JP2023119778A - Method of producing polarizing film - Google Patents

Abstract

An object of the present invention is to provide a method for producing a polarizing film that has excellent humidification reliability and suppresses interference unevenness, thereby providing an excellent appearance. [Solution] A method for manufacturing a polarizing film comprising at least a polarizer, which includes a coating step of applying a curable water-dispersed composition to at least one surface of the polarizer, and drying the curable water-dispersed composition. A method for producing a polarizing film, comprising a drying step of forming a resin layer, wherein the curable water-dispersed composition contains water as a solvent and a polymerizable compound A. The curable water dispersion composition preferably contains, as the polymerizable compound A, a polymerizable compound having a viscosity of 100 mPa·s or more at 25° C. or a solid. [Selection diagram] Figure 1

Description

The present invention relates to a method for producing a polarizing film. The polarizing film can form an image display device such as a mobile phone, a car navigation device, a monitor for a personal computer, or a television as an optical film laminated with the polarizing film alone.

Liquid crystal display devices are rapidly developing in the market for mobile phones, car navigation devices, personal computer monitors, televisions, and the like. A liquid crystal display device visualizes a polarized state by switching liquid crystal, and a polarizer is used from its display principle. In particular, in applications such as TVs, higher brightness, higher contrast, and wider viewing angles are increasingly required, and polarizing films are increasingly required to have higher transmittance, higher degree of polarization, and higher color reproducibility.

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

On the other hand, active energy ray-curable adhesives have been proposed instead of the water-based adhesives. When a polarizing film is produced using an active energy ray-curable adhesive, the productivity of the polarizing film can be improved because a drying step is not required. For example, a radical polymerization type active energy ray-curable adhesive using an N-substituted amide-based monomer as a curable component has been proposed (Patent Document 2 below). The adhesive layer formed using the active energy ray-curable adhesive described in Patent Document 2 is sufficient for a water resistance test that evaluates the presence or absence of color loss and peeling after immersion in hot water at 60 ° C. for 6 hours. Clearable. However, in recent years, polarizing films are often used not only for mobile applications such as mobile phones, but also for image display devices for in-vehicle applications. You have to pass the exam.

Japanese Patent Application Laid-Open No. 2001-296427 Japanese Unexamined Patent Application Publication No. 2012-052000

As a durability test required for polarizing films used for in-vehicle applications, there is a humidification durability test in which, for example, it is exposed to an environment of 85 ° C.-85% humidity for a predetermined period of time. It was found that there is room for further improvement in terms of humidification reliability.

By the way, in recent years, there has been a demand for thinner polarizing films regardless of the application, and for this reason thin polarizers are often used. be. Therefore, there has been a demand to improve the appearance by suppressing the interference unevenness of the polarizing film.

The present invention has been developed in view of the above circumstances, and an object of the present invention is to provide a method for producing a polarizing film having excellent appearance by suppressing interference unevenness and having excellent humidification reliability.

The above problems can be solved by the following configuration. That is, the present invention is a method for producing a polarizing film comprising at least a polarizer, comprising a coating step of applying a curable water-dispersion composition to at least one surface of the polarizer, and the curable water-dispersion composition A method for producing a polarizing film, comprising a drying step of forming a resin layer by drying, wherein the curable aqueous dispersion composition contains water as a solvent and a polymerizable compound A. Regarding.

In the method for producing a polarizing film, the curable water-dispersed composition preferably contains, as the polymerizable compound A, a polymerizable compound having a viscosity of 100 mPa·s or more at 25° C. or a solid polymerizable compound.

In the method for producing a polarizing film, the curable water-dispersed composition preferably contains, as the polymerizable compound A, at least a hydrophobic polymerizable compound having a LogPow of 1.0 or more.

In the method for producing a polarizing film, the curable water-dispersed composition preferably contains, as the polymerizable compound A, at least a trifunctional or higher polyfunctional polymerizable compound.

In the method for producing a polarizing film, the curable aqueous dispersion composition preferably further contains a surfactant.

In the method for producing a polarizing film, the curable water-dispersed composition is preferably a forced emulsification emulsion using the surfactant as an emulsifier.

In the above method for producing a polarizing film, it is preferable that the surfactant is composed of two or more surfactants.

In the method for producing a polarizing film, the surfactant is preferably composed of at least two selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants.

In the method for producing a polarizing film, it is preferable to include a curing step of forming a cured product layer formed by curing the resin layer by irradiating an active energy ray after the drying step.

In the method for producing a polarizing film, the polarizing film is a polarizing film in which the polarizer and the transparent protective film are laminated via an adhesive layer, and after the drying step, the active energy ray is irradiated, and the It is preferable to include a curing step of forming the adhesive layer including at least a cured product layer formed by curing a resin layer.

In general, the polarizer included in the polarizing film has a high refractive index in the absorption axis direction on the long wavelength side. On the other hand, for example, when an adhesive layer (cured layer of a resin layer) is formed on the polarizer in order to adhere the polarizer to another base material, the adhesive layer increases from the short wavelength side to the long wavelength side. The index of refraction of is usually slowly decreasing. Therefore, the difference in refractive index between the polarizer and the adhesive layer becomes large particularly on the long wavelength side, which tends to cause uneven interference, and as a result, the appearance of the polarizing film tends to be impaired.

In the method for producing a polarizing film according to the present invention, a resin layer is formed by applying a curable water-dispersion composition to at least one surface of a polarizer and drying the curable water-dispersion composition. and a drying step. In such a coating step, when a curable water-dispersed composition containing water as a solvent and a polymerizable compound A is applied to at least one surface of the polarizer, the water applied is added to the polarizer. Dissolves iodine complexes present on the surface. As a result, the refractive index of the polarizer on the long wavelength side can be lowered, and when the adhesive layer is finally formed on the polarizer, the refractive index of the polarizer and the adhesive layer on the long wavelength side It is possible to reduce the difference. As a result, it is possible to produce a polarizing film that is less prone to interference unevenness and has excellent appearance.

Furthermore, in the drying step following the coating step, the iodine complex dissolved in water remains in the resin layer when the resin layer containing the polymerizable compound A is formed, even though the water volatilizes. As a result, a polarizing film having a cured product layer (adhesive layer) formed by irradiating the resin layer formed after the drying process with active energy rays was placed in a harsh environment of high temperature and high humidity. Even in this case, elution of iodine in the polarizer is suppressed. Therefore, in the method for producing a polarizing film according to the present invention, a polarizing film having excellent humidification reliability can be produced.

In addition, in the method for producing a polarizing film according to the present invention, when the polymerizable compound A contained in the curable water-dispersion composition has a viscosity of 100 mPa s or more at 25 ° C. or is solid, the curable water-dispersion composition When the product contains a surfactant, the cured product layer formed by irradiating the resin layer formed after the drying step with an active energy ray is formed with a rigid skeleton and exhibits hydrophobicity. As a result, the elution of iodine from the polarizer is suppressed at a higher level even when the polarizing film is placed in a harsh environment of high temperature and high humidity. As a result, it is possible to produce a polarizing film that is particularly excellent in humidification reliability.

BRIEF DESCRIPTION OF THE DRAWINGS It is an example of the cross-sectional schematic diagram of the polarizing film manufactured by the manufacturing method of this invention. It is another example of the cross-sectional schematic diagram of the polarizing film manufactured by the manufacturing method of this invention. It is another example of the cross-sectional schematic diagram of the polarizing film manufactured by the manufacturing method of this invention.

The method for producing a polarizing film according to the present invention comprises a coating step of applying a curable water-dispersed composition to at least one surface of a polarizer, and drying the curable water-dispersed composition to form a resin layer. and a drying step.

The curable aqueous dispersion composition used in the present invention contains water as a solvent and a polymerizable compound A. Each configuration will be described below.

It is preferable that water as a solvent does not contain an organic solvent such as alcohol. It is preferably 5% by weight or less, more preferably 1% by weight or less, and particularly preferably 0.1% by weight or less.

The polymerizable compound A is preferably a polymerizable compound having a viscosity of 100 mPa·s or more at 25° C. or being solid. In the present invention, the polymerizable compound having such properties is a "polyfunctional polymerizable compound having at least trifunctionality", a "hydrophobic polymerizable compound having a LogPow of 1.0 or more", or a "polymerization having a ring structure." It can be broadly classified into "sex compounds".

Examples of polyfunctional polymerizable compounds having at least trifunctionality include pentaerythritol triacrylate (trifunctional, 600 to 1000 (mPa s/25°C)), pentaerythritol tetraacrylate (tetrafunctional, solid at 25°C)), di Pentaerythritol hexaacrylate (trifunctional, 600 to 1000 (mPa s/25°C))), polypentaerythritol acrylate (trifunctional or higher, 9000 to 15000 (mPa s/25°C))), tris isocyanurate (2 -acryloyloxyethyl) (trifunctional, solid at 25°C)), ditrimethylolpropane tetraacrylate (tetrafunctional, 1000 (mPa·s/25°C)), and the like.

