Method for manufacturing polarizing film

Abstract

To provide a method for manufacturing a polarizing film in which an optical film is bonded to the easily adhesive layer surface of a polarizer with an easily adhesive layer via an adhesive layer, and in which at least one resin film selected from the group consisting of polyester resin, (meth)acrylic resin, polystyrene resin, and polycarbonate resin is used as the optical film, a polarizing film with a good appearance can be obtained. [Solution] A method for manufacturing a polarizing film in which an optical film is bonded to the easily bondable layer surface of a polarizer with an easily bondable layer via an adhesive layer, wherein the optical film is at least one resin film selected from the group consisting of polyester resin, (meth)acrylic resin, polystyrene resin, and polycarbonate resin, the adhesive composition contains a cyclic ether group-containing (meth)acrylamide derivative and a (meth)acrylate having a hydrocarbon group having 10 or more carbon atoms, the easily bondable composition contains water, a cyclic ether group-containing (meth)acrylamide derivative and a compound represented by general formula (1), and the solid content concentration in the easily bondable composition is 55% by mass or more and 85% by mass or less, and the method for manufacturing a polarizing film includes the step of adjusting the amount of coating of the adhesive composition and / or the easily bondable composition so that the total proportion of cyclic ether group-containing (meth)acrylamide derivatives in the solid content of the uncured composition layer obtained by bonding the adhesive composition coating and the easily bondable composition coating is 61% by mass or more and 80% by mass or less, thereby forming the uncured composition layer.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a polarizing film. [Background technology]

[0002] Conventionally, polyvinyl alcohol-based films that have been dyed (containing dichroic substances such as iodine or dichroic dyes) have been used as polarizers in various image display devices such as liquid crystal displays and organic EL displays because they possess both high transmittance and high polarization. These polarizers are manufactured by subjecting the polyvinyl alcohol-based film to various treatments such as dyeing, crosslinking, and stretching in a bath (treatment bath), and then drying it. Furthermore, polarizers are usually used as polarizing films (polarizing plates) in which an optical film such as triacetylcellulose is bonded to one or both sides using an adhesive.

[0003] Furthermore, in the polarizing film described above, there is a known configuration in which an optical film is bonded to the easily adhesive layer surface of a polarizer with an easily adhesive layer via an adhesive layer (Patent Documents 1-5). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-160403 [Patent Document 2] Japanese Patent Publication No. 2020-160408 [Patent Document 3] Japanese Patent Publication No. 2020-160391 [Patent Document 4] Japanese Patent Publication No. 2021-39268 [Patent Document 5] Japanese Patent Publication No. 2021-39269 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, in a polarizing film in which an optical film is bonded to the easily adhesive layer surface of a polarizer with an easily adhesive layer as described above, and at least one resin film selected from the group consisting of polyester resin, (meth)acrylic resin, polystyrene resin, and polycarbonate resin is used as the optical film, and furthermore, when the polarizing film is manufactured using the easily adhesive composition and adhesive composition specifically disclosed in Patent Documents 1-5, it has been found that during the manufacturing process of the polarizing film, the components of the adhesive composition separate due to the adhesive composition absorbing moisture from the air or moisture present in the easily adhesive layer seeping into the adhesive composition, resulting in uneven refractive index within the surface of the adhesive layer, and the resulting polarizing film is prone to defects in appearance.

[0006] In view of the above circumstances, the present invention aims to provide a method for manufacturing a polarizing film in which an optical film is bonded to the easily adhesive layer surface of a polarizer with an easily adhesive layer via an adhesive layer, and in which at least one resin film selected from the group consisting of polyester resin, (meth)acrylic resin, polystyrene resin, and polycarbonate resin is used as the optical film, a polarizing film having a good appearance can be obtained. [Means for solving the problem]

[0007] In other words, the present invention is a method for manufacturing a polarizing film in which an optical film is bonded to the easily bonded layer surface of a polarizer with an easily bonded layer via an adhesive layer, and includes the steps of: applying an adhesive composition to the bonded surface of the optical film while transporting the optical film to form a coating of the adhesive composition; and applying an easily bonded composition to the bonded surface of the polarizer while transporting the polarizer to form a coating of the easily bonded composition. The optical film is at least one resin film selected from the group consisting of polyester resins, (meth)acrylic resins, polystyrene resins, and polycarbonate resins, the adhesive composition contains a cyclic ether group-containing (meth)acrylamide derivative and a (meth)acrylate having a hydrocarbon group with 10 or more carbon atoms, and the easy-adhesion composition contains water, a cyclic ether group-containing (meth)acrylamide derivative, and general formula (1): [ka] (In general formula (1), X is a functional group containing a reactive group, and R 1 and R 2 Each of these independently represents a hydrogen atom, an aliphatic hydrocarbon group which may have substituents, an aryl group, or a heterocyclic group. The reactive group contained in X is at least one reactive group selected from the group consisting of vinyl group, (meth)acrylic group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, and mercapto group. The easy-adhesion composition contains a compound represented by ), and the solid content concentration in the easy-adhesion composition is 55% by mass or more and 85% by mass or less. Furthermore, the present invention relates to a method for manufacturing a polarizing film, which includes a step of forming the uncured composition layer by laminating the adhesive composition coating film and / or the easy-adhesion composition coating film, wherein the total proportion of cyclic ether group-containing (meth)acrylamide derivatives in the solid content of the uncured composition layer obtained by laminating the adhesive composition coating film and the easy-adhesion composition coating film is 61% by mass or more and 80% by mass or less.

[0008] Furthermore, the present invention relates to a method for producing the polarizing film, wherein the solid content concentration in the easily adhesive composition is preferably 80% by mass or less.

[0009] Furthermore, the present invention relates to a method for producing the polarizing film, wherein the solid content concentration in the easily adhesive composition is preferably 75% by mass or less.

[0010] Further, the present invention relates to a method for producing a polarizing film, wherein when water is added to 100 parts by mass of the adhesive composition, the mass part of water causing the adhesive composition to become turbid is represented by X, and the clouding water absorption rate (%) = {X / (100 + X)}×100 represented by the formula (1) is preferably 1.5 or more.

[0011] Further, the present invention relates to a method for producing a polarizing film, wherein when water is added to 100 parts by mass of the solid content of the uncured composition layer, the mass part of water causing the solid content of the uncured composition layer to become turbid is represented by Y, and the clouding water absorption rate (%) = {Y / (100 + Y)}×100 represented by the formula (2) is preferably 3.2 or more.

