Method for manufacturing laminated optical film

Abstract

A method for producing a laminated optical film in which at least a first optical film and a second optical film are laminated via an adhesive layer, the adhesive composition for a laminated optical film containing a curable component and metal oxide particles, the coating step is a step for applying a shear force to the adhesive composition for the laminated optical film and coating the adhesive composition.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a laminated optical film. This laminated optical film can be used to form image display devices such as liquid crystal displays (LCDs), organic EL displays, CRTs, and PDPs. Background Technology

[0002] In order to improve the poor visual recognition of the image display caused by external light reflection, background reflection, etc., there is a known image display device with a circular polarizing plate arranged on the visible side of the display panel.

[0003] For example, Patent Document 1 describes a polarizing plate composite comprising, in sequence: a linear polarizing plate, a half-wavelength layer, a first adhesive layer formed by curing an active energy ray curable adhesive, and a quarter-wavelength layer, wherein the angle between the phase advancement axis of the half-wavelength layer and the transmission axis of the linear polarizing plate is 10° or more and 20° or less, and the absolute value of the difference between the refractive index of the first adhesive layer at a wavelength of 589 nm and the refractive index of the half-wavelength layer at a wavelength of 589 nm along the phase advancement axis is less than 0.05.

[0004] Furthermore, Patent Document 2 describes a polarizing plate with a phase retardation layer, which sequentially comprises a polarizing mirror, a first phase retardation layer, and a second phase retardation layer. The polarizing mirror and the first phase retardation layer are bonded together via a first adhesive layer, and the first phase retardation layer and the second phase retardation layer are bonded together via a second adhesive layer. The thickness of the first phase retardation layer and the second phase retardation layer is 5 μm or less, the average refractive index of the second adhesive layer is 1.55 or more, and the difference between the average refractive index of the second adhesive layer and the average refractive index of the first phase retardation layer and the difference between the average refractive index of the second adhesive layer and the average refractive index of the second adhesive layer is less than 0.08.

[0005] Furthermore, in the following Patent Document 3, an active energy ray-curable resin composition and cured product are described with the aim of providing a balance of various properties required for optical sheets and the like for optical applications. The active energy ray-curable resin composition is characterized by containing metal oxide nanoparticles (A), phenoxybenzyl methacrylate (B), and difunctional (meth)acrylate (C) having a (poly)alkylene glycol structure.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-52365

[0009] Patent Document 2: Japanese Patent Application Publication No. 2018-17996

[0010] Patent Document 3: Japanese Patent Application Publication No. 2017-128688 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] Through dedicated research, the inventors have determined that, regarding the technologies described in Patent Documents 1 and 2, there is room for further improvement while stably increasing the refractive index of the interlayer adhesive of the laminated film. It should be noted that the technology described in Patent Document 3 relates to an active energy ray-curable resin composition for manufacturing lenses, and was not originally intended for bonding at least two optical films. Furthermore, since the adhesive composition for laminated optical films is applied to the optical film with a relatively thin film thickness, excellent liquid stability is required when metal oxide particles are present. However, this issue was not addressed in the technology described in Patent Document 3, nor was a method for solving this problem described or taught.

[0013] The present invention was developed in view of the above-mentioned actual situation, and its purpose is to provide a method for manufacturing a laminated optical film having an adhesive layer with high refractive index, excellent adhesion and reduced curing shrinkage, and suppressing appearance defects and interference patterns caused by unevenness.

[0014] Methods for solving problems

[0015] The above-mentioned problems can be solved by the following configuration. That is, the present invention relates to a method for manufacturing a laminated optical film (1), which is a method for manufacturing a laminated optical film having at least a first optical film and a second optical film laminated via an adhesive layer. The method includes: a coating step, coating an adhesive composition for a laminated optical film onto one or both of the bonding surfaces of the first optical film and the second optical film; a bonding step, bonding the first optical film and the second optical film; and an adhesive bonding step, irradiating an active energy ray from the surface side of the first optical film or the surface side of the second optical film to cure at least the adhesive composition for a laminated optical film to form the adhesive layer, and bonding the first optical film and the second optical film via the adhesive layer. The adhesive composition for a laminated optical film contains curing components and metal oxide particles. The coating step is a step of applying shear force to the adhesive composition for a laminated optical film and coating it.

[0016] Preferably, the manufacturing method (2) of the laminated optical film is wherein, in the manufacturing method (1) of the laminated optical film, the coating process is a coating process in which the laminated optical film is coated with an adhesive composition on one or both of the bonding surfaces of the first optical film and the second optical film while transporting the first optical film and the second optical film using a gravure coating machine.

[0017] Preferably, the manufacturing method (3) of the laminated optical film is used, wherein in the manufacturing method (1) or (2) of the laminated optical film, the coating thickness of the adhesive composition for the laminated optical film in the coating process is 0.1 to 3.0 μm.

[0018] Preferably, the manufacturing method (4) of the laminated optical film is used, wherein, in any one of the manufacturing methods (1) to (3) of the laminated optical film, the viscosity of the adhesive composition for the laminated optical film at 25°C is 100 [mPa·s] or less.

[0019] Preferably, the manufacturing method of the laminated optical film is (5), wherein, in any one of the manufacturing methods (1) to (4) of the laminated optical film, the content of the metal oxide particles in the adhesive composition for the laminated optical film is 10 to 50% by mass when the total amount of the composition is set to 100% by mass.

[0020] Preferably, the manufacturing method (6) of the laminated optical film is used, wherein, in any one of the manufacturing methods (1) to (5) of the laminated optical film, the adhesive composition for the laminated optical film further comprises (meth)acrylate containing an aromatic ring skeleton.

[0021] Preferably, the manufacturing method (7) of the laminated optical film is used, wherein, in the manufacturing method (6) of the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the (meth)acrylate containing the aromatic ring skeleton is 30 to 70% by mass.

[0022] Preferably, the manufacturing method (8) of the laminated optical film is used, wherein, in the manufacturing method (6) of the laminated optical film, the (meth)acrylate containing an aromatic ring skeleton comprises at least one selected from (meth)acrylates having a polycyclic aromatic ring skeleton and (meth)acrylates having two or more aromatic rings.

[0023] Preferably, the manufacturing method (9) of the laminated optical film is used, wherein in the manufacturing method (6) of the laminated optical film, the (meth)acrylate containing an aromatic ring skeleton is (meth)acrylate phenoxybenzyl ester.

[0024] Preferably, the manufacturing method (10) of the laminated optical film is used, wherein, in any one of the manufacturing methods (1) to (9) of the laminated optical film, the adhesive composition for the laminated optical film further contains a compound represented by the following general formula (1).

[0025] [Chemical Formula 1]

[0026]

[0027] In the formula, X is a reactive group, Y is an alkylene group with 1 to 12 carbon atoms that is optionally branched, or a phenylene group that is optionally substituent, and R... 1 and R 2 Each can independently represent a hydrogen atom, optionally with substituents, aliphatic hydrocarbon groups, aryl groups, or heterocyclic groups.

[0028] Preferably, the manufacturing method (11) of the laminated optical film is used, wherein, in the manufacturing method (10) of the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the compound represented by the general formula (1) is 0.1 to 10% by mass.

[0029] Preferably, the manufacturing method (12) of the laminated optical film is used, wherein in any of the manufacturing methods (1) to (11) of the laminated optical film, the adhesive composition for the laminated optical film further contains a hydroxyl-containing (meth)acrylate.

[0030] Preferably, the manufacturing method (13) of the laminated optical film is used, wherein, in the manufacturing method (12) of the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the hydroxyl-containing (meth)acrylate is 1 to 30% by mass.

[0031] Preferably, the manufacturing method (14) of the laminated optical film is used, wherein in any of the manufacturing methods (1) to (13) of the laminated optical film, the adhesive composition for the laminated optical film further comprises a leveling agent, wherein the leveling agent contains at least one selected from isocyanurate compounds and polysiloxane compounds.

[0032] Preferably, the manufacturing method (15) of the laminated optical film is used, wherein, in the manufacturing method (14) of the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the isocyanurate compound is 0.05 to 10% by mass.