Hydrophobic polymerizable compounds having a LogPow of 1.0 or more include, for example, a polymethyl methacrylate group (Mn≈6000)-containing macromonomer (solid at 25° C.), a polybutyl acrylate group (Mn≈6000)-containing macromonomer (10000 ( mPa·s/25° C.) or higher), macromonomers having a hydrophobic segment and a polymerizable functional group, and the like.

The octanol/water partition coefficient (logPow) is an index representing the lipophilicity of a substance, and means the logarithm of the octanol/water partition coefficient. High logPow means lipophilicity, ie low water absorption. Although the logPow value can be measured (flask immersion method described in JIS-Z-7260), it can also be calculated by calculation. In this specification, logPow values calculated with ChemDraw Ultra manufactured by Cambridge Soft are used.

Examples of the polymerizable compound having a ring structure include dimethylol-tricyclodecane diacrylate (bifunctional, 130 to 170 (mPa s/25° C.)), ethoxylated bisphenol A dimethacrylate (bifunctional, ethylene oxide repeating unit number 2 .3 (1220 (mPa s / 25 ° C.), ethylene oxide repeating unit number 2.6 (1000 (mPa s / 25 ° C.), ethylene oxide repeating unit number 4 (640 (mPa s / 25 ° C.), ethylene 10 oxide repeating units (450 (mPa s/25°C)), 17 ethylene oxide repeating units (500 (mPa s/25°C), 30 ethylene oxide repeating units (660 (mPa s/25°C) )), ethoxylated-o-phenylphenol acrylate (monofunctional, 130 (mPa s/25° C.)), 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorenediacrylate (bifunctional, 91000 (mPa s / 60 ° C.)), 1-pyrenylmethyl methacrylate (monofunctional, solid at 25 ° C.), 2-naphthyl methacrylate (monofunctional, solid at 25 ° C.), 9-anthrylmethyl methacrylate (monofunctional , solid at 25°C), 1,3-adamantanediol diacrylate (monofunctional, solid at 25°C), rosin acrylate (monofunctional, 10000 (mPa·s/40°C)).

Other polymerizable compounds A include polybutadiene-terminated diacrylate (bifunctional, 4000 to 8000 (mPa·s/25° C.)).

In the curable aqueous dispersion composition used in the present invention, the content of the polymerizable compound A is preferably 10 to 95% by weight, when the total amount excluding water as a solvent is 100% by weight, and 20 to 95% by weight. It is more preferably 93% by weight, and even more preferably 30 to 90% by weight.

The curable aqueous dispersion composition used in the present invention preferably contains water as a solvent, the polymerizable compound A, and a surfactant. Surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants.

Anionic surfactants include sodium stearate, sodium N-lauroylsarcosinate, sodium palmitate, sodium laurate, N-lauroylsarcosine, sodium N-decanoylsarcosinate, N-oleoylsarcosine, sodium myristate, sodium cholate. , carboxylates such as sodium oleate; phosphate ester salts such as sodium monododecyl phosphate; 5-dimethylsodium sulfoisophthalate, sodium 1-undecanesulfonate, sodium 1-pentadecanesulfonate, bis(2- sulfonates such as sodium ethylhexyl), sodium 1-octadecanesulfonate, sodium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium 1-decanesulfonate, sodium 1-dodecanesulfonate; decylsulfuric acid Sulfuric acid ester salts such as sodium, sodium dodecyl sulfate, sodium hexadecyl sulfate, sodium dodecyl sulfate, polyoxyethylene styrenated methylphenyl ether sulfate, polyoxyethylene alkyl ether sulfate, polyoxyethylene cumylphenyl ether sulfate, Examples include polycyclic phenyl ether methacrylate sulfate salts.

Cationic surfactants include n-octyltrimethylammonium bromide, trimethylstearylammonium bromide, hexadecyltrimethylammonium chloride, trimethylstearylammonium chloride, hexadecyltrimethylammonium chloride, trimethylstearylammonium chloride, n-octylamine hydrochloride, octadecylamine. Hydrochloride, n-octylamine hydrobromide, n-octyltrimethylammonium chloride, trimethyltetradecylammonium chloride, heptadecyltrimethylammonium bromide, butyltrimethylammonium bromide, hexadecyltrimethylammonium hexafluorophosphate, hexaperchlorate Decyltrimethylammonium, decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, decyltrimethylammonium bromide, di-n-alkyldimethylammonium chloride, hexadecyltrimethylammonium hydroxide, hexadecyltrimethylammonium bromide, trimethylnonylammonium bromide, dodecylamine hydrochloride fatty amine salts or aliphatic Quaternary ammonium salts; heterocyclic quaternary ammonium salts such as 1-hexadecyl-4-methylpyridinium chloride hydrate, hexadecylpyridinium chloride monohydrate, hexadecylpyridinium bromide hydrate, 1-dodecylpyridinium chloride; benzyl aromatic quaternary ammonium salts such as dodecyldimethylammonium bromide, benzethonium chloride, benzyldimethylstearylammonium chloride, benzylcetyldimethylammonium chloride, benzyldodecyldimethylammonium chloride dihydrate, benzyldimethyltetradecylammonium chloride;

Amphoteric surfactants include octadecyldimethyl(3-sulfopropyl)ammonium hydroxide inner salt, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, dodecyldimethyl(3-sulfopropyl ) ammonium hydroxide inner salt.

Examples of nonionic surfactants include ester ether types such as polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan monolaurate; ethylene glycol monododecyl ether, hexaethylene glycol monododecyl ether, polyethylene glycol monooleyl ether (n≈10), polyethylene glycol monooleyl ether (n≈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≈23), triethylene glycol monododecyl ether, polyethylene glycol mono-4-nonylphenyl ether (n≈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, Ether types such as polyethylene glycol monomethyl ether 550, polyethylene glycol monomethyl ether 2000, polyethylene glycol mono-4-nonylphenyl ether (n≈18), polyethylene glycol 20000; sorbitan monooleate, sorbitan trioleate, sorbitan monopalmitate, monostearin, monopalmitin, 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≈2), monomyristin, polyethylene glycol monostearate (n≈25), polyethylene glycol monostearate (n≈4), polyethylene glycol monostearate acetylenic surfactants having an acetylene bond such as ester types such as alert (n ≈ about 40) and polyethylene glycol monostearate (n ≈ about 10), acetylene alcohol surfactants, acetylene glycol surfactants, etc.; Fluorinated surfactants and the like are included.

The curable aqueous dispersion composition used in the present invention preferably contains two or more surfactants as surfactants in order to achieve both the dispersibility of the polymerizable compound A and the appearance of the coating film. In particular, it preferably contains at least two selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants.

In order to achieve both the dispersibility of the polymerizable compound A and the appearance of the coating film, the content of the surfactant in the curable aqueous dispersion composition used in the present invention is 100 wt. %, it is preferably 0.1 to 20% by weight, more preferably 1 to 15% by weight.

The curable aqueous dispersion composition used in the present invention preferably contains a photopolymerization initiator. A photopolymerization initiator is appropriately selected depending on the active energy ray. When curing with ultraviolet light or visible light, a photopolymerization initiator that is cleaved with ultraviolet light or visible light is used. Examples of the photopolymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3′-dimethyl-4-methoxybenzophenone; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2 -propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenylketone and other aromatic ketone compounds; methoxyacetophenone, 2,2-dimethoxy- Acetophenone compounds such as 2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin methyl ether, Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; aromatic ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4- Thioxanthone compounds such as dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; camphorquinone; halogenated ketone; acylphosphinoxide; acylphosphonate, and the like.

The blending amount of the photopolymerization initiator is 20 parts by weight or less with respect to 100 parts by weight of the total amount of the polymerizable compound A. The blending amount of the photopolymerization initiator is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, further preferably 0.1 to 5 parts by weight.

When the curable water-dispersed composition used in the present invention is a visible light-curable composition, it is preferable to use a photopolymerization initiator that is particularly sensitive to light of 380 nm or longer. A photopolymerization initiator highly sensitive to light of 380 nm or more will be described later.

As the photopolymerization initiator, a compound represented by the following general formula (1);
(wherein R ¹ and R ² represent —H, —CH ₂ CH ₃ , —iPr or Cl, and R ¹ and R ² may be the same or different), or the general formula ( It is preferable to use the compound represented by 1) together with a photopolymerization initiator highly sensitive to light of 380 nm or longer, which will be described later. When the compound represented by the general formula (1) is used, the adhesiveness is superior to that when a photopolymerization initiator highly sensitive to light of 380 nm or more is used alone. Among the compounds represented by general formula (1), diethylthioxanthone in which R ¹ and R ² are —CH ₂ CH ₃ is particularly preferred. The composition ratio of the compound represented by general formula (1) in the curable aqueous dispersion composition is preferably 0.1 to 5% by weight with respect to the total amount of the curable aqueous dispersion composition, and 0.1 to 5% by weight. It is more preferably 5 to 4% by weight, even more preferably 0.9 to 3% by weight.

