JP6931629B2 - Manufacturing method of laminated optical film - Google Patents

Description

The present invention relates to a method for producing a laminated optical film in which at least a first optical film and a second optical film are laminated via an adhesive layer formed by curing an active energy ray-curable adhesive composition. The laminated optical film can form an image display device such as a liquid crystal display (LCD), an organic EL display device, a CRT, or a PDP.

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

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

On the other hand, instead of the water-based adhesive, an active energy ray-curable adhesive has been proposed. 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).

Japanese Unexamined Patent Publication No. 2006-220732 Japanese Unexamined Patent Publication No. 2001-296427 Japanese Unexamined Patent Publication No. 2012-052000 Japanese Unexamined Patent Publication No. 2012-068593

The adhesive layer formed by using the active energy ray-curable adhesive described in Patent Documents 3 and 4 has a water resistance test for evaluating the presence or absence of color loss and peeling after being immersed in warm water at 60 ° C. for 6 hours, for example. , Can be cleared enough. However, in recent years, the adhesive for laminated optical films can pass a more severe water resistance test, which evaluates the presence or absence of peeling when, for example, the end nails are peeled off after being immersed (saturated) in water. However, further improvement in water resistance is required. Therefore, the adhesives for laminated optical 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. Met.

By the way, in recent years, organic polymer materials are often required to have antinomy properties, and it is difficult for a single organic polymer material to satisfy such required properties. In order to satisfy the antinomy required properties, a technique of adding different materials having different properties to an organic polymer material and compounding them has been proposed in many fields. In the bonding technique, for example, when two different types of adherends are bonded together, it is conceivable to form the adhesive layer so as to have a two-layer structure in order to enhance the adhesiveness with each adherend. However, when the adhesive layer is formed into a two-layer structure, stress is concentrated on the interface thereof, and the adhesive force of the adhesive layer may decrease. In particular, in recent years, it has been difficult to establish a technique for forming an adhesive layer into a two-layer structure in an adhesive for a laminated optical film, which is required to be thin, and as far as the present inventors can know, there is no such report. ..

As described above, especially in the field of adhesives for laminated optical films, which are required to be thin, it is difficult to develop a technique for improving water resistance while improving adhesiveness when adhering two different types of optical films. That was the reality.

The present invention has been developed to solve the above problems, and manufactures a laminated optical film provided with an adhesive layer that exhibits high adhesive strength when laminating two different types of optical films and has excellent water resistance. The purpose is to provide a method.

When the optical films to be laminated are different from each other, for example, they exhibit different characteristics from the viewpoint of hydrophilicity. Therefore, forming an adhesive layer for laminating these optical films in a two-layer structure is a process of forming an adhesive layer between the optical films. Although it is advantageous from the viewpoint of improving the adhesive strength, as described above, there is a risk of a decrease in the adhesive strength due to interfacial peeling in the adhesive layer or the like.

On the other hand, an active energy ray containing at least two or more different active energy ray-curable adhesive compositions, including a first active energy ray-curable adhesive composition and a second active energy ray-curable adhesive composition. According to a manufacturing method in which two optical films are bonded together via a curable adhesive composition and then irradiated with active energy rays to bond the first optical film and the second optical film, two or more types are used. The present inventors have found that interfacial peeling in the adhesive layer is unlikely to occur even when different active energy ray-curable adhesive compositions are used. The present invention has been completed based on such a discovery, and has the following configuration.

That is, the present invention is a method for producing a laminated optical film in which at least a first optical film and a second optical film are laminated via an adhesive layer formed by curing an active energy ray-curable adhesive composition. The active energy ray-curable adhesive composition includes at least two or more different types of active energy rays, including a first active energy ray-curable adhesive composition and a second active energy ray-curable adhesive composition. It contains a curable adhesive composition, and the first active energy ray-curable adhesive composition is applied to the bonding surface of the first optical film, and the bonding surface of the second optical film is further coated. A coating step of applying the second active energy ray-curable adhesive composition to the surface, a bonding step of laminating the first optical film and the second optical film, and the surface side of the first optical film or the above. The first optical film and the second optical film are passed through the adhesive layer formed by irradiating active energy rays from the surface side of the second optical film to cure the active energy ray-curable adhesive composition. The present invention relates to a method for producing a laminated optical film, which comprises an adhesive step of adhering an optical film.

According to the method for producing a laminated optical film, the first active energy ray-curable adhesive composition coated on the bonding surface of the first optical film and the bonding surface of the second optical film are coated. The second active energy ray-curable adhesive composition is bonded in a fluid state. As a result, even if the first active energy ray-curable adhesive composition and the second active energy ray-curable adhesive composition have different compositions, some degree of compatibility progresses between the two layers, so that they are adhered. The agent layer does not form a two-layer structure, but forms a component gradient structure. Therefore, interfacial peeling between the first active energy ray-curable adhesive composition and the second active energy ray-curable adhesive composition is unlikely to occur. Therefore, a first active energy ray-curable adhesive composition having a high affinity with the first optical film is appropriately selected, and a second active energy ray-curable adhesive composition having a high affinity with the second optical film is appropriately selected. By selecting, it is possible to produce a laminated optical film having good adhesiveness between the first optical film and the second optical film while preventing delamination in the adhesive layer.

Further, in the method for producing a laminated optical film according to the present invention, at least the first optical film and the second optical film are laminated via an adhesive layer formed by curing an active energy ray-curable adhesive composition. The method for producing a laminated optical film, wherein the active energy ray-curable adhesive composition includes a first active energy ray-curable adhesive composition and a second active energy ray-curable adhesive composition. It contains at least two or more different types of different active energy ray-curable adhesive compositions, and the first active energy ray-curable adhesive composition is applied to the bonding surface of the first optical film to obtain the above. A coating step of overcoating the coated surface coated with the first active energy ray-curable adhesive composition and further coating the second active energy ray-curable adhesive composition, and coating on the first optical film. The bonding step of bonding the second optical film from the coated surface side of the second active energy ray-curable adhesive composition, and the active energy ray from the first optical film surface side or the second optical film surface side. The first optical film and the second optical film are adhered to each other through the adhesive layer formed by curing the active energy ray-curable adhesive composition by irradiating with. The present invention relates to a method for producing a laminated optical film.

According to the method for producing a laminated optical film, the second active energy ray-curable adhesive composition is compared with the first active energy ray-curable adhesive composition coated on the bonded surface of the first optical film. Topcoat is applied. Then, the first active energy ray-curable adhesive composition coated on the bonded surface of the first optical film and the coated surface coated with the first active energy ray-curable adhesive composition were applied. It is in contact with the second active energy ray-curable adhesive composition in a fluid state. As a result, even if the first active energy ray-curable adhesive composition and the second active energy ray-curable adhesive composition have different compositions, some degree of compatibility progresses at these interfaces, and the components are inclined. The structure is formed. Therefore, interfacial peeling between the first active energy ray-curable adhesive composition and the second active energy ray-curable adhesive composition is unlikely to occur. Therefore, a first active energy ray-curable adhesive composition having a high affinity with the first optical film is appropriately selected, and a second active energy ray-curable adhesive composition having a high affinity with the second optical film is appropriately selected. By selecting, it is possible to produce a laminated optical film having good adhesiveness between the first optical film and the second optical film while preventing delamination in the adhesive layer.

In the method for producing a laminated optical film, it is preferable that the liquid viscosity of the first active energy ray-curable adhesive composition is higher than the liquid viscosity of the second active energy ray-curable adhesive composition. When the second active energy ray-curable adhesive composition is overcoated on the first active energy ray-curable adhesive composition coated on the bonded surface of the first optical film, the first active energy ray-curable adhesive composition is applied. When the liquid viscosity of the adhesive composition is higher than the liquid viscosity of the second active energy ray-curable adhesive composition, the second active energy ray-curable adhesive composition is referred to as the first active energy ray-curable adhesive composition. It can be reliably applied on the object.

In the method for producing a laminated optical film, the contact angle of the active energy ray-curable adhesive composition with respect to the first optical film and the second optical film is preferably 5 to 50 degrees. According to this configuration, the active energy ray-curable adhesive composition has excellent wettability with respect to the first optical film and the second optical film, so that the interlayer adhesiveness of the finally obtained laminated optical film is sufficiently ensured. can.

In the method for producing a laminated optical film, the first optical film and the second optical film are selected from the group consisting of a polyvinyl alcohol-based polarizer, an acrylic resin film, a cycloolefin resin film, a polyester resin film, and a polyolefin resin film. The first optical film and the second optical film are preferably from the group consisting of the acrylic resin film, the cycloolefin resin film, the polyester resin film, and the polyolefin resin film. It is preferably at least one optical film of choice. When the optical film to be laminated is the one described above, it is possible to produce a laminated optical film having an adhesive layer that exhibits high adhesive strength when laminated and has excellent water resistance.

In the method for producing a laminated optical film, the acrylic resin film, the cycloolefin resin film, the polyester resin film and the polyolefin resin film have acrylic resin, polyurethane resin, polyvinyl alcohol resin, melamine resin and the like on the bonding surface thereof. When an easy-adhesion layer containing at least one resin selected from the group consisting of oxazoline group-containing resins is formed, the adhesiveness of the laminated optical film is further enhanced, which is preferable.

In the method for producing a laminated optical film, at least the first optical film and the second optical film are selected from the group consisting of the acrylic resin film, the cycloolefin resin film, the polyester resin film, and the polyolefin resin film. In the case of one kind of optical film, the active energy ray-curable adhesive composition contains 25 to 98 radically polymerizable compounds having ^{an SP value of 18 to 21 (MJ / m 3} ) ^1/2. When it is contained in% by weight, the following effects are obtained. Specifically, when the specific optical film is used and the active energy ray-curable adhesive composition contains a predetermined amount of a radically polymerizable compound showing a predetermined SP value, the adhesive layer and A compatible layer is formed with the optical film. As a result, the adhesiveness of the laminated optical film is further enhanced, which is preferable.

In the method for producing a laminated optical film, one of the first optical film and the second optical film is the polyvinyl alcohol-based polarizer, and the active energy applied to the bonding surface of the polyvinyl alcohol-based polarizer. The linear curable adhesive composition preferably contains a hydroxyl group-containing radically polymerizable compound. According to such a configuration, the adhesive force between the polyvinyl alcohol-based polarizer and the adhesive layer is further enhanced, which is preferable.

Schematic diagram showing a method for evaluating a component inclined structure in an adhesive layer using TOF-SIMS.

The laminated optical film according to the present invention is one in which at least a first optical film and a second optical film are laminated via an adhesive layer formed by curing an active energy ray-curable adhesive composition. The adhesive layer is formed of a cured product layer obtained by irradiating an active energy ray-curable adhesive composition with active energy rays.

The active energy ray-curable adhesive composition can be roughly classified into an electron beam-curable type, an ultraviolet-curable type, a visible light-curable type and the like. Further, the ultraviolet curable type adhesive and the visible light curable type adhesive can be classified into a radical polymerization curable type adhesive and a cationic polymerization type adhesive. In the present invention, active energy rays having a wavelength range of 10 nm to less than 380 nm are referred to as ultraviolet rays, and active energy rays having a wavelength range of 380 nm to 800 nm are referred to as visible light.

Examples of the compound constituting the radical polymerization curable adhesive include a radical polymerizable compound. Examples of the radically polymerizable compound include compounds having a radically polymerizable functional group of a carbon-carbon double bond such as a (meth) acryloyl group and a vinyl group. As these curable components, either a monofunctional radical-polymerizable compound or a bifunctional or higher-functional polyfunctional radical-polymerizable compound can be used. In addition, these radically polymerizable compounds may 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, and specifically, the entire amount of the active energy ray-curable adhesive composition is used. When it is 100% by weight, the compound having a (meth) acryloyl group is preferably contained in an amount of 50% by weight or more, more preferably 80% by weight or more. In addition, in this invention, (meth) acryloyl means acryloyl group and / or methacryloyl group, and "(meth)" has the same meaning below.

<Monofunctional radical polymerizable compound>
Examples of the monofunctional radically polymerizable compound include a (meth) acrylamide derivative having a (meth) acrylamide group. The (meth) acrylamide derivative is preferable in terms of ensuring adhesiveness to a polarizer and various transparent protective films, and also in terms of high polymerization rate and excellent productivity. Specific examples of the (meth) acrylamide derivative include N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and N. N-alkyl group-containing (meth) acrylamide derivatives such as −butyl (meth) acrylamide, N-hexyl (meth) acrylamide; N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-methylol-N- N-Hydroxyalkyl group-containing (meth) acrylamide derivatives such as propane (meth) acrylamide; N-aminoalkyl group-containing (meth) acrylamide derivatives such as aminomethyl (meth) acrylamide and aminoethyl (meth) acrylamide; N-methoxymethyl N-alkoxy group-containing (meth) acrylamide derivatives such as acrylamide and N-ethoxymethylacrylamide; N-mercaptoalkyl group-containing (meth) acrylamide derivatives such as mercaptomethyl (meth) acrylamide and mercaptoethyl (meth) acrylamide; Be done. Examples of the heterocyclic (meth) acrylamide derivative in which the nitrogen atom of the (meth) acrylamide group forms a heterocycle include N-acrylloylmorpholine, N-acrylloylpiperidin, N-methacryloylpiperidin, and N-acrylloylpyridine. And so on.

