Curable resin composition, polarizing film, laminated optical film, and image display device

Abstract

The present invention provides a curable resin composition containing a component (A) which is at least one selected from the group consisting of (meth) acrylic acid-modified polybutadiene and (meth) acrylic acid-modified polyisoprene, and a component (B) which contains a (meth) acrylic acid ester monomer. Also provided is a polarizing film in which an optical film is laminated on at least one surface of a polarizer with an adhesive layer interposed therebetween, the adhesive layer being a cured product layer of the curable resin composition.

Description

Technical Field

[0001] The present invention relates to a curable resin composition as a raw material of an adhesive layer of a polarizing film in which an optical film is laminated via an adhesive layer on at least one surface of a polarizer, and a polarizing film. The polarizing film can be formed alone or in the form of a laminated optical film in which the polarizing film is laminated to form an image display device such as a liquid crystal display device (LCD), an organic EL display device, a CRT, or a PDP. Background Art

[0002] In watches, mobile phones, PDAs, laptop computers, computer monitors, DVD players, TVs, etc., liquid crystal display devices are rapidly opening up the market. A liquid crystal display device is a device that visualizes the polarization state of a switch based on liquid crystal. Based on its display principle, a polarizer is used. Especially in applications such as TVs, higher brightness, higher contrast, and a wider viewing angle are increasingly required, and higher transmittance, higher degree of polarization, and higher color reproducibility are also increasingly required for polarizing films.

[0003] As a polarizer, from the aspect of having high transmittance and high degree of polarization, an iodine-based polarizer having a structure in which iodine is adsorbed on polyvinyl alcohol (hereinafter, also simply referred to as "PVA") and stretched is generally most widely used. Generally, as a polarizing film, a polarizing film in which transparent protective films are adhered to both surfaces of a polarizer using a so-called aqueous adhesive obtained by dissolving a polyvinyl alcohol-based material in water (Patent Document 1 below) is used. As the transparent protective film, triacetyl cellulose having a high moisture permeability is used. In the case of using the above aqueous adhesive (so-called wet lamination), after adhering the polarizer and the transparent protective film, a drying process is required.

[0004] On the other hand, a proposal has been made to use a radiation curable adhesive instead of the above aqueous adhesive. In the case of manufacturing a polarizing film using a radiation curable adhesive, since a drying process is not required, the productivity of the polarizing film can be improved. For example, the present inventors have proposed a radical polymerization type radiation curable adhesive using an N-substituted amide monomer as a curable component (Patent Document 2 below).

[0005] In addition, Patent Document 3 below describes a polarizing sheet sequentially including a polarizer, an adhesive layer, and a thermoplastic resin film, wherein the adhesive layer is a cured product layer of a curable adhesive composition including a maleic anhydride-modified compound (A), a (meth)acrylate compound (B), and a photopolymerization initiator (C). Further, Patent Document 4 below describes a curable adhesive composition including a maleic anhydride-modified compound (A), unmodified polybutadiene (B), a (meth)acrylate compound (C), and a photopolymerization initiator (D).

[0006] Prior Art Documents

[0007] Patent document

[0008] Patent document 1: Japanese Unexamined Patent Application Publication No. 2001-296427

[0009] Patent document 2: Japanese Unexamined Patent Application Publication No. 2012-052000

[0010] Patent document 3: Japanese Unexamined Patent Application Publication No. 2021-157164

[0011] Patent document 4: Japanese Unexamined Patent Application Publication No. 2022-104564 Summary of the invention

[0012] Problems to be solved by the invention

[0013] The adhesive layer formed of the active energy ray curable adhesive described in Patent Document 2 can sufficiently withstand a water resistance test for evaluating, for example, whether there is discoloration or peeling after immersion in warm water at 60°C for 6 hours. However, in recent years, in addition to the water resistance test being gradually replaced with more severe conditions, there has been an increasing demand for maintaining the humidity resistance reliability for improving the polarization characteristics of the polarizing film. Therefore, as a matter of fact, including the active energy ray curable adhesive described in Patent Document 2, the polarizing film adhesives reported so far have room for further improvement, particularly in terms of the humidity resistance reliability of the polarization characteristics.

[0014] It should be noted that the technologies described in Patent Documents 3 and 4 are aimed at improving the adhesion between the polarizer and the thermoplastic resin film, and are not technologies that can improve the humidity resistance reliability of the polarization characteristics of the polarizing film.

[0015] The present invention has been developed in view of the above actual situation, and aims to provide a curable resin composition that is a raw material for a polarizing film having excellent humidity resistance reliability of polarization characteristics, and a polarizing film having excellent humidity resistance reliability of polarization characteristics.

[0016] Furthermore, it aims to provide a laminated optical film using the above polarizing film, and an image display device using the above polarizing film or optical film.

[0017] Means for solving the problems

[0018] The above problems can be solved by the following configuration. That is, the present invention relates to a curable resin composition (1) containing component (A) and component (B), wherein component (A) is at least one selected from (meth)acrylic acid modified polybutadiene and (meth)acrylic acid modified polyisoprene, and component (B) contains a (meth)acrylate monomer.

[0019] In the above curable resin composition (1), curable resin composition (2) is preferred, wherein when the total amount of the composition is 100% by mass, the content of the above component (A) is 1 to 80% by mass.

[0020] In the above curable resin composition (1) or (2), curable resin composition (3) is preferred, wherein as the above component (B), (B-1) contains a (meth)acrylate monomer having a logPow of octanol / water partition coefficient of 3 or more. When the total amount of the composition is 100% by mass, the content of the above (meth)acrylate monomer (B-1) is 1 to 80% by mass.

[0021] In addition, the present invention relates to a polarizing film (4) which is a polarizing film in which an optical film is laminated on at least one surface of a polarizer via an adhesive layer, wherein the above adhesive layer is a cured product layer of any one of the curable resin compositions (1) to (3).

[0022] In the above polarizing film (4), polarizing film (5) is preferred, wherein in the above curable resin composition, when the total amount of the composition is 100% by mass, the content of the above component (A) is 1 to 80% by mass.

[0023] In the above polarizing film (4) or (5), polarizing film (6) is preferred, wherein the above curable resin composition contains a (meth)acrylate monomer (B-1) having a logPow of octanol / water partition coefficient of 3 or more as the above component (B). When the total amount of the composition is 100% by mass, the content of the above (meth)acrylate monomer (B-1) is 1 to 80% by mass.

[0024] In addition, the present invention relates to a laminated optical film (7) in which at least one of the above polarizing films (4) to (6) is laminated. Further, the present invention relates to an image display device (8) in which any one of the above polarizing films (4) to (6) or the above laminated optical film (7) is used.

[0025] Effects of the Invention

[0026] The curable resin composition of the present invention contains component (A) and component (B). Component (A) is at least one selected from (meth)acrylate-modified polybutadiene and (meth)acrylate-modified polyisoprene, and component (B) contains a (meth)acrylate monomer. The humidity resistance reliability of the polarization characteristics of a polarizing film having a cured product layer of such a curable resin composition as an adhesive layer is excellent. The reason for obtaining such an effect is not clear yet, but it can be presumed as follows.

[0027] In order to improve the degree of polarization of a polarizing film, it is necessary to maintain a high level of iodine concentration in a polarizer. However, under high temperature and high humidity conditions, iodine leakage from the polarizer occurs (hereinafter, also referred to as "iodine leakage"), and as a result, there is a tendency for the iodine concentration in the polarizer to decrease and the polarization characteristics to deteriorate. The component (A) selected from at least one of (meth)acrylic acid-modified polybutadiene and (meth)acrylic acid-modified polyisoprene contained in the curable resin composition of the present invention reacts with the component (B) containing a (meth)acrylate monomer via a (meth)acrylate group, and thus is uniformly dispersed in the adhesive layer. Since the component (A) has high hydrophobicity, the overall hydrophobicity of the adhesive layer is also increased. However, since the thickness of the adhesive layer is thin, water permeability is often exhibited. However, the inventors of the present invention conducted in-depth research and found that the adhesive layer containing the component (A) can suppress iodine from passing through the adhesive layer while allowing a certain degree of water to pass through, thereby exhibiting the effect of retaining iodine in the polarizer. That is to say, the adhesive layer formed from the curable resin composition of the present invention exhibits the effect of suppressing iodine leakage from the polarizer by introducing the component (A) into the adhesive layer while forming a covalent bond with the component (B). As a result, the humidity resistance reliability of the polarization characteristics can be improved.

[0028] It should be noted that in the polarizing film of the present invention, the improvement of the humidity resistance reliability of the polarization characteristics is attributed to the fact that the polybutadiene and polyisoprene constituting the component (A) are (meth)acrylic acid-modified. When the component (A) does not have a (meth)acrylate group, that is, when it is unmodified polybutadiene that has not been modified with (meth)acrylate, since it cannot react with the component (B), it cannot be introduced into the polymer constituting the adhesive layer. As a result, there is a tendency for the cured product layer (adhesive layer) to become brittle, especially as the blending amount increases. Therefore, there is a tendency that, for example, the polarizer as the adherend and the optical film are likely to peel off in a hot and humid environment and cannot be used as a polarizing film. Detailed Description

[0029] The curable resin composition of the present invention contains a component (A) and a component (B). The component (A) is at least one selected from (meth)acrylic acid-modified polybutadiene and (meth)acrylic acid-modified polyisoprene, and the component (B) contains a (meth)acrylate monomer. Hereinafter, each component will be described.

[0030] <Component (A)>

[0031] The curable resin composition of the present invention contains a component (A), and the component (A) is at least one selected from (meth)acrylic acid-modified polybutadiene and (meth)acrylic acid-modified polyisoprene.

[0032] (Meth)acrylic acid-modified polybutadiene has at least one basic unit selected from the basic unit obtained by 1,2-addition of butadiene monomer, the basic unit obtained by cis-1,4-addition, and the basic unit obtained by trans-1,4-addition, and at least one (meth)acrylate group. For example, a compound represented by the following formula can be suitably used (wherein l, m, and n are integers of 0 or more, and the case where l, m, and n are all 0 is excluded):

[0033] [Chemical formula 1]

[0034] ;

[0035] Or a compound represented by the following formula:

[0036] [Chemical formula 2]

[0037] .

