cationically polymerizable curable adhesive. An oligomer can be included. When the active energy ray-curable adhesive composition contains an acrylic oligomer obtained by polymerizing a non-polymerizable (meth) acrylic monomer, components of the adhesive composition interposed between the polarizer and the transparent protective film may be used. The uneven distribution is easy to progress, and a component gradient structure in which the concentration of the A component on the polarizer side is high is more easily obtained. For this reason, the adhesiveness and the water resistance of the adhesive layer with the polarizer and the transparent protective film are further enhanced, which is preferable. Furthermore, by containing an acrylic oligomer component in the active energy ray-curable adhesive composition, curing shrinkage when irradiating and curing the composition with active energy rays is reduced, and the adhesive, the polarizer and Interfacial stress with an adherend such as a transparent protective 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 more reliably obtain the component gradient structure of the cured product layer (adhesive layer), and to sufficiently suppress curing shrinkage, the total amount of the active energy ray-curable adhesive composition was set to 100% by weight. At this time, the content of the acrylic oligomer is preferably 5 to 30% by weight, more preferably 10 to 20% by weight.

  Since the active energy ray-curable adhesive composition preferably has a low viscosity in consideration of workability and uniformity during coating, an acrylic oligomer (A) obtained by polymerizing a (meth) acrylic monomer is used. Is also preferably low in viscosity. The acrylic oligomer having a low viscosity 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. On the other hand, the weight average molecular weight (Mw) of the acrylic oligomer (A) is preferably 500 or more in order to further promote the uneven distribution of the components of the adhesive composition interposed between the polarizer and the transparent protective film, It is more preferably at least 1,000, particularly preferably at least 1500. Specific examples of the (meth) acrylic monomer constituting the acrylic oligomer (A) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, -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) acryl (Meth) acrylic acid (C1-20) alkyl esters such as methacrylate, 4-methyl-2-propylpentyl (meth) acrylate, N-octadecyl (meth) acrylate, and further, for example, cycloalkyl (meth) Acrylates (eg, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), aralkyl (meth) acrylates (eg, benzyl (meth) acrylate, etc.), polycyclic (meth) acrylates (eg, 2-isobornyl (meth) Acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, etc., hydroxyl group-containing (meth) Acrylic esters (for example, Droxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (meth) methacrylate, etc., and alkoxy or phenoxy group-containing (meth) acrylic esters (2-methoxyethyl ( (Meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, etc.), epoxy Group-containing (meth) acrylates (eg, glycidyl (meth) acrylate), halogen-containing (meth) acrylates (eg, 2,2,2-trifluoroethyl (meth) acrylate, 2,2 , 2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, etc.), alkylaminoalkyl (Meth) acrylate (for example, dimethylaminoethyl (meth) acrylate and the like) and the like. These (meth) acrylates can be used alone or in combination of two or more. Specific examples of the acrylic oligomer (A) include "ARUFON" manufactured by Toagosei Co., Ltd., "ACTFLOW" manufactured by Soken Chemical Co., Ltd., and "JONCRYL" manufactured by BASF Japan.

  When the acrylic oligomer (A) is a liquid, it is preferably used because there is no need to consider the solubility in the adhesive composition. The acrylic oligomer (A) is usually a liquid when the glass transition temperature (Tg) is less than 25 ° C. Further, in order to achieve both compatibility with the adhesive composition and uneven distribution of components in the adhesive layer, the acrylic oligomer (A) preferably contains a polar functional group. Examples of the polar functional group include a hydroxyl group, an epoxy group, a carboxyl group, and an alkoxysilyl group. Specifically, for example, the "ARUFON UH series", the "ARUFOON UC series", the "ARUFON UF series", the "ARUFON UG series", the "ARUFON US series" (all manufactured by Toagosei Co., Ltd.) and the like can be mentioned. Above all, it is preferable to contain an epoxy group since an improvement in adhesion due to interaction with the polarizer is expected. Specifically, for example, "ARUFON UG-4000" and "ARUFON UG-4010" (both manufactured by Toagosei Co., Ltd.) can be mentioned.

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

（ただし、Ｌ^＋は、任意のオニウムカチオンを表す。また、Ｘ⁻は、ＰＦ６_６ ⁻、ＳｂＦ_６ ⁻、ＡｓＦ_６ ⁻、ＳｂＣｌ_６ ⁻、ＢｉＣｌ_５ ⁻、ＳｎＣｌ_６ ⁻、ＣｌＯ_４ ⁻、ジチオカルバメートアニオン、ＳＣＮ−よりからなる群より選択されるカウンターアニオンを表す。） General formula (3)

(However, ^{L +} represents any onium cation addition, X ^{-. _{Is, PF6 6 -, SbF 6 -}} , AsF 6 -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 -, dithiocarbamate Represents a counter anion selected from the group consisting of an anion and SCN-.)

Among the above-mentioned exemplary 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 preferred onium salts that constitute the photoacid generator usable in the present invention include “Siracure UVI-6992” and “Siracure UVI-6974” (both manufactured by Dow Chemical Japan Co., Ltd.). "Adeka Optomer SP150", "Adeka Optomer SP152", "Adeka Optomer SP170", "Adeka Optomer SP172" (all manufactured by ADEKA Corporation), "IRGACURE250" (manufactured by Ciba Specialty Chemicals), " CI-5102 "," CI-2855 "(all manufactured by Nippon Soda Co., Ltd.)," San Aid SI-60L "," San Aid SI-80L "," San Aid SI-100L "," San Aid SI-110L "," Sun Aid SI " -180L "(above, manufactured by Sanshin Chemical Co., Ltd.)," CPI-100 "," CPI-100A "(all manufactured by San Apro Corporation)," WPI-069 "," WPI-113 "," WPI-116 "," WPI-041 "," WPI-044 "," WPI-054 ". , "WPI-055", "WPAG-281", "WPAG-567", "WPAG-596" (all manufactured by Wako Pure Chemical Industries, Ltd.) are preferred specific examples of the photoacid generator of the present invention.

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

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

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

  Examples of the polymer having one or more epoxy groups in a molecule include an epoxy resin, a bisphenol A epoxy resin derived from bisphenol A and epichlorohydrin, and a bisphenol F epoxy resin derived from bisphenol F and epichlorohydrin. Resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, alicyclic epoxy resin, diphenyl ether type epoxy resin, hydroquinone type epoxy resin, Polyfunctional epoxy resins such as naphthalene epoxy resin, biphenyl epoxy resin, fluorene epoxy resin, trifunctional epoxy resin and tetrafunctional epoxy resin, There are ricidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, aliphatic chain type epoxy resin, etc., and these epoxy resins may be halogenated and hydrogenated. May be. Examples of commercially available epoxy resin products include JER Coat 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, YX4000 manufactured by Japan Epoxy Resin Co., Ltd., and Epicron manufactured by DIC Corporation. 830, EXA835LV, HP4032D, HP820, EP4100 series, EP4000 series, EPU series manufactured by ADEKA Corporation, Celoxide series (2021, 2021P, 2083, 2085, 3000, etc.) manufactured by Daicel Chemical Industries, Ltd., Epolide series, EHPE Series, Nippon Steel Chemical's YD series, YDF series, YDCN series, YDB series, phenoxy resin (polyphenol synthesized from bisphenols and epichlorohydrin) B carboxymethyl having an epoxy group at both ends with polyether; YP series, etc.), Nagase ChemteX Corporation of Denacol series manufactured by Kyoeisha but Chemical Co. Epo light series, and the like are not limited thereto. These epoxy resins may be used in combination of two or more.