Among the (meth) acrylamide derivatives, an N-hydroxyalkyl group-containing (meth) acrylamide derivative is preferable from the viewpoint of adhesion to a polarizer and various transparent protective films, and the monofunctional radical polymerizable compound is preferable. For example, various (meth) acrylic acid derivatives having a (meth) acryloyloxy group can be mentioned. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl ( Meta) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-Dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl ( Examples thereof include (meth) acrylic acid (1-20 carbon atoms) alkyl esters such as meta) acrylate and n-octadecyl (meth) acrylate.

Examples of the (meth) acrylic acid derivative include cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate and cyclopentyl (meth) acrylate; aralkyl (meth) acrylates such as benzyl (meth) acrylate; 2-isobornyl. (Meta) 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 acrylicate, dicyclopentenyloxyethyl (meth) acrylicate, dicyclopentanyl (meth) acrylicate, etc .; 2-methoxyethyl (meth) acrylate, 2-ethoxy Ethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, alkylphenoxypolyethylene glycol (meth) acrylate, etc. An alkoxy group- or phenoxy group-containing (meth) acrylate; and the like.

Examples of the (meth) acrylic acid derivative include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-. Hydroxyalkyl (meth) acrylates such as hydroxybutyl (meth) acrylates, 6-hydroxyhexyl (meth) acrylates, 8-hydroxyoctyl (meth) acrylates, 10-hydroxydecyl (meth) acrylates, and 12-hydroxylauryl (meth) acrylates. , [4- (Hydroxymethyl) cyclohexyl] methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate and other hydroxyl group-containing (meth) acrylate; glycidyl (meth) acrylate, 4-Hydroxybutyl (meth) acrylate Epoxy group-containing (meth) acrylate such as glycidyl ether; 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethyl ethyl (meth) acrylate, tetra Halogen-containing (meth) acrylates such as fluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, and 3-chloro-2-hydroxypropyl (meth) acrylate. ) Acrylate; Alkylaminoalkyl (meth) acrylate such as dimethylaminoethyl (meth) acrylate; 3-oxytenylmethyl (meth) acrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth) acrylate , 3-Butyl-oxetanylmethyl (meth) acrylate, 3-hexyluoxetanylmethyl (meth) acrylate and other oxetane group-containing (meth) acrylate; tetrahydrofurfuryl (meth) acrylate, butyrolactone (meth) acrylate, and other heterocycles. (Meta) acrylate having (meth) acrylate, neopentyl glycol (meth) acrylic acid adduct of hydroxypivalate, p-phenylphenol (meth) acrylate and the like can be mentioned.

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

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

<Polyfunctional radical polymerizable compound>
Examples of the bifunctional or higher polyfunctional radical polymerizable compound include tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9. -Nonandiol 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, tricyclodecanedimethanol di (meth) acrylate, cyclic tri Methylolpropanformal (meth) acrylate, dioxane glycol di (meth) acrylate, trimethylpropantri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate , Dipentaerythritol hexa (meth) acrylate, esterified product of (meth) acrylic acid such as EO-modified diglycerin tetra (meth) acrylate and polyhydric alcohol, 9,9-bis [4- (2- (meth) acryloyl) Oxyethoxy) phenyl] Fluolene can be mentioned. 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.), Light Acrylate DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.). , SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer) and the like. Further, if necessary, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various (meth) acrylate-based monomers and the like can be mentioned.

In the present invention, the optical film to be adhered is at least one optical film selected from the group consisting of an acrylic resin film, a cycloolefin resin film, a polyester resin film and a polyolefin resin film, and is an active energy ray. When the curable adhesive composition contains 25 to 98% by weight of a radically polymerizable compound having an SP value of 18 to 21 (MJ / m ³ ) ^{1/2 when the total amount of the composition is 100% by weight.} , More preferably 30 to 90% by weight, more preferably 40 to 80% by weight, a compatible layer is formed between the adhesive layer and the optical film. As a result, the adhesiveness of the laminated optical film is further enhanced, which is preferable.

Here, the method of calculating the SP value (solubility parameter) in the present invention will be described below.

(Calculation method of solubility parameter (SP value))
In the present invention, the solubility parameter (SP value) of a radically polymerizable compound, a polarizer, various transparent protective films, etc. is determined by the FEDORS calculation method [“Polymer Engineering and Science (POLYMER ENG. & SCI.)”, No. Vol. 14, No. 2 (1974), pp. 148-154] That is,

（ただしΔＥＩは原子または基に帰属する２５℃における蒸発エネルギー、ΔＶＩは２５℃におけるモル体積である）にて計算して求めることができる。

(However, ΔEI is the evaporation energy at 25 ° C. attributable to the atom or group, and ΔVI is the molar volume at 25 ° C.).

In ΔEI and ΔVI in the above formula, constant numerical values given to I atoms and groups in the main molecule are shown. In addition, typical examples of the numerical values of ΔE and ΔV given to the atom or group are shown in Table 1 below.

Specific examples of the radically polymerizable compound having an SP value of 18 to 21 (MJ / m ³ ) ^1/2 include, for example, tripropylene glycol diacrylate (SP value 19.0 (MJ / m ³ ) ^1/2 ). , 1,9-Nonandiol diacrylate (SP value 19.2 (MJ / m ³ ) ^1/2 ), Tricyclodecanedimethanol diacrylate (SP value 20.3 (MJ / m ³ ) ^1/2 ), Cyclic trimethylolpropane formal acrylate (SP value 19.1 (MJ / m ³ ) ^1/2 ), dioxane glycol diacrylate (SP value 19.4 (MJ / m ³ ) ^1/2 ), EO-modified diglycerin tetra Examples thereof include acrylate (SP value 20.9 (MJ / m ³ ) ^1/2). As a radically polymerizable compound having an SP value of 18 to 21 (MJ / m ³ ) ^1/2 , a commercially available product can also be preferably used. For example, Aronix M-220 (manufactured by Toa Synthetic Co., Ltd., SP value 19. 0 (MJ / m ³ ) ^1/2 ), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd., SP value 19.2 (MJ / m ³ ) ^1/2 ), light acrylate DGE-4A (Kyoeisha Chemical Co., Ltd.) , SP value 20.9 (MJ / m ³ ) ^1/2 ), Light acrylate DCP-A (manufactured by Kyoeisha Chemical Co., Ltd., SP value 20.3 (MJ / m ³ ) ^1/2 ), SR-531 (SARTOMER) Examples thereof include SP value 19.1 (MJ / m ³ ) ^1/2 ) manufactured by SARTOMER (manufactured by SARTOMER, SP value 19.4 (MJ / m ³ ) ^1/2).

In the method for producing a laminated optical film according to the present invention, the active energy ray-curable adhesive composition used is the first active energy ray-curable adhesive composition and the second active energy ray-curable adhesive composition. It is characterized by containing at least two or more different active energy ray-curable adhesive compositions, including. "The active energy ray-curable adhesive composition is different" means that the radically polymerizable compound contained and the composition ratio are different, so that the active energy ray-curable adhesive composition is different, for example, from the viewpoint of hydrophilicity / hydrophobicity. It means that it has different properties. When the laminated optical film produced by the production method according to the present invention is, for example, a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizing element via an adhesive layer, the polarizer has hydrophilicity. On the other hand, transparent protective films tend to be hydrophobic. Therefore, in the present invention, when the first optical film is a polarizer and the second optical film is a transparent protective film, the first active energy ray-curable type is arranged on the first optical film side in order to improve the adhesiveness. The adhesive composition is preferably hydrophilic, and the second active energy ray-curable adhesive composition is preferably hydrophobic.

In the present invention, logPow is mentioned as an index for evaluating the hydrophilicity and hydrophobicity of the radically polymerizable compound contained in the active energy ray-curable adhesive composition. The octanol / water partition coefficient (logPow) is an index showing the lipophilicity of a substance, and means the logarithmic value of the octanol / water partition coefficient. A high logPow means that it is lipophilic, that is, it has a low water absorption rate. The logPow value can be measured (the flask immersion method described in JIS-Z-7260), but it can also be calculated by calculation. In this specification, the logPow value calculated by Chem Draw Ultra manufactured by Cambridge Soft Co., Ltd. is used.

In particular, in the present invention, when the first optical film is a polarizer and the second optical film is a transparent protective film, the first active energy ray-curable adhesive composition arranged on the first optical film side has logPow. It is preferable that the component A having a log power of -1 to 1 is contained, and the component B having a log power of 2 to 7 is preferably contained in the second active energy ray-curable adhesive composition. In such a configuration, (i) the first active energy ray-curable adhesive composition is applied to the bonding surface of the first optical film, and the second active energy ray-curing surface is further coated with the second active energy ray-curable adhesive composition. When applying the mold adhesive composition, or (ii) applying the first active energy ray-curable adhesive composition to the bonding surface of the first optical film, the first active energy ray-curable adhesive When the second active energy ray-curable adhesive composition is further overcoated on the coated surface coated with the composition, the adhesive layer interposed between the polarizer and the transparent protective film is on the polarizer side. It has a component gradient structure in which the concentration of component A, which exhibits high hydrophilicity, increases. Therefore, it is possible to manufacture a polarizing film having an adhesive layer in which the polarizer and the transparent protective film exhibit excellent adhesiveness and also have excellent water resistance.

For example, as a method for confirming that the adhesive layer of the polarizing film has a component inclined structure in which the concentration of the component A changes in the thickness direction, for example, a time-of-flight secondary ion mass spectrometry method (Time of Flight Second Ion Mass Spectrometry) is used. A method using Spectrometry (TOF-SIMS) can be mentioned. 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 ultra-high vacuum, secondary ions are emitted only from the outermost surface (a few Å of depth) of the sample. A mass spectrum can be obtained by introducing secondary ions into a time-of-flight (TOF) mass spectrometer. Using this principle, information on the elemental composition existing on the outermost surface of the sample and the chemical structure of the compound can be obtained. Further, in the present invention, a cluster ion etching method can be used to confirm the component inclination structure in the thickness direction of the adhesive layer interposed between the transparent protective film and the polarizer.

The "cluster ion etching method" will be described below. For example, when the surface of the adhesive layer is etched by using a general etching method using a monatomic ion beam (Ar ⁺ , Cs ^+, etc.) as etching ions, the molecular structure of the surface of the adhesive layer 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, it is not possible to measure an accurate mass spectrum of the surface of the adhesive layer due to the influence of the damaged layer. On the other hand, when the "cluster ion etching method" using "Ar gas cluster ion (Arn ⁺ )" as the etching ion is used, the damage given to the surface of the adhesive layer after etching is reduced and the damaged layer is formed. Therefore, the surface of the adhesive layer after etching retains the molecular structure of the surface before etching. Therefore, by using TOF-SIMS, the mass spectrum of the surface of the adhesive layer can be accurately measured.

FIG. 1 shows a schematic view showing an evaluation method of a component inclined structure in the thickness direction in an adhesive layer using TOF-SIMS. FIG. 1 (I) shows an example of a polarizing film which is a laminated optical film that can be manufactured in the present invention. In such a polarizing film, a transparent protective film 2 is laminated on both sides of a polarizing element 1 via an adhesive layer 3. Has been done. 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 by 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), the surface of the transparent protective film 2 that has been thinly cut is etched by using the "cluster ion etching method", and then the composition of the surface is analyzed by using TOF-SIMS. Further, as shown in (V), the surface of the transparent protective film 2 is etched by using the "cluster ion etching method" to precipitate the surface of the adhesive layer 3 on the transparent protective film 2 side, and TOF-SIMS is used. Is used to analyze the composition of the surface. After that, the etching process using the "cluster ion etching method" and the analysis of the surface composition of the precipitated adhesive layer 3 are repeated using TOF-SIMS, and etching is performed until the surface of the precipitate is finally reached. The treatment and analysis of the surface composition of the adhesive layer 3 (further, the polarizer 1) are continued. According to the method described above, in the present invention, it is possible to confirm the component inclined structure in the thickness direction in the adhesive layer interposed between the transparent protective film and the polarizer.

As the component A having a log Pow of -1 to 1, any of the above-mentioned radically polymerizable compounds having a log Pow of -1 to 1 can be arbitrarily used, and specifically, for example, hydroxyethyl acrylamide ( Product name "HEAA", manufactured by Kojinsha, LogPower; -0.56), N-vinylformamide (trade name "Beamset 770", manufactured by Arakawa Chemical Co., Ltd., LogPower; -0.25), acrylic morpholine (product) Name "ACMO", manufactured by Kojinsha, LogPow; -0.20), γ-butyrolactone acrylate (trade name "GBLA", manufactured by Osaka Organic Chemical Industry Co., Ltd., LogPow; 0.19), acrylic acid dimer (trade name) "Β-CEA", manufactured by Daicel Co., Ltd., LogPow; 0.2), N-vinylpyrrolidone (trade name "NVP", manufactured by Nippon Catalyst Co., Ltd., LogPow; 0.24), acetoacetoxyethyl methacrylate (trade name "AAEM"). , Nippon Synthetic Chemical Co., Ltd., 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") , Kyoeisha Chemical Co., Ltd., LogPow; 0.57), Dimethylacrylamide (trade name "DMAA", Kojinsha Co., Ltd., LogPow; 0.58), Tetrahydrofurfuryl alcohol acrylic acid multimer ester (trade name "Viscoat # 150D") , Osaka Organic Chemical Industry Co., Ltd., LogPow; 0.60), 4-Hydroxybutyl acrylate (trade name "4-HBA", Osaka Organic Chemical Industry Co., Ltd., LogPow; 0.68), acrylic acid (trade name "acrylic acid") "Acrylic acid", manufactured by Mitsubishi Chemical Corporation, LogPower; 0.69), triethylene glycol diacrylate (trade name "Light acrylate 3EG-A", manufactured by Kyoeisha Chemical Co., Ltd., LogPower; 0.72) and the like. Among these, in the present invention, it is preferable to use a (meth) acrylamide derivative as the component A having a logpower of -1 to 1, and further preferably hydroxyethyl acrylamide, acryloyl morpholine, or dimethyl acrylamide. Other than the (meth) acrylamide derivative, the use of 4-hydroxybutyl acrylate is preferable.