Moreover, it is preferable to add a polymerization initiation aid as necessary. Examples of polymerization initiation aids include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate. and ethyl 4-dimethylaminobenzoate is particularly preferred. When a polymerization initiation aid is used, the amount added is usually 0 to 5% by weight, preferably 0 to 4% by weight, most preferably 0 to 3% by weight, based on the total amount of the curable resin composition. .

Moreover, a well-known photoinitiator can be used together as needed. Since the transparent protective film having UV absorbability does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator that is highly sensitive to light of 380 nm or more. Specifically, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 , 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole- 1-yl)-phenyl) titanium and the like.

The curable aqueous dispersion composition used in the present invention preferably contains a silane coupling agent. Specific examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycide as active energy ray-curable compounds. xypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane silane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and the like.

Preferred are 2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane.

The amount of the silane coupling agent is preferably in the range of 0.01 to 20% by mass, preferably 0.05 to 15% by mass, relative to the total amount of the curable aqueous dispersion composition, and 0.1 to It is more preferably 10% by mass. This is because if the amount exceeds 20% by mass, the storage stability of the curable water-dispersed composition deteriorates, and if the amount is less than 0.1% by mass, the effect of the adhesive water resistance is not sufficiently exhibited.

Specific examples of non-active energy ray-curable silane coupling agents other than the above include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltrimethoxysilane. silane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatopropyltriethoxysilane, imidazolesilane, and the like.

The curable aqueous dispersion composition used in the present invention may contain, as a polymerizable compound, a polymerizable compound other than the polymerizable compound A having a viscosity of 100 mPa·s or more at 25° C. or being solid. Examples of the polymerizable compound that may be contained include a polymerizable compound B that serves as a raw material for the curable resin composition described below. Polymerizable compound B will be described later.

The curable aqueous dispersion composition used in the present invention may optionally further contain a compound represented by the following general formula (3);

(where X is a functional group containing a reactive group, R ⁶ and R ⁷ are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an aryl group, or a heterocyclic group represents), preferably a compound according to the general formula (3′);

(where Y is an organic group, X' is a reactive group contained in X, and R ⁶ and R ⁷ are the same as described above), more preferably the following general formulas (3a) to (3d) Compound;

can be blended. When these compounds are blended in the curable water-dispersed composition, the adhesiveness to the polarizer and the transparent protective film may be improved, which is preferable. From the viewpoint of improving the adhesion and water resistance between the polarizer and the transparent protective film, the content of the compound represented by the general formula (3) in the curable water-dispersible composition is the total amount excluding water as a solvent. Based on 100% by weight, the content is preferably 0.001 to 50% by weight, more preferably 0.1 to 30% by weight, and most preferably 1 to 10% by weight.

In the general formula (3), the aliphatic hydrocarbon group is a linear or branched alkyl group which may have a substituent having 1 to 20 carbon atoms, and a substituent having 3 to 20 carbon atoms. cyclic alkyl groups which may be substituted, and alkenyl groups having 2 to 20 carbon atoms. optionally substituted naphthyl groups and the like, and examples of heterocyclic groups include 5- or 6-membered ring groups containing at least one heteroatom and optionally having substituents. These may be linked together to form a ring. In general formula (3), R ⁶ and R ⁷ are preferably a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms, most preferably a hydrogen atom.

X possessed by the compound represented by the general formula (3) is a functional group containing a reactive group, which is a functional group capable of reacting with the curable component constituting the adhesive layer, and the reactive group contained in X is is, for example, hydroxyl group, amino group, aldehyde group, carboxyl group, vinyl group, (meth)acryl group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, α,β-unsaturated carbonyl groups, mercapto groups, halogen groups, and the like. When the curable resin composition constituting the adhesive layer is active energy ray-curable, the reactive group contained in X is a vinyl group, a (meth)acryl group, a styryl group, a (meth)acrylamide group, a vinyl ether group, X is preferably at least one reactive group selected from the group consisting of an epoxy group, an oxetane group and a mercapto group, especially when the adhesive composition constituting the adhesive layer is radically polymerizable. The reactive group is preferably at least one reactive group selected from the group consisting of a (meth)acryl group, a styryl group and a (meth)acrylamide group, and the compound represented by the general formula (1) is When having a (meth)acrylamide group, the reactivity is high and the copolymerization rate with the active energy ray-curable resin composition is increased, which is more preferable. In addition, the (meth)acrylamide group has a high polarity and is excellent in adhesiveness, so it is preferable from the viewpoint that the effects of the present invention can be obtained efficiently. When the curable resin composition that constitutes the adhesive layer is cationic polymerizable, the reactive group contained in X is a hydroxyl group, an amino group, an aldehyde, a carboxyl group, a vinyl ether group, an epoxy group, an oxetane group, or a mercapto group. It is preferable to have at least one selected functional group, especially when it has an epoxy group, it is preferable for excellent adhesion between the resulting curable resin layer and the adherend, and when it has a vinyl ether group, the curable resin composition is preferred because of its excellent curability.

In the present invention, the compound represented by the general formula (3) may be one in which the reactive group and the boron atom are directly bonded. The compound represented by is preferably one in which a reactive group and a boron atom are bonded via an organic group, that is, a compound represented by general formula (3′). For example, when the compound represented by the general formula (3) is bonded to a reactive group via an oxygen atom bonded to a boron atom, the adhesive water resistance of the polarizing film tends to deteriorate. On the other hand, the compound represented by the general formula (3) does not have a boron-oxygen bond, but has a boron-carbon bond and contains a reactive group by bonding a boron atom and an organic group. When it is a compound (when represented by general formula (3′)), it is preferable because the adhesive water resistance of the polarizing film is improved. The organic group specifically means an organic group having 1 to 20 carbon atoms which may have a substituent, and more specifically, for example, having a substituent having 1 to 20 carbon atoms. A linear or branched alkylene group which may be optionally substituted, a cyclic alkylene group which may have a substituent of 3 to 20 carbon atoms, a phenylene group which may have a substituent of 6 to 20 carbon atoms, a phenylene group which may have a substituent of 10 to 10 carbon atoms. A naphthylene group which may have 20 substituents may be mentioned.

As the compound represented by the general formula (3), in addition to the compounds exemplified above, esters of hydroxyethylacrylamide and boric acid, esters of methylolacrylamide and boric acid, esters of hydroxyethyl acrylate and boric acid, and hydroxybutyl Esters of (meth)acrylates and boric acid can be exemplified, such as esters of acrylate and boric acid.

The curable water-dispersed composition used in the present invention has a viscosity of 100 mPa s or more at 25° C. or a solid in order to achieve both the dispersibility of the polymerizable compound A and the appearance of the coating film. A forced emulsification type emulsion using a surfactant as an emulsifier is preferable in order to improve humidification reliability. In the case of a self-emulsifying type in which a hydrophilic group is introduced into the polymerizable compound or polymer compound contained in the curable water-dispersion composition, it may not be possible to improve the appearance of the coating film and improve the humidification reliability of the polarizing film. Methods for forcibly emulsifying the curable water-dispersed composition include, for example, an ultrasonic homogenizer, a high-speed rotary homogenizer, a grinding device using other cavitation phenomena, a wet atomization device that obliquely collides liquids at high pressure, and a ball mill. It can be carried out by a device for media pulverization, a stirrer using stirring blades, or the like. In the present invention, methods known to those skilled in the art can be used without being limited to this.

The polarizing film produced by the production method according to the present invention is a polarizing film having a cured product layer on at least one surface, and the cured product layer is a cured product layer of the curable water-dispersion composition described above. characterized by In the present invention, the polarizing film is a polarizing film in which a polarizer and a transparent protective film are laminated via an adhesive layer, and the adhesive layer is coated with a curable water-dispersed composition and dried. It is preferable to provide a cured product layer of a resin layer formed by

In the present invention, the polarizer is not particularly limited, and various polarizers can be used. As a polarizer, for example, hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene/vinyl acetate copolymer films are uniaxially stretched with iodine adsorbed thereon. is mentioned. The thickness of the polarizer is, for example, 3 to 20 μm.

However, in the present invention, it is preferable to use a thin polarizer having a thickness of 3 μm or more and 15 μm or less from the viewpoint of improving humidification reliability in a harsh environment of high temperature and high humidity. It is particularly preferably 12 μm or less, more preferably 10 μm or less, particularly preferably 8 μm or less. Such a thin polarizer has little unevenness in thickness, excellent visibility, and little dimensional change, so it is excellent in durability against thermal shock.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or it may be immersed in an aqueous solution of potassium iodide or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol film with water, dirt and anti-blocking agents on the surface of the polyvinyl alcohol film can be washed away, and by swelling the polyvinyl alcohol film, uneven dyeing and other unevenness can be prevented. be. Stretching may be performed after dyeing with iodine, stretching may be performed while dyeing, or dyeing with iodine may be performed after stretching. It can also be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

The polarizer preferably contains boric acid from the viewpoint of stretching stability and humidification reliability. In addition, 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 viewpoint of suppressing the generation of through cracks. From the viewpoint of stretching stability and humidification reliability, the boric acid content relative to the total amount of the polarizer is preferably 10% by mass or more, and more preferably 12% by mass or more.