(Compound and polymer having alkoxyl group)
The compound having an alkoxyl group in the molecule is not particularly limited as long as it has one or more alkoxyl groups in the molecule, and known compounds can be used. Representative examples of such a compound include a melamine compound, an amino resin, and a silane coupling agent.

  The compounding amount of the compound containing 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. In some cases, the impact resistance to the drop test may be deteriorated. The content of the compound 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 at least 2 parts by weight of the compound, more preferably at least 5 parts by weight.

<Silane coupling agent>
When the curable adhesive for a polarizing film of the present invention is an active energy ray-curable type, the silane coupling agent preferably uses an active energy ray-curable compound. The same water resistance can be imparted even without it.

  Specific examples of the silane coupling agent include, as active energy ray-curable compounds, vinyl trichlorosilane, vinyl trimethoxysilane, vinyl triethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, and 3-glycidyl. Xypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxy Examples include silane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.

  Preferably, they are 3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane.

  As a specific example of the silane coupling agent that is not active energy ray-curable, a silane coupling agent having an amino group (D1) 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) Minopropyltrimethoxysilane, 3- (N-ethylamino) -2-methylpropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane , N-benzyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, N-phenylaminomethyl Amino group-containing silanes such as trimethoxysilane, (2-aminoethyl) aminomethyltrimethoxysilane, N, N'-bis [3- (trimethoxysilyl) propyl] ethylenediamine; N- (1,3-dimethylbutyi) Reden)- - it can be exemplified (triethoxysilyl) -1-propane ketimines type silanes such as amines.

  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. Among these, in order to ensure good adhesiveness, γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane Γ- (2-aminoethyl) aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropylmethyldiethoxysilane, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl)- 1-propanamine is preferred.

  The compounding amount of the silane coupling agent is preferably in the range of 0.01 to 20 parts by weight, more preferably 0.05 to 15 parts by weight, and preferably 0.1 to 15 parts by weight, based on 100 parts by weight of the total amount of the curable component. More preferably, it is 10 parts by weight. When the amount is more than 20 parts by weight, the storage stability of the adhesive is deteriorated. When the amount is less than 0.1 part by weight, the effect of water-resistant adhesiveness is not sufficiently exhibited.

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

<Compound having a vinyl ether group>
It is preferable that the curable adhesive composition for a polarizing film of the present invention contains a compound having a vinyl ether group, since the water resistance of the adhesive between the polarizer and the adhesive layer is improved. It is not clear why such an effect is obtained, but one of the reasons is that the vinyl ether group of the compound having a vinyl ether group interacts with the polarizer, thereby increasing the adhesive force between the polarizer and the adhesive layer. It is speculated that there is. In order to further increase the adhesive water resistance between the polarizer and the adhesive layer, the compound having a vinyl ether group is preferably a radical polymerizable compound having a vinyl ether group. The content of the compound having a vinyl ether group is preferably 0.1 to 19 parts by weight based on 100 parts by weight of the total amount of the curable component.

<Keto-enol tautomeric compound>
The curable adhesive composition for a polarizing film of the present invention may contain a compound capable of causing keto-enol tautomerism. For example, in an adhesive composition containing a cross-linking agent or an adhesive composition that can be used by blending a cross-linking agent, an embodiment containing the compound that produces the keto-enol tautomerism can be preferably adopted. This can suppress an excessive increase in viscosity and gelation of the adhesive composition after the organometallic compound is compounded, and suppress the generation of a microgel, thereby achieving an effect of extending the pot life of the composition.

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

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

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

  The amount of the above additives 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.

<Adhesive viscosity>
The active energy ray-curable adhesive composition used in 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. preferable. On the other hand, when the curable adhesive for a polarizing film of the present invention exceeds 100 cp at 25 ° C., the temperature of the adhesive can be controlled at the time of coating to be adjusted to 100 cp or less. A more preferred range of viscosity is 1-80 cp, most preferably 10-50 cp. The viscosity can be measured using an E-type viscometer TVE22LT manufactured by Toki Sangyo Co., Ltd.

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

  The polarizing film according to the present invention is obtained by laminating a transparent protective film on at least one surface of a polarizer via an adhesive layer, and the adhesive layer has a high concentration of the A component on the polarizer side. It is characteristic. The concentration distribution in the thickness direction of the adhesive layer can be analyzed, for example, by alternately repeating etching using cluster ions and TOF-SIMS measurement. Specifically, it is possible to select components secondary to the thickness direction by selecting secondary ions specific to each component of the adhesive composition and comparing the intensity ratio of the secondary ions in the thickness direction. it can. In the evaluation, the ratio of the A component at the polarizer-side interface of the adhesive layer is calculated when the ratio of the A component having a log Pow of −1 to 1 at the center of the adhesive layer in the thickness direction is set to 1. When the ratio of the A component at the interface of the adhesive layer on the polarizer side is greater than 1, it means that the concentration of the A component on the polarizer side of the adhesive layer is high. The ratio of the component A at the polarizer-side interface is preferably 1.05 or more, more preferably 1.10 or more, and most preferably 1.20 or more.

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

  Further, the active energy ray-curable adhesive composition is preferably selected such that the Tg of the adhesive layer formed thereby is 60 ° C. or higher, more preferably 70 ° C. or higher, Is preferably 75 ° C. or more, more preferably 100 ° C. or more, and further preferably 120 ° C. or more. On the other hand, if the Tg of the adhesive layer is too high, the flexibility of the polarizing film is reduced. Therefore, the Tg of the adhesive layer is preferably 300 ° C or lower, more preferably 240 ° C or lower, further preferably 180 ° C or lower. Tg (glass transition temperature) is measured using a dynamic viscoelasticity measuring device RSAIII manufactured by TA Instruments under the following measurement conditions.

Sample size: width 10mm, length 30mm,
Clamp distance 20mm,
Measurement mode: tension, frequency: 1 Hz, heating rate: 5 ° C./min. Dynamic viscoelasticity was measured and adopted as the peak top temperature Tg of tan δ.

Further, the active energy ray-curable adhesive composition is preferably designed so that the storage elastic modulus of the adhesive layer formed thereby becomes 1.0 × 10 ⁶ Pa or more in a region of 70 ° C. or less. . More preferably, the pressure is 1.0 × 10 ⁷ Pa or more. The storage elastic modulus of the adhesive layer affects a polarizer crack when a heat cycle (such as -40 ° C to 80 ° C) is applied to the polarizing film. If the storage elastic modulus is low, a defect of the polarizer crack occurs. Cheap. The temperature range having a high storage modulus is more preferably 80 ° C or lower, most preferably 90 ° C or lower. The storage elastic modulus is measured simultaneously with Tg (glass transition temperature) under the same measurement conditions using a dynamic viscoelasticity measuring device RSAIII manufactured by TA Instruments. The dynamic viscoelasticity was measured, and the value of the storage elastic modulus (E ') was adopted.

  The polarizing film according to the present invention includes, for example, a coating step of coating an active energy ray-curable adhesive composition on at least one surface of a polarizer and a transparent protective film, and attaching the polarizer and the transparent protective film. The bonding step to be combined, the active energy ray is irradiated from the polarizer surface side or the transparent protective film surface side, via the adhesive layer obtained by curing the active energy ray-curable adhesive composition, polarized light And a bonding step of bonding the protective film and the transparent protective film.

  However, in the adhesive layer according to the present invention, in order to increase the concentration of the component A on the polarizer side, the active energy ray-curable adhesive composition after the coating step and before the bonding step. Is preferably adjusted to 15 to 40 ° C. The reason why setting of such temperature conditions is preferable is as follows.