[0033] Preferably, the manufacturing method (16) of the laminated optical film is used, wherein, in the manufacturing method (14) of the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the polysiloxane compound is 0.05 to 2.0% by mass.

[0034] The effects of the invention

[0035] When the adhesive composition for laminated optical films contains metal oxide particles, the thinner the coating is applied, the more unevenness will occur in the coating film due to the metal oxides, resulting in poor appearance and interference patterns during the fabrication of laminated optical films. However, the inventors have conducted in-depth research and discovered that when applying an adhesive composition for laminated optical films containing curing components and metal oxide particles, applying shear force to the adhesive composition during application reduces its viscosity (thixotropy). Even when the adhesive composition is applied thinly, the unevenness on the coating film caused by metal oxides can be suppressed, thus preventing poor appearance and interference patterns during the fabrication of laminated optical films. Furthermore, since an adhesive layer is formed through the cured layer of the adhesive composition for laminated optical films containing curing components and metal oxide particles, the adhesive layer has a high refractive index, excellent adhesion, and reduced curing shrinkage. In particular, when the adhesive composition for laminated optical films contains metal oxide particles and also contains a compound represented by general formula (1), it is preferable to further improve the refractive index and adhesive strength of the adhesive layer. Furthermore, when the adhesive composition for laminated optical films contains metal oxide particles and also contains a (meth)acrylate containing an aromatic ring backbone, it is preferable to further improve the refractive index of the adhesive layer.

[0036] It should be noted that in the manufacturing method of the present invention, when the laminated optical film to be manufactured is a polarizing film having at least a polarizing lens as an optical film, or when it is a laminated optical film having one or more optical films in addition to a polarizing film having a polarizing lens, it is preferable to suppress the change in transmittance after the heat durability test. The reason for obtaining such an effect is not yet clear, but it can be speculated as follows. Compared with the resin component used in conventional adhesives, metal oxide particles expand less due to heating and are less prone to deformation. Therefore, the adhesive layer containing metal oxide particles can suppress expansion and deformation during heating. It can be speculated that for a laminated optical film having an adhesive layer containing metal oxides, since the adhesive layer also suppresses the expansion and contraction of the various optical films constituting the heated laminated optical film, it is possible to suppress the deterioration of the optical film's properties (including a decrease in transmittance). It should be noted that while the adhesive layer formed by the cured layer of the adhesive composition for the laminated optical film containing metal oxide particles can exert the above-mentioned effects when it is in direct contact with the polarizer, the same effect can be achieved even if the adhesive layer is not in direct contact with the polarizer.

[0037] In the manufacturing method of the laminated optical film of the present invention, (i) when the coating thickness of the adhesive composition for the laminated optical film in the coating process is 0.1 to 3.0 μm, and (ii) when the viscosity of the adhesive composition for the laminated optical film at 25°C is 100 [mPa·s] or less, the generation of unevenness on the coating film caused by metal oxides can be suppressed to a high degree, and as a result, the generation of interference patterns during the fabrication of the laminated optical film can be further effectively suppressed due to poor appearance. Attached Figure Description

[0038] Figure 1 This is an example of a laminated optical film manufactured by the method for manufacturing laminated optical films according to the present invention. Detailed Implementation

[0039] Figure 1 An example of a laminated optical film manufactured by the method for manufacturing laminated optical films according to the present invention is shown. Figure 1 In the stacked optical film 10 shown, a first optical film 1 and a second optical film 2 are stacked together via an adhesive layer 3, which is a cured layer of an adhesive composition for stacked optical films. For the adhesive composition for stacked optical films used in this invention to form the adhesive layer 3, the cured layer has a high refractive index due to the stable dispersion of metal oxide particles. Therefore, when a phase retardation film, preferably a liquid crystal-type phase retardation film, is used as the first optical film 1 and the second optical film 2, the refractive index difference between the first optical film 1 and the adhesive layer 3 can be reduced. Similarly, the refractive index difference between the second optical film 2 and the adhesive layer 3 can be reduced, thereby suppressing interference patterns in the stacked optical film and improving visual discernibility.

[0040] The laminated optical film manufactured by the manufacturing method of the present invention is simply a laminated optical film in which at least a first optical film and a second optical film are laminated via an adhesive layer that serves as a cured layer of an adhesive composition for laminated optical films, and may further include any optical film, etc. Figure 1 The stacked optical film 10 shown has a polarizer 5 on top of the first optical film 1 (on the visible side), and further has a transparent protective film 4. It should be noted that an adhesive layer is typically present between the first optical film 1 and the polarizer 5, and between the polarizer 5 and the transparent protective film 4. Figure 1 (omitted in the original text), these adhesive layers can be the same as adhesive layer 3, which is the cured layer of the adhesive composition for laminated optical films used in this invention, or they can be cured layers of adhesive compositions for laminated optical films known to those skilled in the art. Additionally, Figure 1 The stacked optical film 10 shown has an organic light-emitting diode layer 7 sandwiched between an adhesive layer 6 and a second optical film (on the display device side).

[0041] The laminated optical film manufactured by the manufacturing method of the present invention has at least a first optical film and a second optical film laminated together via an adhesive layer. Furthermore, the adhesive layer is formed from a cured layer of an adhesive composition for laminated optical films containing curable components and metal oxide particles. Hereinafter, the adhesive composition for laminated optical films, which serves as the raw material for the adhesive layer, will be described.

[0042] <Metal oxide particles>

[0043] The adhesive composition for laminated optical films used in this invention contains metal oxide particles. Examples of metal oxide particles include: silicon oxide, zirconium oxide, titanium oxide, zinc oxide, antimony pentoxide, tin oxide, aluminum oxide, indium oxide, indium tin oxide, iron oxide, cerium oxide, yttrium oxide, manganese oxide, holmium oxide, copper oxide, bismuth oxide, cobalt oxide, cobalt tetroxide, iron tetroxide, magnesium oxide, lanthanum oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, scandium oxide, tantalum pentoxide, niobium pentoxide, iridium oxide, rhodium oxide, ruthenium oxide, and composite oxides formed by combining these. Zirconia and titanium oxide are preferred, and zirconium oxide is particularly preferred. It should be noted that the metal oxide particles used in this invention may consist only of the metal oxides listed above, or may contain other components, but preferably, the metal oxide constitutes the largest weight percentage of the particles. The metal oxide particles can take any shape, such as spherical, ellipsoidal, cubic, cuboid, or pyramidal. It should be noted that, in this invention, the metal oxide particles used can be those that have undergone surface treatment using methods known to those skilled in the art.

[0044] From the viewpoint of improving the stability of the metal oxide particles in the adhesive composition and increasing the refractive index of the adhesive layer, the average particle size of the metal oxide particles used is preferably 1 to 150 nm, more preferably 1 to 50 nm. In this invention, the average particle size of the metal oxide particles can be observed using a transmission electron microscope (TEM), a field emission transmission electron microscope (FE-TEM), or a field emission scanning electron microscope (FE-SEM), and for example, 1000 particles are randomly selected, their maximum length is measured, and their arithmetic mean is calculated.

[0045] The average particle size of the metal oxide particles incorporated in the adhesive composition can be calculated using dynamic light scattering or laser diffraction. When calculated using dynamic light scattering or laser diffraction, the average particle size refers to the particle size representing the 50% cumulative value in the particle size distribution determined by laser diffraction / scattering.

[0046] From the viewpoint of improving the stability of metal oxide particles in the adhesive composition and improving the refractive index of the adhesive layer, when the total amount of the composition is set to 100% by mass, the amount of metal oxide particles used is preferably 10 to 50% by mass, more preferably 15 to 40% by mass.

[0047] <Curing components>

[0048] The adhesive composition for laminated optical films used in this invention contains a curing component. In this invention, the curing component is preferably a curing component that is cured by active energy rays. As a curing component that is cured by active energy rays, it can be classified as a curing component that is cured by free radical polymerization and a curing component that is cured by cationic polymerization. In this invention, active energy rays with a wavelength range of 10 nm or more and less than 380 nm are described as ultraviolet light, and active energy rays with a wavelength range of 380 nm to 800 nm are described as visible light.