[0012] Further, the present invention preferably relates to a method for producing a polarizing film, which includes a step of irradiating the uncured composition layer with active energy rays to cure the uncured composition layer.

Effects of the Invention

[0013] The method for producing a polarizing film of the present invention is a method for producing a polarizing film in which an optical film is bonded to the easy-adhesion layer surface of a polarizer with an easy-adhesion layer via an adhesive layer. Even when at least one resin film selected from the group consisting of a polyester resin, a (meth)acrylic resin, a polystyrene resin, and a polycarbonate resin is used as the optical film, the solid content concentration of the easy-adhesion composition is adjusted, and the adhesive composition in contact with the easy-adhesion layer surface is less likely to cause separation of components due to moisture, so a polarizing film having a good appearance can be obtained.

Embodiments for Carrying Out the Invention

[0014] The present invention relates to a method for manufacturing a polarizing film in which an optical film is bonded to the easily bondable layer surface of a polarizer with an easily bondable layer via an adhesive layer, and includes the steps of: applying an adhesive composition to the bonding surface of the optical film while transporting the optical film to form a coating of the adhesive composition; and applying an easily bondable composition to the bonding surface of the polarizer while transporting the polarizer to form a coating of the easily bondable composition.

[0015] <Optical film> The optical film is at least one resin film selected from the group consisting of polyester resin, (meth)acrylic resin, polystyrene resin, and polycarbonate resin.

[0016] The optical film may be a transparent protective film having the above configuration used in various image display devices, and may contain any suitable additives such as ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, antistatic agents, pigments, and colorants.

[0017] Furthermore, the optical film may be an optical film having ultraviolet absorbing properties, from the viewpoint of protecting polarizers, liquid crystals, etc., from ultraviolet rays when the polarizing film is incorporated into various image display devices. In this case, the transmittance for 380 nm light is preferably 20% or less, and more preferably 10% or less. To impart ultraviolet absorbing properties to the optical film, for example, the material constituting the optical film may have ultraviolet absorbing properties, an ultraviolet absorber may be added to the material constituting the optical film, or a surface treatment layer containing an ultraviolet absorber may be laminated on the surface of the optical film.

[0018] Examples of the aforementioned ultraviolet absorbers include conventionally known oxybenzophenone compounds, benzotriazole compounds, salicylate ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex salt compounds, and triazine compounds. Examples of commercially available products include Adeka Stab LA-46 (manufactured by ADEKA), Adeka Stab LA-F70 (manufactured by ADEKA), KEMISORB102 (manufactured by Chemipro Chemical Co., Ltd.), Chiguard 5405 (manufactured by Chitec Technology), Tinuvin 405 (manufactured by BASF), Tinuvin 460 (manufactured by BASF), Tinuvin 479 (manufactured by BASF), and Tinuvin 1600 (manufactured by BASF).

[0019] The thickness of the optical film can be determined as appropriate, but generally, from the viewpoint of strength, workability such as handling, and thinness, it is preferably about 1 to 500 μm, more preferably about 1 to 300 μm, and even more preferably about 5 to 100 μm.

[0020] The optical film exhibits superior moisture barrier properties compared to cellulose ester resins such as triacetylcellulose, and its water absorption rate is typically 1% or less, preferably 0.6% or less. The water absorption rate was measured according to the following procedure in accordance with JIS K7209 (2000). A 100 mm × 100 mm test piece (film) was dried in a 50°C oven for 24 hours, cooled to room temperature in a desiccator, and its mass was measured to determine the initial mass (m1). Subsequently, the test piece was immersed in distilled water for 24 hours to allow it to absorb water, then removed, the surface moisture was wiped off, and the mass was measured within 1 minute to determine the mass after water absorption (m2). The water absorption rate can be calculated using the formula ((m2-m1) / m1) × 100.

[0021] From the viewpoint of impact resistance, the optical film is preferably made of a polycarbonate resin, and from the viewpoint of transparency, the polycarbonate resin is preferably made of general formula (2): [ka] It is more preferable to contain a structural unit derived from a dihydroxy compound represented by . Examples of such dihydroxy compounds include isosorbide, isomannide, and isoidet, which are stereoisomers. These may be used individually or in combination of two or more.

[0022] The polycarbonate resin may further contain structural units derived from dihydroxy compounds other than the dihydroxy compound represented by general formula (2) (hereinafter also simply referred to as "other dihydroxy compounds"). By further containing structural units derived from dihydroxy compounds other than the dihydroxy compound represented by general formula (2), it is possible to improve ease of processing, heat resistance, impact resistance, etc.

[0023] Other dihydroxy compounds include, for example, alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, and diols having a cyclic ether structure.

[0024] The alicyclic dihydroxy compound is not particularly limited, but compounds containing a five-membered ring structure or a six-membered ring structure are preferred. The six-membered ring structure may also be fixed in a chair or boat shape by covalent bonds. The heat resistance of the resulting polycarbonate can be increased by having a five-membered ring or a six-membered ring structure for the alicyclic dihydroxy compound. Examples of the alicyclic dihydroxy compound include cyclohexanedimethanol, tricyclodecanedimethanol, adamantanediol, and pentacyclopentadecanedimethanol. From the viewpoint of availability and ease of handling, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, and tricyclodecanedimethanol are preferred.

[0025] Examples of the aliphatic dihydroxy compounds include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, and 1,6-hexanediol. Examples of the oxyalkylene glycols include diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol. Examples of the aromatic dihydroxy compounds include 2,2-bis(4-hydroxyphenyl)propane [=bisphenol A], 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, and 2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane. Examples of the diols having a cyclic ether structure include spiroglycols and dioxane glycols.

[0026] The proportion of the dihydroxy compound represented by general formula (2) to the total dihydroxy compounds constituting the polycarbonate resin is not particularly limited, but is preferably 10 mol% or more, more preferably 40 mol% or more, even more preferably 60 mol% or more, preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 70 mol% or less. If the proportion of constituent units derived from other dihydroxy compounds is too high, it may degrade performance such as optical properties.

[0027] When using an alicyclic dihydroxy compound among the other dihydroxy compounds mentioned above, the total ratio of the dihydroxy compound represented by general formula (2) and the alicyclic dihydroxy compound to the total dihydroxy compounds constituting the polycarbonate is not particularly limited, but is preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more.