  In the adhesive layer, in order to increase the concentration of the component A on the polarizer side, after the coating step, before the bonding step, that is, the adhesive composition is composed of the monomer components before the start of polymerization. At some stage, it is necessary to form a component gradient structure of the A component and the B component. In general, when the temperature of a composition containing two or more components is high, the components are likely to be compatible with each other, and as a result, it is difficult to obtain a component gradient structure. Therefore, in the method for producing a polarizing film according to the present invention, after the coating step and before the bonding step, by adjusting the temperature of the active energy ray-curable adhesive composition to 15 to 40 ° C., the A component And the B component are not completely compatible with each other, and as a result, a component gradient structure of the A component and the B component is easily formed. In order to more reliably form the component gradient structure of the component A and the component B, the temperature of the active energy ray-curable adhesive composition is adjusted to 20 to 35 ° C. after the coating step and before the bonding step. Is more preferably adjusted to 23 to 32 ° C.

  In addition, as a method of setting the temperature of the active energy ray-curable adhesive composition within the above range, for example, a method of setting the ambient temperature at the time of performing each step within the above range may be mentioned.

  Further, the polarizing film according to the present invention is a method for manufacturing a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizer via an adhesive layer, wherein the adhesive layer is An active energy ray-curable adhesive composition is formed by a cured product layer obtained by irradiating an active energy ray to the active energy ray-curable adhesive composition. In the first application step of applying the first active energy ray-curable adhesive composition containing the component A which is -1 to 1, the log Pow is 2 to 7 on the bonding surface of the transparent protective film. A second application step of applying a second active energy ray-curable adhesive composition containing the B component, a bonding step of bonding the polarizer and the transparent protective film, and the polarizer surface side or the Transparency By irradiating active energy rays from the film surface side and bonding the polarizer and the transparent protective film through the adhesive layer obtained by curing the active energy ray-curable adhesive composition And a method of manufacturing a polarizing film, wherein the adhesive layer formed after the bonding step has a high concentration of the component A on the polarizer side.

  In the production method, a first active energy ray-curable adhesive composition containing an A component having a log Pow of -1 to 1 representing an octanol / water partition coefficient is applied to a bonding surface of a polarizer. A coating step, and a second coating step of coating a second active energy ray-curable adhesive composition containing a B component having a log Pow of 2 to 7 on the bonding surface of the transparent protective film. . Thereby, the adhesive layer formed after the bonding step can further increase the concentration of the component A on the polarizer side, and can further improve the component gradient structure such that the concentration of the component A on the polarizer side increases. You will definitely have it. In order to more reliably form such a component gradient structure, when the total amount of the first active energy ray-curable adhesive composition applied to the bonding surface of the polarizer is 100% by weight, log Pow is −1 to 1%. The content of the component A, which is 1, is preferably 50 to 95% by weight, more preferably 60 to 80% by weight. Similarly, when the total amount of the second active energy ray-curable adhesive composition applied to the bonding surface of the transparent protective film is 100% by weight, the content of the B component having a log Pow of 2 to 7 is 50%. The content is preferably from 95 to 95% by weight, more preferably from 60 to 80% by weight. Further, the ratio between the first active energy ray-curable adhesive composition and the second active energy ray-curable adhesive composition is preferably 5:95 to 50:50 as a ratio of the respective applied thicknesses. , And more preferably 10:90 to 40:60.

  In the method for producing a polarizing film according to the present invention, the polarizer and the transparent protective film may be subjected to a surface modification treatment before applying the active energy ray-curable adhesive composition. Specific treatments include corona treatment, plasma treatment, and saponification treatment.

  The method of applying the active energy ray-curable adhesive composition is appropriately selected depending on the viscosity of the composition and the desired thickness. Examples of the coating method include, for example, 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 active energy ray-curable adhesive composition applied as described above. The bonding of the polarizer and the transparent protective film can be performed using a roll laminator or the like.

  It is preferable that the active energy ray-curable adhesive composition contains at least one organic metal compound selected from the group consisting of metal alkoxides and metal chelates. Further, it is preferable that the first active energy ray-curable adhesive composition contains the organometallic compound. Preferably, the metal of the organometallic compound contained in the active energy ray-curable adhesive composition is titanium.

  The active energy ray-curable adhesive composition preferably contains the metal alkoxide as the organometallic compound, and the organic group of the metal alkoxide has 6 or more carbon atoms. It is preferable that the agent composition contains the metal chelate as the organometallic compound, and the organic group of the metal chelate has 4 or more carbon atoms.

The adhesive layer obtained by curing the active energy ray-curable adhesive composition preferably has a storage elastic modulus at 25 ° C. of 1.0 × 10 ⁷ Pa or more.

<Curing of adhesive>
The active energy ray-curable adhesive composition used in the present invention can be used in an electron beam-curable, ultraviolet-curable, or visible light-curable mode. As the active energy ray-curable adhesive composition, a visible light-curable adhesive composition is preferable from the viewpoint of productivity.

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

  In the electron beam curing type, any appropriate condition can be adopted as the irradiation condition of the electron beam as long as the active energy beam curing type adhesive composition can be cured. For example, the electron beam irradiation preferably has an acceleration voltage of 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the accelerating voltage is less than 5 kV, the electron beam may not reach the adhesive and may be insufficiently cured. 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. Can not.

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

  In the method for producing a polarizing film according to the present invention, as the active energy rays, those containing visible light having a wavelength range of 380 nm to 450 nm, particularly those having the largest irradiation amount of visible light having a wavelength range of 380 nm to 450 nm are used. Is preferred. In the case of using a UV-curable or visible-ray-curable transparent protective film (UV-transparent transparent protective film) having an ultraviolet absorbing ability, it absorbs light having a wavelength shorter than 380 nm. Light does not reach the active energy ray-curable adhesive and does not contribute to its polymerization reaction. Furthermore, 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 employing the ultraviolet curing type or the visible light curing type in the present invention, it is preferable to use a device which does not emit light having a wavelength shorter than 380 nm as the active energy ray generator, and more specifically, a wavelength range of 380. The ratio between the integrated illuminance of 440 nm and the integrated illuminance of the wavelength range of 250 to 370 nm is preferably 100: 0 to 100: 50, and more preferably 100: 0 to 100: 40. As the active energy ray according to the present invention, a gallium-filled metal halide lamp and an LED light source that emits light in a wavelength range of 380 to 440 nm are preferable. Or UV light such as low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, incandescent lamp, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excimer laser or sunlight A light source containing visible light can be used, and ultraviolet light having a wavelength shorter than 380 nm can be cut off using a bandpass filter. In order to prevent the curling of the polarizing film while improving the adhesive performance of the adhesive layer between the polarizer and the transparent protective film, a gallium-sealed metal halide lamp can be used, and light having a wavelength shorter than 380 nm can be blocked. It is preferable to use an active energy ray obtained through a band-pass filter or an active energy ray having a wavelength of 405 nm obtained using an LED light source.

  In the ultraviolet-curing type or the visible light-curing type, it is also preferable to heat the active energy ray-curable adhesive after irradiation with ultraviolet light or visible light (heating after irradiation), and in that case, it is preferable to heat the adhesive to 40 ° C. or higher. More preferably, the temperature is raised to 50 ° C. or higher.