As a thin polarizer, typically,
Patent No. 4751486,
Patent No. 4751481 specification,
Patent No. 4815544 specification,
Patent No. 5048120,
WO 2014/077599 pamphlet,
International Publication No. 2014/077636,
and the like, or thin polarizers obtained from the production methods described therein.

As for the thin polarizer, among the production methods including the step of stretching and the step of dyeing in the state of a laminate, it is possible to stretch at a high magnification and improve the polarization performance. Those obtained by a production method including a step of stretching in an aqueous boric acid solution as described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544 are preferred, particularly Japanese Patent No. 4751481 and Japanese Patent No. 4815544. It is preferably obtained by a manufacturing method including a step of auxiliary stretching in the air before stretching in a boric acid aqueous solution. These thin polarizers can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) layer and a stretching resin base material in the state of a laminate, and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching because it is supported by the stretching resin substrate.

In the method for producing a polarizing film according to the present invention, before the coating step of applying the curable water-dispersion composition to at least one surface of the polarizer, the surface coated with the curable water-dispersion composition is subjected to an activation treatment. It is preferable to provide a processing step to carry out. Hydrophilic functional groups (-COOH and -OH) and radical active species are introduced to the surface of the polarizer (polyvinyl alcohol-based polarizer) by the activation treatment. The introduced hydrophilic functional group and radical active species are preferable because the wettability of the curable water-dispersed composition is improved and the adhesion between the resin layer formed through the drying process and the polarizer is improved. In addition, when a cured product layer (adhesive layer) is formed by curing the resin layer, the polymerizable compound A constituting the resin layer reacts with the hydrophilic functional groups and radical active species on the surface of the polarizer. By doing so, the adhesive layer and the polarizer are strongly adhered to each other, which is preferable.

The activation treatment includes at least one treatment selected from corona treatment, plasma treatment, glow treatment and ozone treatment. Corona treatment can be carried out, for example, by discharging in normal pressure air using a corona treatment machine. Plasma treatment can be carried out, for example, by a method of discharging in normal pressure air or in an atmosphere of an inert gas such as nitrogen or argon using a plasma discharger. Glow treatment and ozone treatment can also be carried out according to conventional methods. Among these, corona treatment is preferable in terms of facility costs and processing costs.

In the activation treatment, treatment conditions may be appropriately adjusted so that hydrophilic functional groups and radical active species can be introduced onto the surface of the polarizer. For example, in corona treatment, it is preferable to adjust the amount of discharge to about 10 to 500 W/m ² /min, preferably 20 to 300 W/m ² /min.

As a material for forming the transparent protective film, thermoplastic resins are used which are excellent in transparency, mechanical strength, thermal stability, water barrier properties, isotropy, and the like. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic Polyolefin resins (norbornene-based resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. One or more of any suitable additives may be contained in the transparent protective film. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . If the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

As the material for forming the transparent protective film, a material having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc. is preferable, and in particular, a material having a moisture permeability of 150 g/m ² /24h or less. is more preferred, 140 g/m ² /24h or less is particularly preferred, and 120 g/m ² /24h or less is even more preferred.

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

The thickness of the transparent protective film can be determined as appropriate, but is generally about 1 to 500 μm, preferably 1 to 300 μm, more preferably 5 to 200 μm, from the viewpoint of strength, workability such as handleability, and thinness. preferable. Furthermore, 10 to 200 μm is preferable, and 20 to 80 μm is preferable.

As the transparent protective 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. The front retardation is usually controlled in the range of 40-200 nm, and the thickness direction retardation is usually controlled in the range of 80-300 nm. When a retardation film is used as the transparent protective film, the thickness can be reduced because the retardation film also functions as a transparent protective film.

In order to increase the adhesive strength with the polarizer, the transparent protective film may be subjected to a surface modification treatment on the surface to be bonded with the polarizer. Specific treatments include corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, saponification treatment, and treatment with a coupling agent. Among these, corona treatment is preferable in terms of facility costs and processing costs. Treatment conditions such as the amount of discharge are the same as those for the polarizer.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an oriented film of a liquid crystal polymer, and a film in which an oriented layer of a liquid crystal polymer is supported. Although the thickness of the retardation film is not particularly limited, it is generally about 20 to 150 μm.

As the retardation film, the following formulas (1) to (3):
0.70<Re[450]/Re[550]<0.97 (1)
1.5×10 ⁻³ <Δn<6×10 ⁻³ (2)
1.13<NZ<1.50 (3)
(Wherein, Re [450] and Re [550] are the in-plane retardation values of the retardation film measured with light having wavelengths of 450 nm and 550 nm, respectively, at 23 ° C., and Δn is the slow phase of the retardation film In-plane birefringence that is nx-ny when the refractive indices in the axial direction and the fast axis direction are nx and ny, respectively, and NZ is the refractive index in the thickness direction of the retardation film, (ratio of nx-nz, which is birefringence in the thickness direction, to nx-ny, which is in-plane birefringence) may be used.

A polarizing film produced by the production method according to the present invention may be provided with a retardation layer. The retardation layer may be a single layer or multiple layers, and the retardation layer may also serve as a protective layer for the polarizer. In the polarizing film of the present invention, for example, the first retardation layer and the second retardation layer are attached via an adhesive layer. The type, number, combination, arrangement position, and characteristics of the retardation layer can be appropriately set according to the purpose.

A liquid crystalline compound is preferably used for forming the retardation layer, and a solvent containing the liquid crystalline compound can be applied using, for example, a wire bar, a gap coater, a comma coater, a gravure coater, a slot die, or the like. At this time, the applied liquid crystalline solution may be dried naturally or dried by heating. The liquid crystalline solution is preferably applied at a concentration lower than the isotropic phase-liquid crystal phase transition concentration, that is, in an isotropic phase state. In this case, the orientation can be stably achieved by a method such as rubbing treatment or photo-orientation.

In the polarizing film produced by the production method according to the present invention, it is preferable that a polarizer and a transparent protective film are laminated via an adhesive layer. The adhesive layer may be composed only of a cured product layer of the curable aqueous dispersion composition, or may be composed only of a cured product layer of the curable resin composition, and the adhesive layer is the curable aqueous dispersion composition. A configuration containing a cured product layer of the product and a cured product layer of the curable resin composition may also be used. In the polarizing film shown in FIG. 1, the polarizer 1 and the transparent protective film 3 are combined with the adhesive layer 7 containing the cured product layer 2 of the curable water dispersion composition and the cured product layer 4 of the curable resin composition. Furthermore, the surface of the polarizer 1 opposite to the cured product layer 2 is bonded to the glass substrate 6 with the pressure-sensitive adhesive layer 5 interposed therebetween. The adhesive layer 7 may have a structure in which the cured product layer 2 and the cured product layer 4 are separated, or may have a structure in which at least a part of the cured product layer 2 and the cured product layer 4 are compatible with each other.

Further, the polarizing film produced by the production method according to the present invention includes a laminate in which any layer of a transparent protective film, a retardation film, or a retardation layer is laminated via an adhesive layer. Also good. The adhesive layer may be composed only of a cured product layer of the curable aqueous dispersion composition, or may be composed only of a cured product layer of the curable resin composition, and the adhesive layer is the curable aqueous dispersion composition. A configuration containing a cured product layer of the product and a cured product layer of the curable resin composition may also be used. A polarizing film in which the laminate is further laminated with a polarizer can also be preferably used in the present invention.

In the polarizing film shown in FIG. 1, the film thickness of the cured product layer 2 of the curable water-dispersed composition is preferably 0.1 to 5.0 μm, more preferably 0.3 to 3.0 μm from the viewpoint of improving humidification reliability. 0 μm is more preferable. In addition, the film thickness of the cured product layer 4 of the curable resin composition is preferably 0.1 to 3.0 μm, more preferably 0.3 to 2.0 μm, from the viewpoint of improving humidification reliability and adhesion. is more preferred. Further, the thickness of the adhesive layer 7 (total thickness of the thickness of the cured product layer 2 of the curable water dispersion composition and the thickness of the cured product layer 4 of the curable resin composition) is 0.2 to 5. 0.1 μm, more preferably 0.5 to 3.0 μm.

The polarizing film manufactured by the manufacturing method according to the present invention may have a configuration other than the configuration shown in FIG. In the polarizing film shown in FIG. 2, the polarizer 1 and the transparent protective film 3 are laminated via the adhesive layer 7 provided only with the cured product layer 2 of the curable water dispersion composition, and further the cured product of the polarizer 1 The surface opposite to the layer 2 is attached to the glass substrate 6 with the adhesive layer 5 interposed therebetween. The film thickness of the cured product layer 2 (=thickness of the adhesive layer 7) of the curable water-dispersed composition is preferably 0.1 to 5.0 μm, more preferably 0.3 to 3 μm, from the viewpoint of improving humidification reliability. 0 μm is more preferred.