When the first optical film is a polarizer, the first active energy ray-curable adhesive composition preferably contains a component A having a log power of -1 to 1. Further, in order to improve the adhesive strength and water resistance of the adhesive layer, when the total amount of the first active energy ray-curable adhesive composition is 100% by weight, the logpower of the component A is -1 to 1. The content is preferably 5 to 95% by weight, more preferably 30 to 80% by weight.

In the present invention, when a component having a log Pow of 2 to 7 is used as the B component, the B component exhibits high hydrophobicity. As the B component having a log Pow of 2 to 7, any of the above-mentioned radically polymerizable compounds having a log Pow of 2 to 7 can be arbitrarily used, and specifically, for example, dicyclopentenylacrylate. (Product name "Funkryl FA-511AS", manufactured by Hitachi Kasei Co., Ltd., LogPow; 2.26), butyl acrylate (trade name "Butyl acrylate", manufactured by Mitsubishi Chemical Co., Ltd., LogPow; 2.35), 1, 6-Hexanediol diacrylate (trade name "Light Acrylate 1.6HX-A", manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 2.43), dicyclopentanylacrylate (trade name "Funkryl FA-513AS", Hitachi Kasei Co., Ltd., LogPow; 2.58), Dimethylol-tricyclodecandiacrylate (trade name "Light Acrylate DCP-A", 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 acid adduct with hydroxypivalate (trade name“ Light Acrylate HPP-A ”, manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 3.35) ), 1,9-Nonandiol diacrylate (trade name "Light Acrylate 1,9ND-A", manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 3.68), o-phenylphenol EO modified acrylate (trade name "Funkryl FA-" 301A ”, Hitachi Kasei Co., Ltd., LogPow; 3.98), 2-ethylhexyl oxetane (trade name“ Aron Oxetan OXT-212 ”, manufactured by Toa Synthetic Co., Ltd., LogPow; 4.24), bisphenol-A-diglycidyl ether ( Product name "JER828", manufactured by Mitsubishi Chemical Co., Ltd., LogPow; 4.76), bisphenol A EO 6 mol modified diacrylate (trade name "FA-326A", manufactured by Hitachi Kasei Co., Ltd., LogPow; 4.84), bisphenol A EO 4 mol Modified diacrylate (trade name "FA-324A", manufactured by Hitachi Kasei Co., Ltd., LogPow; 5.15), bisphenol A PO2 molar modified diacrylate (trade name "FA-P320A", manufactured by Hitachi Kasei Co., Ltd., LogPow; 6.10) ), Bisphenol A PO3 molar modified diacrylate (trade name "FA-P323A", manufactured by Hitachi Kasei Co., Ltd., LogPow; 6.26), Bisphenol A PO4 molar modified diacrylate (trade name "FA-P324A", manufactured by Hitachi Kasei Co., Ltd.) , LogP ow; 6.43) and the like. Among these, in the present invention, it is preferable to use a polyfunctional (meth) acrylate as the B component having a logpower of 2 to 7, and further, 1,6-hexanediol diacrylate) and dimethylol-tricyclodecandide. Acrylate, neopentyl glycol acrylic acid adduct with hydroxypivalate, 1,9-nonanediol diacrylate, 2-ethylhexyloxetane, bisphenol-A-diglycidyl ether, bisphenol A EO 6 molar modified diacrylate, bisphenol A EO 4 molar modified diacrylate , Bisphenol A PO2 molar modified diacrylate, bisphenol A PO3 molar modified diacrylate, or bisphenol A PO4 molar modified diacrylate is preferably used.

When the second optical film is a transparent protective film, the second active energy ray-curable adhesive composition preferably contains a component B having a log power of 2 to 7. Further, in order to improve the adhesive strength and water resistance of the adhesive layer, when the total amount of the second active energy ray-curable adhesive composition is 100% by weight, the logpower of the component B is 2 to 7. The content is preferably 30 to 95% by weight, more preferably 50 to 80% by weight.

When an electron beam or the like is used for the active energy ray, the active energy ray-curable adhesive composition does not need to contain a photopolymerization initiator, but is active. When ultraviolet rays or visible rays are used for the energy rays, it is preferable to contain a photopolymerization initiator.

<Photopolymerization initiator>
When a radically polymerizable compound is used, the photopolymerization initiator is appropriately selected by the active energy ray. When curing by ultraviolet rays or visible light, a photopolymerization initiator that cleaves ultraviolet rays or visible light is used. The photopolymerization initiator may be used alone, but when a plurality of photopolymerization initiators are mixed and used, the curing rate and curability can be adjusted, which is preferable. Examples of the photopolymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2). -Propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, 1-hydroxycyclohexylphenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl]- 2-Hydroxy-2-methyl-1-propane-1-one, 2-hirodoxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane Aromatic ketone compounds such as -1-one; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2-Acetphenone compounds such as morpholinopropane-1; benzoin ether compounds such as venzoin methyl ether, venzoin ethyl ether, benzoin isopropyl ether, venzoin butyl ether, anisoin methyl ether; benzyl dimethyl Aromatic ketal compounds such as ketal; aromatic sulfonyl chloride compounds such as 2-naphthalene sulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propandion-2- (o-ethoxycarbonyl) oxime Thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2, Examples thereof include thioxanthone compounds such as 4-diisopropylthioxanthone and dodecylthioxanthone; camphorquinone; ketone halide; acylphosphinoxide; and acylphosphonate.

The blending 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 blending 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.

Further, when the curable adhesive for laminated optical films of the present invention is used in a visible light curable type containing a radically polymerizable compound as a curable component, a photopolymerization initiator having high sensitivity to light of 380 nm or more in particular. Is preferably used. A photopolymerization initiator having high sensitivity to light of 380 nm or more will be described later.

The photopolymerization initiator is a compound represented by the following general formula (1);

（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。接着剤中の一般式（１）で表される化合物の組成比率は、活性エネルギー線硬化型接着剤組成物の全量を１００重量％としたとき、０．１〜５重量％であることが好ましく、０．５〜４重量％であることがより好ましく、０．９〜３重量％であることがさらに好ましい。

(In the formula, R ¹ and R ² indicate -H, -CH ₂ CH ₃ , -iPr or Cl, and R ¹ and R ² may be the same or different), or the general formula (in the formula) may be used alone. 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 is preferably 0.1 to 5% by weight when the total amount of the active energy ray-curable adhesive composition is 100% by weight. , 0.5 to 4% by weight, more preferably 0.9 to 3% 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 preferable. When a polymerization initiation aid is used, the amount added is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, and most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component. be.

In addition, a known photopolymerization initiator can be used in combination if necessary. Since the transparent protective film having a 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 the photopolymerization initiator. Specifically, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-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-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-) 1-yl) -phenyl) titanium and the like can be mentioned.

In particular, as the 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。

(In the formula, R ³ , R ⁴ and R ⁵ indicate -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 preferable to use it. As the compound represented by the general formula (2), 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one (trade name: IRGACURE907 manufacturer: BASF), which is also a commercially available product, is preferable. 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 preferable 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 in the adhesive layer having a high concentration of the A component on the polarizer side is enhanced, and the adhesive layer is increased. Increases the curability of. Examples of the photopolymerization initiator having a hydroxyl group include 2-methyl-2-hydroxypropiophenone (trade name "DAROCUR1173", manufactured by BASF), 1-hydroxycyclohexylphenyl ketone (trade name "IRGACURE184", manufactured by BASF). ), 1- [4- (2-Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one (trade name "IRGACURE2959", manufactured by BASF), 2-hirodoxy-1- Examples thereof include {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one (trade name "IRGACURE127", manufactured by BASF). In particular, 1-hydroxycyclohexylphenyl ketone is more preferable because it has particularly excellent solubility in an adhesive layer having a high concentration of component A.

<Radical polymerizable compound having an active methylene group and a radical polymerization initiator having a hydrogen abstraction action>
When a radically polymerizable compound having an active methylene group is used as the radically polymerizable compound in the above active energy ray-curable adhesive composition, it is preferably used in combination with a radical polymerization initiator having a hydrogen abstraction action. According to such a configuration, the adhesiveness of the adhesive layer of the polarizing film is remarkably improved even immediately after being taken out from a high humidity environment or water (non-drying state). The reason for this is not clear, but the following causes are possible. That is, the radically polymerizable compound having an active methylene group is incorporated into the main chain and / or side chain of the base polymer in the adhesive layer while being polymerized together with other radically polymerizable compounds constituting the adhesive layer, and adheres. Form a layer of agent. In such a polymerization process, when a radical polymerization initiator having a hydrogen abstraction action is present, hydrogen is abstracted from the radical polymerizable compound having an active methylene group to form a methylene group while forming a base polymer constituting the adhesive layer. Radicals are generated. Then, the methylene group in which radicals are generated reacts with the hydroxyl group of a 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 remarkably improved even in a non-drying state.

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

When the radical polymerization compound having an active methylene group and the radical polymerization initiator having a hydrogen abstraction action are contained in the above active energy ray-curable adhesive composition, the total amount of the curable component is set to 100% by weight. When, it is preferable to contain 1 to 50% by weight of the radically polymerizable compound having an active methylene group and 0.1 to 10 parts by weight of the radical polymerization initiator with respect to 100 parts by weight of the total amount of the curable component.

As described above, in the present invention, in the presence of a radical polymerization initiator having a hydrogen abstraction action, a radical is generated in the methylene group of the radically polymerizable compound having an active methylene group, and the methylene group and a polarizer such as PVA are generated. Reacts with the hydroxyl group to form a covalent bond. Therefore, in order to generate a radical in the methylene group of the radically polymerizable compound having an active methylene group and sufficiently form such a covalent bond, when the total amount of the curable component is 100% by weight, the radical having an active methylene group The polymerizable compound is preferably contained in an amount of 1 to 50% by weight, more preferably 3 to 30% by weight. In order to sufficiently improve the water resistance and improve the adhesiveness in the non-drying state, the amount 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, curing failure of the adhesive layer may occur. Further, the radical polymerization initiator having a hydrogen abstraction 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. On the other hand, if it exceeds 10 parts by weight, it may not be completely dissolved in the composition.

<Cationic polymerization curable adhesive>
Examples of the curable component of the cationic polymerization-curable adhesive include compounds 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 the molecule, and various generally known curable epoxy compounds 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 at least one of them having at least two epoxy groups in the molecule. Examples thereof include a compound (alicyclic epoxy compound) formed between two adjacent carbon atoms constituting an alicyclic ring. However, even when a cationic polymerization curable adhesive is used in the adhesive layer in order to realize a component inclined 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 a component A having a log power of -1 to 1 and a component B having a log power of 2 to 7.

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

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

<Acrylic oligomer>
The active energy ray-curable adhesive composition used in the present invention is an acrylic type obtained by polymerizing a (meth) acrylic monomer in addition to a curable component related to the radically polymerizable compound or a cationically polymerizable curable adhesive. It can contain oligomers. When the active energy ray-curable adhesive composition contains an acrylic oligomer obtained by polymerizing a non-polymerizable (meth) acrylic monomer, it is a component of the adhesive composition interposed between the polarizer and the transparent protective film. Uneven distribution is likely to proceed, and a component inclined structure in which the concentration of component A changes in the thickness direction is more likely to be obtained. Therefore, it is preferable because the adhesiveness and water resistance of the adhesive layer to the polarizer and the transparent protective film are further enhanced. Furthermore, by containing an acrylic oligomer component in the active energy ray-curable adhesive composition, the curing shrinkage when irradiating and curing the composition with active energy rays is reduced, and the adhesive, the polarizer and It is possible to reduce the interfacial stress with an adherend such as a transparent protective film. As a result, it is possible to suppress a decrease in the adhesiveness between the adhesive layer and the adherend. In order to obtain the component inclined structure of the cured product layer (adhesive layer) more reliably and further to sufficiently suppress the curing shrinkage, the total amount of the active energy ray-curable adhesive composition was set to 100% by weight. The content of the acrylic oligomer is preferably 5 to 30% by weight, more preferably 10 to 20% by weight.

The active energy ray-curable adhesive composition preferably has a low viscosity in consideration of workability and uniformity during coating. Therefore, an acrylic oligomer (A) formed by polymerizing a (meth) acrylic monomer. Also preferably has a low viscosity. The low-viscosity acrylic oligomer 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, in order to further promote the uneven distribution of the components of the adhesive composition interposed between the polarizer and the transparent protective film, the weight average molecular weight (Mw) of the acrylic oligomer (A) is preferably 500 or more. It is more preferably 1000 or more, and particularly preferably 1500 or more. Specific examples of the (meth) acrylic monomer constituting the acrylic oligomer (A) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and 2 -Methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, S-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2 (Meta) acrylic acid (1-20 carbon atoms) alkyl esters such as −ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, N-octadecyl (meth) acrylate, and further, for example, cyclo. Alkyl (meth) acrylates (eg, cyclohexyl (meth) acrylates, cyclopentyl (meth) acrylates, etc.), aralkyl (meth) acrylates (eg, benzyl (meth) acrylates, 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 Contains (meth) acrylic acid esters (eg, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (meth) methacrylate, etc.), alkoxy group or phenoxy group (containing) Meta) Acrylate 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) acrylic acid esters (eg, glycidyl (meth) acrylate, etc.), halogen-containing (meth) acrylic acid esters (eg, 2,2,2- Trifluoroethyl (meth) acrylate, 2,2 , 2-Trifluoroethyl ethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, etc.), Alkylaminoalkyl (Meta) acrylate (for example, dimethylaminoethyl (meth) acrylate and the like) and the like can be mentioned. These (meth) acrylates can be used alone or in combination of two or more. Specific examples of the acrylic oligomer (A) include "ARUFON" manufactured by Toagosei Co., Ltd., "Actflow" manufactured by Soken Chemical Co., Ltd., and "JONCRYL" manufactured by BASF Japan Ltd.