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

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

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

  After bonding the polarizer and the transparent protective film, an active energy ray (electron beam, ultraviolet ray, visible light, etc.) is irradiated to cure the active energy ray-curable adhesive to form an adhesive layer. The water content of the polarizer when the polarizer and the transparent protective film are bonded to each other is usually 1% or more, preferably 3% or more, and more preferably 5% or more. When the water content of the polarizer is too high, the moisture in the polarizer moves to the adhesive layer after bonding, and the B component having a log POW of 2 to 7 in the adhesive composition undergoes layer separation, resulting in poor appearance. Undesirably. The water content of the polarizer is preferably 18% or less, more preferably 15% or less, and most preferably 12% or less. The moisture content of the polarizer was determined by cutting out a sample of 180 mm × 500 mm from the obtained polarizer and measuring the initial weight (W (g)). After the sample was left in a dryer at 120 ° C. for 6 hours, the weight (D (g)) after drying was measured. From these measured values, the moisture content was determined by the following equation. Moisture percentage (%) = {(WD) / W} × 100 The irradiation direction of the active energy ray (electron beam, ultraviolet ray, visible light, etc.) can be applied from any appropriate direction. Preferably, irradiation is performed from the transparent protective film side. When irradiated from the side of the polarizer, the polarizer may be degraded by active energy rays (such as electron beams, ultraviolet rays, and visible rays).

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

  In the polarizing film of the present invention, the polarizer and the transparent protective film are bonded via an adhesive layer formed by a cured layer of the active energy ray-curable adhesive. An easy-adhesion layer can be provided between the agent layers. The easy-adhesion layer can be formed of, for example, various resins having a polyester skeleton, polyether skeleton, polycarbonate skeleton, polyurethane skeleton, silicone, polyamide skeleton, polyimide skeleton, polyvinyl alcohol skeleton, and the like. These polymer resins can be used alone or in combination of two or more. Further, other additives may be added for forming the easy-adhesion layer. Specifically, stabilizers such as tackifiers, ultraviolet absorbers, antioxidants, and heat stabilizers may be used.

  The easy-adhesion layer is usually provided in advance on the transparent protection film, and the easy-adhesion layer side of the transparent protection film and the polarizer are bonded to each other with an adhesive layer. The easy-adhesion layer is formed by applying and drying a material for forming the easy-adhesion layer on a transparent protective film by a known technique. The material for forming the easily adhesive layer is usually adjusted as a solution diluted to an appropriate concentration in consideration of the thickness after drying, the smoothness of coating, and the like. The thickness of the easy-adhesion layer after drying is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and still more preferably 0.05 to 1 μm. In addition, although a plurality of easy-adhesion layers can be provided, it is preferable that the total thickness of the easy-adhesion layers be in the above range also in this case.

<Polarizer>
The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include, for example, a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, and two colors such as iodine and a dichroic dye. And uniaxially stretched by adsorbing a hydrophilic material, or a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Among these, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is 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 the dye can be produced by, for example, dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching the film to 3 to 7 times its original length. If necessary, it can be immersed in an aqueous solution of boric acid or potassium iodide. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, dirt on the surface of the polyvinyl alcohol-based film and an anti-blocking agent can be washed, and by swelling the polyvinyl alcohol-based film, the effect of preventing unevenness such as uneven dyeing can be obtained. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. Stretching can be performed in an aqueous solution of boric acid or potassium iodide or in a water bath.

  When the active energy ray-curable adhesive composition used in the present invention uses a thin polarizer having a thickness of 10 μm or less as a polarizer, the effect (optical durability in a severe environment under high temperature and high humidity) is obtained. Is satisfied) can be remarkably expressed. The 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 a high-temperature and high-humidity environment. The drop is easy to occur. That is, when the polarizer having a thickness of 10 μm or less is laminated with the adhesive layer of the present invention, the movement of water to the polarizer in a severe high-temperature and high-humidity environment is suppressed, thereby increasing the transmittance of the polarizing film. Deterioration of optical durability such as a decrease in the degree of polarization can be significantly suppressed. The thickness of the polarizer is preferably 1 to 7 μm from the viewpoint of thinning. It is preferable that such a thin polarizer has less thickness unevenness, is excellent in visibility, has little dimensional change, and can be made thinner as a polarizing film.

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

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

  The thin, high-performance polarizing film described in the specification of PCT / JP2010 / 001460 is a thin film having a thickness of 7 μm or less made of a PVA-based resin in which a dichroic substance is oriented, which is formed integrally with a resin base material. A high-performance polarizing film having optical characteristics such that the single transmittance is 42.0% or more and the degree of polarization is 99.95% or more.

  The thin high-performance polarizing film forms a PVA-based resin layer by coating and drying a PVA-based resin on a resin base material having a thickness of at least 20 μm, and the generated PVA-based resin layer is stained with a dichroic dye. The PVA-based resin layer is adsorbed with a dichroic substance, and the PVA-based resin layer adsorbed with the dichroic substance is combined with the resin substrate in a boric acid aqueous solution to obtain a total stretching ratio of the original length. It can be manufactured by stretching so as to be 5 times or more of the following.

  Also, a method for producing a laminated film including a thin high-performance polarizing film in which dichroic substances are oriented, comprising a resin substrate having a thickness of at least 20 μm and a PVA-based resin on one surface of the resin substrate A step of producing a laminate film including a PVA-based resin layer formed by applying and drying an aqueous solution, and the laminate including a resin base material and a PVA-based resin layer formed on one surface of the resin base material A step of adsorbing the dichroic substance on the PVA-based resin layer contained in the laminated film by immersing the film in a dyeing solution containing the dichroic substance; and a step of adsorbing the dichroic substance on the PVA-based resin. Stretching the laminated film including a layer in a boric acid aqueous solution so that the total stretching ratio is at least 5 times the original length; and forming a PVA-based resin layer on which a dichroic substance is adsorbed by a resin substrate. Stretch together with As a result, a thickness of 7 μm or less, a single transmittance of 42.0% or more, and a degree of polarization of 99.95% or more consisting of a PVA-based resin layer in which a dichroic substance is oriented on one surface of the resin substrate. By including the step of manufacturing a laminated film in which a thin high-performance polarizing film having the above optical characteristics is formed, the thin high-performance polarizing film can be manufactured.

The thin polarizing film disclosed in the above-mentioned Japanese Patent Application No. 2010-269002 or Japanese Patent Application No. 2010-263692 is a continuous web polarizing film made of a PVA-based resin in which a dichroic substance is oriented, and has an amorphous property. The laminate including the PVA-based resin layer formed on the ester-based thermoplastic resin base material was stretched in a two-stage stretching process including auxiliary stretching in air and stretching in boric acid in water to have a thickness of 10 μm or less. Things. When such a thin polarizing film has a single transmittance of T and a polarization degree of P, P>-(10 ^{0.929T-42.4-1} ) × 100 (where T <42.3) and P ≧ It is preferable to have optical characteristics satisfying the condition of 99.9 (where T ≧ 42.3).

  Specifically, the thin polarizing film is formed by stretching a PVA-based resin layer formed on an amorphous ester-based thermoplastic resin substrate of a continuous web in the air at a high temperature in the air. A step of producing a product, and a coloring intermediate formed by a PVA-based resin layer in which a dichroic substance (preferably iodine or a mixture of iodine and an organic dye) is oriented by adsorbing the dichroic substance on the stretched intermediate product A thin polarizing film comprising a step of forming a polarizing film having a thickness of 10 μm or less made of a PVA-based resin layer in which a dichroic substance is oriented by stretching a colored intermediate product in boric acid in water. It can be manufactured by a manufacturing method.