[0049] The adhesive composition for laminated optical films used in this invention may contain a monofunctional radical polymerizable compound as a curing agent. Examples of monofunctional radical polymerizable compounds include various (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Specifically, examples include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, 2-methyl-2-nitropropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, tert-pentyl methacrylate, 3-pentyl methacrylate, 2,2-dimethylbutyl methacrylate, n-hexyl methacrylate, hexadecyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, 4-methyl-2-propylpentyl methacrylate, n-octadecyl methacrylate, and other alkyl methacrylates (1-20 carbon atoms).

[0050] In addition, examples of the aforementioned (meth)acrylic acid derivatives include: cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, and other cycloalkyl (meth)acrylates; benzyl (meth)acrylate and other aralkyl (meth)acrylates; 2-isoborneol (meth)acrylate, 2-norborneol methyl (meth)acrylate, 2-norborneol methyl (meth)acrylate, 5-norbornen-2-yl methyl (meth)acrylate, 3-methyl-2-norborneol methyl (meth)acrylate, and (meth)acrylic acid... Polycyclic (meth)acrylates such as dicyclopentenyl acrylate, dicyclopentenoxyethyl acrylate, and dicyclopentyl acrylate; (meth)acrylates containing alkoxy or phenoxy groups such as 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-methoxymethoxyethyl acrylate, 3-methoxybutyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, and alkylphenoxy polyethylene glycol (meth)acrylate; etc. Among these, dicyclopentenoxyethyl acrylate and phenoxyethyl acrylate are preferred from the viewpoint of excellent adhesion to various protective films.

[0051] In addition, examples of the above-mentioned (meth)acrylic acid derivatives include: 2-hydroxyethyl (meth)acrylic acid, 2-hydroxypropyl (meth)acrylic acid, 3-hydroxypropyl (meth)acrylic acid, 2-hydroxybutyl (meth)acrylic acid, 4-hydroxybutyl (meth)acrylic acid, 6-hydroxyhexyl (meth)acrylic acid, 8-hydroxyoctyl (meth)acrylic acid, 10-hydroxydecyl (meth)acrylic acid, 12-hydroxylaurate (meth)acrylic acid, etc.; hydroxyl-containing (meth)acrylic acids such as [4-(hydroxymethyl)cyclohexyl]methyl acrylate, cyclohexanediol mono(meth)acrylic acid, and 2-hydroxy-3-phenoxypropyl (meth)acrylic acid; epoxy-containing (meth)acrylic acids such as glycidyl (meth)acrylic acid and 4-hydroxybutyl (meth)acrylic acid glycidyl ether; and 2,2,2-trifluoroethyl (meth)acrylic acid and methacrylic acid... Halogenated (meth)acrylates such as 2,2,2-trifluoroethyl ethyl ester, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, and 3-chloro-2-hydroxypropyl (meth)acrylate; alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate; oxyheterobutyl (meth)acrylates such as 3-oxetanebutyl methyl (meth)acrylate, 3-methyloxetanebutyl methyl (meth)acrylate, 3-ethyloxetanebutyl methyl (meth)acrylate, 3-butyloxetanebutyl methyl (meth)acrylate, and 3-hexyloxetanebutyl methyl (meth)acrylate; heterocyclic (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and butyrolactone (meth)acrylate; neopentyl glycol (meth)acrylate adducts of hydroxypentanoic acid; and p-phenylphenol (meth)acrylate. Among them, 2-hydroxy-3-phenoxypropyl acrylate is preferred due to its excellent adhesion to various protective films.

[0052] In the case where the adhesive composition for laminated optical films used in this invention contains hydroxyl-containing (meth)acrylates in addition to metal oxide particles and the compound shown in general formula (1), the adhesive strength of the adhesive layer is further improved, which is therefore preferred. From the viewpoint of improving the adhesive strength of the adhesive layer, when the total amount of the composition is set to 100% by mass, the amount of hydroxyl-containing (meth)acrylates is preferably 1 to 30% by mass, more preferably 3 to 20% by mass.

[0053] In addition, examples of monofunctional free radical polymerizable compounds include: (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and other carboxyl-containing monomers.

[0054] In addition, examples of monofunctional free radical polymerizable compounds include: N-vinylpyrrolidone, N-vinyl-ε-caprolactam, methylvinylpyrrolidone, and other lactam vinyl monomers; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazolium, and vinylpyrrole. Vinyl monomers containing nitrogen-containing heterocycles, such as azoles and vinylmorpholine.

[0055] Furthermore, as a monofunctional radical polymerizable compound, a radical polymerizable compound having an active methylene group can be used. A radical polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acrylate group at the end or in the molecule, and having an active methylene group. Examples of active methylene groups include acetoacetyl, alkoxymalonyl, or cyanoacetyl. The preferred active methylene group is acetoacetyl. Specific examples of free radical polymerizable compounds containing an active methylene group include: acetyl acetoxyethyl methacrylate, acetyl acetoxypropyl methacrylate, acetyl acetoxy-1-methylethyl methacrylate, and other acetyl acetoxyalkyl methacrylates; acetyl acetoxyethyl methacrylate, cyanoacetoxyethyl methacrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl)acrylamide, N-(4-acetylacetoxymethylbenzyl)acrylamide, N-(2-acetylacetylaminoethyl)acrylamide, etc. The preferred free radical polymerizable compound containing an active methylene group is an acetyl acetoxyalkyl methacrylate.

[0056] In addition, the adhesive composition for laminated optical films used in this invention can be combined with a multifunctional free radical polymerizable compound with two or more functions as a curing component. Examples of polyfunctional free radical polymerizable compounds include: 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, neopentyl glycol di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, cyclic trimethylolpropane formal(meth)acrylate, and dimethylolpropane formal(meth)acrylate. Esterifications of alkyldiol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, EO-modified diglycerol tetra(meth)acrylate, and other (meth)acrylates with polyols, as well as 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. Specific examples preferably include ARONIX M-220 (manufactured by Toa Synthetic 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 CP-A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer Co., Ltd.), and CD-536 (manufactured by Sartomer Co., Ltd.). In addition, as needed, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, and various (meth)acrylate monomers can be listed. It should be noted that multifunctional (meth)acrylamide derivatives are preferred for inclusion in adhesive compositions because they not only have fast polymerization speeds and excellent productivity, but also exhibit excellent crosslinking properties when the adhesive composition is cured.

[0057] For example, when using polarizers and transparent protective films as optical films, from the viewpoint of combining adhesion to polarizers and various transparent protective films with optical durability in harsh environments, it is preferable to use a combination of monofunctional and polyfunctional free radical polymerizable compounds. When the total amount of the composition is set to 100% by mass, the amount of monofunctional free radical polymerizable compound in the adhesive composition is preferably 10-95% by mass, more preferably 30-80% by mass. When the total amount of the composition is set to 100% by mass, the amount of polyfunctional free radical polymerizable compound in the adhesive composition is preferably 0.5-60% by mass, more preferably 1-40% by mass.

[0058] <(meth)acrylates containing an aromatic ring skeleton>

[0059] The adhesive composition for laminated optical films used in this invention, when containing metal oxide particles and a (meth)acrylate containing an aromatic ring backbone, results in an increased refractive index of the adhesive layer, which is therefore preferred. From the viewpoint of more stably increasing the refractive index of the adhesive layer, in this invention, as the (meth)acrylate containing an aromatic ring backbone, it is preferable to use a (meth)acrylate containing at least one selected from (meth)acrylates having a polycyclic aromatic ring backbone and (meth)acrylates having two or more aromatic rings. Examples of (meth)acrylates containing an aromatic ring backbone include: benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 1-naphthyl (meth)acrylate, phenoxybenzyl (meth)acrylate, ethylene oxide-modified o-phenylphenol (meth)acrylate, and the reaction product of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene and (meth)acrylate, etc. Phenoxybenzyl (meth)acrylate and phenoxyethyl (meth)acrylate are preferred, with phenoxybenzyl (meth)acrylate being particularly preferred. Phenoxybenzyl (meth)acrylate is a compound having the structure shown in formula (A) below.