[0038] In addition, the basic unit obtained by 1,2-addition of butadiene monomer, the basic unit obtained by cis-1,4-addition, and the basic unit obtained by trans-1,4-addition may be at least partially hydrogenated basic units. For example, a compound represented by the following formula can also be suitably used:

[0039] [Chemical formula 3]

[0040] .

[0041] It should be noted that if the molecular weight of (meth)acrylic acid-modified polybutadiene is too high, the compatibility in the curable resin composition tends to deteriorate. On the other hand, if the molecular weight of (meth)acrylic acid-modified polybutadiene is too low, it is difficult to expect an improvement in the humidity resistance of the polarization characteristics of the polarizing film. Therefore, the molecular weight of (meth)acrylic acid-modified polybutadiene is preferably 1000 - 100000 (g / mol).

[0042] (Meth)acrylic acid-modified polyisoprene has at least one basic unit selected from the basic unit obtained by cis-1,4-addition of isoprene monomer and the basic unit obtained by trans-1,4-addition, and at least one (meth)acrylate group. For example, a compound represented by the following formula can be suitably used (wherein m and n are integers of 0 or more, and the case where m and n are all 0 is excluded):

[0043] [Chemical formula 4]

[0044] .

[0045] It should be noted that if the molecular weight of the (meth)acrylic acid-modified polyisoprene is too high, there is a tendency for its compatibility in the curable resin composition to deteriorate. On the other hand, if the molecular weight of the (meth)acrylic acid-modified polyisoprene is too low, it is difficult to expect an improvement in the humidity resistance of the polarization characteristics of the polarizing film. Therefore, the molecular weight of the (meth)acrylic acid-modified polyisoprene is preferably 1,000 to 100,000 (g / mol).

[0046] From the viewpoint of improving the humidity resistance of the polarization characteristics of the polarizing film, when the total amount of the composition is set to 100% by mass, the curable resin composition of the present invention preferably contains 1 to 80% by mass, more preferably 5 to 80% by mass of the component (A).

[0047] It should be noted that the component (A) generally has a high viscosity. If the content of the component (A) in the curable resin composition is increased, it may cause coating unevenness and other defects when coated on the polarizer or optical film, resulting in difficult coating. Therefore, for the curable resin composition of the present invention, when the content of the component (A) is large, water as a solvent can also be added for emulsification.

[0048] The water as a solvent preferably does not contain organic solvents such as alcohols. Even if it is assumed that it contains organic solvents such as alcohols, when the total amount of the solvent is set to 100% by weight, the content of the organic solvents such as alcohols is preferably 10% by weight or less, more preferably 5% by weight or less, further preferably 1% by weight or less, and particularly preferably 0.1% by weight or less.

[0049] When the curable resin composition of the present invention is emulsified, when the total amount of the curable resin composition other than water is set to 100% by mass, the blending amount of water as a solvent is preferably 40 to 300% by mass, more preferably 60 to 200% by mass.

[0050] When the curable resin composition of the present invention is emulsified, a surfactant is preferably contained. Examples of the surfactant include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

[0051] Examples of anionic surfactants include: carboxylates such as sodium stearate, sodium N-lauroylsarcosinate, sodium palmitate, sodium laurate, N-lauroylsarcosine, sodium N-caproylsarcosinate, N-oleoylsarcosine, sodium myristate, sodium cholate, and sodium oleate; phosphate esters such as sodium monododecyl phosphate; sulfonates such as sodium 5-sulfoisophthalate dimethyl, sodium 1-undecanesulfonate, sodium 1-pentadecanesulfonate, sodium bis(2-ethylhexyl) sulfosuccinate, sodium 1-octadecanesulfonate, sodium dodecylbenzenesulfonate, alkylnaphthalenesulfonate, sodium 1-decanesulfonate, and sodium 1-dodecanesulfonate; sulfate esters such as sodium decyl sulfate, sodium dodecyl sulfate, sodium hexadecyl sulfate, and polyoxyethylene styrenated methyl phenyl ether sulfate, polyoxyethylene alkyl ether sulfate, polyoxyethylene cumyl phenyl ether sulfate, and polycyclic phenyl ether methacrylate sulfate.

[0052] Examples of cationic surfactants include: aliphatic amine salts or aliphatic quaternary ammonium salts such as n-octyltrimethylammonium bromide, trimethylstearylammonium bromide, cetyltrimethylammonium chloride, trimethylstearylammonium chloride, cetyltrimethylammonium chloride, trimethylstearylammonium chloride, n-octylamine hydrochloride, octadecylamine hydrochloride, n-octylamine hydrobromide, n-octyltrimethylammonium chloride, trimethyltetradecylammonium chloride, heptadecyltrimethylammonium bromide, butyltrimethylammonium bromide, cetyltrimethylammonium hexafluorophosphate, cetyltrimethylammonium perchlorate, decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, decyltrimethylammonium bromide, di-n-alkyl dimethylammonium chloride, cetyltrimethylammonium hydroxide, cetyltrimethylammonium bromide, trimethylnonylammonium bromide, dodecylamine hydrochloride, cetyltrimethylammonium tetrafluoroborate, hexyltrimethylammonium bromide, cetyltrimethylammonium hydrogen sulfate, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and dodecylamine hydrobromide; heterocyclic quaternary ammonium salts such as 1-hexadecyl-4-methylpyridinium chloride hydrate, cetylpyridinium chloride monohydrate, cetylpyridinium bromide hydrate, and 1-dodecylpyridinium chloride; aromatic quaternary ammonium salts such as benzyl dodecyldimethylammonium bromide, benzethonium chloride, benzyl dimethylstearylammonium chloride, benzyl hexadecyldimethylammonium chloride, benzyl dodecyldimethylammonium chloride dihydrate, and benzyl dimethyltetradecylammonium chloride. hydrate, cetylpyridinium chloride monohydrate, cetylpyridinium bromide hydrate, 1-dodecylpyridinium chloride and so on; aromatic quaternary ammonium salts such as benzyl dodecyldimethylammonium bromide, benzethonium chloride, benzyl dimethylstearylammonium chloride, benzyl hexadecyldimethylammonium chloride, benzyl dodecyldimethylammonium chloride dihydrate, and benzyl dimethyltetradecylammonium chloride, etc.

[0053] Examples of amphoteric surfactants include: intramolecular salts such as octadecyl dimethyl(3-sulfopropyl) ammonium hydroxide, 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate inner salt, and dodecyl dimethyl(3-sulfopropyl) ammonium hydroxide inner salt.

[0054] Examples of nonionic surfactants include: ester ethers such as polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan monolaurate; ethers such as polyethylene glycol monomethyl ether 1000, octaethylene glycol monododecyl ether, hexaethylene glycol monododecyl ether, polyethylene glycol monooleyl ether (n≈about 10), polyethylene glycol monooleyl ether (n≈about 2), pentaethylene glycol monododecyl ether, polyethylene glycol monododecyl ether (n≈about 25), polyethylene glycol 1000, polyethylene glycol monooleyl ether (n≈about 7), polyethylene glycol 11000, polyethylene glycol mono-4-nonylphenyl ether (n≈about 15), polyethylene glycol monooleyl ether (n≈about 50), polyethylene glycol monocetyl ether (n≈about 23), triethylene glycol monododecyl ether, polyethylene glycol mono-4-nonylphenyl ether (n≈about 2), polyethylene glycol mono-4-octylphenyl ether (n≈about 10), polyethylene glycol monooleyl ether (n≈about 20), polyethylene glycol monomethyl ether 400, polyethylene glycol monomethyl ether 4000, polyethylene glycol mono-4-nonylphenyl ether (n≈about 20), diethylene glycol monododecyl ether, polyethylene glycol monomethyl ether 550, polyethylene glycol monomethyl ether 2000, polyethylene glycol mono-4-nonylphenyl ether (n≈about 18), polyethylene glycol 20000; esters such as sorbitan monooleate, sorbitan trioleate, sorbitan monopalmitate, glycerol monostearate, glycerol monopalmitate, polyethylene glycol monolaurate (n≈about 10), sorbitan monostearate, sorbitan monolaurate, polyethylene glycol monostearate (n≈about 45), polyethylene glycol monostearate (n≈about 55), sorbitan sesquioleate, polyethylene glycol monostearate (n≈about 2), glycerol monomyristate, polyethylene glycol monostearate (n≈about 25), polyethylene glycol monostearate (n≈about 4), polyethylene glycol monostearate (n≈about 40), polyethylene glycol monostearate (n≈about 10); acetylene alcohol surfactants, acetylene diol surfactants and other acetylene surfactants having acetylene bonds; fluorine surfactants, etc.

[0055] When emulsifying the curable resin composition of the present invention, in order to balance the dispersibility of component (A) and the appearance of the coating film, as the surfactant, it is preferably to contain two or more surfactants, and particularly preferably to contain at least two selected from anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants.

[0056] In order to balance the dispersibility of component (A) and the appearance of the coating film, when the total amount other than water as the solvent is set to 100% by weight, the content of the surfactant in the curable resin composition is preferably 0.1 to 20% by weight, more preferably 1 to 15% by weight.

[0057] When emulsifying the curable resin composition of the present invention, in order to balance the dispersibility of component (A) and the appearance of the coating film, and further to improve the humidity resistance reliability of the polarizing film, the curable aqueous dispersion composition used in the present invention is preferably a forced emulsification type emulsion using a surfactant as an emulsifier. In the case of a self-emulsifying type in which a hydrophilic group is introduced into the polymerizable compound or high molecular compound contained in the curable resin composition, it may not be possible to improve the appearance of the coating film and the humidity resistance reliability of the polarizing film. Methods for forcibly emulsifying the curable resin composition can be carried out, for example, by an ultrasonic homogenizer, a high-speed rotary homogenizer, other comminution devices utilizing cavitation phenomena, or a wet atomization device that obliquely collides liquids with each other under high pressure, such as a ball mill and other devices for media comminution, and a stirrer using stirring blades. In the present invention, it is not limited thereto, and methods known to those skilled in the art can be used.