  In this manufacturing method, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin base material by the high-temperature stretching in air and the stretching in boric acid in water is set to be 5 times or more. desirable. The liquid temperature of the boric acid aqueous solution for drawing in boric acid in water can be 60 ° C. or higher. Before stretching the colored intermediate product in an aqueous boric acid solution, it is desirable to perform an insolubilization treatment on the colored intermediate product. In this case, the colored intermediate product is added to an aqueous boric acid solution having a liquid temperature not exceeding 40 ° C. Is desirably carried out by immersion. The amorphous ester-based thermoplastic resin base material is an amorphous polyethylene containing copolymerized polyethylene terephthalate obtained by copolymerizing isophthalic acid, copolymerized polyethylene terephthalate obtained by copolymerizing cyclohexanedimethanol, or another copolymerized polyethylene terephthalate. It can be terephthalate and is preferably made of a transparent resin, and its thickness can be at least seven times the thickness of the PVA-based resin layer to be formed. Further, the stretching ratio of the high-temperature aerial stretching is preferably 3.5 times or less, and the stretching temperature of the high-temperature aerial stretching is preferably equal to or higher than the glass transition temperature of the PVA-based resin, specifically, in the range of 95 ° C to 150 ° C. When performing high-temperature stretching in the air by free-end uniaxial stretching, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin base material is preferably 5 times or more and 7.5 times or less. . Further, when the high-temperature stretching in the air is performed by fixed-end uniaxial stretching, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin base material is 5 times or more and 8.5 times or less. Is preferred.

  More specifically, a thin polarizing film can be manufactured by the following method.

  A continuous web substrate of isophthalic acid copolymerized polyethylene terephthalate (amorphous PET) obtained by copolymerizing isophthalic acid at 6 mol% is prepared. The glass transition temperature of amorphous PET is 75 ° C. A laminate composed of a continuous web amorphous PET substrate and a polyvinyl alcohol (PVA) layer is prepared as follows. Incidentally, the glass transition temperature of PVA is 80 ° C.

  An amorphous PET substrate having a thickness of 200 μm and a 4-5% aqueous PVA solution prepared by dissolving PVA powder having a degree of polymerization of 1000 or more and a degree of saponification of 99% or more in water are prepared. Next, a PVA aqueous solution is applied to an amorphous PET substrate having a thickness of 200 μm and dried at a temperature of 50 to 60 ° C. to obtain a laminate in which a 7 μm thick PVA layer is formed on the amorphous PET substrate. .

  A 3 μm-thick thin high-performance polarizing film is manufactured from the laminate including a 7 μm-thick PVA layer through the following steps including a two-stage stretching step of an air-assisted stretching and a boric acid aqueous stretching. In the first-stage auxiliary aerial stretching step, the laminate including the 7 μm-thick PVA layer is integrally stretched with the amorphous PET substrate to produce a stretched laminate including the 5 μm-thick PVA layer. Specifically, this stretched laminate is subjected to a stretching device provided in an oven set to a stretching temperature environment of 130 ° C., with a laminate including a 7 μm-thick PVA layer, so that the stretching ratio becomes 1.8 times. At the free end uniaxially. By this stretching treatment, the PVA layer included in the stretched laminate is changed into a 5 μm-thick PVA layer in which PVA molecules are oriented.

  Next, by a dyeing process, a colored laminate in which iodine is adsorbed on a 5 μm-thick PVA layer in which PVA molecules are oriented is generated. Specifically, this colored laminate is prepared by applying the stretched laminate to a dye solution containing iodine and potassium iodide at a liquid temperature of 30 ° C. by passing the single transmittance of the PVA layer constituting the high-performance polarizing film finally produced. The iodine is adsorbed on the PVA layer contained in the stretched laminate by immersing it for an arbitrary time so that the ratio becomes 40 to 44%. In this step, the dyeing solution is adjusted to have an iodine concentration of 0.12 to 0.30% by weight and a potassium iodide concentration of 0.7 to 2.1% by weight using water as a solvent. The ratio between the concentrations of iodine and potassium iodide is 1: 7. Incidentally, potassium iodide is required to dissolve iodine in water. More specifically, the stretched laminate is immersed in a dyeing solution having an iodine concentration of 0.30% by weight and a potassium iodide concentration of 2.1% by weight for 60 seconds, so that a 5 μm-thick PVA layer in which PVA molecules are oriented is provided with iodine. To produce a colored laminate to which is adsorbed.

  Further, the colored laminate is further stretched integrally with the amorphous PET substrate by the second stage of boric acid in water stretching process to produce a 3 μm thick optical film laminate including a PVA layer constituting a highly functional polarizing film. I do. Specifically, this optical film laminate is subjected to a stretching apparatus provided with a processing apparatus set in a boric acid aqueous solution having a liquid temperature range of 60 to 85 ° C. containing boric acid and potassium iodide, and stretching the colored laminate. The film is uniaxially stretched at the free end so that the magnification becomes 3.3 times. More specifically, the liquid temperature of the boric acid aqueous solution is 65 ° C. It also has a boric acid content of 4 parts by weight for 100 parts by weight of water and a potassium iodide content of 5 parts by weight for 100 parts by weight of water. In this step, the colored laminate having the adjusted iodine adsorption amount is first immersed in a boric acid aqueous solution for 5 to 10 seconds. Thereafter, the colored laminate is passed as it is between a plurality of sets of rolls having different peripheral speeds, which are stretching devices provided in a processing device, and freely stretched to have a stretching ratio of 3.3 times in 30 to 90 seconds. Stretch uniaxially. By this stretching treatment, the PVA layer contained in the colored laminate is changed into a 3 μm thick PVA layer in which the adsorbed iodine is unidirectionally oriented as a polyiodide ion complex in one direction. This PVA layer constitutes a high-performance polarizing film of the optical film laminate.

  Although not an essential step in the production of the optical film laminate, the optical film laminate was removed from the aqueous boric acid solution by a washing step and adhered to the surface of the 3 μm-thick PVA layer formed on the amorphous PET substrate. Preferably, boric acid is washed with an aqueous solution of potassium iodide. Thereafter, the washed optical film laminate is dried by a drying process using hot air at 60 ° C. The washing step is a step for eliminating appearance defects such as boric acid precipitation.

Similarly, it is not an essential step for the production of an optical film laminate, but an adhesive is applied to the surface of a 3 μm thick PVA layer formed on an amorphous PET substrate by a bonding and / or transfer step. While laminating an 80 μm-thick triacetyl cellulose film, the amorphous PET substrate can be peeled off, and the 3 μm-thick PVA layer can be transferred to the 80 μm-thick triacetyl cellulose film.
[Other steps]
The above method for producing a thin polarizing film may include other steps in addition to the above steps. Other steps include, for example, an insolubilization step, a cross-linking step, a drying (adjustment of moisture content) step, and the like. Other steps can be performed at any appropriate timing.

  The insolubilization step is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution. By performing the insolubilization treatment, water resistance can be imparted to the PVA-based resin layer. The concentration of the boric acid aqueous solution is preferably 1 part by weight to 4 parts by weight based on 100 parts by weight of water. The liquid temperature of the insolubilizing bath (boric acid aqueous solution) is preferably from 20C to 50C. Preferably, the insolubilization step is performed after the production of the laminate and before the dyeing step or the underwater stretching step.