[0060] [Chemical Formula 2]

[0061]

[0062] In formula (A) above, X represents a single bond forming part of an adjacent bond and group, or represents a repeating structure having 1 to 5 ethylene oxide, propylene oxide, butane oxide, or styrene oxide structures. R represents a hydrogen atom or a methyl group. The adhesive composition for laminated optical films used in this invention preferably contains phenoxybenzyl (meth)acrylate as an ortho- or meta-substituted product, as shown in formula (A-1) below.

[0063] [Chemical Formula 3]

[0064]

[0065] From the viewpoint of increasing the refractive index of the adhesive layer, when the total amount of the composition is set to 100% by mass, the amount of (meth)acrylate containing an aromatic ring skeleton, especially (meth)acrylate phenoxybenzyl ester, is preferably 30 to 70% by mass.

[0066] <Compounds represented by general formula (1)>

[0067] The adhesive composition for laminated optical films used in this invention contains metal oxide particles and a compound represented by the following general formula (1) (where X is a reactive group, Y is an alkylene group having 1 to 12 carbon atoms with optional branches or a phenylene group having optional substituents, R...).1 and R 2 When each hydrogen atom is independently represented, or optionally an aliphatic hydrocarbon group, aryl group, or heterocyclic group with substituents, the adhesive strength of the adhesive layer is further improved, and therefore it is preferred.

[0068] [Chemical Formula 4]

[0069]

[0070] In addition, when the adhesive composition for the laminated optical film used in this invention contains metal oxide particles and a compound represented by the above general formula (1), the curing shrinkage rate of the adhesive layer is reduced. Therefore, when forming the laminated optical film, the stress applied to each optical film can be reduced, and thus the durability of the laminated optical film can be expected to be improved, which is preferred.

[0071] Examples of aliphatic hydrocarbon groups include linear or branched alkyl groups with 1 to 20 carbon atoms that are optionally substituented, cyclic alkyl groups with 3 to 20 carbon atoms that are optionally substituented, and alkenyl groups with 2 to 20 carbon atoms. Examples of aryl groups include phenyl groups with 6 to 20 carbon atoms that are optionally substituented, and naphthyl groups with 10 to 20 carbon atoms that are optionally substituented. Examples of heterocyclic groups include, for example, 5-membered or 6-membered ring groups that are optionally substituented and contain at least one heteroatom. They can be linked together to form a ring. In general formula (1), R is... 1 and R 2 Preferably, it is a straight-chain or branched alkyl group with 1 to 3 carbon atoms, and most preferably a hydrogen atom.

[0072] The compound represented by general formula (1) has a reactive group X, which is a functional group that can react with the curing components that constitute the cured layer, especially the adhesive layer. Examples include: hydroxyl, amino, aldehyde, carboxyl, vinyl, (meth)acryloyl, styrene, (meth)acrylamide, vinyl ether, epoxy, oxetyl, α,β-unsaturated carbonyl, mercapto, halogen, etc. When the curable resin composition constituting the cured layer, especially the adhesive layer, is ray-curable, the reactive group X is preferably selected from at least one reactive group chosen from vinyl, (meth)acryloyl, styrene, (meth)acrylamide, vinyl ether, epoxy, oxetyl, and mercapto. When the curable resin composition constituting the cured layer, especially the adhesive layer, is free radical polymerizable, the reactive group X is preferably selected from at least one reactive group chosen from (meth)acryloyl, styrene, and (meth)acrylamide. When the compound represented by general formula (1) has a (meth)acrylamide group, it has high reactivity and a higher copolymerization rate with the curing components in the cured layer, especially the adhesive layer, which is therefore more preferable. In addition, the (meth)acrylamide group has high polarity and excellent adhesion, which is also preferable from the perspective of efficiently obtaining the effects of the present invention. When the curable resin composition constituting the cured layer, especially the adhesive layer, is cationicly polymerizable, the reactive group X preferably has at least one functional group selected from hydroxyl, amino, aldehyde, carboxyl, vinyl ether, epoxy, oxetyl, and mercapto. In particular, when epoxy is present, the resulting cured layer, especially the adhesive layer, has excellent adhesion to the adhered object, and is therefore preferred. When vinyl ether is present, the curability of the curable resin composition is excellent, and is therefore preferred.

[0073] Preferred specific examples of compounds represented by general formula (1) include the following compounds (1a) to (1d). It should be noted that R in general formulas (1a) and (1b) 3 It can be a hydrogen atom or a methyl group.

[0074] [Chemical Formula 5]

[0075]

[0076] As compounds represented by general formula (1), in addition to the compounds exemplified above, esters formed by hydroxyethyl acrylamide and boric acid, esters formed by hydroxymethyl acrylamide and boric acid, esters formed by hydroxyethyl acrylate and boric acid, and esters formed by hydroxybutyl acrylate and boric acid, etc., formed by (meth)acrylates and boric acid, can also be exemplified.

[0077] From the viewpoint of improving the adhesive strength of the adhesive layer, when the total amount of the composition is set to 100% by mass, the amount of compound represented by the general formula (1) used is preferably 0.1 to 10% by mass, more preferably 0.3 to 5% by mass.

[0078] The adhesive composition for laminated optical films used in this invention contains at least one selected from isocyanurate compounds and polysiloxane compounds, which allows for the stable dispersion of metal oxide particles. Therefore, despite the presence of metal oxide particles, the viscosity can be suppressed to a low level. From the viewpoint of achieving thinner adhesive layers and laminated optical films by thinly applying the adhesive composition to the optical film, it is preferable to set the viscosity of the composition at 25°C to 100 mPa·s or less, more preferably 60 mPa·s or less.

[0079] Leveling agent

[0080] The adhesive composition for laminated optical films used in this invention preferably contains at least one selected from isocyanurate compounds and polysiloxane compounds as a leveling agent. By containing at least one selected from isocyanurate compounds and polysiloxane compounds in the composition, metal oxide particles can be stably dispersed, thereby resulting in excellent liquid stability of the adhesive composition for laminated optical films. Furthermore, by containing metal oxide particles and at least one selected from isocyanurate compounds and polysiloxane compounds in the composition, the formation of pinholes and bubbles during coating on the optical film can be suppressed. From the viewpoint of further improving the above-mentioned effects, the adhesive composition for laminated optical films used in this invention preferably contains both isocyanurate compounds and polysiloxane compounds. When the adhesive composition for laminated optical films contains both isocyanurate compounds and polysiloxane compounds, and the total amount of the composition is set to 100% by mass, the amount of the compound is preferably 0.1 to 4% by mass, more preferably 0.1 to 2% by mass. It should be noted that, as described later, when isocyanurate compounds are also used as crosslinking agents, when the adhesive composition for laminated optical films contains both isocyanurate compounds and polysiloxane compounds, and the total amount of the composition is set to 100% by mass, the amount of these compounds is preferably 0.1 to 14% by mass, more preferably 0.1 to 7% by mass.

[0081] <Isocyanurate compounds>

[0082] Isocyanurate compounds are compounds containing an isocyanurate ring structure formed by the trimerization reaction of isocyanates. In this invention, modified isocyanurate compounds having reactive groups are particularly preferred. Examples of reactive groups in modified isocyanurate compounds include polymerizable functional groups, specifically such as: (meth)acryloyl, vinyl, allyl, and other free radical polymerizable functional groups having olefinic double bonds; epoxy groups such as glycidyl; oxetyl, vinyl ether, cyclic ether, cyclic thioether, lactone, and other cationic polymerizable functional groups. From the viewpoint of reactivity in the adhesive composition for laminated optical films, modified isocyanurate compounds having double bonds as reactive groups are preferred, and modified isocyanurate compounds having (meth)acryloyl groups are more preferred. When the total amount of the composition is set to 100% by mass, the amount of isocyanurate compound in the adhesive composition for laminated optical films is preferably 0.05 to 2% by mass, more preferably 0.05 to 1% by mass.