[0028] <Adhesive layer> The adhesive layer is a layer formed from an adhesive composition, and the adhesive composition is an active energy ray curable adhesive composition containing a cyclic ether group-containing (meth)acrylamide derivative and a (meth)acrylate having a hydrocarbon group with 10 or more carbon atoms.

[0029] Examples of the cyclic ether group-containing (meth)acrylamide derivatives include heterocyclic (meth)acrylamide derivatives in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle, such as N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. Among these, N-hydroxyethylacrylamide and N-acryloylmorpholine are preferred due to their excellent reactivity, ability to produce cured products with high elastic modulus, and excellent adhesion to polarizers.

[0030] The (meth)acrylate having a hydrocarbon group with 10 or more carbon atoms is an alkyl (meth)acrylate having an alkyl group with 10 or more carbon atoms at the end of the ester group, and the alkyl chain may be a straight chain or a branched chain. From the viewpoint of adhesion, the number of carbon atoms is preferably 12 or more, and from the viewpoint of deterioration of appearance due to component separation, it is preferably 18 or less, and more preferably 14 or less.

[0031] In the solid content of the adhesive composition, the proportion of the cyclic ether group-containing (meth)acrylamide derivative is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, from the viewpoint of appearance, and preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less, from the viewpoint of adhesion.

[0032] In the solid content of the adhesive composition, the proportion of (meth)acrylate having a hydrocarbon group with 10 or more carbon atoms is more preferably 5% by mass or more, even more preferably 20% by mass or more, from the viewpoint of adhesion, and from the viewpoint of appearance, it is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 25% by mass or less.

[0033] Furthermore, in addition to the above-mentioned compounds, the adhesive composition may also contain other monofunctional radical polymerizable compounds as curing components, from the viewpoint of enabling the adhesive composition to exhibit various functions. Examples of other monofunctional radical polymerizable compounds include various (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Specifically, examples include N-alkyl group-containing (meth)acrylamide derivatives such as N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-butyl(meth)acrylamide, and N-hexyl(meth)acrylamide; N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as N-methylol(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, and N-methylol-N-propane(meth)acrylamide; N-alkoxy group-containing (meth)acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide; and (meth)acrylates having a hydrocarbon group with 9 or fewer carbon atoms.

[0034] Furthermore, the (meth)acrylic acid derivatives include, for example, cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; 2-isobornyl (meth)acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl Examples include polycyclic (meth)acrylates such as oxyethyl (meth)acrylate and dicyclopentanyl (meth)acrylate; and alkoxy group or phenoxy group-containing (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxyethyl (meth)acrylate, and alkylphenoxypolyethylene glycol (meth)acrylate.

[0035] Furthermore, the (meth)acrylic acid derivatives include hydroxyalkyl compounds such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate. (meth)acrylates, hydroxyl group-containing (meth)acrylates such as [4-(hydroxymethyl)cyclohexyl]methyl acrylate, cyclohexanedimethanol mono(meth)acrylate, and 2-hydroxy-3-phenoxypropyl(meth)acrylate; epoxy group-containing (meth)acrylates such as glycidyl(meth)acrylate and 4-hydroxybutyl(meth)acrylate glycidyl ether; 2,2,2-trifluoroethyl(meth)acrylate and 2,2,2-trifluoroethylethyl(meth)acrylate. )Halogen-containing (meth)acrylates such as acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate; alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate; 3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth) Examples include acrylates, oxetane group-containing (meth)acrylates such as 3-ethyl-oxetanylmethyl (meth)acrylate, 3-butyl-oxetanylmethyl (meth)acrylate, and 3-hexyl-oxetanylmethyl (meth)acrylate; heterocyclic (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and butyrolactone (meth)acrylate; and neopentyl glycol (meth)acrylic acid adducts of hydroxypivalate and p-phenylphenol (meth)acrylate.

[0036] Other monofunctional radical 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.

[0037] Other monofunctional radical polymerizable compounds include, for example, lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; and nitrogen-containing heterocyclic vinyl monomers such as vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine.

[0038] Furthermore, other monofunctional radical polymerizable compounds can be used, including radical polymerizable compounds having an active methylene group. A radical polymerizable compound having an active methylene group is a compound that has an active double bond group such as a (meth)acrylic group at its terminal or in the molecule, and also has an active methylene group. Examples of active methylene groups include acetoacetyl, alkoxymalonyl, or cyanoacetyl groups. It is preferable that the active methylene group is an acetoacetyl group. Specific examples of radical polymerizable compounds having an active methylene group include, for example, acetoacetoxyalkyl (meth)acrylates such as 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, and 2-acetoacetoxy-1-methylethyl (meth)acrylate; 2-ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl)acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, and N-(2-acetoacetylaminoethyl)acrylamide.

[0039] From the viewpoint of achieving both adhesion to optical films and optical durability under harsh environments, it is preferable to use a combination of monofunctional and polyfunctional radical polymerizable compounds. Since monofunctional radical polymerizable compounds have relatively low liquid viscosity, their inclusion in the adhesive composition can reduce the viscosity of the adhesive composition. Furthermore, since polyfunctional radical polymerizable compounds can cause three-dimensional crosslinking of the cured product of the adhesive composition, their inclusion in the adhesive composition is preferable.

[0040] <Bifunctional or polyfunctional radical polymerizable compounds> Examples of the polyfunctional radical polymerizable compounds with two or more functions include polyfunctional (meth)acrylamide derivatives such as N,N'-methylenebis(meth)acrylamide, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, and Examples include esters of (meth)acrylic acid with polyhydric alcohols such as opentyl glycol di(meth)acrylate, dimethylol tricyclodecane diacrylate, dimethylol dicyclopentane diacrylate, 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)acrylate, dipentaerythritol hexa(meth)acrylate, and EO-modified diglycerin tetra(meth)acrylate, as well as 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. Commercially available products include Arronix M-220 (manufactured by Toagosei Co., Ltd.), Light Acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer), etc. Additionally, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, and various (meth)acrylate monomers may be used as needed. Among these, Arronix M-220 and Light Acrylate 1,9ND-A are preferred from the viewpoint of viscosity and compatibility.

[0041] When the monofunctional radical polymerizable compound and the polyfunctional radical polymerizable compound are used in combination, the proportion of the monofunctional radical polymerizable compound in the radical polymerizable compound is preferably 65% ​​by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and from the viewpoint of adhesive strength, it is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. In this case, the proportion of the polyfunctional radical polymerizable compound in the radical polymerizable compound is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, from the viewpoint of adhesive strength.