  The cross-linking step is typically performed by immersing the PVA-based resin layer in a boric acid aqueous solution. By performing the cross-linking treatment, water resistance can be imparted to the PVA-based resin layer. The concentration of the boric acid aqueous solution is preferably 1 part by weight to 4 parts by weight based on 100 parts by weight of water. When the crosslinking step is performed after the above-mentioned dyeing step, it is preferable to further mix iodide. By blending iodide, elution of iodine adsorbed on the PVA-based resin layer can be suppressed. The amount of iodide is preferably 1 to 5 parts by weight based on 100 parts by weight of water. Specific examples of iodide are as described above. The liquid temperature of the crosslinking bath (boric acid aqueous solution) is preferably from 20C to 50C. Preferably, the cross-linking step is performed before the second boric acid aqueous stretching step. In a preferred embodiment, the dyeing step, the crosslinking step, and the second drawing step in boric acid in water are performed in this order.

<Transparent protective film>
As a material for forming the transparent protective film provided on one or both surfaces of the polarizer, a material having excellent transparency, mechanical strength, heat stability, moisture barrier properties, isotropy, and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; acrylic polymers such as polymethyl methacrylate; styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin) Polymers, polycarbonate polymers, and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, polyolefin-based polymers such as ethylene-propylene copolymer, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamide, imide-based polymers, and sulfone-based polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Blends of polymers and the like are also mentioned as examples of the polymer forming the transparent protective film. The transparent protective film may contain one or more optional appropriate additives. Examples of the additives include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by 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 inherent in the thermoplastic resin may not be sufficiently exhibited.

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

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

As the material for forming the transparent protective film provided on one or both surfaces of the polarizer, those having excellent transparency, mechanical strength, heat stability, moisture barrier properties, isotropy and the like are preferable, and particularly, the moisture permeability is 150 g. / ^m, more preferably not more 2 / 24h or less, particularly preferably those following 140 g ^/ m 2 / 24h, more preferably the following 120 g ^/ m 2 / 24h. The moisture permeability is determined by the method described in the examples.

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

  Although the thickness of the transparent protective film can be determined as appropriate, it is generally about 1 to 100 μm from the viewpoint of workability such as strength and handleability and thinness. Particularly, it is preferably 1 to 80 μm, more preferably 3 to 60 μm.

  When a transparent protective film is provided on both sides of the polarizer, a transparent protective film made of the same polymer material may be used on the front and back sides, or a transparent protective film made of a different polymer material may be used. Examples of the combination of the transparent protective film include a polyethylene terephthalate film and a cyclic polyolefin resin film, a (meth) acrylic resin film and a cyclic polyolefin resin film, and a combination of a (meth) acrylic resin film and a (meth) acrylic resin film. It is preferable from the viewpoint of moisture permeability. By providing a transparent protective film having low moisture permeability on both surfaces of the polarizer, it is difficult for moisture to enter the polarizing film, and a polarizing film having particularly excellent water resistance can be obtained.

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

<Optical film>
The polarizing film of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited. For example, it is used for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including a wavelength plate such as や or や), a viewing angle compensation film, and the like. One or more optical layers that may be used may be used. In particular, a reflective polarizing film or a transflective polarizing film in which a polarizing plate or a transflective reflecting plate is further laminated on the polarizing film of the present invention, an elliptically polarizing film or a circularly polarized light in which a retardation plate is further laminated on a polarizing film A wide viewing angle polarizing film in which a viewing angle compensation film is further laminated on a film or a polarizing film, or a polarizing film in which a brightness enhancement film is further laminated on a polarizing film is preferable.

  An optical film obtained by laminating the above-mentioned optical layer on a polarizing film can also be formed by a method of sequentially laminating the optical film in a manufacturing process of a liquid crystal display device or the like. It is excellent in stability, assembling work, and the like, and has an advantage that a manufacturing process of a liquid crystal display device or the like can be improved. Appropriate bonding means such as an adhesive layer can be used for lamination. When bonding the above-mentioned polarizing film and other optical films, their optical axes can be arranged at an appropriate angle depending on the intended retardation characteristics and the like.

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

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

  A separator is temporarily attached to the exposed surface of the adhesive layer for the purpose of preventing contamination and the like until the adhesive layer is put to practical use and covered. Thus, it is possible to prevent the adhesive layer from coming into contact with the adhesive layer in a normal handling state. Except for the above thickness conditions, for example, a suitable thin leaf such as a plastic film, a rubber sheet, paper, cloth, nonwoven fabric, a net, a foamed sheet or a metal foil, or a laminate thereof may be used as a separator. Appropriate conventional ones, such as those coated with an appropriate release agent such as a chain alkyl type, fluorine type or molybdenum sulfide, may be used.

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

  A suitable liquid crystal display device such as a liquid crystal display device in which a polarizing film or an optical film is arranged on one or both sides of a liquid crystal cell, or a lighting system using a backlight or a reflector can be formed. In that case, the polarizing film or the optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When a polarizing film or an optical film is provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a suitable component such as 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 backlight, etc. Two or more layers can be arranged.

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

Production Example 1
<Preparation of polyvinyl alcohol-based polarizer X>
A 75 μm thick polyvinyl alcohol film having an average degree of polymerization of 2400 and a degree of saponification of 99.9 mol% was immersed in warm water at 30 ° C. for 60 seconds to swell. Next, the film was immersed in a 0.3% aqueous solution of iodine / potassium iodide (weight ratio = 0.5 / 8), and the film was dyed while being stretched to 3.5 times. Thereafter, the film was stretched in a boric acid ester aqueous solution at 65 ° C. so that the total stretching ratio became 6 times. After stretching, drying was performed in a 40 ° C. oven for 3 minutes to obtain a polyvinyl alcohol-based polarizer X (thickness: 23 μm).

Production Example 2
<Preparation of polyvinyl alcohol-based thin polarizer Y>
In order to produce a thin polarizer Y, first, a laminate in which a 24 μm-thick PVA layer was formed on an amorphous PET substrate was subjected to in-air auxiliary stretching at a stretching temperature of 130 ° C. to form a stretched laminate, A colored laminate is produced by dyeing the stretched laminate, and the colored laminate is further stretched integrally with an amorphous PET base material by stretching in water of boric acid at a stretching temperature of 65 ° C. so that the total stretching ratio becomes 5.94 times. An optical film laminate including the applied 10 μm thick PVA layer was produced. By such two-stage stretching, the PVA molecules of the PVA layer formed on the amorphous PET base material are highly oriented, and the iodine adsorbed by the dyeing is highly unidirectionally oriented as a polyiodide ion complex. An optical film laminate including a PVA layer having a thickness of 10 μm and constituting the polyvinyl alcohol-based thin polarizer Y was produced.

<Transparent protective film>
Transparent protective film A: 100 parts by weight of the imidized MS resin described in Production Example 1 of JP-A-2010-284840 and 0.62 parts by weight of a triazine-based ultraviolet absorber (trade name: T-712, manufactured by Adeka Corporation) The mixture was mixed at 220 ° C. using a twin-screw kneader to produce resin pellets. The obtained resin pellet was dried at 100.5 kPa and 100 ° C. for 12 hours, and extruded from a T-die at a die temperature of 270 ° C. with a single screw extruder to form a film (thickness: 160 μm). Further, the film is stretched in the transport direction in an atmosphere of 150 ° C. (thickness: 80 μm), and then an easy adhesive containing an aqueous urethane resin is applied, and then stretched in an atmosphere of 150 ° C. in a direction orthogonal to the film transport direction. to obtain a transparent protective film a having a thickness of 40 [mu] m (moisture permeability ^58g / m 2 / 24h).
Transparent protective film B: a cyclic polyolefin film having a thickness of 55 .mu.m: was used after subjected to a corona treatment (manufactured by Zeon Corporation ZEONOR, moisture permeability ^11g / m 2 / 24h).
Transparent protective film C: A film obtained by subjecting a bonding surface of a PET film having a thickness of 80 μm (manufactured by Toyobo Co., Ltd., moisture permeability 13 g / m ² / 24h) to an easy adhesion treatment using a urethane resin was used.