The polarizing film shown in FIG. 3 is provided with a cured product layer 2 of a curable water-dispersed composition on one surface of the polarizer 1, and the surface opposite to the cured product layer 2 of the polarizer 1 is a cured resin composition. It is pasted (bonded) to the transparent protective film 3 via the material layer 4 . The surface of the transparent protective film 3 opposite to the cured product layer 4 is adhered to the glass substrate 6 via the adhesive layer 5 . The polarizing film shown in FIG. 3 contains the cured product layer 2 of the curable water dispersion composition in the adhesive layer (cured product layer 4 of the curable resin composition) between the polarizer 1 and the transparent protective film 3. However, since the cured product layer 2 is provided on the surface of the polarizer 1 opposite to the transparent protective film, the elution of iodine from the polarizer is also suppressed, and the humidification reliability is significantly improved.

In the polarizing film shown in FIG. 3, the film thickness of the cured product layer 2 of the curable water-dispersed composition is preferably 0.1 to 10 μm, more preferably 0.3 to 5.0 μm, from the viewpoint of improving humidification reliability. It is more preferable to have In addition, the film thickness of the cured product layer (adhesive layer) 4 of the curable resin composition is preferably 0.1 to 3.0 μm from the viewpoint of improving humidification reliability and adhesiveness, and 0.3 to 2 μm. 0 μm is more preferred.

The curable resin composition constituting the adhesive layer (cured material layer) of the polarizing film produced by the production method according to the present invention will be described below. In the present invention, the "curable aqueous dispersion composition" contains water as a solvent and a polymerizable compound A. Preferably, the polymerizable compound A has a viscosity of 100 mPa s or more at 25 ° C. or a solid A polymerizable compound A and a surfactant are included. On the other hand, the "curable resin composition" mainly contains a polymerizable compound B other than the polymerizable compound A, does not contain water as a solvent, even if it contains water, the total amount in the curable resin composition is 100% by weight, the water content is 5.0% by weight or less, particularly 2.0% by weight or less, and more particularly 1.0% by weight or less.

The curable resin composition can be classified into a radically polymerizable curable resin composition and a cationically polymerizable curable resin composition. In the present invention, active energy rays with a wavelength range of 10 nm to less than 380 nm are expressed as ultraviolet rays, and active energy rays with a wavelength range of 380 nm to 800 nm are expressed as visible rays.

Examples of the monomer component constituting the radically polymerizable curable resin composition include the polymerizable compound B other than the polymerizable compound A, and the polymerizable compound having a viscosity at 25° C. of less than 100 mPa·s. More preferably, the polymerizable compound has a viscosity of 50 mPa·s or less at 25°C.

Examples of the polymerizable compound B include compounds having radically polymerizable functional groups of carbon-carbon double bonds such as (meth)acryloyl groups and vinyl groups. These monomer components can be either monofunctional radically polymerizable compounds or multifunctional radically polymerizable compounds having two or more polymerizable functional groups. Moreover, these radical polymerizable compounds can be used individually by 1 type or in combination of 2 or more types. As these radically polymerizable compounds, for example, compounds having a (meth)acryloyl group are suitable. In the present invention, (meth)acryloyl means an acryloyl group and/or a methacryloyl group, and "(meth)" has the same meaning below.

Examples of monofunctional radically polymerizable compounds include (meth)acrylamide derivatives having a (meth)acrylamide group. A (meth)acrylamide derivative is preferable in terms of ensuring adhesiveness to a polarizer and various transparent protective films, and in terms of high polymerization rate and excellent productivity. Specific examples of (meth)acrylamide derivatives include N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N - N-alkyl group-containing (meth)acrylamide derivatives such as butyl (meth)acrylamide and N-hexyl (meth)acrylamide; N-methylol (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, N-methylol-N- N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as propane (meth)acrylamide; N-aminoalkyl group-containing (meth)acrylamide derivatives such as aminomethyl (meth)acrylamide and aminoethyl (meth)acrylamide; N-methoxymethyl N-alkoxy group-containing (meth)acrylamide derivatives such as acrylamide and N-ethoxymethylacrylamide; N-mercaptoalkyl group-containing (meth)acrylamide derivatives such as mercaptomethyl (meth)acrylamide and mercaptoethyl (meth)acrylamide; be done. Further, the heterocycle-containing (meth)acrylamide derivative in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle includes, for example, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloyl pyrrolidine and the like.

Among the (meth)acrylamide derivatives, N-hydroxyalkyl group-containing (meth)acrylamide derivatives are preferred from the viewpoint of adhesion to polarizers and various transparent protective films. , for example, various (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl ( meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl ( Examples include (meth)acrylic acid (C1-20) alkyl esters such as meth)acrylate and n-octadecyl (meth)acrylate.

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

Further, the (meth)acrylic acid derivatives include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4- Hydroxyalkyl (meth)acrylates such as hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate and hydroxyl group-containing (meth) acrylates such as [4-(hydroxymethyl) cyclohexyl] methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate; glycidyl (meth) acrylate, Epoxy group-containing (meth)acrylates such as 4-hydroxybutyl (meth)acrylate glycidyl ether; 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate, tetra Halogen-containing (meth)acrylate such as fluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, etc. ) acrylates; alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate; 3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth)acrylate, 3-ethyl-oxetanylmethyl (meth)acrylate , 3-Butyl-oxetanylmethyl (meth)acrylate, 3-hexyloxetanylmethyl (meth)acrylate and other oxetane group-containing (meth)acrylates; Tetrahydrofurfuryl (meth)acrylate, butyrolactone (meth)acrylate, and other heterocycles (Meth) acrylate, neopentyl glycol hydroxypivalate (meth) acrylic acid adduct, p-phenylphenol (meth) acrylate, and the like.

Examples of monofunctional radically polymerizable compounds include carboxyl group-containing monomers such as (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and isocrotonic acid.

Examples of monofunctional radically polymerizable compounds include lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, Vinyl-based monomers having a nitrogen-containing heterocyclic ring such as vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine are included.

Moreover, a radically polymerizable compound having an active methylene group can be used as the monofunctional radically polymerizable compound. A radically polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acrylic group at the end or in the molecule and an active methylene group. Active methylene groups include, for example, an acetoacetyl group, an alkoxymalonyl group, a cyanoacetyl group, and the like. Preferably, the active methylene group is an acetoacetyl group. Specific examples of radically polymerizable compounds having an active methylene group include 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, 2-acetoacetoxy-1-methylethyl (meth)acrylate, and the like. 2-ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl) acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, N-(2-acetoacetylaminoethyl)acrylamide and the like. The radically polymerizable compound having an active methylene group is preferably acetoacetoxyalkyl (meth)acrylate.

Examples of polyfunctional radically polymerizable compounds having two or more polymerizable functional groups include tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. , 1,9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide addition di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecanedimethanol di(meth) Acrylates, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta (Meth)acrylates, dipentaerythritol hexa(meth)acrylate, esters of (meth)acrylic acid and polyhydric alcohols such as EO-modified diglycerin tetra(meth)acrylate, 9,9-bis[4-(2- (Meth)acryloyloxyethoxy)phenyl]fluorene. Specific examples include Aronix M-220 (manufactured by Toagosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DCP-A (Kyoeisha Chemical Co., Ltd.) (manufactured by Sartomer), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer) and the like. Various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, various (meth)acrylate monomers, and the like can also be used as necessary.

In the present invention, the curable resin composition may contain an acrylic oligomer obtained by polymerizing a (meth)acrylic monomer in addition to the radically polymerizable compound. By containing an acrylic oligomer in the adhesive composition, curing shrinkage when the composition is irradiated with an active energy ray and cured is reduced, and the adhesive layer and the adherend such as a polarizer and an optical film It is possible to reduce the interfacial stress with As a result, deterioration in adhesion between the adhesive layer and the adherend can be suppressed.