[0042] When using one of the above-mentioned monofunctional radical polymerizable compounds as the aforementioned monofunctional radical polymerizable compound, the proportion of the other monofunctional radical polymerizable compound in the aforementioned radical polymerizable compound is usually about 30% by mass or less.

[0043] From the viewpoint of preventing separation of components of the adhesive composition due to moisture and improving adhesion between the optical film and the polarizer, it is preferable that the adhesive composition satisfies the condition that when water is added to 100 parts by mass of the adhesive composition, the amount of water that causes the adhesive composition to become cloudy is X, and the amount of water that causes cloudiness is expressed by formula (1): Cloudiness water absorption rate (%) = {X / (100+X)} × 100 is 1.5 or more, and more preferably 3.0 or more.

[0044] When ultraviolet or visible light is used as the active energy ray, the adhesive composition preferably contains a photopolymerization initiator. In the production of a polarizing film, the adhesive composition is more preferably visible light curable using visible light in the range of 380 nm to 450 nm, from the viewpoint of the UV absorption of the resin film.

[0045] <Photopolymerization initiator> The photopolymerization initiator is appropriately selected by active energy rays. When curing is performed by ultraviolet light or visible light, a photopolymerization initiator that cleaves with ultraviolet 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; aromatic ketone compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and α-hydroxycyclohexylphenyl ketone; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzioin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and Examples include benzoin alkyl ether compounds such as benzoin butyl ether and anisoin methyl ether; aromatic ketal compounds such as benzyldimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxides; and acylphosphonates.

[0046] Furthermore, if the optical film used for bonding the adhesive composition has difficulty transmitting light below 380 nm, it is preferable that the adhesive composition be curable with visible light, in which case the photopolymerization initiator is of general formula (3): [ka] (In general formula (3), R 4 and R5 independently represents -H, -CH2CH3, -iPr or Cl.), and / or a compound represented by the general formula (4): [Chemical formula] (In the general formula (4), R 6 , R 7 and R 8 independently represent -H, -CH3, -CH2CH3, -iPr or Cl.). It is preferable to contain. Among the compounds represented by the general formula (3), diethylthioxanthone in which R 4 and R 5 are -CH2CH3 is preferable. As the compound represented by the general formula (4), as a commercially available product, for example, 2-methyl-1-(4-methylphenyl)-2-morpholinopropan-1-one (trade name: Omnirad907 manufacturer: IGM Resins) is suitable. Also, from the viewpoint of sensitivity, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name: Omnirad369 manufacturer: IGM Resins), 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: Omnirad379 manufacturer: IGM Resins) are preferable.

[0047] Examples of the photoinitiator highly sensitive to light of 380 nm or more described above include 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-pyrrol-1-yl)-phenyl)titanium, and the like.

[0048] Furthermore, examples of the photopolymerization initiators include oxime ester-based photopolymerization initiators such as compounds described in Japanese Patent Publication No. 2000-80068, Japanese Patent Publication No. 2001-233842, Japanese Patent Publication No. 2010-527339, Japanese Patent Publication No. 2010-527338, Japanese Patent Publication No. 2013-041153, and International Publication No. 2015 / 036910. Specific examples of compounds include 1,2-octanedione, 1-4-(phenylthio)-2-(O-benzoyl oxime), ethanone, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyl oxime). Furthermore, commercially available products include compounds with a carbazole skeleton such as Irgacure OXE-02 (BASF), Adeka Arclus NCI-831 (ADEKA), N-1919 (ADEKA), and TR-PBG-304 (Changzhou Strong Electronic Materials Co., Ltd.); compounds with a diphenyl sulfide skeleton such as Irgacure OXE-01 (BASF), Adeka Arclus NCI-930 (ADEKA), TR-PBG-345 (Changzhou Strong Electronic Materials Co., Ltd.), and TR-PBG-3057 (Changzhou Strong Electronic Materials Co., Ltd.); and compounds with a fluorene skeleton such as TR-PBG-365 (Changzhou Strong Electronic Materials Co., Ltd.).

[0049] The amount of the photopolymerization initiator can be set as appropriate, for example, it is usually 20 parts by mass or less per 100 parts by mass of the radical polymerizable compound. Preferably, the amount of the photopolymerization initiator is 1 to 15 parts by mass, and more preferably 3 to 10 parts by mass, per 100 parts by mass of the radical polymerizable compound.

[0050] Furthermore, polymerization initiators may be added as needed. Examples of polymerization initiators include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate. When using polymerization initiators, the amount added is usually about 5 parts by mass or less per 100 parts by mass of the adhesive composition.

[0051] Furthermore, when using a radical polymerizable compound having an active methylene group, it is preferable to use it in combination with a radical polymerization initiator that has a hydrogen abstraction effect. With this configuration, the adhesion of the adhesive layer of the polarizing film is significantly improved, especially in high humidity environments or immediately after removal from water (non-dry state). Examples of the radical polymerization initiator with a hydrogen abstraction effect include thioxanthone-based radical polymerization initiators and benzophenone-based radical polymerization initiators. The radical polymerization initiator is preferably a thioxanthone-based radical polymerization initiator. Examples of thioxanthone-based radical polymerization initiators include compounds represented by the above general formula (3).

[0052] The adhesive composition may contain various additives as other optional components, as long as they do not impair the objectives and effects of the present invention. Examples of such additives include polymers such as chlorinated polyolefins, epoxy resins, polyamides, polyamide-imides, polyurethanes, polybutadienes, polychloroprenes, polyethers, polyesters, styrene-butadiene block copolymers, petroleum resins, xylene resins, ketone resins, and cellulose resins; oligomers such as acrylic oligomers, fluorine oligomers, silicone oligomers, and polysulfide oligomers; sensitizers, photoacid generators, photobase generators, silane coupling agents, polyrotaxanes, organometallic compounds, polymerization inhibitors, bubble inhibitors, surfactants, plasticizers, ultraviolet absorbers, inorganic fillers, pigments, dyes, and the like.

[0053] <Polarizer with easy-adhesion layer> The polarizer with the easy-adhesion layer has the easy-adhesion composition coated on the bonding surface of the polarizer (the bonding surface with the optical film).