<Moisture permeability of transparent protective film>
The moisture permeability was measured according to the moisture permeability test (cup method) of JIS Z0208. A sample cut to a diameter of 60 mm was set in a moisture-permeable cup containing about 15 g of calcium chloride, and was heated at a temperature of 40 ° C. and a humidity of 90% RH. H. Was placed in a thermostat, and the weight increase of calcium chloride before and after standing for 24 hours was measured to determine the moisture permeability (g / m ² / 24h).

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

Examples 1 to 5 and Comparative Examples 1 and 2
(Preparation of active energy ray-curable adhesive composition)
According to the composition table shown in Table 1, each component was mixed and stirred at 50 ° C. for 1 hour to obtain active energy ray-curable adhesive compositions according to Examples 1 to 5 and Comparative Examples 1 and 2.

(Preparation of polarizing film)
An active energy ray-curable adhesive composition according to Examples 1 to 5 or Comparative Examples 1 and 2 was coated on the transparent protective film A, B or C with an MCD coater (manufactured by Fuji Machine Co., Ltd.) (cell shape: honeycomb, (Gravure roll line number: 1000 lines / inch, rotation speed 140% / line speed), and the thickness of the adhesive layer shown in Table 1 is applied. Transparent protective films were bonded on both sides with a roll machine. On the other hand, when the thin polarizer Y was used, a transparent protective film was bonded only to the surface opposite to the PVA layer using a roll machine. Then, from the side of the bonded transparent protective film (both sides in the case of using the polarizer X), the mixture was heated to 50 ° C. using an IR heater, and the visible light was applied to both sides to irradiate both sides. After the active energy ray-curable adhesive compositions according to Examples 1 and 2 were cured, they were dried with hot air at 70 ° C. for 3 minutes to obtain a polarizing film having a transparent protective film on both sides of the polarizer. The bonding line speed was 25 m / min.

  The following evaluation was performed about the polarizing film obtained by the said Example and the comparative example. Table 1 shows the evaluation results.

<Confirmation of the component gradient structure of the adhesive layer>
After mechanically cutting the transparent protective film to expose the adhesive layer, the thickness direction analysis of the adhesive layer was performed by alternately repeating etching using cluster ions and TOF-SIMS measurement. For TOF-SIMS, "TRIVTV" manufactured by ULVAC-PHI was used. By selecting secondary ions unique to each component and comparing the intensity ratios of the secondary ions in the thickness direction, components unevenly distributed in the thickness direction were identified. The evaluation was performed by calculating the ratio of the A component at the polarizer-side interface of the adhesive layer when the ratio of the A component having a log Pow of −1 to 1 at the center of the adhesive layer in the thickness direction was set to 1. Was. When the ratio of the component A at the interface of the adhesive layer on the polarizer side is larger than 1, it means that the concentration of the component A on the polarizer side of the adhesive layer is high. Table 1 shows the evaluation results.

<Temperature measurement of active energy ray-curable adhesive composition>
The surface of the transparent protective film to which the adhesive composition was applied was measured with a thermography “FLIR-E49001” manufactured by FLIR. Since the applied adhesive layer is very thin with respect to the transparent protective film, it can be estimated that the temperature of the adhesive composition becomes equivalent to that of the transparent protective film immediately after application.

<Adhesive strength>
The polarizing film obtained in each example was cut out into a size of 200 mm in a direction parallel to the stretching direction of the polarizer and 20 mm in a direction perpendicular thereto, and a cut was made between the transparent protective film and the polarizer with a cutter knife, and the polarizing film was made of glass. Pasted to the board. The transparent protective film and the polarizer were peeled off at a peeling speed of 500 mm / min in a 90 ° direction using Tensilon, and the peeling strength was measured. Further, the infrared absorption spectrum of the peeled surface after peeling was measured by the ATR method, and the peeling interface was evaluated based on the following criteria.
A: Cohesive failure of transparent protective film B: Interfacial peeling between transparent protective film / adhesive layer C: Interfacial peeling between adhesive layer / polarizer D: Cohesive failure of polarizer In the above criteria, A and D represent adhesive strength. Is greater than the cohesive strength of the film, which means that the adhesive strength is very excellent. On the other hand, B and C mean that the adhesive force at the interface between the transparent protective film and the adhesive layer (adhesive layer / polarizer) is insufficient (adhesive force is poor). Taking these into consideration, the adhesive strength in the case of A or D is evaluated as ○, AB (“cohesive failure of the transparent protective film” and “interfacial peeling between the transparent protective film / adhesive layer occur simultaneously”) or A The adhesive force in the case of C (“cohesive failure of the transparent protective film” and the “separation of the interface between the adhesive layer and the polarizer” occur simultaneously) is Δ, and the adhesive force in the case of B or C is ×. I do.

<Adhesive durability (hot water immersion test)>
The polarizing film obtained in each example was cut into a rectangle of 50 mm in the stretching direction of the polarizer and 25 mm in the vertical direction. After immersing the polarizing film in warm water at 60 ° C. for 6 hours, the peeled length was visually measured with a magnifying glass. The measurement was taken as the maximum value of the vertical distance from the cross section of the part where the peeling occurred (mm).

<Adhesive durability (water-peeling resistance)>
The polarizing film obtained in each example was cut into a size of 200 mm in parallel with the stretching direction of the polarizer and 20 mm in a direction perpendicular thereto. After the polarizing film was immersed in pure water at 23 ° C. for 24 hours, taken out of the pure water and wiped off with a dry cloth, a cut was made between the transparent protective film and the polarizer with a cutter knife, and the polarizing film was made of glass. Pasted to the board. From removal from pure water to evaluation was performed within one minute. Thereafter, the same evaluation as the above <Adhesive force> was performed.

In Table 1, the compounds used were
4HBA; 4-hydroxybutyl acrylate, logPow = 0.68, manufactured by Osaka Organic Chemical Industry,
HEAA: hydroxyethyl acrylamide, log Pow = -0.56, manufactured by Kojin Co.,
ACMO: acryloylmorpholine, logPow = 0.20, manufactured by Kojin,
Fancryl FA511AS; dicyclopentenyl acrylate, log Pow = 2.26, manufactured by Hitachi Chemical Co., Ltd.
Light acrylate DCP-A: tricyclodecane dimethanol diacrylate, logPow = 3.05, manufactured by Kyoeisha Chemical Co., Ltd.
Light acrylate 1,9ND-A: 1,9-nonanediol diacrylate, logPow = 3.68, manufactured by Kyoeisha Chemical Co.,
Fancryl FA-P324A: bisphenol A PO4 mole modified diacrylate, log Pow = 6.43, manufactured by Hitachi Chemical Co., Ltd.
Aronix M-220: tripropylene glycol diacrylate, log Pow = 1.68, manufactured by Toagosei Co., Ltd.
Aronix M-5700: 2-hydroxy-3-phenoxypropyl acrylate, logPow = 1.17, manufactured by Toagosei Co., Ltd.
ARUFON UG-4010: an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer, manufactured by Toagosei Co., Ltd.
Nicanol Y-1000: xylene resin, IRGACURE907 manufactured by Fudoh; 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, manufactured by BASF;
KAYACURE DETX-S; diethylthioxanthone, manufactured by Nippon Kayaku Co., Ltd.
IRGACURE 184; 1-hydroxycyclohexyl phenyl ketone, manufactured by BASF.