When the acrylic oligomer (A) is a liquid, it is preferably used because it is not necessary 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. Specific examples thereof include "ARUFON UH series", "ARUFON UC series", "ARUFON UF series", "ARUFON UG series", and "ARUFON US series" (all manufactured by Toagosei Co., Ltd.). Above all, it is preferable to contain an epoxy group because it is expected that the adhesiveness will be improved by the interaction with the polarizer. Specific examples thereof include "ARUFON UG-4000" and "ARUFON UG-4010" (both manufactured by Toagosei Co., Ltd.).

<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。）
一般式（３）を構成するオニウムカチオンＬ^＋として好ましいオニウムカチオンの構造としては、下記一般式（４）〜一般式（１２）から選ばれるオニウムカチオンをあげることができる。 General formula (3)

(However, L ⁺ represents an arbitrary onium cation, and X ⁻ is PF6 ₆ ⁻ , SbF.
Represents a counter anion selected from the group consisting of ₆ ⁻ , AsF ₆ ⁻ , SbCl ₆ ⁻ , BiCl ₅ ⁻ , SnCl ₆ ⁻ , ClO ₄ ^{−, dithiocarbamate anion, and SCN −.} )
^{As a preferable structure of the onium cation as the onium cation L +} constituting the general formula (3), an onium cation selected from the following general formulas (4) to (12) can be mentioned.

General formula (4)

General formula (5)

General formula (6)

General formula (7)

General formula (8)

General formula (9)

General formula (10)

General formula (11)

（上記一般式（４）−（１２）中、ただし、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立に、水素原子、置換もしくは未置換のアルキル基、置換もしくは未置換のアルケニル基、置換もしくは未置換のアリール基、置換もしくは未置換の複素環基、置換もしくは未置換のアルコキシル基、置換もしくは未置換のアリールオキシ基、置換もしくは未置換の複素環オキシ基、置換もしくは未置換のアシル基、置換もしくは未置換のカルボニルオキシ基、置換もしくは未置換のオキシカルボニル基、またはハロゲン原子より選ばれる基を表す。Ｒ^４は、Ｒ^１、Ｒ^２およびＲ^３に記載した基と同様の基を表す。Ｒ^５は、置換もしくは未置換のアルキル基、置換もしくは未置換のアルキルチオ基を表す。Ｒ^６およびＲ^７は、それぞれ独立に、置換もしくは未置換のアルキル基、置換もしくは未置換のアルコキシル基を表す。Ｒは、ハロゲン原子、水酸基、カルボキシル基、メルカプト基、シアノ基、ニトロ基、置換もしくは未置換のカルバモイル基、置換もしくは未置換のアルキル基、置換もしくは未置換のアルケニル基、置換もしくは未置換のアリール基、置換もしくは未置換の複素環基、置換もしくは未置換のアルコキシル基、置換もしくは未置換のアリールオキシ基、置換もしくは未置換の複素環オキシ基、置換もしくは未置換のアルキルチオ基、置換もしくは未置換のアリールチオ基、置換もしくは未置換の複素環チオ基、置換もしくは未置換のアシル基、置換もしくは未置換のカルボニルオキシ基、置換もしくは未置換のオキシカルボニル基のいずれかを表す。Ａｒ^４、Ａｒ^５は、置換もしくは未置換のアリール基、置換もしくは未置換の複素環基のいずれかを表す。Ｘは、酸素もしくは硫黄原子を表す。ｉは０〜５の整数を表す。ｊは０〜４の整数を表す。ｋは０〜３の整数を表す。また、隣接したＲ同士、Ａｒ^４とＡｒ^５、Ｒ^２とＲ^３、Ｒ^２とＲ^４、Ｒ^３とＲ^４、Ｒ^１とＲ^２、Ｒ^１とＲ^３、Ｒ^１とＲ^４、Ｒ^１とＲ、もしくはＲ^１とＲ^５は、相互に結合した環状構造であってもよい。） General formula (12)

(In the above general formulas (4)-(12), however, R ¹ , R ² and R ³ are independently hydrogen atoms, substituted or unsubstituted alkyl groups, substituted or unsubstituted alkenyl groups, substituted or Unsubstituted aryl group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted alkoxyl group, substituted or unsubstituted aryloxy group, substituted or unsubstituted heterocyclic oxy group, substituted or unsubstituted acyl group, Represents a substituted or unsubstituted carbonyloxy group, a substituted or unsubstituted oxycarbonyl group, or a group selected from a halogen atom. R ⁴ represents a group similar to the group described in R ¹ , R ² and R ^3. R ⁵ represents a substituted or unsubstituted alkyl group and a substituted or unsubstituted alkyl thio group. R ⁶ and R ⁷ each independently contain a substituted or unsubstituted alkyl group and a substituted or unsubstituted alkoxyl group. R represents a halogen atom, a hydroxyl group, a carboxyl group, a mercapto group, a cyano group, a nitro group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkenyl group. Aryl group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted alkoxyl group, substituted or unsubstituted aryloxy group, substituted or unsubstituted heterocyclic oxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted arylthio group, a substituted or unsubstituted heterocyclic thio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted carbonyloxy group, .Ar ⁴ represent either a substituted or unsubstituted oxycarbonyl group, Ar ⁵ represents either a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group. X represents an oxygen or sulfur atom. I represents an integer of 0 to 5. j represents 0 to 0. Represents an integer of 4. k represents an integer of 0 to ^{3. Also, adjacent Rs, Ar 4} and Ar ⁵ , R ² and R 3, R ² and R ⁴ , R ³ and R ⁴ , R ¹ and R ^{2, R 1} and ^R 3, ^{R 1} and ^R 4, ^{R 1} and R, or ^{R 1} and ^{R 5} may be a cyclic structure bound to one another.)

Onium cation (sulfonium cation) corresponding to the general formula (4):
Dimethylphenyl sulfonium, dimethyl (o-fluorophenyl) sulfonium, dimethyl (m-chlorophenyl) sulfonium, dimethyl (p-bromophenyl) sulfonium, dimethyl (p-cyanophenyl) sulfonium, dimethyl (m-nitrophenyl) sulfonium, dimethyl ( 2,4,6-tribromophenyl) sulfonium, dimethyl (pentafluorophenyl) sulfonium, dimethyl (p- (trifluoromethyl) phenyl) sulfonium, dimethyl (p-hydroxyphenyl) sulfonium, dimethyl (p-mercaptophenyl) sulfonium , Dimethyl (p-methylsulfinylphenyl) sulfonium, dimethyl (p-methylsulfonylphenyl) sulfonium, dimethyl (o-acetylphenyl) sulfonium, dimethyl (o-benzoylphenyl) sulfonium, dimethyl (p-methylphenyl) sulfonium, dimethyl ( p-isopropylphenyl) sulfonium, dimethyl (p-octadecylphenyl) sulfonium, dimethyl (p-cyclohexylphenyl) sulfonium, dimethyl (p-methoxyphenyl) sulfonium, dimethyl (o-methoxycarbonylphenyl) sulfonium, dimethyl (p-phenylsulfanyl) Phenyl) Sulfonium, (7-methoxy-2-oxo-2H-chromen-4-yl) dimethyl sulfonium, (4-methoxynaphthalen-1-yl) dimethyl sulfonium, dimethyl (p-isopropoxycarbonylphenyl) sulfonium, dimethyl ( 2-naphthyl) sulfonium, dimethyl (9-anthrill) sulfonium, diethylphenylsulfonium, methylethylphenylsulfonium, methyldiphenylsulfonium, triphenylsulfonium, diisopropylphenylsulfonium, diphenyl (4-phenylsulfonyl-phenyl) -sulfonium, 4,4 '-Bis (diphenylsulfonium) diphenylsulfide, 4,4'-bis [di [(4- (2-hydroxy-ethoxy) -phenyl)] sulfonium]] diphenylsulfide, 4,4'-bis (diphenylsulfonium) biphenylene , Diphenyl (o-fluorophenyl) sulfonium, diphenyl (m-chlorophenyl) sulfonium, diphenyl (p-bromophenyl) sulfonium, diphenyl (p-cyanophenyl) sulfonium, diphenyl (m-nitrofe) Nyl) sulfonium, diphenyl (2,4,6-tribromophenyl) sulfonium, diphenyl (pentafluorophenyl) sulfonium, diphenyl (p- (trifluoromethyl) phenyl) sulfonium, diphenyl (p-hydroxyphenyl) sulfonium, diphenyl ( p-mercaptophenyl) sulfonium, diphenyl (p-methylsulfinylphenyl) sulfonium, diphenyl (p-methylsulfonylphenyl) sulfonium, diphenyl (o-acetylphenyl) sulfonium, diphenyl (o-benzoylphenyl) sulfonium, diphenyl (p-methyl) Phenyl) sulfonium, diphenyl (p-isopropylphenyl) sulfonium, diphenyl (p-octadecylphenyl) sulfonium, diphenyl (p-cyclohexylphenyl) sulfonium, diphenyl (p-methoxyphenyl) sulfonium, diphenyl (o-methoxycarbonylphenyl) sulfonium, Diphenyl (p-phenylsulfanylphenyl) sulfonium, (7-methoxy-2-oxo-2H-chromen-4-yl) diphenylsulfonium, (4-methoxynaphthalen-1-yl) diphenylsulfonium, diphenyl (p-isopropoxycarbonyl) Phenyl) sulfonium, diphenyl (2-naphthyl) sulfonium, diphenyl (9-anthrill) sulfonium, ethyldiphenylsulfonium, methylethyl (o-tolyl) sulfonium, methyldi (p-tolyl) sulfonium, tri (p-tolyl) sulfonium, diisopropyl Examples thereof include (4-phenylsulfanylphenyl) sulfonium, diphenyl (2-thienyl) sulfonium, diphenyl (2-furyl) sulfonium, diphenyl (9-ethyl-9H carbazole-3-yl) sulfonium, but are limited thereto. It is not something that is done.

Onium cation (sulfoxonium cation) corresponding to the general formula (5):
Dimethylphenylsulfoxonium, dimethyl (o-fluorophenyl) sulfoxonium, dimethyl (m-chlorophenyl) sulfoxonium, dimethyl (p-bromophenyl) sulfoxonium, dimethyl (p-cyanophenyl) sulfoxonium, dimethyl (M-Nitrophenyl) Sulfoxonium, Dimethyl (2,4,6-Tribromophenyl) Sulfoxonium, Dimethyl (Pentafluorophenyl) Sulfoxonium, Dimethyl (p- (Trifluoromethyl) Phenyl) Sulfoxonium , Dimethyl (p-hydroxyphenyl) sulfoxonium, dimethyl (p-mercaptophenyl) sulfoxonium, dimethyl (p-methylsulfinylphenyl) sulfoxonium, dimethyl (p-methylsulfonylphenyl) sulfoxonium, dimethyl (o) -Acetylphenyl) sulfoxonium, dimethyl (o-benzoylphenyl) sulfoxonium, dimethyl (p-methylphenyl) sulfoxonium, dimethyl (p-isopropylphenyl) sulfoxonium, dimethyl (p-octadecylphenyl) sulfoxonium Nium, dimethyl (p-cyclohexylphenyl) sulfoxonium, dimethyl (p-methoxyphenyl) sulfoxonium, dimethyl (o-methoxycarbonylphenyl) sulfoxonium, dimethyl (p-phenylsulfanylphenyl) sulfoxonium, (7) −methoxy-2-oxo-2H-chromen-4-yl) dimethylsulfoxonium, (4-methoxynaphthalene-1-yl) dimethylsulfoxonium, dimethyl (p-isopropoxycarbonylphenyl) sulfoxonium, dimethyl ( 2-naphthyl) sulfoxonium, dimethyl (9-anthryl) sulfoxonium, diethylphenylsulfoxonium, methylethylphenylsulfoxonium, methyldiphenylsulfoxonium, triphenylsulfoxonium, diisopropylphenylsulfoxonium, diphenyl (4-Phenylsulfanyl-phenyl) -sulfoxonium, 4,4'-bis (diphenylsulfoxonium) diphenylsulfide, 4,4'-bis [di [(4- (2-hydroxy-ethoxy) -phenyl) ] Sulfoxysonium] Diphenyl sulfide, 4,4'-bis (diphenyl sulfoxonium) biphenylene, diphenyl (o-fluorophenyl) sulfoxonium, diphenyl (m-) Chlorophenyl) sulfoxonium, diphenyl (p-bromophenyl) sulfoxonium, diphenyl (p-cyanophenyl) sulfoxonium, diphenyl (m-nitrophenyl) sulfoxonium, diphenyl (2,4,6-tribromophenyl) ) Sulfoxonium, diphenyl (pentafluorophenyl) sulfoxonium, diphenyl (p- (trifluoromethyl) phenyl) sulfoxonium, diphenyl (p-hydroxyphenyl) sulfoxonium, diphenyl (p-mercaptophenyl) sulfoxo Nium, diphenyl (p-methylsulfinylphenyl) sulfoxonium, diphenyl (p-methylsulfonylphenyl) sulfoxonium, diphenyl (o-acetylphenyl) sulfoxonium, diphenyl (o-benzoylphenyl) sulfoxonium, diphenyl ( p-Methylphenyl) sulfoxonium, diphenyl (p-isopropylphenyl) sulfoxonium, diphenyl (p-octadecylphenyl) sulfoxonium, diphenyl (p-cyclohexylphenyl) sulfoxonium, diphenyl (p-methoxyphenyl) sulfo Xonium, diphenyl (o-methoxycarbonylphenyl) sulfoxonium, diphenyl (p-phenylsulfanylphenyl) sulfoxonium, (7-methoxy-2-oxo-2H-chromen-4-yl) diphenylsulfoxonium, ( 4-methoxynaphthalene-1-yl) diphenylsulfoxonium, diphenyl (p-isopropoxycarbonylphenyl) sulfoxonium, diphenyl (2-naphthyl) sulfoxonium, diphenyl (9-anthryl) sulfoxonium, ethyldiphenylsulfo Xonium, methylethyl (o-tolyl) sulfoxonium, methyldi (p-tolyl) sulfoxonium, tri (p-tolyl) sulfoxonium, diisopropyl (4-phenylsulfanylphenyl) sulfoxonium, diphenyl (2-) Examples include, but are not limited to, thienyl) sulfoxonium, diphenyl (2-furyl) sulfoxonium, diphenyl (9-ethyl-9H carbazole-3-yl) sulfoxonium and the like.