[0083] It should be noted that isocyanurate compounds not only help stabilize the dispersion of metal oxide particles in the composition, but also have the effect of reducing, for example, the curing shrinkage rate when forming the adhesive layer. Therefore, when isocyanurate compounds are used as crosslinking agents in the adhesive composition for laminated optical films used in this invention, it is preferable to use a larger amount of isocyanurate compounds. Specifically, when the total amount of the composition is set to 100% by mass, it is preferably 0.05 to 10% by mass, more preferably 0.05 to 5% by mass.

[0084] <Polysiloxane compounds>

[0085] The polysiloxane compound is a compound having a polysiloxane backbone, such as polydimethylsiloxane. In this invention, modified polysiloxane compounds having reactive groups are particularly preferred. Examples of reactive groups in the modified polysiloxane compound include polymerizable functional groups, specifically such as: free radical polymerizable functional groups having olefinic double bonds, such as (meth)acryloyl, vinyl, and allyl; epoxy groups such as glycidyl; oxetyl, vinyl ether, cyclic ether, cyclic thioether, and cationic polymerizable functional groups such as lactone. From the viewpoint of reactivity in the adhesive composition for laminated optical films, modified polysiloxane compounds having double bonds as reactive groups are preferred, and modified polysiloxane compounds having (meth)acryloyl groups are more preferred. When the total amount of the composition is set to 100% by mass, the amount of polysiloxane compound in the adhesive composition for laminated optical films is preferably 0.05 to 2% by mass, more preferably 0.05 to 1% by mass.

[0086] Regarding the adhesive composition for laminated optical films used in this invention, when the curing component is used as an active energy ray curing component, it can be used as an active energy ray curable adhesive composition. For the above-mentioned active energy ray curable adhesive composition, when the active energy ray uses an electron beam or the like, the active energy ray curable adhesive composition does not need to contain a photopolymerization initiator; however, when the active energy ray uses ultraviolet or visible light, it is preferable to contain a photopolymerization initiator.

[0087] Photopolymerization initiators can be appropriately selected based on the active energy of the radiation. In cases of curing by ultraviolet or visible light, photopolymerization initiators that undergo ultraviolet or visible light degradation can be used. Examples of such photopolymerization initiators include: benzoyl, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, and other benzophenone compounds; aromatic ketone compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)one, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxyphenylacetone, 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-one; and benzoin methyl ether. Benzoin ethers, such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisolein methyl ether; aromatic ketals, such as benzoin dimethyl ketal; aromatic sulfonyl chlorides, such as 2-naphthalenesulfonyl chloride; photoactive oximes, such as 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthones, such as 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone; camphorquinone; haloketones; acylphosphine oxides; and acylphosphonates.

[0088] When the total amount of the composition is set to 100% by mass, the amount of the above-mentioned photopolymerization initiator is preferably 0.5 to 5% by mass, more preferably 1 to 4% by mass.

[0089] Furthermore, when using an active energy ray-curable adhesive composition that is visible light-curable, it is particularly preferable to use a photopolymerization initiator that is highly sensitive to light above 380 nm. The use of photopolymerization initiators that are highly sensitive to light above 380 nm will be explained later.

[0090] As the above-mentioned photopolymerization initiator, it is preferable to use the compound represented by the following general formula (3) alone (where R is a compound represented by a general formula (3)). 7 and R 8Represents -H, -CH2CH3, -iPr, or Cl, R 7 and R 8 (They may be the same or different), or the compound shown in general formula (3) may be used in combination with the photopolymerization initiator that is highly sensitive to light above 380 nm, as described later.

[0091] [Chemical Formula 6]

[0092]

[0093] Compared to using a photopolymerization initiator that is highly sensitive to light above 380 nm alone, the use of the compound shown in general formula (3) results in superior adhesion. Among the compounds shown in general formula (3), R is particularly preferred. 7 and R 8 Diethylthioxanthone of the form -CH2CH3. When the total amount of the composition is set to 100% by mass, the amount of the compound represented by general formula (3) in the active energy ray curable adhesive composition is preferably 0.1 to 5% by mass, more preferably 0.3 to 3% by mass.

[0094] Furthermore, a polymerization initiator is preferably 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, with ethyl 4-dimethylaminobenzoate being particularly preferred. When using a polymerization initiator, if the total amount of the composition is set to 100% by mass, the amount added is preferably 0.1 to 2% by mass, more preferably 0.3 to 1% by mass.

[0095] In addition, known photopolymerization initiators can be used in combination as needed. Since optical functional layers and substrate films with UV absorption capabilities do not transmit light below 380 nm, photopolymerization initiators that are highly sensitive to light above 380 nm are preferred. Specifically, examples include: 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis(η5-2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium, etc.

[0096] In this invention, the adhesive composition for laminated optical films preferably contains an acrylic oligomer formed by polymerizing (meth)acrylic acid monomers. By including an acrylic oligomer in the adhesive composition for laminated optical films, curing shrinkage during irradiation with active energy rays and subsequent curing can be reduced, and interfacial stress between the adhesive layer and the optical film can be decreased. As a result, the reduction in the adhesion between the adhesive layer and the optical film can be suppressed.

[0097] Considering operability and uniformity during application, the adhesive composition for laminated optical films is preferably low in viscosity; therefore, the acrylic oligomers polymerized from (meth)acrylic monomers are also preferably low in viscosity. As a low-viscosity acrylic oligomer capable of preventing curing shrinkage of the adhesive layer, its weight-average molecular weight (Mw) is preferably 15,000 or less, more preferably 10,000 or less, and particularly preferably 5,000 or less. On the other hand, to sufficiently suppress curing shrinkage of the cured layer (adhesive layer), the weight-average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1,000 or more, and particularly preferably 1,500 or more.Examples of (meth)acrylic acid monomers constituting acrylic oligomers include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, 2-methyl-2-nitropropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, tert-pentyl methacrylate, 3-pentyl methacrylate, 2,2-dimethylbutyl methacrylate, n-hexyl methacrylate, etc. Cetyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, 4-methyl-2-propylpentyl methacrylate, n-octadecyl methacrylate, and other alkyl methacrylates (1-20 carbon atoms), as well as cycloalkyl methacrylates (e.g., cyclohexyl methacrylate, cyclopentyl methacrylate, etc.), aralkyl methacrylates (e.g., benzyl methacrylate, etc.), polycyclic methacrylates (e.g., 2-isobornyl methacrylate, 2-norbornyl methacrylate, etc.). Borneol methyl ester, 5-norbornen-2-yl methyl methacrylate, 3-methyl-2-norbornol methyl methacrylate, etc.; hydroxyl-containing (meth)acrylates (e.g., hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,3-dihydroxypropyl methyl butyl methacrylate, etc.); alkoxy or phenoxy-containing (meth)acrylates (2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-methoxymethoxyethyl methacrylate, 3-methoxybutyl methacrylate, etc.). These include ethyl carbitol acrylate, phenoxyethyl acrylate, etc.; epoxy-containing methacrylates (e.g., glycidyl methacrylate); halogen-containing methacrylates (e.g., 2,2,2-trifluoroethyl methacrylate, 2,2,2-trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, hexafluoropropyl methacrylate, octafluoropentyl methacrylate, heptadecafluorodecyl methacrylate, etc.); and alkylaminoalkyl methacrylates (e.g., dimethylaminoethyl methacrylate). These methacrylates can be used alone or in combination of two or more. Specific examples of acrylic oligomers (E) include "ARUFON" manufactured by Toa Synthetic Co., Ltd., "ACTFLOW" manufactured by Soken Chemical Co., Ltd., and "JONCRYL" manufactured by BASF Japan Ltd.

[0098] The amount of acrylic oligomer in the adhesive composition for laminated optical films is preferably 3 to 40% by mass, more preferably 5 to 20% by mass.

[0099] The adhesive composition for laminated optical films used in this invention may contain a silane coupling agent. Specific examples of silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, etc., which are compounds that can be cured by active energy rays.

[0100] Preferably, it is 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, or 3-epoxypropoxypropyltriethoxysilane.