Example 6
An active energy ray-curable adhesive composition containing the following compounds was prepared.
First active energy ray-curable adhesive composition (liquid viscosity 10 mPa · s / 25 ° C.); HEAA 94% by weight, IRGACURE907 3% by weight, KAYACURE DETX-S
3% by weight
Second active energy ray-curable adhesive composition (liquid viscosity 350 mPa · s / 25 ° C.); 94% by weight of light acrylate 1,9ND-A, 3% by weight of IRGACURE907, 3% by weight of KAYACURE DETX-S

(Preparation of polarizing film)
The first active energy ray-curable adhesive composition was applied to the surface of the PVA layer of the thin polarizer Y (the thickness of the adhesive layer was 0.3 μm). Further, the second active energy ray-curable adhesive composition was applied to the bonding surface of the transparent protective film A (the thickness of the adhesive layer was 0.7 μm), and these were bonded by a roll machine. The ratio of the first active energy ray-curable adhesive composition to the second active energy ray-curable adhesive composition is 30:70. Then, from the side of the bonded transparent protective film, the mixture was heated to 50 ° C. using an IR heater, and the visible light was irradiated to both sides to cure the first and second active energy ray-curable adhesive compositions. Thereafter, the film was dried with hot air at 70 ° C. for 3 minutes to obtain a polarizing film having a transparent protective film on both sides of the polarizer. The bonding line speed was 25 m / min.

  The polarizing film obtained in Example 6 was evaluated for adhesive strength to the thin polarizer Y and the transparent protective film A. Further, the contact angle of the first active energy ray-curable adhesive composition to the thin polarizer Y and the contact angle of the second active energy ray-curable adhesive composition to the transparent protective film Y were evaluated. The evaluation of the contact angle was performed based on JIS-K6768. Table 2 shows the evaluation results.

<Storage modulus>
The storage elastic modulus was measured using a dynamic viscoelasticity measuring device RSAIII manufactured by TA Instruments under the following measurement conditions.
Sample size: width 10mm, length 30mm,
Clamp distance 20mm,
Measurement mode: tension, frequency: 1 Hz, heating rate: 5 ° C./min. Dynamic viscoelasticity was measured, and the measured value of the storage elastic modulus at 25 ° C. was used.

Examples 7 to 15 and Comparative Example 3
(Preparation of active energy ray-curable adhesive composition)
According to the composition table shown in Table 3, the respective components were mixed and stirred at 50 ° C. for 1 hour to obtain active energy ray-curable adhesive compositions according to Examples 7 to 15 and Comparative Example 3.

In Table 3, the compounds used are:
TPGDA: tripropylene glycol diacrylate, manufactured by Toagosei Co., Ltd. (Aronix M-220),
Metal alkoxides and metal chelates are
TC-750: ethyl acetoacetate chelate (carbon number of organic group: 6), manufactured by Matsumoto Fine Chemical Co .;
TC-100: titanium acetylacetonate (carbon number of organic group: 5), manufactured by Matsumoto Fine Chemical Co .;
TA-30: titanium octoxide (carbon number of organic group: 8), manufactured by Matsumoto Fine Chemical Co .;
D20: titanium butoxide (carbon number of organic group is 4), manufactured by Shin-Etsu Silicone Co .;
ZA65: zirconium butoxide (carbon number of the 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 Chemical Co .;
Vinyl ether compounds are
VEEA: 2- (2-vinyloxyethoxy) ethyl acrylate, manufactured by Nippon Shokubai Co., Ltd.,
The photoacid generator is
CPI-100P, manufactured by San Apro Co .;

Examples 16 to 19 and Comparative Examples 4 to 7
(Preparation of active energy ray-curable adhesive composition)
According to the composition table shown in Table 4, the respective components were mixed and stirred at 50 ° C. for 1 hour to obtain active energy ray-curable adhesive compositions according to Examples 16 to 19 and Comparative Examples 4 to 7.

In Table 4, the alkoxysilane group-containing compounds are:
TA polymer SA100S: Main chain (meth) acrylic polymer type, manufactured by Kaneka Corporation X-MAP SA110S: Main chain (meth) acrylic polymer type, manufactured by Kaneka Corporation X-40-9225: Oligomeric alkoxysilane group-containing compound, Shin-Etsu Silicone,
KR-213: oligomer type alkoxysilane group-containing compound, manufactured by Shin-Etsu Silicone Co., Ltd.
KC-89S: low molecular weight alkoxysilane group-containing compound, manufactured by Shin-Etsu Silicone Co., Ltd.
KBM403: low molecular weight alkoxysilane group-containing compound, manufactured by Shin-Etsu Silicone Co., Ltd.
Is shown.

Claims (13)

At least one surface of the polarizer, a polarizing film laminated with a transparent protective film via an adhesive layer,
The adhesive layer is an active energy ray-curable adhesive composition (however, an acid group-containing (meth) acrylate monomer in which a (meth) acryloyl group and an acid group are bonded via an organic group having 1 to 10 carbon atoms) Excluding an active energy ray-curable adhesive composition containing the same), which is formed by a cured product layer obtained by irradiating the composition with an active energy ray,
The active energy ray-curable adhesive composition contains an A component having a logPow representing an octanol / water partition coefficient of -1 to 1 and a B component having a logPow of 2 to 7;
A polarizing film, wherein the adhesive layer has a high concentration of the component A on the polarizer side.   The polarizing film according to claim 1, wherein the active energy ray-curable adhesive composition contains a (meth) acrylamide derivative as the component A.   The polarizing film according to claim 1, wherein the active energy ray-curable adhesive composition contains a polyfunctional (meth) acrylate as the B component.   The polarizing film according to any one of claims 1 to 3, wherein the active energy ray-curable adhesive composition contains an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer.   The polarizing film according to claim 1, wherein the active energy ray-curable adhesive composition contains a hydroxyl group-containing photopolymerization initiator.   The polarizing film according to any one of claims 1 to 5, wherein the active energy ray-curable adhesive composition contains at least one organic metal compound selected from the group consisting of metal alkoxides and metal chelates.   The polarizing film according to claim 6, wherein the metal of the organometallic compound contained in the active energy ray-curable adhesive composition is titanium.   8. The polarizing film according to claim 6, wherein the active energy ray-curable adhesive composition contains the metal alkoxide as the organometallic compound, and the metal group has 6 or more carbon atoms in an organic group. 9.   The polarizing film according to claim 6, wherein the active energy ray-curable adhesive composition contains the metal chelate as the organometallic compound, and the metal group has 4 or more carbon atoms in an organic group. 9.   The polarizing film according to any one of claims 1 to 9, further comprising an alkoxysilane group-containing compound having a viscosity of 15 mPa · s or more.   The polarizing film according to claim 10, wherein the main chain of the alkoxysilane group-containing compound has an acrylic polymer structure. The polarized light according to any one of claims 1 to 11, wherein the adhesive layer obtained by curing the active energy ray-curable adhesive composition has a storage elastic modulus at 25 ° C of 1.0 × 10 ⁷ Pa or more. the film. It is a manufacturing method of the polarizing film according to any one of claims 1 to 12,
A coating step of coating the active energy ray-curable adhesive composition on at least one surface of the polarizer and the transparent protective film,
A bonding step of bonding the polarizer and the transparent protective film,
By irradiating active energy rays from the polarizer surface side or the transparent protective film surface side, and curing the active energy ray-curable adhesive composition, the polarizer through the adhesive layer obtained And an adhesion step of adhering the transparent protective film,
A method for producing a polarizing film, wherein the temperature of the active energy ray-curable adhesive composition is adjusted to 15 to 40 ° C. after the coating step until the bonding step.

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