[0058] <Component B>

[0059] The curable resin composition of the present invention contains component (B) comprising a (meth)acrylate monomer. The (meth)acrylate monomer may be a monofunctional (meth)acrylate monomer or a polyfunctional (meth)acrylate monomer. It should be noted that in the present invention, (meth)acrylate refers to acrylate and / or methacrylate, and the (meth)acrylate monomer refers to a monomer containing an acrylate group and / or a methacrylate group. Hereinafter, "(meth)" has the same meaning.

[0060] From the viewpoints of ensuring the solubility of component (A) in the composition and improving the humidity resistance reliability of the polarization characteristics of the polarizing film, when the total amount of the composition is set to 100% by mass, the curable resin composition of the present invention preferably contains 1 to 80% by mass of component (B), more preferably 5 to 80% by mass.

[0061] As monofunctional (meth)acrylate monomers, for example, the following can be cited: (meth)acrylamide derivatives having a (meth)acrylamide group. (Meth)acrylamide derivatives are preferred in terms of ensuring adhesion to a polarizing plate and various transparent protective films, and having a fast polymerization rate and excellent productivity. Specific examples of the (meth)acrylamide derivatives include, for example: N-alkyl(meth)acrylamide derivatives such as N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-butyl(meth)acrylamide, and N-hexyl(meth)acrylamide; N-hydroxyalkyl(meth)acrylamide derivatives such as N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, and N-hydroxymethyl-N-propyl(meth)acrylamide; N-aminoalkyl(meth)acrylamide derivatives such as aminomethyl(meth)acrylamide and aminoethyl(meth)acrylamide; N-alkoxymethyl(meth)acrylamide derivatives such as N-methoxymethyl acrylamide and N-ethoxymethyl acrylamide; N-mercaptoalkyl(meth)acrylamide derivatives such as mercaptomethyl(meth)acrylamide and mercaptoethyl(meth)acrylamide; and the like. In addition, as heterocyclic (meth)acrylamide derivatives in which the nitrogen atom of the (meth)acrylamide group forms a heterocyclic ring, for example, N-acryloylmorpholine, N-acryloylpiperidine, N-methylacryloylpiperidine, N-acryloylpyrrolidine, and the like can be cited. Among the above (meth)acrylamide derivatives, N-acryloylmorpholine is preferred from the viewpoint of adhesion to a polarizing plate and various transparent protective films.

[0062] In addition, as monofunctional (meth)acrylate monomers, for example, various (meth)acrylic acid derivatives having a (meth)acrylate group can be cited. Specifically, for example: (meth)acrylic acid alkyl esters having 1 to 20 carbon atoms such as (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid n-propyl ester, (meth)acrylic acid isopropyl ester, (meth)acrylic acid 2-methyl-2-nitropropyl ester, (meth)acrylic acid n-butyl ester, (meth)acrylic acid isobutyl ester, (meth)acrylic acid sec-butyl ester, (meth)acrylic acid tert-butyl ester, (meth)acrylic acid n-pentyl ester, (meth)acrylic acid tert-pentyl ester, (meth)acrylic acid 3-pentyl ester, (meth)acrylic acid 2,2-dimethylbutyl ester, (meth)acrylic acid n-hexyl ester, (meth)acrylic acid hexadecyl ester, (meth)acrylic acid n-octyl ester, (meth)acrylic acid 2-ethylhexyl ester, (meth)acrylic acid 4-methyl-2-propylpentyl ester, (meth)acrylic acid n-octadecyl ester, lauryl acrylate, stearyl acrylate, isostearyl acrylate.

[0063] In addition, examples of the above-mentioned (meth)acrylic acid derivatives include: cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, tert-butylcyclohexyl acrylate, and cyclopentyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; polycyclic (meth)acrylates such as 2-isobornyl (meth)acrylate, 2-norbornanyl methyl (meth)acrylate, 2-norbornanyl methyl (meth)acrylate, 5-norbornen-2-yl methyl (meth)acrylate, 3-methyl-2-norbornanyl methyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenoxyethyl (meth)acrylate, and dicyclopentyl (meth)acrylate; alkoxy- or phenoxy-containing (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxyethyl (meth)acrylate, and alkylphenoxypolyethylene glycol (meth)acrylate; and the like.

[0064] In addition, examples of the above-mentioned (meth)acrylic acid derivatives include: hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate; hydroxy-containing (meth)acrylates such as [4-(hydroxymethyl)cyclohexyl]methyl acrylate and cyclohexanedimethanol mono(meth)acrylate; epoxy-containing (meth)acrylates such as glycidyl (meth)acrylate and glycidyl ether of 4-hydroxybutyl (meth)acrylate; halogen-containing (meth)acrylates such as 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, and 3-chloro-2-hydroxypropyl (meth)acrylate; alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate; oxetanyl-containing (meth)acrylates such as 3-oxetanyl methyl (meth)acrylate, 3-methyloxetanyl methyl (meth)acrylate, 3-ethyloxetanyl methyl (meth)acrylate, 3-butyloxetanyl methyl (meth)acrylate, and 3-hexyloxetanyl methyl (meth)acrylate; heterocyclic-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and butyrolactone (meth)acrylate; hydroxy pivalic acid neopentyl glycol (meth)acrylate adduct; and p-phenylphenol (meth)acrylate.

[0065] In addition, as the monofunctional (meth)acrylate monomer, examples 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.

[0066] In addition, as the monofunctional (meth)acrylate monomer, a radical polymerizable compound having an active methylene group can be used. The radical polymerizable compound having an active methylene group is a compound having an active double bond group such as (meth)acryloyl group at the terminal or in the molecule and having an active methylene group. Examples of the active methylene group include: acetoacetyl group, alkoxy malonyl group, or cyanoacetyl group, etc. The above-mentioned active methylene group is preferably an acetoacetyl group. Specific examples of the radical polymerizable compound having an active methylene group include: (meth)acrylic acid 2-acetoacetoxyethyl ester, (meth)acrylic acid 2-acetoacetoxypropyl ester, (meth)acrylic acid 2-acetoacetoxy-1-methylethyl ester, etc. (meth)acrylic acid acetoacetoxyalkyl esters; (meth)acrylic acid 2-ethoxy malonyloxyethyl ester, (meth)acrylic acid 2-cyanoacetoxyethyl ester, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl)acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, N-(2-acetoacetylaminoethyl)acrylamide, etc. The radical polymerizable compound having an active methylene group is preferably (meth)acrylic acid acetoacetoxyalkyl ester.

[0067] In addition, as the polyfunctional (meth)acrylate monomer having two or more polymerizable functional groups, examples include: tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropylene glycol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, di Alkylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ester compounds of (meth)acrylic acid and polyols such as EO-modified diglycerol tetra(meth)acrylate, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. As specific examples, ARONIX M-220 (manufactured by Toagosei Co., Ltd.), LIGHT ACRYLATE 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), LIGHT ACRYLATE DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), LIGHT ACRYLATE DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer Company), CD-536 (manufactured by Sartomer Company), etc. can be cited. In addition, as needed, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, various (meth)acrylate monomers, etc. can be cited.

[0068] It should be noted that when the curable resin composition of the present invention contains a (meth)acrylate monomer (B-1) having a logPow representing the octanol / water partition coefficient of 3 or more as the component (B) and the content of the (meth)acrylate monomer (B-1) is 1 to 80% by mass based on the total amount of the composition being 100% by mass, the humidity reliability of the polarization characteristics of the polarizing film will be particularly improved eventually, and thus it is preferred. The reason for obtaining such an effect is not clear yet, but it can be presumed that the (meth)acrylate monomer (B-1) ensures the solubility of the above-mentioned component (A) in the curable resin composition and promotes the uniform dispersion of the component (A) in the cured product layer (adhesive layer), thereby improving the effect of suppressing the leakage of iodine from the polarizer.

[0069] The octanol / water partition coefficient (logPow) is an index indicating the lipophilicity of a substance and is the logarithm of the octanol / water partition coefficient. A high logPow indicates lipophilicity, that is, a low water absorption rate. For the logPow value, it can be measured (the flask immersion method described in JIS-Z-7260) or calculated. In this specification, the logPow value calculated by Chem Draw Ultra manufactured by CambridgeSoft Corporation is used.

[0070] As the (meth)acrylate monomer (B-1) with logPow of 3 or more, for example, the following can be cited: dimethylol tricyclodecane diacrylate (trade name "LIGHT ACRYLATE DCP-A", manufactured by Kyoeisha Chemical Co., Ltd., LogPow: 3.05), isobornyl acrylate (trade name "LIGHT ACRYLATE IB-XA", manufactured by Kyoeisha Chemical Co., Ltd., LogPow: 3.27), hydroxypivalic acid neopentyl glycol acrylate adduct (trade name "LIGHT ACRYLATE HPP-A", manufactured by Kyoeisha Chemical Co., Ltd., LogPow: 3.35), 1,9-nonanediol diacrylate (trade name "LIGHT ACRYLATE 1,9ND-A", manufactured by Kyoeisha Chemical Co., Ltd., LogPow: 3.68), o-phenylphenol EO modified acrylate (trade name "Fancryl FA-301A", manufactured by Hitachi Chemical Co., Ltd., LogPow: 3.98), 2-ethylhexyl oxetane (trade name "ARONOXETANE OXT-212", manufactured by Toagosei Co., Ltd., LogPow: 4.24), bisphenol A diglycidyl ether (trade name "JER828", manufactured by Mitsubishi Chemical Corporation, LogPow: 4.76), bisphenol A EO6 mono-modified diacrylate (trade name "FA-326A", manufactured by Hitachi Chemical Co., Ltd., LogPow: 4.84), bisphenol A EO4 mono-modified diacrylate (trade name "FA-324A", manufactured by Hitachi Chemical Co., Ltd., LogPow: 5.15), bisphenol A PO2 mono-modified diacrylate (trade name "FA-P320A", manufactured by Hitachi Chemical Co., Ltd., LogPow: 6.10), bisphenol A PO3 mono-modified diacrylate (trade name "FA-P323A", manufactured by Hitachi Chemical Co., Ltd., LogPow: 6.26), bisphenol A PO4 mono-modified diacrylate (trade name "FA-P324A", manufactured by Hitachi Chemical Co., Ltd., LogPow: 6.43), lauryl acrylate (trade name "LIGHT ACRYLATE L-A", manufactured by Kyoeisha Chemical Co., Ltd., LogPow: 6), isostearyl acrylate (trade name "ISTA", manufactured by Osaka Organic Chemical Industry Co., Ltd.; LogPow: 7.46), etc.