Onium cation (phosphonium cation) corresponding to the general formula (6):
Examples of phosphonium cations:
Trimethylphenylphosphonium, triethylphenylphosphonium, tetraphenylphosphonium, triphenyl (p-fluorophenyl) phosphonium, triphenyl (o-chlorophenyl) phosphonium, triphenyl (m-bromophenyl) phosphonium, triphenyl (p-cyanophenyl) phosphonium , Triphenyl (m-nitrophenyl) phosphonium, triphenyl (p-phenylsulfanylphenyl) phosphonium, (7-methoxy-2-oxo-2H-chromen-4-yl) triphenylphosphonium, triphenyl (o-hydroxyphenyl) ) Phenylnium, triphenyl (o-acetylphenyl) phosphonium, triphenyl (m-benzoylphenyl) phosphonium, triphenyl (p-methylphenyl) phosphonium, triphenyl (p-isopropoxyphenyl) phosphonium, triphenyl (o-methoxy) Methoxyphenyl) phosphonium, triphenyl (1-naphthyl) phosphonium, triphenyl (9-anthryl) phosphonium, triphenyl (2-thienyl) phosphonium, triphenyl (2-furyl) phosphonium, triphenyl (9-ethyl-9H carbazole) -3-Il) Phenylnium and the like can be mentioned, but are not limited thereto.

Onium cation (pyridinium cation) corresponding to the general formula (7):
Example of pyridinium cation:
N-Phenylpyridinium, N- (o-chlorophenyl) pyridinium, N- (m-chlorophenyl) pyridinium, N- (p-cyanophenyl) pyridinium, N- (o-nitrophenyl) pyridinium, N- (p-acetylphenyl) ) Pyridinium, N- (p-isopropylphenyl) pyridinium, N- (p-octadecyloxyphenyl) pyridinium, N- (p-methoxycarbonylphenyl) pyridinium, N- (9-anthrill) pyridinium, 2-chloro-1- Phenylpyridinium, 2-cyano-1-phenylpyridinium, 2-methyl-1-phenylpyridinium, 2-vinyl-1-phenylpyridinium, 2-phenyl-1-phenylpyridinium, 1,2-diphenylpyridinium, 2-methoxy- 1-Phenylpyridinium, 2-Phenylpyridinium, 2-Acetyl-1- (p-tolyl) pyridinium, 2-methoxycarbonyl-1- (p-tolyl) pyridinium, 3-Fluoro-1-naphthylpyridinium, Examples thereof include, but are not limited to, 4-methyl-1- (2-furyl) pyridinium, N-methylpyridinium, N-ethylpyridinium and the like.

Onium cation (quinolinium cation) corresponding to the general formula (8):
Examples of quinolinium cations:
N-Methylquinolinium, N-Ethylquinolinium, N-Phenylquinolinium, N-naphthylquinolinium, N- (o-chlorophenyl) quinolinium, N- (m-chlorophenyl) quinolinium, N- (p) -Cyanophenyl) quinolinium, N- (o-nitrophenyl) quinolinium, N- (p-acetylphenyl) quinolinium, N- (p-isopropylphenyl) quinolinium, N- (p-octadecyloxyphenyl) quinolinium, N-( p-methoxycarbonylphenyl) quinolinium, N- (9-anthrill) quinolinium, 2-chloro-1-phenylquinolinium, 2-cyano-1-phenylquinolinium, 2-methyl-1-phenylquinolinium, 2-Vinyl-1-phenylquinolinium, 2-phenyl-1-phenylquinolinium, 1,2-diphenylquinolinium, 2-methoxy-1-phenylquinolinium, 2-phenoxy-1-phenylki Norinium, 2-acetyl-1-phenylquinolinium, 2-methoxycarbonyl-1-phenylquinolinium, 3-fluoro-1-phenylquinolinium, 4-methyl-1-phenylquinolinium, 2- Methoxy-1- (p-tolyl) quinolinium, 2-phenoxy-1- (2-furyl) quinolinium, 2-acetyl-1- (2-thienyl) quinolinium, 2-methoxycarbonyl-1-methylquinolinium, 3 −Fluoro-1-ethylquinolinium, 4-methyl-1-isopropylquinolinium and the like can be mentioned, but the present invention is not limited thereto.

Onium cation (isoquinolinium cation) corresponding to the general formula (9):
Examples of isoquinolinium cations:
N-Phenylisoquinolinium, N-methylisoquinolinium, N-ethylisoquinolinium, N- (o-chlorophenyl) isoquinolinium, N- (m-chlorophenyl) isoquinolinium, N- (p-cyanophenyl) Isoquinolinium, N- (o-nitrophenyl) isoquinolinium, N- (p-acetylphenyl) isoquinolinium, N- (p-isopropylphenyl) isoquinolinium, N- (p-octadecyloxyphenyl) isoquinolinium, N- (p-methoxycarbonyl) Phenyl) isoquinolinium, N- (9-anthrill) isoquinolinium, 1,2-diphenylisoquinolinium, N- (2-furyl) isoquinolinium, N- (2-thienyl) isoquinolinium, N-naphthylisoquinolinium, etc. It can be mentioned, but it is not limited to these.

Onium cations (benzoxadiazole cations, benzothiazolium cations) corresponding to the general formula (10):
Examples of benzoxadiazole cations:
N-Methylbenzoxazoleium, N-ethylbenzoxazoleium, N-naphthylbenzooxazoleium, N-phenylbenzoxazoleium, N- (p-fluorophenyl) benzoxazolium, N- (p-) Chlorophenyl) benzoxazolium, N- (p-cyanophenyl) benzoxazolium, N- (o-methoxycarbonylphenyl) benzoxazolium, N- (2-furyl) benzoxazolium, N- (o) -Fluorophenyl) benzoxazolium, N- (p-cyanophenyl) benzoxazolium, N- (m-nitrophenyl) benzoxazolium, N- (p-isopropoxycarbonylphenyl) benzoxazolium, N- (2-thienyl) benzoxazolium, N- (m-carboxyphenyl) benzoxazolium, 2-mercapto-3-phenylbenzoxazoleium, 2-methyl-3-phenylbenzoxazolium, 2 -Methylthio-3- (4-phenylsulfanylphenyl) benzoxazolium, 6-hydroxy-3- (p-tolyl) benzoxazolium, 7-mercapto-3-phenylbenzoxazolium, 4,5-difluoro -3-Ethylbenzoxazoleium and the like can be mentioned, but the present invention is not limited thereto.

Examples of benzothiazolium cations:
N-Methylbenzothiazolium, N-ethylbenzothiazolium, N-phenylbenzothiazolium, N- (1-naphthyl) benzothiazolium, N- (p-fluorophenyl) benzothiazolium, N -(P-Chlorophenyl) benzothiazolium, N- (p-cyanophenyl) benzothiazolium, N- (o-methoxycarbonylphenyl) benzothiazolium, N- (p-tolyl) benzothiazolium, N- (o-fluorophenyl) benzothiazolium, N- (m-nitrophenyl) benzothiazolium, N- (p-isopropoxycarbonylphenyl) benzothiazolium, N- (2-furyl) benzothia Zorium, N- (4-methylthiophenyl) benzothiazolium, N- (4-phenylsulfanylphenyl) benzothiazolium, N- (2-naphthyl) benzothiazolium, N- (m-carboxyphenyl) Benzothiazolium, 2-mercapto-3-phenylbenzothiazolium, 2-methyl-3-phenylbenzothiazolium, 2-methylthio-3-phenylbenzothiazolium, 6-hydroxy-3-phenylbenzothia Zorium, 7-mercapto-3-phenylbenzothiazolium, 4,5-difluoro-3-phenylbenzothiazolium and the like can be mentioned, but are not limited thereto.

Onium cation (frill or thienyl iodonium cation) corresponding to the general formula (11):
Difuryl iodonium, dithienyl iodonium, bis (4,5-dimethyl-2-frill) iodonium, bis (5-chloro-2-thienyl) iodonium, bis (5-cyano-2-frill) iodonium, bis (5-) Nitro-2-thienyl) iodonium, bis (5-acetyl-2-frill) iodonium, bis (5-carboxy-2-thienyl) iodonium, bis (5-methoxycarbonyl-2-frill) iodonium, bis (5-phenyl) -2-Frill) iodonium, bis (5- (p-methoxyphenyl) -2-thienyl) iodonium, bis (5-vinyl-2-frill) iodonium, bis (5-ethynyl-2-thienyl) iodonium, bis ( 5-Cyclohexyl-2-frill) iodonium, bis (5-hydroxy-2-thienyl) iodonium, bis (5-phenoxy-2-frill) iodonium, bis (5-mercapto-2-thienyl) iodonium, bis (5-) Butylthio-2-thienyl) iodonium, bis (5-phenylthio-2-thienyl) iodonium and the like can be mentioned, but the present invention is not limited thereto.

Onium cation (diaryliodonium cation) corresponding to the general formula (12):
Diphenyl iodonium, bis (p-tolyl) iodonium, bis (p-octylphenyl) iodonium, bis (p-octadecylphenyl) iodonium, bis (p-octyloxyphenyl) iodonium, bis (p-octadecyloxyphenyl) iodonium, phenyl (P-Octadecyloxyphenyl) iodonium, 4-isopropyl-4'-methyldiphenyl iodonium, (4-isobutylphenyl) -p-tolyl iodonium, bis (1-naphthyl) iodonium, bis (4-phenylsulfanylphenyl) iodonium, Phenyl (6-benzoyl-9-ethyl-9H-carbazole-3-yl) iodonium, (7-methoxy-2-oxo-2H-chromen-3-yl) -4'-isopropylphenyliodonium and the like can be mentioned. However, it is not limited to these.

^{Next, the counter anion X −} in the general formula (3) will be described.

^{The counter anion X −} in the general formula (3) is not particularly limited in principle, but a non-nucleophilic anion is preferable. When the counter anion X ⁻ is a non-nucleophilic anion, the nucleophilic reaction is unlikely to occur in the cation coexisting in the molecule or various materials used in combination, and as a result, the photoacid generator itself represented by the general formula (2) itself. And the stability of the composition using it over time can be improved. The non-nucleophilic anion here refers to an anion having a low ability to cause a nucleophilic reaction. Examples of such anions include PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , SbCl ₆ ⁻ _{, BiCl 5-} ⁻ , SnCl ₆ ⁻ , ClO ₄ ⁻ , dithiocarbamate anion, SCN ^{− and the} like.

Among the exemplary anions described above, particularly preferable ones as the general formula (3) in counter anion X- _is, ^PF 6 -, SbF ₆ ^- and AsF ₆ ^- and the like, particularly _preferably, ^PF 6 -, SbF ₆ ^- and the like.

Therefore, specific examples of the preferable onium salt constituting the photoacid generator that can be used in the present invention include specific examples of the structure of the onium cation represented by the above-exemplified general formulas (3) to (12). ^{_{PF 6 -, SbF 6 -,}} AsF 6 -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 - is a more onium salt consisting of an anion selected ^-, dithiocarbamate anion, SCN.

Specifically, "Cyracure UVI-6992", "Cyracure UVI-6974" (all manufactured by Dow Chemical Japan Co., Ltd.), "Adeka Putmer SP150", "Adeka Putmer SP152", "Adeka Putmer" SP170 "," ADEKA PUTMER SP172 "(above, ADEKA Corporation)," IRGACURE250 "(manufactured by Ciba Specialty Chemicals)," CI-5102 "," CI-2855 "(above, manufactured by Nippon Soda), "Sun Aid SI-60L", "Sun Aid SI-80L", "Sun Aid SI-100L", "Sun Aid SI-110L", "Sun Aid SI-180L" (all manufactured by Sanshin Kagaku Co., Ltd.), "CPI-100P", "CPI-100A" (all manufactured by Sun Appro Co., Ltd.), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044", "WPI-054", "WPI-055", "WPAG-281", "WPAG-567", and "WPAG-596" (all manufactured by Wako Pure Chemical Industries, Ltd.) are mentioned as preferable 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 0.05 to 5 parts by weight with respect to 100 parts by weight of the total amount of the curable component. It is more preferable, and it is particularly preferable that it is 0.1 to 3 parts by weight.