Since the curable resin composition preferably has a low viscosity in consideration of workability and uniformity during coating, an acrylic oligomer obtained by polymerizing a (meth)acrylic monomer should also have a low viscosity. preferable. The acrylic oligomer which has a low viscosity and can prevent curing shrinkage of the adhesive layer preferably has a weight-average molecular weight (Mw) of 15,000 or less, more preferably 10,000 or less, and particularly 5,000 or less. preferable. On the other hand, in order to sufficiently suppress 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 1000 or more. 1500 or more is particularly preferable. Specific examples of the (meth)acrylic monomer constituting the acrylic oligomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, 2-methyl- 2-nitropropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, S-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl ( (Meth)acrylic acid (C1-20) alkyl esters such as meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, N-octadecyl (meth)acrylate, and further, for example, cycloalkyl (meth) ) acrylates (e.g., cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), aralkyl (meth) acrylates (e.g., benzyl (meth) acrylate, etc.), polycyclic (meth) acrylates (e.g., 2-isobornyl (meth) ) acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, etc.), hydroxyl group-containing (meth) ) Acrylic esters (e.g., hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate, etc.), alkoxy group- or phenoxy group-containing (meth)acryl Acid esters (2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxy ethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic acid esters (e.g., glycidyl (meth)acrylate, etc.), halogen-containing (meth)acrylic acid esters (e.g., 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) ) acrylate, etc.), alkylaminoalkyl (meth)acrylate (eg, dimethylaminoethyl (meth)acrylate, etc.), and the like. These (meth)acrylates can be used alone or in combination of two or more. Specific examples of the acrylic oligomer (E) include "ARUFON" manufactured by Toagosei Co., Ltd., "ACT FLOW" manufactured by Soken Chemical Co., Ltd., and "JONCRYL" manufactured by BASF Japan.

The amount of the acrylic oligomer to be blended is generally preferably 15 parts by weight or less with respect to 100 parts by weight of the total amount of the monomer components in the curable resin composition. If the content of the acrylic oligomer in the composition is too high, the reaction rate when the composition is irradiated with an active energy ray will decrease significantly, resulting in poor curing in some cases. On the other hand, in order to sufficiently suppress curing shrinkage of the adhesive layer, the composition preferably contains 3 parts by weight or more of the acrylic oligomer.

A photopolymerization initiator is preferably blended in the curable resin composition, and the same photopolymerization initiator as the photopolymerization initiator that can be blended in the curable aqueous dispersion composition is used as the photopolymerization initiator. Available.

The cationically polymerizable compound used in the cationically polymerizable curable resin composition includes a monofunctional cationically polymerizable compound having one cationically polymerizable functional group in the molecule and two or more cationically polymerizable functional groups in the molecule. It is classified into polyfunctional cationic polymerizable compounds with Since the monofunctional cationically polymerizable compound has a relatively low liquid viscosity, the liquid viscosity can be reduced by including it in the cationically polymerizable curable resin composition. In addition, the monofunctional cationically polymerizable compound often has a functional group that exhibits various functions. Various functions can be expressed in the cured product of the curable resin composition. Since the polyfunctional cationically polymerizable compound can three-dimensionally crosslink the cured product of the cationically polymerizable curable resin composition, it is preferably contained in the cationically polymerizable curable resin composition. The ratio of the monofunctional cationically polymerizable compound and the polyfunctional cationically polymerizable compound is such that 100 parts by weight of the monofunctional cationically polymerizable compound is mixed with 10 parts by weight to 1000 parts by weight of the polyfunctional cationically polymerizable compound. is preferred. Examples of cationic polymerizable functional groups include epoxy groups, oxetanyl groups, and vinyl ether groups. Compounds having an epoxy group include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds. It is particularly preferred to contain an alicyclic epoxy compound. Alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, caprolactone-modified products of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and trimethylcaprolactone-modified products. and valerolactone modified products, and specifically, Celoxide 2021, Celoxide 2021A, Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085 (manufactured by Daicel Chemical Industries, Ltd., Cyracure UVR-6105, Cyracure UVR -6107, Cyracure 30, R-6110 (manufactured by Dow Chemical Japan Co., Ltd.), etc. Compounds having an oxetanyl group improve the curability of the cationic polymerizable adhesive composition, Compounds having an oxetanyl group include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanyl ) methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, di[(3-ethyl-3-oxetanyl)methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, phenol 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.) and the like are commercially available. A compound having a vinyl ether group has the effect of improving the curability of the cationic polymerizable adhesive composition and lowering the liquid viscosity of the composition, and is therefore preferably contained. , 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, and the like.

The cationically polymerizable curable resin composition contains at least one compound selected from the epoxy group-containing compound, the oxetanyl group-containing compound, and the vinyl ether group-containing compound described above as a curable component. A photo cationic polymerization initiator is blended because it is cured by This cationic photopolymerization initiator generates cationic species or Lewis acid upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays and electron beams, and initiates the polymerization reaction of epoxy groups and oxetanyl groups. As the photocationic polymerization initiator, a photoacid generator described later is preferably used. Further, when the cationic polymerizable adhesive composition is used with visible light curing, it is preferable to use a cationic photopolymerization initiator that is particularly sensitive to light of 380 nm or more. Since it is a compound that exhibits maximum absorption in a wavelength region near or shorter than 300 nm, by blending a photosensitizer that exhibits maximum absorption in a wavelength region longer than that, specifically, light with a wavelength longer than 380 nm, this It can respond to light of a wavelength in the vicinity and promote the generation of cationic species or acid from the photocationic polymerization initiator. Examples of photosensitizers include anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, and the like. You may use it in mixture of 2 or more types. Anthracene compounds are particularly preferable because of their excellent photosensitizing effect, and specific examples thereof include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Kasei Co., Ltd.). The content of the photosensitizer is preferably 0.1 wt % to 5 wt %, more preferably 0.5 wt % to 3 wt %.

The method for producing a polarizing film according to the present invention comprises a coating step of applying a curable water-dispersed composition to at least one surface of a polarizer, and drying the curable water-dispersed composition to form a resin layer. and a drying step. Preferably, after the drying step, it further comprises a curing step of forming a cured layer formed by curing the resin layer by irradiating it with an active energy ray, or an adhesive layer comprising at least the cured layer. Also preferably, a treatment step of performing an activation treatment on the coated surface of the curable water-dispersion composition is provided before the coating step of applying the curable water-dispersion composition to at least one surface of the polarizer. . Each step will be described below.

(Coating process)
In the coating step, the curable water-dispersed composition is applied to at least one surface of the polarizer. In such a coating step, when a curable water-dispersed composition containing water as a solvent and a polymerizable compound A is applied to at least one surface of the polarizer, the water applied is added to the polarizer. Dissolves iodine complexes present on the surface. As a result, the refractive index of the polarizer on the long wavelength side can be lowered, and when the adhesive layer is finally formed on the polarizer, the refractive index of the polarizer and the adhesive layer on the long wavelength side It is possible to reduce the difference. As a result, it is possible to produce a polarizing film that is less prone to interference unevenness and has excellent appearance. The method of applying the curable water-dispersed composition and/or the curable resin composition is appropriately selected depending on the viscosity of the composition and the desired thickness. Examples include reverse coaters and gravure coaters (direct, reverse and offset). , bar reverse coater, roll coater, die coater, bar coater, rod coater and the like. Bonding of adherends such as polarizers and optical films can be carried out using a roll laminator or the like.

When the optical film according to the present invention, particularly the polarizing film, is produced on a continuous line, the line speed is preferably 5 to 100 m/min, although it depends on the curing time of the curable water-dispersed composition and/or the curable resin composition. , more preferably 10 to 50 m/min, more preferably 20 to 30 m/min. If the line speed is too low, the productivity is poor, or the damage to the transparent protective film is too great, and a polarizing film that can withstand a durability test or the like cannot be produced. If the line speed is too high, the curing of the curable water-dispersed composition and/or the curable resin composition may be insufficient, and the intended adhesiveness may not be obtained.

(Drying process)
In the drying step, the resin layer is formed by drying the curable water dispersion composition. In the drying step, although the water volatilizes, the iodine complex dissolved in water remains in the resin layer when the resin layer containing the polymerizable compound A is formed. As a result, a polarizing film having a cured product layer (adhesive layer) formed by irradiating the resin layer formed after the drying process with active energy rays was placed in a harsh environment of high temperature and high humidity. Even in this case, elution of iodine in the polarizer is suppressed. Therefore, in the method for producing a polarizing film according to the present invention, a polarizing film having excellent humidification reliability can be produced. As drying means used in the drying step, methods known to those skilled in the art (for example, a blower (which can be adjusted in temperature as necessary), etc.) can be used.

(Curing process)
In the curing step, after the drying step, an active energy ray is irradiated to form a cured layer formed by curing the resin layer, or an adhesive layer comprising at least the cured layer. The irradiation direction of the active energy rays (electron beam, ultraviolet rays, visible rays, etc.) can be any suitable direction.

(Processing process)
In the treatment step, before the coating step of applying the curable water-dispersion composition to at least one surface of the polarizer, the surface to which the curable water-dispersion composition is applied is subjected to an activation treatment. As described above, hydrophilic functional groups and radical active species are introduced to the surface of the polarizer by activation treatment such as corona treatment. When the polarizing film is a polarizing film in which a polarizer and a transparent protective film are laminated via an adhesive layer, the transparent protective film may also be subjected to the treatment step.

The polarizing film manufactured by the manufacturing method according to the present invention can be used as an optical film laminated with other optical layers in practical use. The optical layer is not particularly limited. One or more optical layers may be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film obtained by further laminating a reflector or a semi-transmitting reflector on the polarizing film of the present invention, an elliptical polarizing film or circularly polarized light obtained by further laminating a retardation plate on the polarizing film A film, a wide viewing angle polarizing film obtained by further laminating a viewing angle compensation film on a polarizing film, or a polarizing film obtained by further laminating a brightness enhancement film on a polarizing film are preferable.