[0054] <Easy adhesion layer> The easy-adhesion composition that forms the easy-adhesion layer comprises water, a cyclic ether group-containing (meth)acrylamide derivative, and general formula (1): [ka] (In general formula (1), X is a functional group containing a reactive group, and R 1 and R 2 Each of these independently represents a hydrogen atom, an aliphatic hydrocarbon group which may have substituents, an aryl group, or a heterocyclic group. The reactive group contained in X is at least one reactive group selected from the group consisting of vinyl group, (meth)acrylic group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, and mercapto group. The easy-adhesion composition contains a compound represented by ), and the solid content concentration in the easy-adhesion composition is 55% by mass or more and 85% by mass or less.

[0055] The water is a medium in the easy-adhesion composition, and its content may be appropriately set so that the solid content concentration is between 55% by mass and 85% by mass.

[0056] The cyclic ether group-containing (meth)acrylamide derivatives include heterocyclic (meth)acrylamide derivatives in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle, such as N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. From the viewpoint of facilitating the dispersion of the compound represented by the general formula (1) in the composition, the cyclic ether group-containing (meth)acrylamide derivative is preferably present in an amount of 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more of the solid content of the easy-to-adhere composition.

[0057] The compounds represented by the general formula (1) can be found in the compounds exemplified in Japanese Patent Publication No. 2020-160403, 2020-160408, 2020-160391, 2021-39268, 2021-39269, etc. Preferably, R 1 and R 2Each of these is independently a hydrogen atom, a linear or branched alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom. Furthermore, X is preferably an epoxy group from the viewpoint of excellent adhesion between the resulting adhesive layer and the adherend, and a vinyl ether group from the viewpoint of excellent curability of the adhesive composition. A preferred specific example is general formula (1'): [ka] (In general formula (1'), Y is an organic group, X' is a reactive group contained in X, and R 1 and R 2 The same as above.) are examples. More preferably, the following compounds (1a) to (1d) are examples. [ka]

[0058] If the content of the compound represented by general formula (1) in the easy-adhesion composition is too low, the proportion of the compound represented by general formula (1) present at the interface between the polarizer and the adhesive layer decreases, which may reduce the easy-adhesion effect. Therefore, the content of the compound represented by general formula (1) in the solid content of the easy-adhesion composition is preferably 0.02% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and usually 5% by mass or less, and preferably 3% by mass or less.

[0059] The easy-adhesion composition has a solid content concentration of 55% by mass or more and 85% by mass or less. From the viewpoint of improving the appearance of the polarizing film, the easy-adhesion composition preferably has a solid content concentration of 60% by mass or more, more preferably 65% ​​by mass or more, and from the viewpoint of improving adhesion, the easy-adhesion composition preferably has a solid content concentration of 80% by mass or less, more preferably 75% by mass or less, and even more preferably 72% by mass or less.

[0060] The aforementioned easy-adhesion composition may contain, to the extent that it does not impair the objectives and effects of the present invention, organometallic compounds such as organosilicon compounds, metal alkoxides, and metal chelates; organic solvents, binder resins, surfactants, plasticizers, tackifiers, low molecular weight polymers, polymerizable monomers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, polymerization initiators, polymerization inhibitors, silane coupling agents, titanium coupling agents, inorganic or organic fillers, metal powders, particulate matter, foil-like materials, etc.

[0061] <Polarizer> The polarizer described above can be a known polarizer formed by the adsorption and orientation of dichroic substances such as iodine or dichroic dyes onto a polyvinyl alcohol-based film.

[0062] From the viewpoint of improving optical durability in harsh environments with high temperature and humidity, it is preferable to use a polarizer with a thickness of 3 μm to 15 μm, more preferably 12 μm or less, even more preferably 10 μm or less, and particularly preferably 8 μm or less. Such thin polarizers have less thickness variation, excellent visibility, and excellent durability against thermal shock due to minimal dimensional change.

[0063] <Method for manufacturing polarizing film> The method for manufacturing the polarizing film includes (i) a step of applying the adhesive composition to the bonding surface of the optical film while transporting the optical film to form a coating of the adhesive composition; a step of applying the easy-adhesion composition to the bonding surface of the polarizer while transporting the polarizer to form a coating of the easy-adhesion composition; (ii) a step of adjusting the amount of coating of the adhesive composition and / or the easy-adhesion composition to form the uncured composition layer, such that the total proportion of cyclic ether group-containing (meth)acrylamide derivatives in the solid content of the uncured composition layer obtained by bonding the adhesive composition coating and the easy-adhesion composition coating is 61% by mass or more and 80% by mass or less; and (iii) a step of curing the uncured composition layer by irradiating the uncured composition layer with active energy rays.

[0064] In step (i) above, the coating method is appropriately selected depending on the viscosity of each composition and the desired thickness, but it is preferable to use a post-metering coating method from the viewpoint of removing foreign matter from the surface of the polarizer and optical film, coating properties, and controlling the thickness of the coating film. Specific examples of post-metering coating methods include gravure roll coating, forward roll coating, air knife coating, and rod / bar coating. Among these, the gravure roll coating method is particularly preferred from the viewpoint of removing foreign matter from the surface of the polarizer and optical film, coating properties, and controlling the thickness of the coating film.

[0065] In the gravure roll coating method, various patterns can be formed on the surface of the gravure roll, such as honeycomb mesh patterns, trapezoidal patterns, grid patterns, pyramidal patterns, or diagonal line patterns. To effectively prevent the occurrence of appearance defects in the final polarizing film, it is preferable that the pattern formed on the surface of the gravure roll is a honeycomb mesh pattern. In the case of a honeycomb mesh pattern, the cell volume should be 1 to 5 cm³ to improve the surface accuracy of the coated surface after coating. 3 / m 2 Preferably, 2-3 cm 3 / m 2 It is more preferable that this is the case. Similarly, in order to improve the surface accuracy of the coated surface after coating, it is preferable that the number of cells per inch of the roll be 200 to 3000 lines / inch. In addition, it is preferable that the rotation speed ratio of the gravure roll to the travel speed of the polarizer and optical film be 100 to 300%.

[0066] In step (i) above, a drying step may be provided to dry the media contained in each composition. In particular, since the easily bondable composition contains water, it is preferable to remove the water in the drying step from the viewpoint of suppressing the separation of components due to moisture in the adhesive composition in contact with the easily bondable layer surface. The drying step can be a known method, such as air drying, heat drying, or hot air drying.