[0071] The curable resin composition of the present invention may also contain components other than the component (A) and the component (B). For example, it may contain a compound represented by the following general formula (1):

[0072] [Chemical formula 5]

[0073]

[0074] (In the formula, X is a reactive group, Y is an alkylene group having 1 to 12 carbon atoms which may optionally have a branched chain, or a phenylene group which may optionally have a substituent, and R 1 and R 2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group which may optionally have a substituent, an aryl group or a heterocyclic group). Examples of the above aliphatic hydrocarbon group include a linear or branched alkyl group having 1 to 20 carbon atoms which may optionally have a substituent, a cyclic alkyl group having 3 to 20 carbon atoms which may optionally have a substituent, and an alkenyl group having 2 to 20 carbon atoms. Examples of the aryl group include a phenyl group having 6 to 20 carbon atoms which may optionally have a substituent, a naphthyl group having 10 to 20 carbon atoms which may optionally have a substituent, etc. Examples of the heterocyclic group include a group having a 5-membered ring or a 6-membered ring which contains at least one heteroatom and may optionally have a substituent. They may also be linked to each other to form a ring. In the general formula (1), as R 1 and R 2 , a hydrogen atom, a linear or branched alkyl group having 1 to 3 carbon atoms is preferred, and a hydrogen atom is most preferred.

[0075] X in the compound represented by the general formula (1) is a reactive group, that is, a functional group capable of reacting with the component (A) and the component (B). Examples thereof include a hydroxyl group, an amino group, an aldehyde group, a carboxyl group, a vinyl group, a (meth)acryloyl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetanyl group, an α,β-unsaturated carbonyl group, a mercapto group, a halogen group, etc. When the curable resin composition of the present invention is curable by active energy rays, the reactive group X is preferably at least one reactive group selected from a vinyl group, a (meth)acryloyl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetanyl group and a mercapto group. When the curable resin composition of the present invention is free-radically polymerizable, the reactive group X is preferably at least one reactive group selected from a (meth)acryloyl group, a styryl group and a (meth)acrylamide group. Since the compound represented by the general formula (1) has a high reactivity when it has a (meth)acrylamide group and the copolymerization rate with the curable components in the cured product layer, particularly the adhesive layer, is increased, it is more preferred. In addition, since the (meth)acrylamide group has a high polarity and excellent adhesiveness, it is also preferred in terms of effectively obtaining the effects of the present invention. When the curable resin composition of the present invention is cationically polymerizable, the reactive group X preferably has at least one functional group selected from a hydroxyl group, an amino group, an aldehyde group, a carboxyl group, a vinyl ether group, an epoxy group, an oxetanyl group and a mercapto group. Particularly when it has an epoxy group, the obtained cured product layer, particularly the adhesive layer, has excellent adhesion to the adherend, and thus is preferred. When it has a vinyl ether group, the curability of the curable resin composition is excellent, and thus is preferred.

[0076] As preferred specific examples of the compound represented by the general formula (1), the following compounds (1a) to (1d) can be cited. It should be noted that R in the general formulas (1a) and (1b) 3 is a hydrogen atom or a methyl group.

[0077] [Chemical formula 6]

[0078]

[0079] As the compound represented by the general formula (1), in addition to the compounds exemplified above, esters formed from hydroxyethyl acrylamide and boric acid, esters formed from hydroxymethyl acrylamide and boric acid, esters formed from 2-hydroxyethyl acrylate and boric acid, and esters formed from 2-hydroxybutyl acrylate and boric acid, etc., (meth)acrylate esters formed with boric acid can also be exemplified.

[0080] The curable resin composition of the present invention is preferably a radiation curable resin composition. The radiation curable resin composition can be classified into a free radical polymerization curable resin composition and a cationic polymerization curable resin composition. Regarding the radiation curable resin composition, when the radiation is an electron beam or the like, the radiation curable resin composition does not necessarily contain a photoinitiator, and when the radiation is ultraviolet light or visible light, it preferably contains a photoinitiator.

[0081] The photoinitiator can be appropriately selected according to the active energy rays. In the case of curing with ultraviolet rays or visible light, a photoinitiator that can be cleaved by ultraviolet rays or visible light can be used. As the above-mentioned photoinitiator, for example, there can be mentioned: benzil, benzophenone, benzoylbenzoic acid, benzophenone compounds such as 3,3'-dimethyl-4-methoxybenzophenone; aromatic ketone compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexyl phenyl ketone; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, anisoin methyl ether; aromatic ketal compounds such as benzil dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-phenyl-1,1-propanedione-2-(O-ethoxycarbonyl)oxime; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; camphorquinone; halogenated ketones; acylphosphine oxides; acylphosphonates, etc.

[0082] Regarding the blending amount of the above-mentioned photoinitiator, when the total amount of the active energy ray-curable resin composition is set to 100 parts by mass, it is preferably contained in an amount of 0.5 to 5 parts by mass, more preferably 1 to 4 parts by mass.

[0083] In addition, in the case of using the active energy ray-curable resin composition as a visible light-curable type, it is particularly preferable to use a photoinitiator that is highly sensitive to light of 380 nm or more. The photoinitiator that is highly sensitive to light of 380 nm or more will be described later.

[0084] As the above-mentioned photoinitiator, it is preferable to use alone the compound represented by the following general formula (3); or to use in combination the compound represented by the general formula (3) and the photoinitiator that is highly sensitive to light of 380 nm or more described later.

[0085] [Chemical formula 7]

[0086]

[0087] (In the formula, R 7 and R 8 represent -H, -CH2CH3, -iPr or Cl, R 7 and R 8(which may be the same or different). In the case of using the compound represented by the general formula (3), the adhesiveness is excellent as compared with the case of using a photoinitiator having high sensitivity to light of 380 nm or more alone. In the compound represented by the general formula (3), R 7 and R 8 are preferably diethylthioxanthone in which -CH2CH3. Regarding the blending amount of the compound represented by the general formula (3) in the active energy ray-curable resin composition, when the total amount of the curable resin composition is 100% by mass, it is preferably contained in an amount of 0.1 to 4% by mass, more preferably 0.5 to 3% by mass.

[0088] In addition, a polymerization initiator aid is preferably added as needed. Examples of the polymerization initiator aid include: triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isopentyl 4-dimethylaminobenzoate, etc., and ethyl 4-dimethylaminobenzoate is particularly preferred. When using a polymerization initiator aid, when the total amount of the active energy ray-curable resin composition is 100 parts by mass, its addition amount is preferably contained in an amount of 0.1 to 3 parts by mass, more preferably 0.3 to 1 part by mass.

[0089] In addition, a known photoinitiator can be used in combination as needed. Since the optical functional layer and the substrate film having UV absorption ability do not transmit light of 380 nm or less, as the photoinitiator, a photoinitiator having high sensitivity to light of 380 nm or more is preferably used. Specific examples include: 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, etc.

[0090] In the present invention, the curable resin composition may contain an acrylic oligomer obtained by polymerizing a (meth)acrylic monomer. By containing an acrylic oligomer in the curable resin composition, the curing shrinkage when irradiating the composition with active energy rays and curing it can be reduced, and the interfacial stress between the adhesive layer and adherends such as the optical functional layer and the substrate film can be reduced. As a result, a decrease in the adhesion between the adhesive layer and the adherend can be suppressed.

[0091] In consideration of workability and uniformity during coating, it is preferred that the energy ray-curable resin composition has a low viscosity. Therefore, it is also preferred that the acrylic oligomer formed by polymerizing (meth)acrylic monomers has a low viscosity. As the acrylic oligomer that has a low viscosity and can prevent the curing shrinkage of the adhesive layer, its weight average molecular weight (Mw) is preferably 15,000 or less, more preferably 10,000 or less, and particularly preferably 5,000 or less. On the other hand, in order to sufficiently suppress the curing shrinkage of the cured product layer (adhesive layer), the weight average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1,000 or more, and particularly preferably 1,500 or more.As the (meth)acrylic monomer constituting the acrylic oligomer, specifically, for example, (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid n-propyl ester, (meth)acrylic acid isopropyl ester, 2-methyl-2-nitropropyl (meth)acrylate, (meth)acrylic acid n-butyl ester, (meth)acrylic acid isobutyl ester, (meth)acrylic acid sec-butyl ester, (meth)acrylic acid tert-butyl ester, (meth)acrylic acid n-pentyl ester, (meth)acrylic acid tert-pentyl ester, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, (meth)acrylic acid n-hexyl ester, (meth)acrylic acid cetyl ester, (meth)acrylic acid n-octyl ester, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, n-octadecyl (meth)acrylate and other (meth)acrylic acid (C1-C20) alkyl esters, and for example, (meth)acrylic acid cycloalkyl esters (such as cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, etc.), (meth)acrylic acid aralkyl esters (such as benzyl (meth)acrylate, etc.), polycyclic (meth)acrylic esters (such as 2-isobornyl (meth)acrylate, 2-norbornanyl methyl (meth)acrylate, 5-norbornen-2-yl methyl (meth)acrylate, 3-methyl-2-norbornanyl methyl (meth)acrylate, etc.), hydroxyl group-containing (meth)acrylic esters (such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropyl methyl butyl (meth)acrylate, etc.), alkoxy group-containing or phenoxy group-containing (meth)acrylic esters ((meth)acrylic acid 2-methoxyethyl ester, (meth)acrylic acid 2-ethoxyethyl ester, (meth)acrylic acid 2-methoxymethoxyethyl ester, (meth)acrylic acid 3-methoxybutyl ester, ethyl carbitol (meth)acrylate, phenoxyethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic esters (such as glycidyl (meth)acrylate, etc.), halogen-containing (meth)acrylic esters (such as 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.), (meth)acrylic acid alkylaminoalkyl esters (such as dimethylaminoethyl (meth)acrylate, etc.), etc. These (meth)acrylic esters can be used alone or in combination of two or more. As a specific example of the acrylic oligomer (E), "ARUFON" manufactured by Toagosei Co., Ltd., "ACTFLOW" manufactured by Soken Chemical & Engineering Co., Ltd., "JONCRYL" manufactured by BASF Japan Ltd., etc. can be cited.