An optical film obtained by laminating the above optical layer on a polarizing film can be formed by a method of sequentially and separately laminating in the manufacturing process of a liquid crystal display device or the like. It has the advantage of improving the manufacturing process of liquid crystal display devices due to its excellent stability and assembly work. Appropriate adhesive means such as an adhesive layer can be used for lamination. When the above polarizing film and other optical films are adhered, their optical axes can be arranged at an appropriate angle according to the desired retardation characteristics.

The polarizing film and the optical film having at least one layer of polarizing film laminated thereon may be provided with an adhesive layer for adhering to other members such as a liquid crystal cell. The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer is not particularly limited, but for example, an acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based polymer, rubber-based polymer, or the like is appropriately selected. can be used as In particular, adhesives such as acrylic pressure-sensitive adhesives which are excellent in optical transparency, exhibit appropriate wettability, cohesiveness and adhesive properties, and are excellent in weather resistance and heat resistance can be preferably used.

The adhesive layer can also be provided on one side or both sides of the polarizing film or the optical film as a superimposed layer of different compositions or types. Further, when the adhesive layer is provided on both sides, the front and back surfaces of the polarizing film or the optical film may have adhesive layers with different compositions, types, thicknesses, and the like. The thickness of the adhesive layer can be appropriately determined according to the purpose of use, adhesive strength, etc., and is generally 1 to 100 μm, preferably 5 to 30 μm, particularly preferably 10 to 20 μm.

The exposed surface of the adhesive layer is temporarily covered by a separator for the purpose of preventing contamination, etc., until the adhesive layer is put into practical use. This prevents contact with the adhesive layer during normal handling conditions. As the separator, excluding the above thickness conditions, suitable thin sheets such as plastic films, rubber sheets, paper, cloth, non-woven fabrics, nets, foam sheets, metal foils, and laminates thereof may be used. An appropriate release agent according to the prior art, such as one coated with an appropriate release agent such as chain alkyl, fluorine, or molybdenum sulfide, can be used.

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

Appropriate liquid crystal display devices such as a liquid crystal display device having a polarizing film or an optical film arranged on one side or both sides of a liquid crystal cell, or a device using a backlight or a reflector for an illumination system can be formed. In that case, the polarizing film or optical film according to the present invention can be placed on one side or both sides of the liquid crystal cell. When polarizing films or optical films are provided on both sides, they may be the same or different. Furthermore, when forming a liquid crystal display device, for example, appropriate parts such as a diffuser plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, and a backlight are arranged in a single layer or at an appropriate position. Two or more layers can be arranged. Furthermore, examples of the image display device of the present invention include an organic EL (electroluminescence) display device, a PDP (plasma display panel), an electronic paper, and the like. be done. In addition, as for the application of the image display device, it can be preferably applied to the application that requires a member that is required to have durability characteristics in a high humidity and heat environment, such as a foldable display device and a vehicle display device.

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

<Production of polarizer>
A laminate in which a PVA layer having a thickness of 9 μm is formed on an amorphous PET base material is subjected to auxiliary stretching in the air at a stretching temperature of 130° C. to produce a stretched laminate, and then the stretched laminate is dyed to produce a colored laminate. Further, the colored laminate is stretched in boric acid water at a stretching temperature of 65° C. so that the total stretching ratio is 5.94 times, and the optical film includes a 5 μm thick PVA layer integrally stretched with the amorphous PET substrate. A laminate was produced. By such two-stage stretching, the PVA molecules of the PVA layer formed on the amorphous PET substrate are highly oriented, and the iodine adsorbed by dyeing is highly oriented in one direction as a polyiodine ion complex. Thus, an optical film laminate including a PVA layer having a thickness of 5 μm, which constitutes a thin polarizer, was obtained.

<Transparent protective film>
The following films were used as transparent protective films.
“PET”; PET film (trade name “Cosmo Shine 4300”, thickness 50 μm, manufactured by Toyobo Co., Ltd.)
"TAC"; triacetyl cellulose (TAC) film (trade name "TG60UL", thickness 60 µm, manufactured by Fujifilm Corporation)

<Active energy ray>
As the active energy ray, visible light (gallium-filled metal halide lamp) Irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc. Bulb: V bulb Peak illuminance: 1600 mW/cm ² , integrated irradiation amount 1000/mJ/cm ² (wavelength 380- 440 nm) was used. The illuminance of visible light was measured using a Sola-Check system manufactured by Solatell.

According to the formulation shown in Table 1, curable aqueous dispersion compositions used in Examples 1 to 7 were prepared by the method shown below. Each material described in Table 1 will be described later.

According to the formulation shown in Table 1, the materials excluding water as a solvent were uniformly mixed, and then water as a solvent was mixed. A curable water-dispersed composition, which is a forced emulsification type emulsion used in Examples 1 to 8, was prepared by emulsifying under conditions of a pressurization pressure of 200 MPa and a temperature of 25°C.

According to the formulation shown in Table 2, it was prepared by mixing the curable resin compositions used in Comparative Examples 1 to 4, which did not contain water as a solvent.

Each material described in Tables 1 and 2 is as follows.
<Polymerizable compound A>
・ Ethoxylated bisphenol A dimethacrylate [(liquid) / 1220 (mPa s / 25 ° C.)], trade name “BPE-80N”, manufactured by Shin Nakamura Chemical Co., Ltd. ・ Ethoxylated -o-phenylphenol acrylate [(liquid) / 130 (mPa s / 25 ° C.)], trade name “A-LEN-10”, manufactured by Shin-Nakamura Chemical Co., Ltd. 9,9-bis[4-(2-acryloyloxyethoxy) phenyl]fluorene [(liquid ) /> 100000 (mPa s / 25 ° C.)], manufactured by Shin-Nakamura Chemical Co., Ltd., dimethylol-tricyclodecane diacrylate [(liquid) / viscosity 150 (mPa s / 25 ° C.)], trade name “light acrylate DCP-A", manufactured by Kyoeisha Chemical Co., Ltd., epoxy monomer 1 having a binaphthyl skeleton [(liquid) /> 100000 (mPa s / 25 ° C.)], trade name "TBIS-RXG", manufactured by Taoka Chemical Co., Ltd., binaphthyl skeleton Epoxy monomer 2 [(solid) / -], trade name “TBIS-GG”, manufactured by Taoka Chemical Co., Ltd., naphthalene-type epoxy monomer [(liquid) / 23000 (mPa s / 25 ° C.)], trade name “ HP-4032D", manufactured by DIC, bisphenol-type epoxy monomer [(liquid)/13000 (mPa s/25°C)], trade name "jER828", manufactured by Mitsubishi Chemical Corporation, dicyclopentadiene-type epoxy monomer [(liquid) / 230 (mPa s / 25 ° C.)], trade name “EP-4088S”, manufactured by ADEKA

<Polymerizable compound B>
· 3-Phenoxybenzyl acrylate [(liquid) / 18 (mPa · s / 25 ° C.)], trade name "Light Acrylate POB-A", manufactured by Kyoeisha Chemical Co., Ltd. · Benzyl acrylate [(liquid) / 3 (mPa · s / 25 ° C.)], trade name “Viscoat # 160”, manufactured by Osaka Organic Chemical Industry Co., Ltd., phenoxyethyl acrylate [(liquid) / 9 (mPa s / 25 ° C.)], trade name “Viscoat # 192”, Osaka Organic Chemical Kogyo Co., Ltd. p-tert-butyl phenyl glycidyl ether [(liquid) / 20 (mPa s / 25 ° C.)], trade name “Denacol EX-146”, Nagase ChemteX Co., Ltd. acryloyl morpholine [(liquid) / 12 (mPa s / 25 ° C.)], trade name “ACMO”, manufactured by KJ Chemicals 1,4-cyclohexanedimethanol monoacrylate [(liquid) / 88 (mPa s / 25 ° C.)], trade name "CHDMMA", Mitsubishi Chemical Co., Ltd., polypropylene glycol diacrylate [(liquid) / 14 (mPa s / 25 ° C.)], trade name "Aronix M-220", Toagosei Co., Ltd., alicyclic epoxy compound [( liquid) / 20 (mPa s / 25 ° C.)], trade name “Epocalic THI-DE”, manufactured by ENEOS 3-ethyl-3 {[(3-ethyloxetan-3-yl) methoxy] methyl} oxetane [ (Liquid) / 12 (mPa s / 25 ° C.)], trade name “Aron Oxetane OXT-221”, manufactured by Toagosei Co., Ltd.