[0101] Specific examples of inactive energy-curable silane coupling agents other than those mentioned above include: 3-ureopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanate-propyltriethoxysilane, imidazole silane, etc.

[0102] The adhesive composition for laminated optical films used in this invention can be a cationic polymeric curing adhesive composition. The curing component (cationic polymeric compound) used in the cationic polymeric curing adhesive composition can be classified as a monofunctional cationic polymeric compound having one cationic polymeric functional group within its molecule, and a polyfunctional cationic polymeric compound having two or more cationic polymeric functional groups within its molecule. Monofunctional cationic polymeric compounds have lower liquid viscosity; therefore, by including them in the cationic polymeric curing adhesive composition, the liquid viscosity can be reduced. Furthermore, monofunctional cationic polymeric compounds often possess functional groups exhibiting various functions; by including them in the cationic polymeric curing adhesive composition, the cationic polymeric curing adhesive composition and / or the cured product of the cationic polymeric curing adhesive composition can exhibit various functions. Polyfunctional cationic polymeric compounds can enable three-dimensional crosslinking of the cured product of the cationic polymeric curing resin composition; therefore, they are preferably included in the cationic polymeric curing adhesive composition. Regarding the ratio of monofunctional cationic polymeric compounds to polyfunctional cationic polymeric compounds, it is preferable to mix the polyfunctional cationic polymeric compounds in the range of 10% to 1000% by mass relative to 100% by mass of the monofunctional cationic polymeric compound. Examples of cationic polymeric functional groups include epoxy groups, oxetyl groups, and vinyl ether groups. Examples of compounds containing epoxy groups include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds. From the perspective of excellent curability and adhesion, the cationic polymeric resin composition of the present invention particularly preferably contains an alicyclic epoxy compound. Examples of alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, caprolactone-modified, trimethylcaprolactone-modified, and valproic acid-modified versions of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, and more specifically, CELLOXIDE2021, CELLOXIDE2021A, CELLOXIDE2021P, CELLOXIDE2081, CELLOXIDE2083, CELLOXIDE2085 (all manufactured by Celebratory Chemical Industry Co., Ltd.), Cyracure UVR-6105, Cyracure UVR-6107, Cyracure30, and R-6110 (all manufactured by Dow Chemical Japan Ltd.). Compounds containing oxetane butyl groups are preferred because they improve the curability of cationic polymerizable adhesive compositions and reduce the liquid viscosity of the composition.Examples of compounds containing oxetane groups include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetane)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, di[(3-ethyl-3-oxetane)methyl] ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, and phenolic varnish oxetane. Commercially available examples include ARON OXETANE OXT-101, ARON OXETANE OXT-121, ARON OXETANE OXT-211, ARON OXETANE OXT-221, and ARON OXETANE OXT-212 (all manufactured by Toa Synthetic Co., Ltd.). Compounds containing vinyl ether groups are preferred because they improve the curability of cationic polymerizable adhesive compositions and reduce the liquid viscosity of the composition. Examples of compounds containing a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, cyclohexanediethanol divinyl ether, cyclohexanediethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, and pentaerythritol-type tetravinyl ether.

[0103] The cationic polymerizable adhesive composition contains at least one compound selected from the above-described compounds having epoxy groups, oxetyl compounds, and vinyl ether groups as a curing component. These are all substances that cure via cationic polymerization, and therefore can be combined with a photocationic polymerization initiator. This photocationic polymerization initiator generates cationic species or Lewis acids upon irradiation with active energy rays such as visible light, ultraviolet light, X-rays, and electron beams, thereby initiating the polymerization reaction of epoxy groups and oxetyl groups. As the photocationic polymerization initiator, a photoacid generator described later is preferred. Furthermore, when using the cationic polymerizable adhesive composition for visible light curability, a photocationic polymerization initiator with high sensitivity to light above 380 nm is particularly preferred. However, photocationic polymerization initiators are compounds that typically exhibit maximum absorption in the wavelength region around 300 nm or shorter than 300 nm. Therefore, by combining a photosensitizer that exhibits maximum absorption in a longer wavelength region, specifically longer than 380 nm, light at nearby wavelengths can be sensed, promoting the generation of cationic species or acids from the photocationic polymerization initiator. Examples of photosensitizers include anthracene compounds, pyrene compounds, carbonyl compounds, organosulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreducing pigments. Two or more of these can also be used in combination. Anthracene compounds, in particular, exhibit excellent photosensitizing effects and are therefore preferred. Specific examples include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Chemical Co., Ltd.). The photosensitizer content is preferably 0.1% to 5% by mass, more preferably 0.5% to 3% by mass.

[0104] In this invention, the adhesive composition for laminated optical films may contain a photoacid generator. Compared to the case without a photoacid generator, the water resistance and durability of the adhesive layer can be significantly improved when the adhesive composition for laminated optical films contains a photoacid generator. The photoacid generator can be represented by the following general formula (4).

[0105] [Chemical Formula 7]

[0106]

[0107] (where L is in the formula) + Indicates any Cations. Additionally, X - Indicates selection from PF66 - SbF6 - AsF6 - SbCl6 - BiCl5 - SnCl6 - ClO4- Dithiocarbamate anion, SCN - (The counteracting anions in the middle.)

[0108] Next, the counter anion X in general formula (4) - Please provide an explanation.

[0109] In principle, the counter anion X in general formula (4) - There are no particular limitations, but non-nucleophilic anions are preferred. When the counter anion X is a non-nucleophilic anion, the photoacid generator represented by general formula (4) and the composition using it are more stable over time because it is less likely to cause nucleophilic reactions in intramolecularly coexisting cations and various materials used in combination. Here, non-nucleophilic anions refer to anions with low ability to cause nucleophilic reactions. PF6 is an example of such anion. - SbF6 - AsF6 - SbCl6 - BiCl5 - SnCl6 - ClO4 - B(C6H5)4 - Dithiocarbamate anion, SCN - wait.

[0110] Specifically, preferred examples of the photoacid-generating agents of the present invention include: “CYRACURE UVI-6992”, “CYRACURE UVI-6974” (manufactured by DOW CHEMICAL JAPAN), “Adeka Optomer SP150”, “Adeka Optomer SP152”, “Adeka Optomer SP170”, “Adeka Optomer SP172” (manufactured by ADEKA), “Omnicat250” (manufactured by IGM Resins BV), “CI-5102”, “CI-2855” (manufactured by Nippon Soda Co., Ltd.), “San-Aid SI-60L”, “San-Aid SI-80L”, “San-Aid SI-100L”, “San-Aid SI-110L”, “San-Aid… ... SI-180L (manufactured by Sanshin Chemical Co., Ltd.), IK-1, CPI-100P, CPI-101A, CPI-110P, CPI-200K, CPI-210S, CPI-310B, CPI-410B, CPI-410S (manufactured by SAN-APRO), WPI-069, WPI-113, WPI-116, WPI-041, WPI-044, WPI-054, WPI-055, WPAG-281, WPAG-567, WPAG-596 (manufactured by Fujifilm and Koh Genuine Chemicals Co., Ltd.).

[0111] The laminated optical film manufactured by the manufacturing method of the present invention is a laminated optical film in which at least a first optical film and a second optical film are laminated via an adhesive layer, and the adhesive layer is a cured layer of the adhesive composition for laminated optical films described above.

[0112] The adhesive composition for laminated optical films used in this invention contains metal oxide particles. When further containing at least one selected from isocyanurate compounds and polysiloxane compounds, the metal oxide particles can be stably dispersed, thereby suppressing the viscosity of the composition to a low level. Therefore, since the adhesive composition for laminated optical films can be thinly applied to the optical film, the thickness of the adhesive layer can be reduced.

[0113] The thickness of the adhesive layer in the laminated optical film manufactured by the manufacturing method of the present invention is preferably 0.1 to 5 μm, more preferably 0.3 to 3 μm.

[0114] Examples of the first and second optical films constituting the stacked optical films manufactured by the manufacturing method of the present invention include polarizers, transparent protective films, and phase difference films.