[0092] The curable resin composition of the present invention may contain a silane coupling agent. Specific examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, etc., which are compounds curable by active energy rays.

[0093] Preference is given to 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane.

[0094] Specific examples of the silane coupling agent that is not curable by active energy rays other than the above include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatopropyltriethoxysilane, imidazole silane, etc.

[0095] The curable resin composition of the present invention may also be a cationic polymerization curable resin composition. As the cationic polymerizable compound used in the cationic polymerization curable resin composition, it can be classified into a monofunctional cationic polymerizable compound having 1 cationic polymerizable functional group in the molecule and a polyfunctional cationic polymerizable compound having 2 or more cationic polymerizable functional groups in the molecule. Since the liquid viscosity of the monofunctional cationic polymerizable compound is low, the liquid viscosity can be reduced by containing the monofunctional cationic polymerizable compound in the cationic polymerization curable resin composition. In addition, the monofunctional cationic polymerizable compound usually has functional groups that exhibit various functions. By containing the monofunctional cationic polymerizable compound in the cationic polymerization curable resin composition, various functions can be exhibited in the cationic polymerization curable resin composition and / or the cured product of the cationic polymerization curable resin composition. Since the polyfunctional cationic polymerizable compound can three-dimensionally crosslink the cured product of the cationic polymerization curable resin composition, it is preferably contained in the cationic polymerization curable resin composition. Regarding the ratio of the monofunctional cationic polymerizable compound to the polyfunctional cationic polymerizable compound, it is preferably mixed in the range of 10 parts by mass to 1000 parts by mass of the polyfunctional cationic polymerizable compound relative to 100 parts by mass of the monofunctional cationic polymerizable compound. Examples of the cationic polymerizable functional group include an epoxy group, an oxetanyl group, and a vinyl ether group. Examples of the compound having an epoxy group include an aliphatic epoxy compound, an alicyclic epoxy compound, and an aromatic epoxy compound. Since it has excellent curability and adhesiveness, it is particularly preferred to contain an alicyclic epoxy compound as the cationic polymerizable resin composition of the present invention. Examples of the alicyclic epoxy compound include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, a caprolactone-modified product of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, a trimethylcaprolactone-modified product, a valerolactone-modified product, etc. Specific examples include CELLOXIDE 2021, CELLOXIDE 2021A, CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE 2083, CELLOXIDE 2085 (manufactured by Daicel Chemical Industries, Ltd.), Cyracure UVR-6105, Cyracure UVR-6107, Cyracure 30, R-6110 (manufactured by Dow Chemical Japan Ltd.), etc. Since it has the effect of improving the curability of the cationic polymerizable resin composition and reducing the liquid viscosity of the composition, it is preferably contained a compound having an oxetanyl group.Examples of the compound having an oxetanyl group include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, bis[(3-ethyl-3-oxetanyl)methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, novolac oxetane, etc. Commercially available products include ARON OXETANE OXT-101, ARON OXETANE OXT-121, ARON OXETANE OXT-211, ARON OXETANE OXT-221, ARON OXETANE OXT-212 (manufactured by Toagosei Co., Ltd. etc.). Since it has the effects of improving the curability of the cationic polymerizable resin composition and reducing the liquid viscosity of the composition, a compound having a vinyl ether group is preferably contained. Examples of the compound having a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, cyclohexanedimethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, pentaerythritol type tetravinyl ether, etc.

[0096] The cationic polymerization curable resin composition contains at least one compound selected from the compounds having an epoxy group, the compounds having an oxetanyl group, and the compounds having a vinyl ether group described above as curable components. They are all substances curable by cationic polymerization, so a photo cationic polymerization initiator is incorporated. This photo cationic polymerization initiator generates cation species or Lewis acids by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, thereby initiating the polymerization reaction of epoxy groups and oxetanyl groups. As the photo cationic polymerization initiator, a photoacid generator described later can be appropriately used. In addition, when using the cationic polymerizable resin composition as visible light curable, it is particularly preferable to use a photo cationic polymerization initiator highly sensitive to light of 380 nm or more. However, since the photo cationic polymerization initiator is a compound that generally shows a maximum absorption in the wavelength region near 300 nm or shorter than 300 nm, by incorporating a photosensitizer that shows a maximum absorption under light of a longer wavelength region, specifically, light of a wavelength longer than 380 nm, it is possible to sense light of a wavelength in its vicinity and promote the generation of cation species or acids from the photo cationic polymerization initiator. As the photosensitizer, for example, anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, polysulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible pigments, etc. can be cited, and two or more of them can also be used in combination. In particular, anthracene compounds have excellent photosensitizing effects and are thus preferred. Specifically, Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Kasei Co., Ltd.) can be cited. The content of the photosensitizer is preferably 0.1% by mass to 5% by mass, more preferably 0.5% by mass to 3% by mass.

[0097] The curable resin composition of the present invention 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 no photoacid generator is contained. The photoacid generator can be represented by the following general formula (4).

[0098] General formula (4)

[0099] [Chemical formula 8]

[0100]

[0101] (In the formula, L ＋ represents an arbitrary cation. In addition, X - represents a group selected from PF6 - , SbF6 - , AsF6 - , SbCl6 - , BiCl5 -, SnCl6 - , ClO4 - , the counter anions in dithiocarbamate anions, SCN−.)

[0102] Next, the counter anion X in the general formula (4) - will be described.

[0103] For the counter anion X in the general formula (4) - , there is no particular limitation in principle, but non-nucleophilic anions are preferred. When the counter anion X - is a non-nucleophilic anion, since it is not likely to initiate nucleophilic reactions of the cations coexisting in the molecule and various materials used in combination, as a result, the time-dependent stability of the photoacid generator represented by the general formula (4) itself and the composition using the same can be improved. The non-nucleophilic anion described here means an anion with low ability to initiate nucleophilic reactions. Examples of such anions include: PF6 - , SbF6 - , AsF6 - , SbCl6 - , BiCl5 - , SnCl6 - , ClO4 - , B(C6H5)4 - , dithiocarbamate anions, SCN - , etc.

[0104] Specifically, preferred specific examples of the photoacid generator of the present invention include "CYRACURE UVI-6992", "CYRACURE UVI-6974" (both manufactured by Dow Chemical Japan Limited), "Adekaoptomer SP150", "Adekaoptomer SP152", "Adekaoptomer SP170", "Adekaoptomer SP172" (all manufactured by ADEKA CORPORATION), "Omnicat250" (manufactured by IGM Resins B.V.), "CI-5102", "CI-2855" (both manufactured by Nippon Soda Co., Ltd.), "San-Aid SI-60L", "San-Aid SI-80L", "San-Aid SI-100L", "San-Aid SI-110L", "San-Aid SI-180L" (all manufactured by Shin Shin Chemical Co., Ltd.), "IK-1", "CPI-100P", "CPI-101A", "CPI-110P", "CPI-200K", "CPI-210S", "CPI-310B", "CPI-410B", "CPI-410S" (all manufactured by San-Apro Ltd.), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044", "WPI-054", "WPI-055", "WPAG-281", "WPAG-567", "WPAG-596" (all manufactured by Fujifilm Wako Pure Chemical Corporation).

[0105] The polarizing film of the present invention is a polarizing film in which an optical film is laminated via an adhesive layer on at least one surface of a polarizer, and the adhesive layer is a cured product layer of the above curable resin composition.

[0106] From the viewpoint of improving the humidity resistance reliability of the polarization characteristics of the polarizing film, the thickness of the cured product layer (adhesive layer) is preferably 0.1 μm or more and 5 μm or less, more preferably 0.2 μm or more and 3 μm or less.

[0107] In the present invention, the polarizer is not particularly limited, and various polarizers can be used. As the polarizer, for example, a film obtained by adsorbing iodine on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or a partially saponified ethylene-vinyl acetate copolymer film and performing unidirectional stretching can be mentioned. As the thickness of the polarizer, for example, 3 to 20 μm can be mentioned.

[0108] However, it should be noted that in the present invention, from the viewpoint of improving the humidification reliability in a harsh environment under high temperature and high humidity, as the polarizer, a thin polarizer with a thickness of 3 μm or more and 15 μm or less is preferably used. In particular, it is preferably 12 μm or less, more preferably 10 μm or less, and particularly preferably 8 μm or less. Such a thin polarizer has less thickness unevenness, excellent visual recognition, and less dimensional change, and therefore, has excellent durability against thermal shock.

[0109] A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and performing unidirectional stretching can be produced, for example, as follows: The polyvinyl alcohol is dyed by immersing it in an aqueous solution of iodine, and stretched to 3 to 7 times the initial length. If necessary, it can also be immersed in an aqueous solution of potassium iodide optionally containing boric acid, zinc sulfate, zinc chloride, etc. In addition, if necessary, the polyvinyl alcohol-based film can be immersed in water for water washing before dyeing. By washing the polyvinyl alcohol-based film with water, not only can the stains and anti-blocking agents on the surface of the polyvinyl alcohol-based film be removed, but also the effect of preventing unevenness such as uneven dyeing can be achieved by swelling the polyvinyl alcohol-based film. The stretching can be performed after dyeing with iodine, or can be performed while dyeing, or can also be dyed with iodine after stretching. The stretching can also be performed in an aqueous solution of boric acid, potassium iodide, etc. or in a water bath.