<Silane coupling agent>
・ 2-(3,4-Epoxycyclohexyl) ethyltrimethoxysilane, trade name “KBM403”, manufactured by Shin-Etsu Chemical Co., Ltd. ・ 3-Methacryloxypropyltrimethoxysilane, trade name “KBM503”, manufactured by Shin-Etsu Chemical Co., Ltd. <Photoradical generation agent>
・Bis(2,4,6-trimethylbenzoyl)phenylphosphorin oxide, trade name “Omnirad 819”, manufactured by IGMresins ・1-Hydroxycyclohexyl-phenylketone, trade name “Omnirad 184”, manufactured by IGMresins <photoacid generation agent>
4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate (propylene carbonate solution, solid content 75% product), trade name “Omnicat 250D”, manufactured by IGM resins <Photosensitizer>
・ Diethylthioxanthone, trade name “KAYACURE DETX-S”, manufactured by Nippon Kayaku Co., Ltd. <Surfactant>
・Polyoxyethylene styrenated methyl phenyl ether sulfate sodium salt, (anionic surfactant, trade name “Newcol 707-SN”, manufactured by Nippon Nyukazai Co., Ltd. <Surface conditioner>
・Product name “EXP.4200”, manufactured by Nissin Chemical Industry Co., Ltd.

(Production of polarizing film (polarizing film shown in FIG. 2))
A corona irradiation machine (manufactured by Kasuga Denki Co., Ltd., CT-0212) was used to apply the thin polarizer side of the optical film laminate (coated side of the curable water dispersion composition) and the transparent protective film ("PET" and "TAC"). mating side) was subjected to corona treatment at a discharge amount of 50 W/m ² /min (treatment step).

Using an MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, number of gravure roll lines: listed in Table 1, rotation speed 140%/relative to line speed), the thin polarizer side (processed surface side) of the optical film laminate ) was coated with the curable aqueous dispersion composition used in Examples 1 to 7 or the curable resin composition used in Comparative Examples 1 to 4 (coating step), and air-dried using a blower (drying process). The coated surface side of the curable water-dispersed composition (or curable resin composition) of the thin polarizer and the treated surface side of the transparent protective film 3 of the type described in Table 3 were laminated with a roll machine (laminated line speed is 25m/min). After that, from the protective film 3 side, the curable aqueous dispersion composition and the curable resin composition are irradiated with a visible light irradiation device to cure (curing step), and then the amorphous PET substrate of the optical film laminate is peeled off. By removing the cured product layer (= adhesive layer) 2 of the curable water dispersion composition in Examples 1 to 8, and the cured product layer (= adhesive layer) of the curable resin composition in Comparative Examples 1 to 4 A polarizing film was produced by laminating a polarizer 1 and a transparent protective film 3 with an agent layer) 2 interposed therebetween. Table 1 shows the thickness of the adhesive layer of the obtained polarizing film.

<Humidification durability test>
A polarizing film (humidification resistant A sample for sex test evaluation) was prepared. After placing the sample in an environment of 85° C. and 85% humidity, a humidification durability test was carried out. Details of the humidification durability test are shown below.

The resulting polarizing film was exposed to an environment of 85° C. and 85% RH for 120 hours, and the degree of polarization before and after the application was measured using a spectrophotometer with an integrating sphere (V7100 manufactured by JASCO Corporation). Then, the degree of polarization change ΔY (%)=|(degree of polarization (%) before application)−(degree of polarization (%) after application)| was obtained. It was judged that the smaller the amount of change ΔY in the degree of polarization, the better the optical durability in a harsh humidified environment.

<Appearance (interference unevenness) evaluation test>
In the polarizing films produced in Examples 1 to 8 or Comparative Examples 1 to 4, the refractive indices (absorption axis direction of the polarizer) of the polarizer, the adhesive layer and the protective film were adjusted to the long wavelength side (782 nm) and the short wavelength side. (594 nm). If either the refractive index difference between the polarizer and the adhesive layer or the refractive index difference between the transparent protective film and the adhesive layer is large on the long wavelength side (782 nm) and the short wavelength side (594 nm), , interference unevenness occurs. The presence or absence of interference unevenness was visually evaluated, and the case where interference unevenness was not observed at all was evaluated as ⊚, the case where interference unevenness was hardly observed was evaluated as ◯, and the case where interference interference unevenness was observed was evaluated as ×. Table 3 shows the results. The method for measuring the refractive index in the absorption axis direction of the polarizer and the method for measuring the refractive indices of the adhesive layer and the transparent protective film will be described below.

(Method for measuring refractive index of polarizer in absorption axis direction)
The surface opposite to the polarizer surface (that is, the PET surface) of the optical film laminate (laminate of stretched base material and polarizing film) obtained during the production method of each of the above Examples and Comparative Examples ) was uniformly roughened with sandpaper, and then colored by applying a black paint so that the visible light transmittance was 5% or less. Then, using a spectrophotometer (trade name “U-4100” manufactured by Hitachi High-Tech Co., Ltd.), polarized light is incident on the measurement surface, that is, the polarizer at an incident angle of 10 degrees, and the transmission of the polarizer for wavelengths 594 nm and 782 nm Axial and absorption axis reflectances were measured.

From the values of the reflectance Rt in the direction of the transmission axis and the reflectance Ra in the direction of the absorption axis measured above, the refractive index of air is 1, the refractive index of the polarizer in the direction of the transmission axis is nt, and the refractive index in the direction of the absorption axis is na , using the relational expressions: Rt = ((1-nt) / (1 + nt)) ² , Ra = ((1-na) / (1 + na)) ² , the long wavelength side (782 nm) and the short wavelength side (594 nm ), the refractive index of the polarizer was derived (converted refractive index).

(Manufacture of adhesive layer for refractive index measurement)
An adhesive layer formed by curing the curable water dispersion composition used in Examples 1 to 7 or the curable resin composition used in Comparative Examples 1 to 4 was measured by the following method for refractive index measurement. manufactured.

Using a wire bar #10, each of the above curable water dispersion compositions was applied to the surface of a COP film (ZF14, 23 μm, manufactured by Nippon Zeon Co., Ltd.), and another COP film was coated with the curable water dispersion composition. An adhesive layer was formed by laminating it on a work surface and irradiating it with an active energy ray using a UV lamp (gallium lamp). After that, the COP films on both sides were peeled off to prepare an adhesive layer for refractive index measurement.

(Method for Measuring Refractive Index of Adhesive Layer and Transparent Protective Film)
The refractive indices of the adhesive layer for refractive index measurement and the transparent protective film obtained above were measured using a prism coupler device (2010/M) manufactured by METRICON under the following measurement conditions.
(Measurement condition)
Light source: 594nm or 782nm
Mode: TE
Scan: 300 to -300
Measurement type: Bulk/Substrate
The measurement detected the mode (called Knee). Table 3 shows the measured refractive indices of both the adhesive layer for refractive index measurement and the transparent protective film.

From the results in Table 3, in the polarizing films produced in Examples 1 to 7, the difference in refractive index between the polarizer and the adhesive layer, particularly on the long wavelength side, was higher than that of the polarizing films produced in Comparative Examples 1 to 4. , is significantly reduced. Therefore, in Examples 1 to 8, interference unevenness was sufficiently suppressed, and it was found that a polarizing film having excellent appearance and excellent humidification reliability could be produced.

Claims (10)

A method for producing a polarizing film comprising at least a polarizer,
a coating step of coating a curable water-dispersed composition on at least one surface of the polarizer;
A drying step of forming a resin layer by drying the curable aqueous dispersion composition,
A method for producing a polarizing film, wherein the curable water-dispersed composition contains water as a solvent and a polymerizable compound A. 2. The method for producing a polarizing film according to claim 1, wherein the curable water-dispersed composition contains, as the polymerizable compound A, a polymerizable compound having a viscosity of 100 mPa·s or more at 25° C. or a solid. 3. The method for producing a polarizing film according to claim 1, wherein the curable water-dispersed composition contains, as the polymerizable compound A, at least a hydrophobic polymerizable compound having a LogPow of 1.0 or more. The method for producing a polarizing film according to any one of claims 1 to 3, wherein the curable water-dispersed composition contains, as the polymerizable compound A, at least a trifunctional or higher polyfunctional polymerizable compound. The method for producing a polarizing film according to any one of claims 1 to 4, wherein the curable water-dispersed composition further contains a surfactant. 6. The method for producing a polarizing film according to claim 5, wherein the curable water-dispersed composition is a forced emulsification type emulsion using the surfactant as an emulsifier. The method for producing a polarizing film according to claim 5 or 6, wherein the surfactant comprises two or more surfactants. The polarizing film according to any one of claims 5 to 7, wherein the surfactant comprises at least two selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants. manufacturing method. The method for producing a polarizing film according to any one of claims 1 to 8, comprising a curing step of forming a cured product layer formed by curing the resin layer by irradiating an active energy ray after the drying step. The polarizing film is a polarizing film in which the polarizer and a transparent protective film are laminated via an adhesive layer,
9. The method according to any one of claims 1 to 8, further comprising a curing step of forming the adhesive layer comprising at least a cured product layer formed by curing the resin layer by irradiating an active energy ray after the drying step. manufacturing method of the polarizing film.