[0115] In this invention, there are no particular limitations on the polarizer, and various polarizers can be used. Examples of polarizers include those formed by uniaxially stretching hydrophilic polymer films such as polyvinyl alcohol films, partially methylated polyvinyl alcohol films, and partially saponified films of ethylene-vinyl acetate copolymers, to which iodine is adsorbed. Examples of polarizer thicknesses include 3 to 20 μm.

[0116] In this invention, from the viewpoint of improving heating durability in harsh environments at high temperatures, a thin polarizer with a thickness of 3 μm or more and 15 μm or less is preferably used as the polarizer. Particularly preferred is 12 μm or less, further preferred is 10 μm or less, and especially preferred is 8 μm or less. Such a thin polarizer has less thickness unevenness, excellent visual visibility, and minimal dimensional variation, thus exhibiting excellent durability against thermal shock.

[0117] A polarizing mirror, made by dyeing a polyvinyl alcohol (PVA) film with iodine and then unidirectionally stretching it, can be manufactured as follows: The PVA film is dyed by immersing it in an aqueous solution of iodine and then stretched to 3-7 times its initial length. Depending on the requirements, it can also be immersed in an aqueous solution of boric acid, zinc sulfate, zinc chloride, or potassium iodide. Furthermore, if necessary, the PVA film can be washed with water before dyeing. Washing the PVA film not only removes stains and anti-blocking agents from its surface but also prevents uneven dyeing by causing the PVA film to swell. Stretching can be performed after dyeing with iodine, or during dyeing, or after stretching. Stretching can also be performed in an aqueous solution of boric acid, potassium iodide, or a water bath.

[0118] From the perspective of tensile stability and humidification reliability, it is preferable that the polarizer contains boric acid. Furthermore, from the viewpoint of suppressing the occurrence of through-cracks, the boric acid content in the polarizer is preferably 22% by mass or less, and more preferably 20% by mass or less, relative to the total amount of the polarizer. From the viewpoint of tensile stability and humidification reliability, the boric acid content is preferably 10% by mass or more, and more preferably 12% by mass or more, relative to the total amount of the polarizer.

[0119] Representative examples of thin polarizers include those described in Japanese Patent No. 4751486, Japanese Patent No. 4751481, Japanese Patent No. 4815544, Japanese Patent No. 5048120, International Publication No. 2014 / 077599, and International Publication No. 2014 / 077636, or thin polarizers manufactured using the methods described in these documents.

[0120] As for the aforementioned thin polarizer, in the manufacturing method including the stretching process in a laminated state and the dyeing process, from the viewpoint of being able to stretch to a high magnification and improve polarization performance, it is preferable to use a thin polarizer obtained by a manufacturing method including a stretching process in a boric acid aqueous solution as described in Japanese Patent Nos. 4751486, 4751481, and 4815544. Particularly preferred are thin polarizers obtained by a manufacturing method described in Japanese Patent Nos. 4751481 and 4815544, which includes an auxiliary stretching process in a gas atmosphere before stretching in a boric acid aqueous solution. These thin polarizing films can be obtained by a manufacturing method including a stretching process of a polyvinyl alcohol resin (hereinafter also referred to as PVA resin) layer and a stretching resin substrate in a laminated state and a dyeing process. If this method is used, even if the PVA resin layer is thin, it can be stretched by being supported by a stretched resin substrate without causing defects such as breakage due to stretching.

[0121] As materials constituting the transparent protective film, thermoplastic resins with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy can be used, for example. Specific examples of such thermoplastic resins include cellulose resins such as cellulose triacetate resin films, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The transparent protective film may contain one or more suitable additives. Examples of additives include: ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, etc. The content of the aforementioned thermoplastic resin in the transparent protective film is preferably 50-100% by weight, more preferably 50-99% by weight, further preferably 60-98% by weight, and particularly preferably 70-97% by weight. When the content of the aforementioned thermoplastic resin in the transparent protective film is less than 50% by weight, there is a potential risk that the high transparency originally possessed by the thermoplastic resin may not be fully manifested.

[0122] Furthermore, the preferred material for forming the transparent protective film is one with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy; more particularly, a moisture permeability of 150 g / m² is preferred. 2 / less than 24h, especially preferably 140g / m 2 / 24h or less, further preferably 120g / m 2 / 24h or less

[0123] Functional layers such as a hard coating layer, anti-reflective layer, anti-adhesion layer, diffusion layer, or anti-glare layer can be applied to the side of the transparent protective film that is not bonded to the polarizer. It should be noted that the aforementioned functional layers such as the hard coating layer, anti-reflective layer, anti-adhesion layer, diffusion layer, and anti-glare layer can be either the transparent protective film itself or layers different from the transparent protective film.

[0124] The thickness of the transparent protective film can be appropriately determined. Generally speaking, considering factors such as strength, processability, operability, and thinness, it is about 1 to 500 μm, preferably 1 to 300 μm, more preferably 5 to 200 μm, even more preferably 10 to 200 μm, and even more preferably 20 to 80 μm.

[0125] As the aforementioned transparent protective film, a phase retardation film can be used, having a frontal phase difference of 40 nm or more and / or a thickness-direction phase difference of 80 nm or more. Typically, the frontal phase difference is controlled within the range of 40–200 nm, and the thickness-direction phase difference is typically controlled within the range of 80–300 nm. When a phase retardation film is used as a transparent protective film, it also functions as a transparent protective film, thus enabling thinner designs.

[0126] Examples of phase retardation films include: birefringent films formed by unidirectional or bidirectional stretching of polymer raw materials, alignment films of liquid crystal polymers, and materials formed by supporting alignment layers of liquid crystal polymers with films. The thickness of phase retardation films is not particularly limited, typically ranging from 1 to 150 μm.

[0127] As a phase retardation film, a phase retardation film with inverse wavelength dispersion that satisfies the following equations (1) to (3) can be used.

[0128] 0.70 <Re

[450] / Re

[550] <0.97···(1)

[0129] 1.5×10 -3 <Δn<6×10 -3 ···(2)

[0130] 1.13 < NZ < 1.50 ···(3)

[0131] (In the formula, Re

[450] and Re

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

[0132] A phase retardation layer can be provided in the stacked optical film manufactured by the manufacturing method of the present invention. The phase retardation layer can be a single layer or multiple layers, and the phase retardation layer can also serve as a protective layer for the polarizer.

[0133] In the formation of the phase retardation layer, a liquid crystal compound is preferably used. A solution containing the liquid crystal compound can be coated using, for example, a wire rod, a slit coater, a comma coater, a gravure coater, or a slot die. The coated liquid crystal solution can then be air-dried or heat-dried. It should be noted that the liquid crystal solution is preferably coated at a concentration lower than the isotropic phase-liquid phase transition concentration, i.e., in an isotropic phase state. In this case, it can be stably oriented by methods such as rubbing treatment or photo-alignment.

[0134] The method for manufacturing the laminated optical film of the present invention specifically comprises the following components.

[0135] A method for manufacturing a laminated optical film, comprising at least a first optical film and a second optical film laminated together via an adhesive layer, the method comprising: a coating step, wherein an adhesive composition for the laminated optical film is applied to one or both of the bonding surfaces of the first optical film and the second optical film; a bonding step, wherein the first optical film and the second optical film are bonded together; and an adhesive bonding step, wherein active energy rays are irradiated from the surface side of the first optical film or the surface side of the second optical film to cure at least the adhesive composition for the laminated optical film to form the adhesive layer, and the first optical film and the second optical film are bonded together via the adhesive layer, wherein the adhesive composition for the laminated optical film contains curing components and metal oxide particles, and the coating step is a step of applying shear force to the adhesive composition for the laminated optical film and applying it.