[0110] From the viewpoints of stretching stability and humidification reliability, it is preferable that the polarizer contains boric acid. In addition, from the viewpoint of suppressing the occurrence of through-cracks, the content of boric acid contained in the polarizer is preferably 22% by mass or less, more preferably 20% by mass or less, relative to the total amount of the polarizer. From the viewpoints of stretching stability and humidification reliability, the boric acid content is preferably 10% by mass or more, more preferably 12% by mass or more, relative to the total amount of the polarizer.

[0111] As representative thin polarizers, there can be mentioned the thin polarizers described in the specifications of Japanese Patent No. 4751486, Japanese Patent No. 4751481, Japanese Patent No. 4815544, Japanese Patent No. 5048120, Pamphlet of International Publication No. 2014 / 077599, Pamphlet of International Publication No. 2014 / 077636, etc., or the thin polarizers obtained by the manufacturing methods described in these documents.

[0112] As the above-mentioned thin polarizer, in the manufacturing method including a stretching step and a dyeing step in a laminated state, from the viewpoint of being able to stretch to a high magnification to improve the polarization performance, it is preferably a thin polarizer obtained by a manufacturing method including a stretching step in an aqueous boric acid solution as described in the specifications of Japanese Patent No. 4751486, Japanese Patent No. 4751481, and Japanese Patent No. 4815544. Particularly preferably, it is a thin polarizer obtained by a manufacturing method including a stretching step in a gas atmosphere as an auxiliary before stretching in an aqueous boric acid solution as described in the specifications of Japanese Patent No. 4751481 and Japanese Patent No. 4815544. These thin polarizing films can be obtained by a manufacturing method including a stretching step of stretching a polyvinyl alcohol resin (hereinafter, also referred to as a PVA resin) layer and a stretching resin substrate in a laminated state and a dyeing step. If it is this manufacturing method, even if the PVA resin layer is thin, it can be stretched by being supported by the stretching resin substrate without causing defects such as breakage due to stretching.

[0113] As the optical film, for example, a transparent protective film can be cited. As the material constituting the transparent protective film, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, etc. can be used. Specific examples of such thermoplastic resins include: cellulose resins such as triacetyl cellulose resin films, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic olefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The transparent protective film may contain one or more arbitrary appropriate additives. As the additives, for example, ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, coloring agents, etc. can be cited. The content of the above thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When the content of the above thermoplastic resin in the transparent protective film is 50% by weight or less, there is a risk that the high transparency and the like originally possessed by the thermoplastic resin cannot be fully exhibited.

[0114] In addition, as the material for forming the transparent protective film, a material having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, etc. is preferred. In particular, a material with a moisture permeability of 150 g / m 2 / 24 h or less is more preferred, a material with a moisture permeability of 140 g / m 2 / 24 h or less is more preferred, and a material with a moisture permeability of 120 g / m 2 / 24 h or less is further preferred.

[0115] Functional layers such as a hard coat layer, an antireflection layer, an anti-adhesion layer, a diffusion layer, or an antiglare layer can be provided on the side of the transparent protective film that is not adhered to the polarizer. It should be noted that the above-mentioned functional layers such as the hard coat layer, the antireflection layer, the anti-adhesion layer, the diffusion layer, and the antiglare layer can be provided not only to protect the transparent protective film itself, but also can be provided as layers different from the transparent protective film.

[0116] The thickness of the transparent protective film can be appropriately determined. Generally speaking, considering from aspects such as strength, processability and other operability, thin layer property, etc., it is about 1 to 500 μm, preferably 1 to 300 μm, more preferably 5 to 200 μm, further preferably 10 to 200 μm, and even more preferably 20 to 80 μm.

[0117] As the optical film, a retardation film having a front retardation of 40 nm or more and / or a thickness direction retardation of 80 nm or more can be used. Usually, the front retardation is controlled in the range of 40 to 200 nm, and usually the thickness direction retardation is controlled in the range of 80 to 300 nm. When using a retardation film as the transparent protective film, the retardation film also functions as the transparent protective film, so that thinning can be achieved.

[0118] Examples of the retardation film include: a birefringent film obtained by unidirectionally or bidirectionally stretching a polymer raw material, an alignment film of a liquid crystal polymer, and a retardation film formed by supporting an alignment layer of a liquid crystal polymer with a film. The thickness of the retardation film is not particularly limited, and is usually about 1 to 150 μm.

[0119] As the retardation film, a reverse wavelength dispersion type retardation film satisfying the following formulas (1) to (3) can be used:

[0120] 0.70 < Re

[450] / Re

[550] < 0.97 ··· (1)

[0121] 1.5×10 -3 <Δn<6×10 -3 ··· (2)

[0122] 1.13 < NZ < 1.50 ··· (3)

[0123] (In the formula, Re

[450] and Re

[550] are the in-plane phase difference values of the retardation film measured with light of wavelengths 450 nm and 550 nm at 23°C, respectively. Δn is the in-plane birefringence, which is nx - ny when the refractive indices in the slow axis direction and the fast axis direction of the retardation film are nx and ny, respectively. NZ is the ratio of nx - nz to nx - ny when nz is the refractive index in the thickness direction of the retardation film, where nx - nz is the thickness direction birefringence and nx - ny is the in-plane birefringence).

[0124] In the polarizing film of the present invention, a retardation layer may also be provided. The retardation layer may be a single layer or multiple layers, and the retardation layer can also be used as a protective layer for the polarizer at the same time.

[0125] In the formation of the retardation layer, a liquid crystalline compound is preferably used. For example, a solution containing the liquid crystalline compound can be coated using a wire bar, a slot coater, a comma coater, a gravure coater, a slit die coater, etc. At this time, the coated liquid crystalline solution can be naturally dried or dried by heating. It should be noted that the liquid crystalline solution is preferably coated in a concentration lower than the isotropic phase-liquid crystal phase transition concentration, that is, in an isotropic phase state. In this case, it can be stably oriented by methods such as rubbing treatment and photoalignment.

[0126] The polarizing film of the present invention can be manufactured, for example, by the following manufacturing method.

[0127] A method for manufacturing a polarizing film, which is a method for manufacturing a polarizing film in which an optical film is laminated on at least one surface of a polarizer via an adhesive layer, the adhesive layer being a cured product layer of a curable resin composition, the curable resin composition containing component (A) and component (B), the component (A) being at least one selected from (meth)acrylic acid-modified polybutadiene and (meth)acrylic acid-modified polyisoprene, the component (B) containing a (meth)acrylate monomer, the method comprising: a coating step of coating the curable resin composition on either or both of the bonding surfaces of the polarizer and the transparent protective film; a bonding step of bonding the polarizer and the optical film; and a bonding step of irradiating active energy rays from the polarizer surface side or the optical film surface side to cure the curable resin composition, so that the polarizer and the optical film are bonded via the adhesive layer obtained by the above curing. Hereinafter, each step and the like will be described.

[0128] As a method for coating the curable resin composition, it can be appropriately selected according to the viscosity of the composition and the target thickness. For example, a reverse coater, a gravure coater (direct, reverse, or offset), a rod reverse coater, a roll coater, a die coater, a wire wound rod coater, and a rod coater can be cited. The viscosity of the curable resin composition is preferably 3 to 100 mPa·s, more preferably 5 to 50 mPa·s, and most preferably 10 to 30 mPa·s. When the viscosity of the composition is high, the surface smoothness after coating is insufficient, resulting in poor appearance, so it is not preferred. Therefore, the composition can be coated after heating or cooling to adjust the viscosity to the preferred range.

[0129] It should be noted that for the polarizer and / or the optical film, surface modification treatment can also be carried out before the coating process. It is particularly preferred to carry out surface modification treatment on the polarizer. As the surface modification treatment, treatments such as corona treatment, plasma treatment, and ITRO treatment can be cited, and corona treatment is particularly preferred. By carrying out corona treatment, reactive functional groups such as carbonyl groups and amino groups are generated on the surface of the polarizer, thereby improving the adhesion with the adhesive layer. In addition, foreign substances on the surface can be removed or the surface unevenness can be reduced through the ashing effect, thereby producing a polarizing film with excellent appearance characteristics.

[0130] Use a roll laminator or the like to bond the polarizer and the optical film via the curable resin composition coated as described above (bonding process).

[0131] After bonding the polarizer and the optical film, irradiate active energy rays (electron beam, ultraviolet ray, visible light, etc.) to cure the curable resin composition to form an adhesive layer. The irradiation direction of the active energy rays (electron beam, ultraviolet ray, visible light, etc.) can be irradiated from any appropriate direction.

[0132] The irradiation conditions in the case of irradiating an electron beam only need to be conditions that can cure the above-mentioned curable resin composition, and any appropriate conditions can be adopted. For example, the acceleration voltage of electron beam irradiation is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. When the acceleration voltage is less than 5 kV, there is a risk that the electron beam cannot reach the adhesive, resulting in insufficient curing. If the acceleration voltage is greater than 300 kV, there is a risk that the penetration force through the sample is too strong, causing damage to the polarizer and the transparent protective film. As the irradiation dose, it is 5 to 100 kGy, and more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the curing of the adhesive is insufficient. If it is greater than 100 kGy, it will cause damage to the optical functional layer and the substrate film, resulting in a decrease in mechanical strength and yellowing, and the given optical characteristics cannot be obtained.

[0133] Electron beam irradiation is usually carried out in an inert gas and can be carried out in the atmosphere or under the condition of a small amount of oxygen introduced as needed. Although it depends on the materials of the polarizer and the transparent protective film, by appropriately introducing oxygen, an oxygen barrier is generated on the surface of the initially electron beam-irradiated optical functional layer and the substrate film, thereby preventing damage to the polarizer and the transparent protective film, and the electron beam can be effectively irradiated only to the adhesive.