[0067] In steps (i) and (ii) above, the thickness of the adhesive film is preferably about 0.1 to 100 μm, more preferably about 0.3 to 10 μm, and even more preferably about 0.5 to 5 μm, from the viewpoint of productivity and adhesion. Furthermore, the thickness of the easy-to-adhere composition is preferably about 0.1 to 100 μm, more preferably about 0.3 to 10 μm, and even more preferably about 0.5 to 5 μm, from the viewpoint of productivity and adhesion.

[0068] In step (ii) above, the amount of coating of the adhesive composition and / or the easy-adhesion composition is adjusted so that the total proportion of cyclic ether group-containing (meth)acrylamide derivatives in the solid content of the uncured composition layer obtained by bonding the adhesive composition and the easy-adhesion composition is 61% by mass or more and 80% by mass or less, thereby forming the uncured composition layer. From the viewpoint of appearance, the total proportion of cyclic ether group-containing (meth)acrylamide derivatives in the solid content of the uncured composition layer is preferably 63% by mass or more, more preferably 68% by mass or more, and even more preferably 70% by mass or more, and from the viewpoint of adhesion, it is preferably 75% by mass or less, and more preferably 72.5% by mass or less.

[0069] The coating amount of each composition can usually be controlled by measuring the thickness of each coating film in-line. In-line measurement is preferably performed using an optical (non-contact) film thickness meter. The optical (non-contact) film thickness meter is not particularly limited and examples include spectroscopic interference film thickness meters, reflection spectroscopic film thickness meters, and confocal film thickness meters. A spectroscopic interference film thickness meter, which can measure the thickness of the coating film across its entire width, is particularly preferred.

[0070] In step (ii) above, from the viewpoint of preventing separation of components of the adhesive composition due to moisture and improving adhesion between the optical film and the polarizer, it is preferable that the solid content of the uncured composition layer satisfies the condition that, when water is added to 100 parts by mass of the solid content of the uncured composition layer, the amount of water that causes the solid content of the uncured composition layer to become cloudy is 3.2 or more, and more preferably 3.6 or more.

[0071] The above bonding method can be carried out using a roll laminator or similar device.

[0072] In step (iii) above, the irradiation direction of the active energy rays (electron beam, ultraviolet light, visible light, etc.) can be any appropriate direction. However, in the case of a polarizing film, if irradiation is performed from the polarizer side, the polarizer may be degraded by the active energy rays.

[0073] The irradiation conditions for the active energy rays described above can be any suitable conditions, as long as they are capable of curing the uncured composition layer. For example, when using ultraviolet or visible light as the active energy ray, the illuminance in the wavelength range of 395 to 445 nm should be 200 to 2000 mW / cm². 2 The cumulative light intensity is 100-1500 mJ / cm². 2 It is to that extent.

[0074] <Laminated polarizing film> The polarizing film is used in practical applications as a laminated polarizing film laminated with other optical layers. The polarizing film may have a transparent protective film on the surface (polarizer surface) that is not laminated with the optical film. Various transparent protective films used in various image display devices can be used as the transparent protective film. The transparent protective film may be the same as or different from the optical film. In addition, the above-mentioned easy-adhesion layer may be provided between the polarizer and the transparent protective film.

[0075] The optical film and / or transparent protective film may use a phase difference plate having a front phase difference of 40 nm or more and / or a thickness direction phase difference of 80 nm or more. The front phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. When a phase difference plate is used as the transparent protective film, the phase difference plate also functions as a transparent protective film, thus enabling a thinner design.

[0076] Examples of the phase difference plate include a birefringent film obtained by uniaxial or biaxial stretching of a polymer material, an orientation film of a liquid crystal polymer, and a liquid crystal polymer orientation layer supported by a film. The thickness of the phase difference plate is not particularly limited, but it is generally around 20 to 150 μm. The phase difference plate may also be used by laminating it to a transparent protective film that does not have a phase difference.

[0077] In the laminated polarizing film, functional layers such as a hard coat layer, anti-reflective layer, anti-sticking layer, diffusion layer, or anti-glare layer can be provided on the surface of the optical film and / or transparent protective film to which the polarizer is not bonded. These functional layers, such as the hard coat layer, anti-reflective layer, anti-sticking layer, diffusion layer, or anti-glare layer, can be provided on the protective film itself, or they can be provided separately from the protective film.

[0078] In the laminated polarizing film, the optical film and the transparent protective film may be laminated with intervening layers such as a surface modification layer, an easy-adhesion layer, a block layer, or a refractive index adjustment layer in between.

[0079] Examples of surface modification treatments for forming the aforementioned surface modification layer include corona treatment, plasma treatment, primer treatment, and saponification treatment.

[0080] Examples of easily adhesives for forming the easily adhesive layer include forming materials containing various resins having a polyester skeleton, polyether skeleton, polycarbonate skeleton, polyurethane skeleton, silicone-based materials, polyamide skeleton, polyimide skeleton, polyvinyl alcohol skeleton, and the like.

[0081] The aforementioned block layer is a layer that functions to prevent impurities such as oligomers and ions eluted from optical films from migrating (penetrating) into optical films such as polarizers. The block layer only needs to be transparent and capable of preventing impurities from eluting from optical films. Examples of materials that form the block layer include urethane prepolymer-based forming materials, cyanoacrylate-based forming materials, epoxy-based forming materials, and the like.

[0082] The refractive index adjusting layer is provided to suppress the decrease in transmittance due to reflection between layers with different refractive indices in the optical film. Examples of refractive index adjusting materials for forming the refractive index adjusting layer include various resins and additives such as silica-based, acrylic-based, acrylic-styrene-based, and melamine-based resins.

[0083] An adhesive layer for bonding other components may be attached to one or both sides of the laminated polarizing film. A tack layer is preferred as the adhesive layer. The tack layer forming the tack layer is not particularly limited, but for example, acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorine-based polymers, rubber-based polymers, etc., can be appropriately selected and used. In particular, tacks containing acrylic polymers are preferred as they have excellent optical transparency, exhibit appropriate wettability, cohesiveness and adhesion, and have excellent weather resistance and heat resistance.

[0084] The adhesive layer can be attached to one or both sides of the laminated polarizing film by any suitable method. Examples of methods for attaching the adhesive layer include preparing an adhesive solution and directly attaching it to the laminated polarizing film by a suitable deployment method such as casting or coating, or forming an adhesive layer on a release film and transferring it to the laminated polarizing film. The thickness of the adhesive layer can be appropriately determined according to the intended use and adhesive strength, and is generally 1 to 500 μm, preferably 5 to 200 μm, and more preferably 10 to 100 μm.