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

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

Examples of the polymer having one or more epoxy groups in the molecule include an epoxy resin, a bisphenol A type epoxy resin derived from bisphenol A and epichlorohydrin, and a bisphenol F type epoxy derived from bisphenol F and epichlorohydrin. Resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, diphenyl ether type epoxy resin, hydroquinone type epoxy resin, Naphthalene type epoxy resin, biphenyl type epoxy resin, fluorene type epoxy resin, polyfunctional epoxy resin such as trifunctional epoxy resin and tetrafunctional epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hidden in type epoxy resin , Isocyanurate type epoxy resin, aliphatic chain epoxy resin and the like, and these epoxy resins may be halogenated or hydrogenated. Examples of commercially available epoxy resin products include 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 Co., Ltd., seroxide series (2021, 2021P, 2083, 2085, 3000, etc.) manufactured by Daicel Chemical Co., Ltd., Epoxy series, EHPE Series, YD series manufactured by Nippon Steel Chemical Co., Ltd., YDF series, YDCN series, YDB series, phenoxy resin (polyhydroxypolyether synthesized from bisphenols and epichlorohydrin, which has epoxy groups at both ends; YP series, etc.), Examples include, but are not limited to, the Denacol series manufactured by Nagase ChemteX and the Epoxy series manufactured by Kyoeisha Chemical Co., Ltd. Two or more of these epoxy resins may be used in combination. When calculating the glass transition temperature Tg of the adhesive layer, compounds and polymers having an epoxy group are not included in the calculation.

(Compounds and polymers having an 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. Typical examples of such compounds include melamine compounds, amino resins, and silane coupling agents. When calculating the glass transition temperature Tg of the adhesive layer, compounds and polymers having an alkoxyl group are not included in the calculation.

The blending amount of the compound containing either the alkoxy group or the epoxy group is usually 30 parts by weight or less with respect to 100 parts by weight of the total amount of the curable component, and if the content of the compound in the composition is too large, it adheres. The property may be reduced and 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 2 parts by weight or more of the compound, and more preferably 5 parts by weight or more.

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

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

Preferred are 3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane.

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

As the silane coupling agent (D1) having an amino group, only one type may be used, or a plurality of types may be used in combination. Of these, in order to ensure good adhesion, 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 blending amount of the silane coupling agent is preferably in the range of 0.01 to 20 parts by weight, preferably 0.05 to 15 parts by weight, preferably 0.1 to 1 parts by weight, based on 100 parts by weight of the total amount of the curable component. It is more preferably 10 parts by weight. This is because if the blending amount exceeds 20 parts by weight, the storage stability of the adhesive deteriorates, and if it is less than 0.1 parts by weight, the effect of water resistance is not sufficiently exhibited. When calculating the glass transition temperature Tg of the adhesive layer, the silane coupling agent is not included in the calculation.

Specific examples of non-active energy ray-curable silane coupling agents other than the above include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltrimethoxy. Examples thereof include silane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatepropyltriethoxysilane, and imidazole silane.

<Additives other than the above>
Further, in the active energy ray-curable adhesive composition used in the present invention, various additives can be blended as other optional components as long as the object and effect of the present invention are not impaired. Examples of such additives include epoxy resins, polyamides, polyamideimides, polyurethanes, polybutadienes, polychloroprenes, polyethers, polyesters, styrene-butadiene block copolymers, petroleum resins, xylene resins, ketone resins, cellulose resins, and fluorine-based oligomers. Polymers or oligomers such as silicone-based oligomers and polysulfide-based oligomers; polymerization inhibitors such as phenothiazine and 2,6-di-t-butyl-4-methylphenol; polymerization initiators; leveling agents; wettability improvers; surface activity Agents; plasticizers; UV absorbers; inorganic fillers; pigments; dyes and the like.

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

<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 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 adjust the temperature to 100 cp or less. A more preferred range of viscosity is 1 to 80 cp, most preferably 10 to 50 cp. The viscosity can be measured using an E-type viscometer TVE22LT manufactured by Toki Sangyo Co., Ltd.

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

In the laminated optical film produced by the production method according to the present invention, at least the first optical film and the second optical film are formed through an adhesive layer formed by curing the active energy ray-curable adhesive composition. It is a laminated product.

<Adhesive layer>
The thickness of the adhesive layer formed by 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 that the thickness of the adhesive layer is 0.1 μm or more in order to prevent the occurrence of poor adhesion due to the cohesive force of the adhesive layer and the occurrence of poor appearance (air bubbles) during laminating. On the other hand, if the adhesive layer is thicker than 3 μm, the polarizing film may not be able to satisfy the durability.

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

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

The active energy ray-curable adhesive composition is preferably designed storage modulus of the adhesive layer thereby formed is such that the following regions 70 ℃ 1.0 × 10 6 ^Pa or more .. Further more preferably 1.0 × ¹⁰ 7 Pa or higher. The storage elastic modulus of the adhesive layer affects the polarizer cracks when the polarizing film is heat-cycled (-40 ° C to 80 ° C, etc.), and when the storage elastic modulus is low, defects of the polarizing element cracks occur. Cheap. The temperature range having a high storage elastic modulus is more preferably 80 ° C. or lower, and most preferably 90 ° C. or lower. The storage elastic modulus is measured at the same time as Tg (glass transition temperature) under the same measurement conditions using the 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.

In the method for producing a laminated optical film according to the present invention, at least the first optical film and the second optical film are laminated via an adhesive layer formed by curing an active energy ray-curable adhesive composition. A method for producing a laminated optical film, wherein the active energy ray-curable adhesive composition contains at least two active energy ray-curable adhesive compositions and a second active energy ray-curable adhesive composition. It contains more than one kind of different active energy ray-curable adhesive composition, and the first active energy ray-curable adhesive composition is applied to the bonding surface of the first optical film, and further, the first 2. A coating step of applying the second active energy ray-curable adhesive composition to the bonding surface of the optical film, a bonding step of bonding the first optical film and the second optical film, and the first. The first via the adhesive layer formed by irradiating active energy rays from the surface side of the optical film or the surface side of the second optical film to cure the active energy ray-curable adhesive composition. 1 It is characterized by including an adhesive step of adhering an optical film and the second optical film.

In another method for producing a laminated optical film according to the present invention, at least the first optical film and the second optical film are laminated via an adhesive layer formed by curing an active energy ray-curable adhesive composition. The method for producing a laminated optical film, wherein the active energy ray-curable adhesive composition includes a first active energy ray-curable adhesive composition and a second active energy ray-curable adhesive composition. It contains at least two or more different types of different active energy ray-curable adhesive compositions, and the first active energy ray-curable adhesive composition is applied to the bonding surface of the first optical film to obtain the above. A coating step of overcoating the coated surface coated with the first active energy ray-curable adhesive composition and further coating the second active energy ray-curable adhesive composition, and coating on the first optical film. A bonding step of bonding the second optical film from the coated surface side of the second active energy ray-curable adhesive composition, and a bonding step of bonding the first optical film and the second optical film. Through the adhesive layer formed by irradiating active energy rays from the surface side of the first optical film or the surface side of the second optical film to cure the active energy ray-curable adhesive composition, It is characterized by including an adhesion step of adhering the first optical film and the second optical film.

In the method for producing a laminated optical film according to the present invention, when the laminated optical film is a polarizing film, the polarizing element and the transparent protective film are surface-modified before applying the active energy ray-curable adhesive composition. Quality treatment may be performed. Specific treatments include corona treatment, plasma treatment, and saponification treatment.

The coating method of 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 a reverse coater, a gravure coater (direct, reverse and 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.

Two different optical films, such as a polarizer and a transparent protective film, are bonded together via the active energy ray-curable adhesive composition coated as described above. The polarizer and the transparent protective film can be bonded by a roll laminator or the like.

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

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

In the electron beam curing type, any appropriate conditions can be adopted as the electron beam irradiation conditions as long as the above-mentioned active energy ray-curable adhesive composition can be cured. For example, in electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the adhesive and curing may be insufficient. If the acceleration voltage exceeds 300 kV, the penetrating power through the sample is too strong and damages the transparent protective film and the polarizer. May be given. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the adhesive is insufficiently cured, and when it exceeds 100 kGy, the transparent protective film and the polarizer are damaged, the mechanical strength is lowered and yellowing occurs, and the predetermined optical characteristics are obtained. I can't.

The electron beam irradiation is usually performed in an inert gas, but if necessary, it may be performed in the atmosphere or under conditions in which a small amount of oxygen is introduced. Depending on the material of the transparent protective film, by appropriately introducing oxygen, oxygen inhibition can be caused on the surface of the transparent protective film that is first hit by the electron beam, and damage to the transparent protective film can be prevented, only for the adhesive. The electron beam can be efficiently irradiated.

In the method for producing a laminated optical film according to the present invention, particularly the method for producing a polarizing film, an amount of visible light having a wavelength range of 380 nm to 450 nm is contained as an active energy ray, particularly an amount of visible light having a wavelength range of 380 nm to 450 nm. It is preferable to use the most active energy rays. In the ultraviolet curable type and the visible light curable type, when a transparent protective film having an ultraviolet absorbing ability (ultraviolet opaque transparent protective film) is used, it absorbs light having a wavelength shorter than about 380 nm, and therefore has a wavelength shorter than 380 nm. Light does not reach the active energy ray-curable adhesive and does not contribute to its polymerization reaction. Further, the light having a wavelength shorter than 380 nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, which causes defects such as curl and wrinkles of the polarizing film. Therefore, when the ultraviolet curable type or the visible light curable type is adopted in the present invention, it is preferable to use a device that does not emit light having a wavelength shorter than 380 nm as an active energy ray generator, and more specifically, a wavelength range of 380. The ratio of the integrated illuminance of about 440 nm to the integrated illuminance of the wavelength range of 250 to 370 nm is preferably 100: 0 to 100: 50, and more preferably 100: 0 to 100:40. As the active energy ray according to the present invention, a gallium-filled metal halide lamp and an LED light source that emits a wavelength range of 380 to 440 nm are preferable. Alternatively, with ultraviolet rays 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, excima laser or sunlight. A light source containing visible light can be used, and a bandpass filter can be used to block ultraviolet rays having a wavelength shorter than 380 nm. In order to prevent curling of the polarizing film while improving the adhesive performance of the adhesive layer between the polarizer and the transparent protective film, a gallium-filled 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 bandpass filter or an active energy ray having a wavelength of 405 nm obtained by using an LED light source.

In the ultraviolet curable type or the visible light curable type, it is also preferable to heat the active energy ray-curable adhesive after irradiation with ultraviolet rays or visible light (warming after irradiation), and in that case, it is preferable to heat the adhesive to 40 ° C. or higher. , It is more preferable to heat to 50 ° C. or higher.

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

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

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

After adhering two different types of optical films, such as a polarizer and a transparent protective film, they are irradiated with active energy rays (electron beam, ultraviolet rays, visible light, etc.) to cure the active energy ray-curable adhesive. Form a layer. The moisture content of the polarizing element when the polarizer and the transparent protective film are bonded is usually 1% or more, preferably 3% or more, and more preferably 5% or more. If 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 is layer-separated, resulting in poor appearance. Is not preferable because it causes. The polarizer moisture content is preferably 18% or less, more preferably 15% or less, and most preferably 12% or less. For the water content of the polarizer, a 180 mm × 500 mm sample was cut out from the obtained polarizer, and the initial weight (W (g)) thereof was measured. The sample was left in a dryer at 120 ° C. for 6 hours, and then the weight (D (g)) after drying was measured. From these measured values, the water content was calculated by the following formula.
Moisture content (%) = {(WD) / W} x 100
The irradiation direction of the active energy rays (electron beam, ultraviolet rays, visible rays, etc.) can be any suitable direction. Preferably, the irradiation is performed from the transparent protective film side. When irradiated from the polarizer side, the polarizer may be deteriorated by active energy rays (electron beam, ultraviolet rays, visible light, etc.).

When the laminated optical film according to the present invention is produced 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 further preferably 10 to 100 m. / Min. If the line speed is too low, the productivity is poor, or the damage to the transparent protective film is too great, and a polarizing film that can withstand durability tests cannot be produced. If the line speed is too high, the adhesive may not be sufficiently cured and the desired adhesiveness may not be obtained.

In the method for producing a laminated optical film according to the present invention, when the laminated optical film is a polarizing film, the polarizer and the transparent protective film are adhered to each other formed by a cured product layer of the active energy ray-curable adhesive. Although they are bonded together via the agent layer, an easy-adhesive layer can be provided between the transparent protective film and the adhesive layer. The easy-adhesion layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based material, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins may be used alone or in combination of two or more. Further, other additives may be added to form the easy-adhesion layer. Specifically, a tackifier, an ultraviolet absorber, an antioxidant, a stabilizer such as a heat-resistant stabilizer, or the like may be used.