[0134] When manufacturing the polarizing film of the present invention, as the active energy ray, an active energy ray containing visible light in the wavelength range of 380 nm to 450 nm, particularly an active energy ray with the largest irradiation amount of visible light in the wavelength range of 380 nm to 450 nm, is preferably used. When using ultraviolet light, visible light, and a transparent protective film (ultraviolet non-transmissive type transparent protective film) having ultraviolet absorption ability, light with a wavelength shorter than about 380 nm is absorbed, so light with a wavelength shorter than 380 nm does not reach the curable resin composition and does not contribute to its polymerization reaction. In addition, the light with a wavelength shorter than 380 nm absorbed by the polarizer or the transparent protective film is converted into heat, and the polarizer or the transparent protective film itself generates heat, which becomes a cause of defects such as curling / creasing of the polarizing film. Therefore, in the present invention, when using ultraviolet light and visible light, it is preferable to use a device that does not emit light with a wavelength shorter than 380 nm as the active energy ray generating device. More specifically, the ratio of the cumulative illuminance in the wavelength range of 380 to 440 nm to the cumulative illuminance in the wavelength range of 250 to 370 nm is preferably 100:0 to 100:50, more preferably 100:0 to 100:40. When manufacturing the polarizing film of the present invention, as the active energy ray, a metal halide lamp sealed with gallium, an LED light source emitting light in the wavelength range of 380 to 440 nm, or a light source containing ultraviolet light and visible light such as a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an incandescent lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, a gallium lamp, an excimer laser, or sunlight can be used, and it can also be used after blocking the ultraviolet light with a wavelength shorter than 380 nm with a band-pass filter. In order to improve the adhesion performance of the adhesive layer between the polarizer and the transparent protective film and prevent curling of the polarizing film, it is preferable to use: an active energy ray obtained by using a metal halide lamp sealed with gallium and a band-pass filter capable of blocking light with a wavelength shorter than 380 nm, or an active energy ray with a wavelength of 405 nm obtained by using an LED light source.

[0135] When manufacturing the polarizing film of the present invention by a continuous production line, the linear speed varies depending on the curing time of the curable resin composition, and is preferably 1 to 500 m / min, more preferably 5 to 300 m / min, and further preferably 10 to 100 m / min. When the linear speed is too small, the productivity is insufficient, or the damage to the optical polarizer or the transparent protective film is too large, and a polarizing film that can withstand durability tests and the like cannot be produced. When the linear speed is too large, the curing of the curable resin composition may sometimes become insufficient, and the target adhesiveness cannot be obtained.

[0136] When emulsifying the curable resin composition of the present invention, the polarizing film of the present invention can be manufactured, for example, by the following manufacturing method.

[0137] A method for manufacturing a polarizing film, which is a method for manufacturing a polarizing film in which an optical film is laminated on at least one surface of a polarizer via an adhesive layer, the method comprising: an emulsification step of emulsifying by adding water as a solvent to a curable resin composition containing component (A) and component (B), wherein component (A) is at least one selected from (meth)acrylic acid-modified polybutadiene and (meth)acrylic acid-modified polyisoprene, and component (B) contains a (meth)acrylate monomer; a coating step of coating the emulsified curable resin composition on at least one surface of the polarizer and the optical film; a drying step of forming a resin layer on at least one surface of the polarizer and the optical film by drying and removing water as a solvent from the curable resin composition; a bonding step of bonding the polarizer and the optical film via the resin layer; and a bonding step of irradiating active energy rays from the polarizer surface side or the optical film surface side to cure the resin layer and bond the polarizer and the optical film via the adhesive layer obtained by the above curing. In the above emulsification step, it is preferable that the curable resin composition contains a surfactant. Further, the above emulsification step is preferably a forced emulsification step using a surfactant as an emulsifier.

[0138] A bonding layer for bonding to other components such as a liquid crystal cell can also be provided on the above polarizing film or a laminated optical film having at least one layer of polarizing film laminated thereon. There is no particular limitation on the adhesive for forming the bonding layer, and an adhesive using, for example, a polymer such as an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine-based, or a rubber-based polymer as a base polymer can be appropriately selected. An adhesive such as an acrylic adhesive, which has excellent optical transparency, exhibits appropriate wetting properties, cohesiveness, and adhesive properties, and has excellent weather resistance, heat resistance, etc., can be particularly preferably used.

[0139] The bonding layer can be provided in the form of a laminated layer of layers having different compositions or types, etc., on one or both surfaces of the polarizing film and the optical film. Further, in the case of providing on both surfaces, bonding layers having different compositions, types, thicknesses, etc. can also be formed on the front and back surfaces of the polarizing film and the optical film. The thickness of the bonding layer can be appropriately determined according to the use purpose, adhesive force, etc., and is usually 1 to 500 μm, preferably 1 to 200 μm, and particularly preferably 1 to 100 μm.

[0140] For the exposed surface of the adhesive layer, during the period until it is actually used, for the purpose of preventing its contamination, etc., a separator may be temporarily adhered to cover it. Thereby, contact with the adhesive layer can be prevented in the normal handling state. As the separator, a separator or the like that is appropriately formed by coating a suitable thin layer body such as a plastic film, a rubber sheet, paper, cloth, non-woven fabric, net, foamed sheet, metal foil, or a laminate thereof with a suitable release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum disulfide-based release agent as needed, in addition to the above thickness conditions, can be used.

[0141] The polarizing film and optical film of the present invention can be preferably used for forming various devices such as liquid crystal display devices. The formation of a liquid crystal display device can be carried out according to the conventional method. That is, a liquid crystal display device is usually formed by appropriately assembling components such as a liquid crystal cell, a polarizing film or an optical film, and an illumination system used as needed and installing a drive circuit, etc. In the present invention, except for using the polarizing film or optical film of the present invention, there is no particular limitation, and it can be carried out according to the conventional method. Regarding the liquid crystal cell, any type of liquid crystal cell such as a TN type, an STN type, or a π type can be used.

[0142] A liquid crystal display device in which an optical laminate is disposed on one or both sides of the liquid crystal cell, a liquid crystal display device using a backlight or a reflector in the illumination system, etc., can be formed. In this case, the optical laminate of the present invention can be provided on one or both sides of the liquid crystal cell. When the optical laminates are provided on both sides, they can be the same or different. Further, when forming the liquid crystal display device, one layer or two or more layers of suitable components such as a diffusion plate, an antiglare layer, an antireflection film, a protection plate, a prism array, a lens array sheet, a light diffusion plate, and a backlight can be disposed at appropriate positions.

[0143] Examples

[0144] Examples of the present invention are described below, but the embodiments of the present invention are not limited to these.

[0145] <Polarizer>

[0146] A stretched laminate was produced by auxiliary stretching in a gas atmosphere at a stretching temperature of 130°C of a laminate having a 9-μm-thick PVA layer formed on an amorphous PET substrate. Next, a colored laminate was produced by dyeing the stretched laminate. Further, by stretching the colored laminate in an aqueous boric acid solution at a stretching temperature of 65°C, an optical film laminate was produced that included a 5-μm-thick PVA layer integrally stretched with the amorphous PET substrate in such a way that the total stretching magnification reached 5.94 times. By such two-step stretching, the PVA molecules in the PVA layer formed on the amorphous PET substrate were highly oriented, and an optical film laminate was obtained that included a 5.5-μm-thick PVA layer and constituted a thin polarizer in which iodine adsorbed by dyeing was highly oriented in one direction in the form of a polyiodide complex.

[0147] <Optical film (transparent protective film)>

[0148] First, a resin (imide-modified MS resin) composed of an imidized methyl methacrylate-styrene copolymer was produced by the method described in Production Example 1 of JP-A-2010-284840. Next, using a twin-screw kneader, 100 parts by weight of the imide-modified MS resin and 0.62 part by weight of a triazine-based ultraviolet absorber (manufactured by ADEKA Corporation, trade name: T-712) were mixed at 220°C to produce resin pellets. The obtained resin pellets were dried in an environment of 100.5 kPa and 100°C for 12 hours. Next, using a single-screw extruder, the resin pellets were extruded from a T-die at a die temperature of 270°C to produce a film with a thickness of 160 μm. Further, the film was stretched in an atmosphere at 150°C along its transport direction to adjust the thickness to 80 μm. Next, an easy-bonding agent containing an aqueous urethane resin was applied to the film, and then the film was stretched in an atmosphere at 150°C along a direction orthogonal to the transport direction to obtain a transparent protective film with a thickness of 40 μm. The water vapor transmission rate of this transparent protective film was 58 g / m 2 / 24h.

[0149] <Actinic energy rays>

[0150] As actinic energy rays, a visible light (metal halide lamp filled with gallium) irradiation device: Light HAMMER10 Mark III manufactured by Heraeus Company, valve: V valve, peak illuminance: 1600 mW / cm 2 、cumulative irradiation dose 1000 / mJ / cm 2 (wavelength 380 - 440 nm). It should be noted that the illuminance of visible light was measured using Power Puck 2 (manufactured by EIT Corporation, UVV measurement value).

[0151] (Adjustment of curable resin composition)

[0152] According to the formulations in Table 1, curable resin compositions of Examples 1 to 8 and Comparative Examples 1 to 6 were prepared. The values in the table represent weight percentages when the total amount of each composition is set to 100% by mass. The following shows each material constituting the curable resin composition.

[0153] (Component (A))

[0154] ·(Meth)acrylic acid-modified polybutadiene: trade name “BAC-45” (compound described by the following formula)

[0155] [Chemical formula 9]

[0156]

[0157] (Molecular weight: about 10,000), manufactured by Osaka Organic Chemical Industry Co., Ltd.

[0158] ·(Meth)acrylic acid-modified polyisoprene: trade name “UC-102M” (compound described by the following formula)

[0159] [Chemical formula 10]

[0160]

[0161] (Molecular weight: about 17,000), manufactured by Kuraray Co., Ltd.

[0162] (Component (B))

[0163] ·N-acryloylmorpholine: trade name “ACMO”, LogPow: -0.20, manufactured by KJ Chemicals Co., Ltd.