[0085] It is preferable that a separator be temporarily attached to the exposed surface of the adhesive layer to prevent contamination until it is put into practical use. This prevents contamination of the adhesive layer under normal handling conditions. As the separator, for example, a suitable thin sheet such as a plastic film, rubber sheet, paper, cloth, nonwoven fabric, net, foam sheet, metal foil, or laminate thereof may be used, and may be coated with a suitable release agent such as silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide as needed.

[0086] The laminated polarizing film can be used in various image display devices such as liquid crystal displays and organic EL displays. [Examples]

[0087] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0088] <Examples 1-9, Comparative Examples 1-2> <Preparation of adhesive composition> In each example and comparative example, the following components were mixed at 25°C for 1 hour in the amounts shown in Table 1 to prepare the adhesive composition (the units of the amounts shown in Table 1 are relative "parts by mass"). ACMO:N-Acryloylmorpholine, manufactured by KJ Chemicals. HEAA: Hydroxyethylacrylamide, manufactured by KJ Chemicals. LA: Lauryl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. ISTA: Isostearyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. 1,9NDA: 1,9-nonanediol diacrylate, manufactured by Kyoeisha Chemical Co., Ltd. M220: "Arronix M220", Tripropylene glycol diacrylate, manufactured by Toagosei Co., Ltd. DCPA: "Light Acrylate DCP-A", Dimethylol Tricyclodecane Diacrylate, manufactured by Kyoeisha Chemical Co., Ltd. 907: Product name "Omnirad 907", 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, manufactured by IGM Resins. DETX-S: Product name "KAYACURE DETX-S", 2,4-diethylthioxanthone, manufactured by Nippon Kayaku Co., Ltd. MAPBA: Product name "MAPBA", 3-methacrylamide phenylboronic acid, manufactured by Junsei Chemical Co., Ltd.

[0089] <Preparation of easily adhesive compositions> In each example and comparative example, the following components were mixed at 25°C for 1 hour in the amounts shown in Table 1 to prepare an easy-to-adhere composition (the units of the amounts shown in Table 1 are relative "parts by mass"). water ACMO:N-Acryloylmorpholine, manufactured by KJ Chemicals. MAPBA: Product name "MAPBA", 3-methacrylamide phenylboronic acid, manufactured by Junsei Chemical Co., Ltd.

[0090] <Preparation of optical film (polycarbonate resin film)> 81.98 parts by mass of isosorbide, 47.19 parts by mass of tricyclodecanedimethanol, 175.1 parts by mass of diphenyl carbonate, and 0.979 parts by mass of a 0.2% by mass aqueous solution of cesium carbonate as a catalyst were added to the reaction vessel. In the first stage of the reaction, under a nitrogen atmosphere, the heating vessel temperature was raised to 150°C, and the raw materials were dissolved while stirring as needed (for about 15 minutes). Next, the pressure was increased from atmospheric pressure to 13.3 kPa, and the heating vessel temperature was raised to 190°C over 1 hour, while the generated phenol was removed from the reaction vessel. After holding the entire reaction vessel at 190°C for 15 minutes, in the second stage, the pressure inside the reaction vessel was set to 6.67 kPa, and the heating vessel temperature was raised to 230°C over 15 minutes, while the generated phenol was removed from the reaction vessel. As the stirring torque of the stirrer increased, the temperature was raised to 250°C in 8 minutes, and then the pressure inside the reaction vessel was reduced to 0.200 kPa or less to remove the generated phenol. After reaching the predetermined stirring torque, the reaction was terminated, and the resulting reactants were extruded into water to obtain polycarbonate resin pellets. Subsequently, Adekastab LA-F70 was kneaded in as an ultraviolet absorber to obtain polycarbonate resin pellets with ultraviolet absorption capabilities. The obtained polycarbonate resin with ultraviolet absorption capabilities was vacuum dried at 80°C for 5 hours, and then an optical film composed of the polycarbonate resin was fabricated using a film manufacturing apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder setting temperature: 250°C), a T-die (width 300 mm, setting temperature: 250°C), a chill roll (setting temperature: 120~130°C), and a winding machine. The thickness of the obtained optical film was 20 μm.

[0091] <Preparing the polarizer> As a thermoplastic resin substrate, an amorphous isophthalic copolymer polyethylene terephthalate film (thickness: 100 μm) with a long length and a Tg of approximately 75°C was used, and one side of the resin substrate was subjected to corona treatment. A PVA aqueous solution (coating solution) was prepared by dissolving 100 parts by weight of a PVA-based resin, which was a mixture of polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosephymer") in a 9:1 ratio, with 13 parts by weight of potassium iodide added, in water. The PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60°C to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate. The obtained laminate was uniaxially stretched 3.0 times in the longitudinal direction (longitudinal direction) in an oven at 140°C (air-assisted stretching treatment). Next, the laminate was immersed for 30 seconds in an insolubilization bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) (insolubilization treatment). Next, it was immersed for 60 seconds in a staining bath at a liquid temperature of 30°C (a iodine aqueous solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) while adjusting the concentration so that the final transmittance (Ts) of the polarizer obtained would be the desired value (staining treatment). Next, it was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) (crosslinking treatment). Subsequently, the laminate was immersed in a boric acid aqueous solution (boric acid concentration 4% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 64°C and uniaxially stretched between rolls with different peripheral speeds to achieve a total stretch ratio of 5.5 times in the longitudinal direction (water stretching treatment). After that, the laminate was immersed in a washing bath at a liquid temperature of 20°C (an aqueous solution obtained by mixing 3 parts by weight of potassium iodide with 100 parts by weight of water) (washing treatment). After that, while drying in an oven maintained at approximately 90°C, it was brought into contact with a SUS heated roll whose surface temperature was maintained at approximately 75°C (drying shrinkage treatment). In this way, a polarizer with a thickness of 5.5 μm was formed on the resin substrate, and a resin substrate-mounted polarizer having a resin substrate / polarizer configuration was obtained.