The easy-adhesion layer is usually provided in advance on the transparent protective film, and the easy-adhesion layer side of the transparent protective film and the polarizing element are bonded to each other by an adhesive layer. The easy-adhesive layer is formed by applying a material for forming the easy-adhesive layer onto a transparent protective film by a known technique and drying it. The material for forming the easy-adhesion 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 further preferably 0.05 to 1 μm. A plurality of easy-adhesive layers can be provided, but even in this case, it is preferable that the total thickness of the easy-adhesive layers is within the above range.

<Polarizer>
The production method according to the present invention is particularly useful as a production method for a polarizing film. The polarizer used in producing the polarizing film is not particularly limited, and various types can be used. As the polarizer, for example, a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymerization system partially saponified film, and two colors such as iodine and a bicolor dye are used. Examples thereof include a uniaxially stretched film obtained by adsorbing a sex material, a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrogenated product of polyvinyl chloride. Among these, a polarizer made 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 it can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it 3 to 7 times its original length. If necessary, it can be immersed in an aqueous solution such as boric acid or potassium iodide. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. In addition to being able to clean the surface of the polyvinyl alcohol film and blocking inhibitors by washing the polyvinyl alcohol film with water, it also has the effect of preventing non-uniformity such as uneven dyeing by swelling the polyvinyl alcohol film. be. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. It can be stretched in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Further, the active energy ray-curable adhesive composition used in the present invention has an effect (optical durability in a harsh environment under high temperature and high humidity) when a thin polarizing element having a thickness of 10 μm or less is used as the polarizer. Can be remarkably expressed. The above-mentioned polarizer having a thickness of 10 μm or less has a relatively large influence of moisture as compared with a polarizer having a thickness of more than 10 μm, has insufficient optical durability in an environment of high temperature and high humidity, and has increased transmittance and degree of polarization. Decrease is likely to occur. That is, when the above-mentioned polarizer of 10 μm or less is laminated with the adhesive layer having a bulk water absorption of 10% by weight or less of the present invention, the movement of water to the polarizer is suppressed in a harsh high temperature and high humidity environment. As a result, deterioration of optical durability such as an increase in the transmittance of the polarizing film and a decrease in the degree of polarization can be remarkably suppressed. The thickness of the polarizer is preferably 1 to 7 μm from the viewpoint of thinning. It is preferable that such a thin polarizing element has less uneven thickness, excellent visibility, less dimensional change, and can be made thinner as a polarizing film.

Typical examples of the thin polarizing element include JP-A-51-069644, JP-A-2000-338329, WO2010 / 100917 pamphlet, PCT / JP2010 / 00146, or Japanese Patent Application No. 2010-. Examples thereof include the thin polarizing film described in the specification of No. 269002 and the specification of Japanese Patent Application No. 2010-263692. 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 PVA-based resin) layer and a resin base material for stretching in a laminated state and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching because it is supported by the stretching resin base material.

Among the manufacturing methods including a step of stretching in a laminated state and a step of dyeing, the thin polarizing film can be stretched at a high magnification and the polarization performance can be improved. It is preferably obtained by a production method including a step of stretching in an aqueous boric acid solution as described in JP2010 / 00460, or in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692, particularly preferably. It is preferably obtained by a production method including a step of auxiliary stretching in the air before stretching in the boric acid aqueous solution described in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692.

The thin and high-performance polarizing film described in the above description of PCT / JP2010 / 00160 is a thin 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 integrally formed on a resin substrate. It is a high-performance polarizing film and has optical characteristics such as a single transmittance of 42.0% or more and a degree of polarization of 99.95% or more.

In the thin and high-performance polarizing film, a PVA-based resin layer is formed by applying 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 used as a dyeing solution for a dichroic substance. Dichroic substance is adsorbed on the PVA-based resin layer by immersing in It can be produced by stretching so as to be 5 times or more of.

Further, it is a method for producing a laminated film containing a thin and highly functional polarizing film in which a bicolor substance is oriented, and contains a resin base material having a thickness of at least 20 μm and a PVA-based resin on one side of the resin base material. The laminate containing a step of producing a laminate film containing a PVA-based resin layer formed by applying and drying an aqueous solution, and a PVA-based resin layer formed on one side of the resin base material and the resin base material. A step of adsorbing a bicolor substance on a PVA-based resin layer contained in a laminated film by immersing the film in a dyeing solution containing a bicolor substance, and a PVA-based resin adsorbing the bicolor substance. The step of stretching the laminated film containing the layer so that the total draw ratio is 5 times or more of the original length in the boric acid aqueous solution, and the PVA-based resin layer on which the bicolor substance is adsorbed are the resin base material. The thickness is 7 μm or less, the single permeability is 42.0% or more, and the degree of polarization is 99. The thin and highly functional polarizing film can be produced by including the step of producing a laminated film obtained by forming a thin and highly functional polarizing film having an optical characteristic of .95% or more.

The thin polarizing film of Japanese Patent Application No. 2010-269002 and 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 is amorphous. The laminate containing the PVA-based resin layer formed on the ester-based thermoplastic resin base material was stretched in a two-step stretching step consisting of aerial auxiliary stretching and boric acid water stretching to obtain a thickness of 10 μm or less. It is a thing. In such a thin polarizing film, when the simple substance transmittance is T and the degree of polarization is P, P>-(10 ^{0.929T-42.4-1} ) × 100 (where T <42.3), and P ≧ It is preferable that the material has optical characteristics that satisfy the condition of 99.9 (however, T ≧ 42.3).

Specifically, the thin polarizing film is a stretching intermediate composed of a PVA-based resin layer oriented by high-temperature stretching in the air with respect to a PVA-based resin layer formed on a continuous web amorphous ester-based thermoplastic resin base material. Colored intermediate formation consisting of a PVA-based resin layer in which a bicolor substance (preferably iodine or a mixture of iodine and an organic dye) is oriented by a step of producing a product and adsorption of the bicolor substance to the stretching intermediate product. A thin polarizing film including a step of forming a substance and a step of forming a polarizing film having a thickness of 10 μm or less composed of a PVA-based resin layer in which a bicolor substance is oriented by stretching in boric acid with respect to a colored intermediate product. It can be manufactured by a manufacturing method.

In this production method, the total draw ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin base material by high-temperature stretching in the air and stretching in water boric acid is set to 5 times or more. desirable. The liquid temperature of the boric acid aqueous solution for stretching in boric acid water can be 60 ° C. or higher. Before stretching the colored intermediate product in the boric acid aqueous solution, it is desirable to insolubilize the colored intermediate product. In that case, the colored intermediate product is added to the boric acid aqueous solution whose liquid temperature does not exceed 40 ° C. It is desirable to do this by immersing. The amorphous ester-based thermoplastic resin base material is an amorphous polyethylene containing copolymerized polyethylene terephthalate copolymerized with isophthalic acid, copolymerized polyethylene terephthalate copolymerized with cyclohexanedimethanol, or other copolymerized polyethylene terephthalate. It can be made of terephthalate, preferably made of a transparent resin, and its thickness can be 7 times or more the thickness of the PVA-based resin layer to be formed. The stretching ratio of the high-temperature stretching in the air is preferably 3.5 times or less, and the stretching temperature of the high-temperature stretching in the air 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 high-temperature stretching in the air is performed 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 high-temperature stretching in the air is performed by uniaxial stretching at a fixed end, 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 preferable.

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 6 mol% of isophthalic acid is prepared. The glass transition temperature of amorphous PET is 75 ° C. A laminate composed of an amorphous PET substrate of a continuous web 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 PVA aqueous solution having a degree of polymerization of 1000 or more and a PVA powder having a degree of polymerization of 99% or more dissolved in water and having a concentration of 4 to 5% are prepared. Next, a PVA aqueous solution is applied to a 200 μm-thick amorphous PET base material 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 base material. ..

A thin, high-performance polarizing film having a thickness of 3 μm is produced from a laminate containing a PVA layer having a thickness of 7 μm through the following steps including a two-step stretching step of auxiliary stretching in the air and stretching in boric acid in water. By the first-stage aerial auxiliary stretching step, the laminated body containing the PVA layer having a thickness of 7 μm is stretched integrally with the amorphous PET substrate to produce a stretched laminated body containing the PVA layer having a thickness of 5 μm. Specifically, this stretched laminate is subjected to a stretching device provided in an oven set to a stretching temperature environment of 130 ° C. to obtain a stretching ratio of 1.8 times. It is stretched uniaxially at the free end. By this stretching treatment, the PVA layer contained in the stretched laminate is changed into a 5 μm-thick PVA layer in which PVA molecules are oriented.

Next, the dyeing step produces a colored laminate in which iodine is adsorbed on a 5 μm-thick PVA layer in which PVA molecules are oriented. Specifically, in this colored laminate, the stretched laminate is mixed with a dyeing solution containing iodine and potassium iodide at a liquid temperature of 30 ° C., and the single transmittance of the PVA layer constituting the high-performance polarizing film finally produced is obtained. Iodine is adsorbed on the PVA layer contained in the stretched laminate by immersing it for an arbitrary time so that the content is 40 to 44%. In this step, the dyeing solution uses water as a solvent and has an iodine concentration in the range of 0.12 to 0.30% by weight and a potassium iodide concentration in the range of 0.7 to 2.1% by weight. The ratio of iodine to potassium iodide concentrations is 1: 7. By the way, potassium iodide is required to dissolve iodine in water. More specifically, by immersing the stretched laminate 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, iodine is added to a 5 μm-thick PVA layer in which PVA molecules are oriented. To produce a colored laminate in which iodine is adsorbed.

Further, by the second step of stretching in boric acid in water, the colored laminate is further stretched integrally with the amorphous PET substrate to generate an optical film laminate containing a PVA layer constituting a high-performance polarizing film having a thickness of 3 μm. do. Specifically, this optical film laminate is stretched by subjecting the colored laminate to a stretching device installed in a processing device set in a boric acid aqueous solution having a liquid temperature range of 60 to 85 ° C. containing boric acid and potassium iodide. It is stretched uniaxially at the free end so that the magnification is 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 with respect to 100 parts by weight of water and a potassium iodide content of 5 parts by weight with respect to 100 parts by weight of water. In this step, the colored laminate having an adjusted iodine adsorption amount is first immersed in a boric acid aqueous solution for 5 to 10 seconds. After that, the colored laminate is passed as it is between a plurality of sets of rolls having different peripheral speeds, which is a stretching device deployed in the processing device, and the stretching ratio is freely increased to 3.3 times over 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 highly oriented in one direction as a polyiodine ion complex. This PVA layer constitutes a high-performance polarizing film of an optical film laminate.

Although not an essential step in the production of the optical film laminate, the optical film laminate was taken out from the boric acid aqueous solution by the cleaning step and adhered to the surface of the 3 μm-thick PVA layer formed on the amorphous PET substrate. It is preferable to wash boric acid with an aqueous solution of potassium iodide. After that, the washed optical film laminate is dried by a drying step with warm air at 60 ° C. The cleaning step is a step for eliminating appearance defects such as boric acid precipitation.

Similarly, although it is not an essential process for producing an optical film laminate, 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 process. However, after the 80 μm-thick triacetyl cellulose film is attached, 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 processes]
The method for producing a thin polarizing film may include other steps in addition to the above steps. Examples of other steps include an insolubilization step, a cross-linking step, a drying (adjustment of water content) step, and the like. Other steps can be performed at any suitable timing.

The insolubilization step is typically performed by immersing a PVA-based resin layer in an aqueous boric acid solution. By applying 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 with respect to 100 parts by weight of water. The liquid temperature of the insolubilizing bath (boric acid aqueous solution) is preferably 20 ° C to 50 ° C. Preferably, the insolubilization step is performed after the laminate is prepared and before the dyeing step and the underwater stretching step.

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

<Transparent protective film>
As the material for forming the transparent protective film provided on one side or both sides of the polarizer, those having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropic property and the like are preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples thereof include based polymers and polystyrene polymers. In addition, polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, polyolefin-based polymers such as ethylene / propylene copolymers, 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, allylate polymer, polyoxymethylene polymer, epoxy polymer, or the above. Polymer blends and the like are also examples of polymers that form the transparent protective film. The transparent protective film may contain one or more of any suitable additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a color retardant, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a colorant and the like. 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, still more 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.

Further, as the transparent protective film, a polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and a side Examples thereof include resin compositions containing thermoplastic resins having substituted and / or unsubstituted phenyls and nitrile groups in the chains. Specific examples include a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of a resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, problems such as unevenness due to distortion of the polarizing film can be eliminated, and since the moisture permeability is small, they are excellent in humidification durability.

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

As the material for forming the transparent protective film provided on one side or both sides of the polarizer, a material having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc. is preferable, and the moisture permeability is particularly 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. Moisture permeability is determined by the method described in 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; allylate resins; amide resins such as nylon and aromatic polyamides; polyethylene and polypropylene. , Polyethylene-based polymers such as ethylene / propylene copolymers, cyclic olefin-based resins having a cyclo-based or norbornene structure, (meth) acrylic-based resins, or mixtures thereof can be used. Among the resins, a polycarbonate resin, a cyclic polyolefin resin, and a (meth) acrylic resin are preferable, and a cyclic polyolefin resin and a (meth) acrylic resin are particularly preferable.