[0164] ·4-hydroxybutyl acrylate: trade name “4-HBA”, LogPow: 0.68, manufactured by Osaka Organic Chemical Industry Co., Ltd.

[0165] ·Lauryl acrylate: trade name “LIGHT ACRYLATE L-A”, LogPow: 6, manufactured by Kyoeisha Chemical Co., Ltd.

[0166] ·1,9-nonanediol diacrylate: trade name “LIGHT ACRYLATE 1,9ND-A”, LogPow: 3.68, manufactured by Kyoeisha Chemical Co., Ltd.

[0167] ·Dimethylol tricyclodecane diacrylate: trade name “LIGHT ACRYLATE DCP-A”, LogPow: 3.05, manufactured by Kyoeisha Chemical Co., Ltd.

[0168] (Other components)

[0169] · Liquid polybutadiene 1 (polybutadiene not modified with (meth)acrylic acid): Trade name “LBR-305” (molecular weight approximately 26,000), manufactured by Kuraray Co., Ltd.

[0170] · Liquid polybutadiene 2 (polybutadiene not modified with (meth)acrylic acid): Trade name “LBR-307” (molecular weight approximately 8,000), manufactured by Kuraray Co., Ltd.

[0171] · Coupling agent: Trade name “KBM303”, manufactured by Shin-Etsu Chemical Co., Ltd.

[0172] · Acrylic oligomer (acrylic oligomer formed by polymerization of (meth)acrylic acid monomers): Trade name “ARUFON UP-1190”, manufactured by Toagosei Co., Ltd.

[0173] (Initiator)

[0174] · 2-Methyl-4'-methylthio-2-morpholinopropiophenone: Trade name “Omnirad 907”, manufactured by IGM Resins B.V.

[0175] · Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide: Trade name “Omnirad 819”, manufactured by IGM Resins B.V.

[0176] · 1-Hydroxycyclohexyl phenyl ketone: Trade name “Omnirad 184”, manufactured by IGM Resins B.V.

[0177] · Diethylthioxanthone: Trade name “KAYACURE DETX-S (denoted as “DETX-S” in Table 1)”, manufactured by Nippon Kayaku Co., Ltd.

[0178] (Manufacture of polarizing film)

[0179] Examples 1 to 4 and Comparative Examples 1 to 6

[0180] Using an MCD coater (manufactured by Fuji Machinery Co., Ltd.) (unit shape: honeycomb, gravure roll line count: 700 lines per inch, rotation speed 140% / linear speed), the curable resin compositions of Examples 1 to 4 and Comparative Examples 1 to 6 were coated on the thin polarizing mirror side of the optical film laminate (coating process). The optical film was adhered to the coating surface of the curable resin composition of the thin polarizing mirror using a roller machine (adhesion process). Then, the above visible light was irradiated from the adhered optical film side through an active energy ray irradiation device to cure the curable resin composition, and the thin polarizing mirror and the above optical protective film were adhered via the adhesive layer obtained by the above curing. Regarding the thickness of the obtained adhesive layer, as a pretreatment, cross-section cutting was performed using a microtome (manufactured by Leica, "EM UC7"), and after performing metal ion sputtering on the cut surface, the film thickness was measured using an SEM (manufactured by JEOL Ltd., "JSM-7100F"). Next, the amorphous PET substrate of the optical film laminate was peeled off.

[0181] <Humidity Reliability Evaluation of Polarization Characteristics of Polarizing Film>

[0182] Polarizing films (samples for humidity durability test evaluation) were prepared by adhering the polarizing films manufactured in Examples 1 to 8 or Comparative Examples 1 to 6 to one side of an alkali-free glass with a thickness of 0.7 mm via an adhesive layer (thickness 20 μm). Using this sample, a humidity reliability test of polarization characteristics was carried out in an environment of 85°C - 85% humidity. The details of the humidity reliability test are shown below.

[0183] The obtained polarizing film was exposed in an environment of 85°C and 85% RH for 72 hours, and the polarization degree before and after input was measured using a spectrophotometer with an integrating sphere (V7100 manufactured by JASCO Corporation), and the change amount of polarization degree △Y (%) = |(polarization degree before input (%)) - (polarization degree after input (%))| was obtained. The smaller the change amount of polarization degree △Y (%), the better the humidity reliability of the polarization characteristics in a harsh humid environment can be judged.

[0184] <Evaluation of Tensile Strength of Adhesive Layer>

[0185] The tensile strength of the adhesive layer was evaluated by the following method. The lower the tensile strength, the more brittle the adhesive layer and the easier it is to peel in a humid and hot environment.

[0186] First, prepare two pieces of materials (hereinafter referred to as "film molds") obtained by laminating a cyclic olefin polymer (COP) film (manufactured by Zeon Corporation, ZF14, 50 μm) on the entire surface of a glass plate (manufactured by Matsunami Glass Industry Co., Ltd., soda lime glass) using a double-sided adhesive tape (manufactured by Nitto Denko Corporation, No. 5610). Next, paste a double-sided adhesive tape (manufactured by Nitto Denko Corporation, No. 5610) at a certain interval on the COP film side of one film mold, and laminate the other film mold from the COP film side. Thus, a space with a thickness portion is formed and clamped by the film molds, and the adhesive composition to be evaluated is introduced into the above space. Then, active energy rays are irradiated (Light HAMMER10 Mark III manufactured by Heraeus Corporation, valve: V valve, peak illuminance: 1600 mW / cm 2 , cumulative irradiation dose: 1000 / mJ / cm 2 ), and curing is carried out to produce a film equivalent to the adhesive layer with a thickness of 100 μm. It should be noted that the illuminance and cumulative irradiation dose of the active energy rays were measured using Power Puck 2 (manufactured by EIT Corporation, UVV measurement value). A 10-mm-wide sample was cut from the manufactured film equivalent to the adhesive layer with a thickness of 100 μm, and a tensile test was performed at a tensile speed of 200 mm / min using a precision universal testing machine (AG-IS manufactured by Shimadzu Corporation), and the stress (N) at break was measured.

[0187]

[0188] From the results in Table 1, it can be seen that the humidity resistance reliability of the polarization characteristics of the polarizing films manufactured using the curable resin compositions of Examples 1 to 4 is excellent. On the other hand, it can be seen that the humidity resistance reliability of the polarization characteristics of the polarizing films manufactured using the curable resin compositions of Comparative Examples 1 and 2 deteriorates.

[0189] It should be noted that although the humidity resistance reliability of the polarization characteristics of the polarizing films manufactured using the curable resin compositions of Comparative Examples 3 and 4 is slightly improved, the adhesive layer becomes brittle due to polybutadiene without (meth)acrylate modification, resulting in a decrease in the breaking stress. In addition, the breaking stress of the adhesive layer of the polarizing films manufactured using the curable resin compositions of Comparative Examples 5 and 6 is significantly poor, resulting in peeling between the polarizer and the optical film as the adherend in a humid and hot environment, and thus they cannot be used as polarizing films.

[0190] (Manufacture of Polarizing Film)

[0191] Examples 5 to 8

[0192] Using an MCD coater (manufactured by Fuji Machinery Co., Ltd.) (unit shape: honeycomb, number of gravure roll lines: 240, rotational speed 140% / linear speed), a curable resin composition used in Examples 5 to 8 (a composition obtained by forcibly emulsifying and liquefying each component and water described in Table 2) was coated on the thin polarizer side (treatment surface side) of the optical film laminate (coating step), and it was air-dried using a blower (drying step). The coated surface side of the curable resin composition of the thin polarizer was adhered to the transparent protective film using a roller machine (adhesion linear speed: 25 m / min). Then, irradiation was performed from the protective film side using a visible light irradiation device to cure the curable resin composition (curing step), and then the amorphous PET substrate of the optical film laminate was peeled off and removed, thereby manufacturing the polarizing films of Examples 5 to 8. The film thickness and evaluation results of the adhesive layer of the obtained polarizing films are shown in Table 2. In Table 2, the "anionic surfactant" is sodium polyoxyethylene styrenated methyl phenyl ether sulfate (trade name "NEWCOL 707-SN", manufactured by Nippon Emulsion Co., Ltd.), and the "surface conditioner" is a product named "EXP.4200", manufactured by Nisshin Chemical Industry Co., Ltd.

[0193]

[0194] From the results in Table 2, it can be seen that the polarizing films manufactured using the curable resin compositions of Examples 5 to 8 have a very high breaking stress in the adhesive layer and extremely excellent humidity resistance reliability of the polarization characteristics.

Claims

1. A curable resin composition containing component (A) and component (B), wherein component (A) is at least one selected from (meth)acrylic acid-modified polybutadiene and (meth)acrylic acid-modified polyisoprene, and component (B) contains a (meth)acrylate monomer.

2. The curable resin composition according to claim 1, wherein when the total amount of the composition is set to 100% by mass, the content of component (A) is 1 to 80% by mass.

3. The curable resin composition according to claim 1 or 2, wherein as component (B), it contains a (meth)acrylate monomer (B-1) having a logPow (octanol / water partition coefficient) of 3 or more, and when the total amount of the composition is set to 100% by mass, the content of the (meth)acrylate monomer (B-1) is 1 to 80% by mass.

4. A polarizing film in which an optical film is laminated via an adhesive layer on at least one surface of a polarizer. Among them, The adhesive layer is a cured product layer of the curable resin composition according to any one of claims 1 to 3.

5. The polarizing film according to claim 4, wherein in the curable resin composition, when the total amount of the composition is set to 100% by mass, the content of component (A) is 1 to 80% by mass.

6. The polarizing film according to claim 4 or 5, wherein the curable resin composition contains a (meth)acrylate monomer (B-1) having a logPow (octanol / water partition coefficient) of 3 or more as component (B), and when the total amount of the composition is set to 100% by mass, the content of the (meth)acrylate monomer (B-1) is 1 to 80% by mass.

7. A laminated optical film in which at least one polarizing film according to any one of claims 4 to 6 is laminated.

8. An image display device in which the polarizing film according to any one of claims 4 to 6 or the laminated optical film according to claim 7 is used.

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