[0092] <Preparation of polarizing film> A polarizer with an easy-adhesion layer was fabricated by coating the polarizer surface (the side opposite to the resin substrate) of the resin substrate polarizer obtained above with an easy-adhesion composition adjusted to a film thickness of 1.0 μm, and then air-drying it at 25°C for 1 minute. An MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roll line count 1000 lines / inch, rotation speed 140% / line speed) was used for coating. As an optical film, an adhesive composition was coated onto the 20 μm thick polycarbonate resin film obtained above with an adhesive composition adjusted to a film thickness of 1.0 μm. An MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roll line count 1000 lines / inch, rotation speed 140% / line speed) was used for coating. Next, the easy-adhesion layer side of the polarizer with the easy-adhesion layer was bonded to the optical film via the adhesive composition coating to form an uncured composition layer. Next, the adhesive composition and easy-adhesion composition between the films were cured by irradiating the optical film side of the resulting laminate with ultraviolet light to obtain a polarizing film. A gallium lamp was used for ultraviolet irradiation, with an irradiance of 1000 mW / cm² in the wavelength range of 395-445 nm. 2 The cumulative light intensity is 600 mJ / cm². 2 I adjusted it so that it would be as follows.

[0093] <Method for measuring the water absorption rate of turbidity> When 100g of the adhesive composition was stirred and water was gradually added, and the weight of water added until turbidity was visually observed in the adhesive composition was denoted as X (g), the value shown in formula (1) was defined as the turbidity absorption rate. Formula (1): Cloudy water absorption rate (%)={X / (100+X)}×100 The turbidity water absorption rate of the uncured composition layer (a composition combining the solid content of the adhesive composition and the easy-to-adhere composition) was calculated by mixing the above components in the amounts shown in Table 1 at 25°C for 1 hour to prepare the uncured composition (solid content of the uncured composition layer), and then calculating it using the following method (the units of the amounts shown in Table 1 are relative "parts by mass"). When 100g of the uncured composition (solid content of the uncured composition layer) was stirred and water was gradually added, and the weight of water added until turbidity was visually confirmed in the uncured composition was denoted as Y(g), the value shown in equation (2) was defined as the turbidity absorption rate. Formula (2): Cloudy water absorption rate (%)={Y / (100+Y)}×100

[0094] <Evaluation of appearance> For the visual evaluation, a sample of polarizing film attached to a blackboard was used, and light was incident from an oblique direction using an LED lamp. The presence or absence of granular surface defects was judged visually according to the following criteria. Note that "polarizing film + anti-reflective film" refers to a laminated polarizing film in which an anti-reflective film (product name: AR200, manufactured by Dexerials) is bonded to the polarizing film via an acrylic adhesive. [Table 1]

[0095] <Evaluation of initial adhesion> The obtained polarizing film was cut to a size of 200 mm parallel to the stretching direction of the polarizer and 15 mm perpendicular to it, and the polarizing film was bonded to a glass plate. Then, an incision was made between the transparent protective film and the polarizer with a utility knife, and the protective film and polarizer were peeled off at a 90-degree angle at a peeling speed of 300 mm / min using a Tensilon, and the peel strength (N / 15 mm) was measured. A value of 1.5 N / 15 mm or more was marked "○", 1.0 N / 15 mm or more was marked "△", and less than 1.0 N / 15 mm was marked "×".

[0096] <Evaluation of humidification adhesion> The humidified adhesion performance was evaluated by leaving the obtained polarizing film in a 20°C, 98% RH environment for 240 hours, followed by the adhesion test described above. A result of 1.5 N / 15 mm or higher was marked "○", 1.0 N / 15 mm or higher was marked "△", and less than 1.0 N / 15 mm was marked "×".

[0097] [Table 2]

Claims

1. This is a method for manufacturing a polarizing film in which an optical film is bonded to the easily adhesive layer surface of a polarizer with an easily adhesive layer via an adhesive layer. The process includes the steps of: applying an adhesive composition to the bonding surface of the optical film while conveying the optical film to form a coating of the adhesive composition; and applying an easy-adhesion composition to the bonding surface of the polarizer while conveying the polarizer to form a coating of the easy-adhesion composition. The optical film is at least one resin film selected from the group consisting of polyester resin, (meth)acrylic resin, polystyrene resin, and polycarbonate resin. The adhesive composition contains a cyclic ether group-containing (meth)acrylamide derivative and a (meth)acrylate having a hydrocarbon group with 10 or more carbon atoms. The aforementioned easy-adhesion composition comprises water, a cyclic ether group-containing (meth)acrylamide derivative, and general formula (1): 【Chemistry 1】 (In general formula (1), X is a functional group containing a reactive group, and R １ and R ２ Each of these independently represents a hydrogen atom, an aliphatic hydrocarbon group which may have substituents, an aryl group, or a heterocyclic group. The reactive group contained in X is at least one reactive group selected from the group consisting of vinyl group, (meth)acrylic group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, and mercapto group. The easy-adhesion composition contains a compound represented by ), and the solid content concentration in the easy-adhesion composition is 55% by mass or more and 85% by mass or less. A method for producing a polarizing film, further comprising the step of forming the uncured composition layer by adjusting the coating amounts of the adhesive composition coating and / or the easy-adhesion composition coating so that the total proportion of cyclic ether group-containing (meth)acrylamide derivatives in the solid content of the uncured composition layer obtained by laminating the adhesive composition coating and the easy-adhesion composition coating is 61% by mass or more and 80% by mass or less.

2. The method for producing a polarizing film according to claim 1 or 2, characterized in that the solid content concentration in the easy-adhesion composition is 80% by mass or less.

3. The method for producing a polarizing film according to claim 1 or 2, characterized in that the solid content concentration in the easy-adhesion composition is 75% by mass or less.

4. The method for manufacturing a polarizing film according to claim 1 or 2, characterized in that the adhesive composition satisfies the condition that when water is added to 100 parts by mass of the adhesive composition, the amount of water that causes the adhesive composition to become cloudy is X, and the cloudiness absorption rate shown by formula (1): Cloudiness absorption rate (%) = {X / (100 + X)} × 100 is 1.5 or more.

5. The method for manufacturing a polarizing film according to claim 1 or 2, characterized in that the solid content of the uncured composition layer satisfies the condition that, when water is added to 100 parts by mass of the solid content of the uncured composition layer, the amount of water that causes the solid content of the uncured composition layer to become cloudy is 3.2 or more, as shown in formula (2): Cloudiness water absorption rate (%) = {Y / (100 + Y)} × 100.

6. A method for manufacturing a polarizing film according to claim 1 or 2, comprising the step of irradiating the uncured composition layer with active energy rays to cure the uncured composition layer.

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