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

When the transparent protective films are provided on both sides of the polarizer, the transparent protective films made of the same polymer material may be used on the front and back sides thereof, or the transparent protective films made of different polymer materials may be used. As a combination of the transparent protective film, a combination of a polyethylene terephthalate film and a cyclic polyolefin resin film, a (meth) acrylic resin film and a cyclic polyolefin resin film, and a (meth) acrylic resin film and a (meth) acrylic resin film is available. It is preferable from the viewpoint of moisture permeability. By providing a transparent protective film having low moisture permeability on both sides of the polarizing element, 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 anti-sticking layer, a diffusion layer or an anti-glare layer can be provided on the surface of the transparent protective film to which the polarizer is not adhered. The functional layers such as the hard coat layer, the antireflection layer, the sticking prevention layer, the diffusion layer and the antiglare layer can be provided on the transparent protective film itself, and are separately provided separately from the transparent protective film. You can also do it.

<Optical film>
The polarizing film can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited, but is used for forming, for example, a reflector, a transflective plate, a retardation plate (including a wave plate such as 1/2 or 1/4), a liquid crystal display device such as a viewing angle compensation film, and the like. One or two or more optical layers that may be used can be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film in which a reflecting plate or a semi-transmissive 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 compensating film is further laminated on a film or a polarizing film, or a polarizing film in which a brightness improving film is further laminated on a polarizing film is preferable.

An optical film in which the above optical layer is laminated on a polarizing film can also be formed by a method of sequentially and separately laminating in a manufacturing process of a liquid crystal display or the like, but a pre-laminated optical film is of good quality. It is excellent in stability and assembly work, and has the advantage of being able to improve the manufacturing process of liquid crystal displays and the like. An appropriate adhesive means such as an adhesive layer may be used for laminating. When adhering the above-mentioned polarizing film and other optical films, their optical axes can be arranged at an appropriate arrangement angle according to a target phase difference characteristic or the like.

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

The adhesive layer can also be provided on one or both sides of a polarizing film or an optical film as a superimposing layer of different compositions or types. Further, when provided on both sides, adhesive layers having different compositions, types and thicknesses can be formed on the front and back surfaces of the polarizing film or the optical film. The thickness of the adhesive layer can be appropriately determined according to the purpose of use, adhesive strength, etc., and is generally 1 to 500 μm, preferably 1 to 200 μm, and particularly preferably 1 to 100 μm.

The exposed surface of the adhesive layer is temporarily covered with a separator for the purpose of preventing contamination until it is put into practical use. As a result, it is possible to prevent the adhesive layer from coming into contact with the adhesive layer in the usual handling state. As the separator, except for the above-mentioned thickness condition, for example, an appropriate thin leaf body such as a plastic film, a rubber sheet, a paper, a cloth, a non-woven fabric, a net, a foam sheet or a metal foil, or a laminate thereof may be used, if necessary, in a silicone type or a length. Appropriate conventional ones such as those coated with an appropriate release agent such as chain alkyl type, fluorine type and molybdenum sulfide can be used.

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

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

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

Manufacturing example 1
<Manufacturing of polyvinyl alcohol-based thin polarizing element (corresponding to the first optical film)>
In order to produce a thin polarizer, first, a laminated body in which a PVA layer having a thickness of 24 μm is formed on an amorphous PET substrate is subjected to aerial auxiliary stretching at a stretching temperature of 130 ° C. to produce a stretched laminated body, and then stretching. A colored laminate is produced by dyeing the laminate, and the colored laminate is further stretched integrally with the amorphous PET substrate by stretching in boric acid water at a stretching temperature of 65 ° C so that the total stretching ratio becomes 5.94 times. An optical film laminate containing a PVA layer having a thickness of 10 μm was produced. The PVA molecules in the PVA layer formed on the amorphous PET substrate by such two-step stretching are highly oriented, and the iodine adsorbed by dyeing is highly oriented in one direction as a polyiodine ion complex. It was possible to produce an optical film laminate containing a PVA layer having a thickness of 10 μm, which constitutes a polyvinyl alcohol-based thin polarizer.

Manufacturing example 2
<Making a transparent protective film (corresponding to the second optical film)>
A twin-screw kneader containing 100 parts by weight of the imidized MS resin and 0.62 parts by weight of a triazine-based ultraviolet absorber (trade name: T-712) described in Production Example 1 of JP-A-2010-284840. The mixture was mixed at 220 ° C. to prepare resin pellets. The obtained resin pellets were dried at 100.5 kPa at 100 ° C. for 12 hours and extruded from a T-die at a die temperature of 270 ° C. using a single-screw extruder to form a film (thickness 160 μm). Further, the film is stretched in an atmosphere of 150 ° C. in the transport direction (thickness 80 μm), then coated with an easy-adhesive containing an aqueous urethane resin, and then stretched in an atmosphere of 150 ° C. in a direction orthogonal to the film transport direction. Then, an acrylic film (transparent protective film) having a thickness of 40 μm (water permeability 58 g / m ^{2 / 24h) was obtained.}

<Humidity permeability of transparent protective film>
The moisture permeability was measured according to the JIS Z0208 moisture permeability test (cup method). A sample cut to a diameter of 60 mm was set in a moisture-permeable cup containing about 15 g of calcium chloride, and the temperature was 40 ° C. and the humidity was 90%. H. ^{The moisture permeability (g / m 2} / 24h) was determined by measuring the weight increase of calcium chloride before and after being placed in the thermostat and left for 24 hours.

<Active energy ray>
Visible light (gallium-filled metal halide lamp) as active energy rays Irradiator: Fusion UV Systems, Inc. Light HAMMER10 bulb: V bulb Peak illuminance: 1600 mW / cm ² , integrated irradiation dose 1000 / mJ / cm ² (wavelength 380-) 440 nm) was used. The illuminance of visible light was measured using a Solar-Check system manufactured by Solarll.

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

The compound used was
HEAA: Hydroxyethyl acrylamide, logPow = -0.56, manufactured by Kojinsha,
Light Acrylate 1,9ND-A: 1,9-Nonanediol Diacrylate, logPow = 3.68, manufactured by Kyoeisha Chemical Co., Ltd.,
IRGACURE907; 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, manufactured by BASF, Inc.
KAYACURE DETX-S; diethyl thioxanthone, manufactured by Nippon Kayaku Co., Ltd.,

(Preparation of polarizing film)
The PVA layer surface of the thin polarizing element corresponding to the first optical film was coated with a first active energy ray-curable adhesive composition which was heated to 40 ° C. and adjusted to a liquid viscosity of 80 cp (adhesive layer thickness). 0.3 μm). Further, the second active energy ray-curable adhesive composition is applied to the bonding surface of the transparent protective film corresponding to the second optical film (adhesive layer thickness 0.7 μm), and these are bonded with a roll machine. I matched it. The ratio of the first active energy ray-curable adhesive composition to the second active energy ray-curable adhesive composition is 30:70. Then, the visible light is irradiated on both sides to cure the first and second active energy ray-curable adhesive compositions, and then hot air dried at 70 ° C. for 3 minutes to put transparent protective films on both sides of the polarizer. A polarizing film (laminated optical film) was obtained. The bonding line speed was 25 m / min.

The polarizing film obtained in Example 1 was evaluated for its adhesive strength to a thin polarizing element and a transparent protective film. Further, the contact angle of the first active energy ray-curable adhesive composition with respect to the thin polarizing element and the contact angle of the second active energy ray-curable adhesive composition with respect to the transparent protective film were evaluated. The contact angle was evaluated based on JIS-K 6768. The evaluation results are shown in Table 2.

Example 2
Instead of the coating step of applying the second active energy ray-curable adhesive composition to the bonding surface of the transparent protective film corresponding to the second optical film, the thin polarizing element corresponding to the first optical film is bonded. Example 1 except that a coating step of further coating a second active energy ray-curable adhesive composition on a coated surface coated with the first active energy ray-curable adhesive composition was carried out. A polarizing film (laminated optical film) having transparent protective films on both sides of the polarizer was obtained by the same method as in the above.

Comparative Example 1
The first activity containing 47% by weight of HEAA, 1,9ND-A of light acrylate, 3% by weight of IRGACURE907, and 3% by weight of KAYACURE DETX-S on the bonding surface of the thin polarizing element corresponding to the first optical film. The same method as in Example 1 except that an energy ray-curable adhesive composition (liquid viscosity 21 mPa · s / 25 ° C.) was applied and a transparent protective film corresponding to the second optical film was attached thereto. A polarizing film (laminated optical film) having transparent protective films on both sides of the polarizer was obtained.

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

<Adhesive strength>
The polarizing film obtained in each example was cut into a size of 200 mm parallel to the stretching direction of the polarizer and 20 mm in the orthogonal direction, and a notch was made between the transparent protective film and the polarizer with a cutter knife to cut the polarizing film into glass. It was pasted on a board. The transparent protective film and the polarizer were peeled off at a peeling speed of 500 mm / min in the 90-degree direction with Tencilon, and the peeling strength was measured. In addition, 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 destruction of transparent protective film B: Interfacial peeling between transparent protective film / adhesive layer C: Interfacial peeling between adhesive layer / polarizer D: Cohesive destruction of polarizer In the above criteria, A and D are adhesive forces. Is more than the cohesive force of the film, which means that the adhesive force is very excellent. On the other hand, B and C mean that the adhesive strength at the transparent protective film / adhesive layer (adhesive layer / polarizer) interface is insufficient (adhesive strength is inferior). In consideration of these, the adhesive strength in the case of A or D is ○, A / B (“cohesive failure of transparent protective film” and “interfacial peeling between transparent protective film / adhesive layer” occur at the same time) or A. -The adhesive strength in the case of C (“aggregation breakage of transparent protective film” and “interfacial peeling between adhesive layer / polarizer” occur at the same time) is Δ, and the adhesive strength in the case of B or C is ×. do.

Claims (9)

A method for producing a polarizing film in which at least a first optical film and a second optical film are laminated via an adhesive layer formed by curing an active energy ray-curable adhesive composition.
The first optical film and the second optical film are of different types.
The thickness of the adhesive layer is 0.1 to 3 μm.
The active energy ray-curable adhesive composition comprises at least two or more different active energy ray-curable adhesive compositions, including a first active energy ray-curable adhesive composition and a second active energy ray-curable adhesive composition. It contains an agent composition and
The first active energy ray-curable adhesive composition has a high affinity with the first optical film, and the second active energy ray-curable adhesive composition has a high affinity with the second optical film.
The first active energy ray-curable adhesive composition is applied to the bonding surface of the first optical film, and the second active energy ray-curable adhesive composition is further coated on the bonding surface of the second optical film. And the coating process
The bonding step of bonding the first optical film and the second optical film, and
Through the adhesive layer formed by irradiating active energy rays from the surface side of the first optical film or the surface side of the second optical film to cure the active energy ray-curable adhesive composition, A method for producing a polarizing film, which comprises an bonding step of adhering the first optical film and the second optical film. A method for producing a polarizing film in which at least a first optical film and a second optical film are laminated via an adhesive layer formed by curing an active energy ray-curable adhesive composition.
The first optical film and the second optical film are of different types.
The thickness of the adhesive layer is 0.1 to 3 μm.
The active energy ray-curable adhesive composition comprises at least two or more different active energy ray-curable adhesive compositions, including a first active energy ray-curable adhesive composition and a second active energy ray-curable adhesive composition. It contains an agent composition and
The first active energy ray-curable adhesive composition has a high affinity with the first optical film, and the second active energy ray-curable adhesive composition has a high affinity with the second optical film.
The first active energy ray-curable adhesive composition is coated on the bonded surface of the first optical film, and the coated surface coated with the first active energy ray-curable adhesive composition is further coated with the first active energy ray-curable adhesive composition. 2 The coating process of overcoating the active energy ray-curable adhesive composition and
A bonding step of bonding the second optical film from the coated surface side of the second active energy ray-curable adhesive composition coated on the first optical film, and
Through the adhesive layer formed by irradiating active energy rays from the surface side of the first optical film or the surface side of the second optical film to cure the active energy ray-curable adhesive composition, A method for producing a polarizing film, which comprises an bonding step of adhering the first optical film and the second optical film. The method for producing a polarizing film according to claim 2, wherein the liquid viscosity of the first active energy ray-curable adhesive composition is higher than the liquid viscosity of the second active energy ray-curable adhesive composition. The active energy ray-curable adhesive composition is any one of claims 1 to 3 which is an active energy ray-curable adhesive composition containing no oligomer having a diene-based or hydrogenated diene-based skeleton. The method for producing a polarizing film according to. The first optical film and the second optical film are at least one optical film selected from the group consisting of a polyvinyl alcohol-based polarizer, an acrylic resin film, a cycloolefin resin film, a polyester resin film, and a polyolefin resin film. The method for producing a polarizing film according to any one of claims 1 to 4. Claim that the first optical film and the second optical film are at least one optical film selected from the group consisting of the acrylic resin film, the cycloolefin resin film, the polyester resin film and the polyolefin resin film. 5. The method for producing a polarizing film according to 5. The acrylic resin film, the cycloolefin resin film, the polyester resin film, and the polyolefin resin film are selected from the group consisting of an acrylic resin, a polyurethane resin, a polyvinyl alcohol resin, a melamine resin, and an oxazoline group-containing resin on the bonding surface thereof. The method for producing a polarizing film according to claim 5 or 6, wherein an easy-adhesion layer containing at least one kind of resin is formed. The polarized light according to claim 6 or 7, wherein the active energy ray-curable adhesive composition contains 25 to 98% by weight of a radically polymerizable compound having an SP value of 18 to 21 (MJ / m ³ ) ^1/2. Film manufacturing method. The method for producing a polarizing film according to any one of claims 1 to 8, wherein the polarizing film includes at least a polarizing element.

Images