[0136] In the above coating process, when applying the adhesive composition for the laminated optical film to one or both of the bonding surfaces of the first optical film and the second optical film, the method of applying the adhesive composition for the laminated optical film while applying shear force can be exemplified by using a reverse coater, a gravure coater (direct, reverse, or offset), a bar reverse coater, a roller coater, a die coater, a bar coater, or a rod coater. In these coating methods, the method of using a gravure coating machine to apply a laminated optical film adhesive composition to one or both of the bonding surfaces of the first and second optical films while transporting the first and second optical films further reduces the viscosity (thixotropy) of the laminated optical film adhesive composition. Even if the laminated optical film adhesive composition is applied thinly, the generation of unevenness on the coating film caused by metal oxide particles can be particularly suppressed. As a result, the generation of interference patterns during the formation of laminated optical films can be more effectively suppressed, which is therefore preferred.

[0137] The coating method using a gravure coating machine involves using a gravure roller with numerous units (recesses) formed on its surface to transfer a laminated optical film adhesive composition placed within such units onto the optical film. In this invention, it is preferable to use a gravure roller with units having an aperture ratio of 7% to 55% to coat the laminated optical film adhesive composition containing metal oxide particles. When coating the laminated optical film adhesive composition containing metal oxide particles using such a gravure roller, the generation of unevenness on the coated film caused by the metal oxide particles can be particularly suppressed. Furthermore, according to this invention, even with prolonged manufacturing of the laminated optical film, the coating thickness of the adhesive layer is not easily reduced, enabling the production of a uniform laminated optical film. Gravure rollers with an aperture ratio of less than 7% result in areas where the laminated optical film adhesive composition does not adhere to the film (uneven coating) because the depth of the unit is too small relative to the aperture width. Gravure rollers with an aperture ratio greater than 55% sometimes fail to completely transfer the adhesive composition for laminated optical films from the unit to the film due to the excessive depth of the unit relative to the aperture width. Therefore, if the production line runs for an extended period, adhesive composition for laminated optical films, particularly metal oxide particles, remains at the deepest part of the unit and solidifies, reducing the unit volume and gradually decreasing the thickness of the adhesive layer. Especially when using adhesive compositions for laminated optical films that are cured by visible light, the adhesive composition remaining in the unit easily solidifies under normal conditions, leading to a reduction in unit volume if the production line runs for a long time. In this invention, when using a gravure roller with units having an aperture ratio of 7% to 55% to apply the adhesive composition for laminated optical films, a uniform adhesive layer can be formed even when the adhesive composition contains metal oxide particles, which is therefore preferable. Furthermore, in this invention, when using a gravure roller with units having an aperture ratio of 7% to 55% to apply the adhesive composition for laminated optical films, it is less likely to generate tiny air bubbles on the bonding surfaces of the first and second optical films, enabling the manufacture of laminated optical films with good optical performance over a long period of time.

[0138] It should be noted that the first optical film and / or the second optical film can undergo surface modification treatment before the coating process. Especially when a polarizer is used as the optical film, surface modification treatment of the polarizer is preferred. Examples of surface modification treatments include corona treatment, plasma treatment, and ITRO treatment, with corona treatment being particularly preferred. Corona treatment generates reactive functional groups such as carbonyl and amino groups on the surface of the polarizer, improving adhesion to the adhesive layer. Furthermore, the ashing effect can remove surface impurities or reduce surface unevenness, thereby producing a laminated optical film with excellent appearance properties.

[0139] The first optical film and the second optical film are bonded together using a roller laminator or the like via the adhesive composition for the laminated optical film applied as described above (lamination process).

[0140] After the first and second optical films are laminated, they are irradiated with active energy rays (electron beams, ultraviolet light, visible light, etc.) to cure the laminated optical films with an adhesive composition, forming an adhesive layer. The irradiation direction of the active energy rays (electron beams, ultraviolet light, visible light, etc.) can be any suitable direction.

[0141] The irradiation conditions under electron beam irradiation are only required to cure the adhesive composition for the laminated optical films; any suitable conditions can be used. For example, the accelerating voltage for electron beam irradiation is preferably 5 kV to 300 kV, more preferably 10 kV to 250 kV. If the accelerating voltage is less than 5 kV, there is a risk that the electron beam may not reach the adhesive, resulting in insufficient curing. If the accelerating voltage exceeds 300 kV, there is a risk that the penetration force through the sample may be too strong, causing damage to the first and second optical films. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. If the irradiation dose is less than 5 kGy, the adhesive will not cure sufficiently; if it is greater than 100 kGy, it will damage the first and second optical films, causing a decrease in mechanical strength, yellowing, and preventing the acquisition of the desired optical properties.

[0142] Electron beam irradiation is typically carried out in an inert gas environment, but can be performed in the atmosphere with a small amount of oxygen introduced as needed. Although this depends on the materials of the first and second optical films, by appropriately introducing oxygen, an oxygen shield can be actively created on the surfaces of the first and second optical films initially irradiated by the electron beam. This prevents damage to the first and second optical films, allowing for efficient irradiation of the adhesive with the electron beam.

[0143] In the manufacturing method of the laminated optical film of the present invention, as the active energy ray, it is preferable to use an active energy ray containing visible light in the wavelength range of 380 nm to 450 nm, especially an active energy ray with the highest irradiation amount of visible light in the wavelength range of 380 nm to 450 nm. When using ultraviolet light, visible light, and a transparent protective film (ultraviolet-proof transparent protective film) that imparts ultraviolet absorption capability as the optical film, light with wavelengths shorter than 380 nm is absorbed. Therefore, light with wavelengths shorter than 380 nm will not reach the curable resin composition and will not contribute to its polymerization reaction. Furthermore, the light with wavelengths shorter than 380 nm absorbed by the first and second optical films will be converted into heat, causing the first or second optical film to heat up, which may lead to defects such as curling / wrinkling of the laminated optical film. Therefore, in this invention, when using ultraviolet or visible light, it is preferable to use a device that does not emit light with wavelengths shorter than 380 nm as the active energy ray generator. More specifically, the ratio of cumulative illuminance in the wavelength range of 380-440 nm to cumulative illuminance in the wavelength range of 250-370 nm is preferably 100:0 to 100:50, more preferably 100:0 to 100:40. When manufacturing the laminated optical film of this invention, gallium-encapsulated metal halide lamps and LED light sources emitting light in the wavelength range of 380-440 nm are preferred as active energy rays. Alternatively, light sources containing ultraviolet and visible light, such as low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, incandescent lamps, xenon lamps, halogen lamps, carbon arc lamps, metal halide lamps, fluorescent lamps, tungsten lamps, gallium lamps, excimer lasers, or sunlight, can be used. Alternatively, ultraviolet light with wavelengths shorter than 380 nm can be blocked using a bandpass filter. To improve the adhesion performance of the adhesive layer between the first and second optical films and to prevent the stacked optical films from curling, it is preferable to use a gallium-encapsulated metal halide lamp and to use active energy rays obtained by passing through a bandpass filter that can block light with a wavelength shorter than 380 nm, or active energy rays with a wavelength of 405 nm obtained by using an LED light source.

[0144] When the method for manufacturing the laminated optical film of the present invention is carried out on a continuous production line, the linear speed varies depending on the curing time of the adhesive composition for the laminated optical film, and is preferably 1 to 500 m / min, more preferably 5 to 300 m / min, and even more preferably 10 to 100 m / min. If the linear speed is too low, productivity is insufficient, or excessive damage is caused to the first and second optical films, making it impossible to produce a laminated optical film capable of withstanding durability tests, etc. If the linear speed is too high, sometimes the curing of the adhesive composition for the laminated optical film becomes insufficient, and the desired adhesion cannot be obtained.

[0145] The laminated optical film manufactured according to this invention can also include an adhesive layer for bonding with other components such as liquid crystal cells. There are no particular limitations on the adhesive forming the adhesive layer; adhesives using polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorinated polymers, and rubbers as the base polymer can be appropriately selected. Acrylic adhesives, which exhibit excellent optical transparency and moderate wetting, cohesiveness, and adhesion properties, as well as excellent weather resistance and heat resistance, are particularly preferred.

[0146] The adhesive layer can be provided on one or both sides of the laminated optical film of the present invention in the form of a composite layer of layers with different compositions or types. Furthermore, when provided on both sides, adhesive layers with different compositions, types, and thicknesses can be formed on the front and back sides of the laminated optical film of the present invention. The thickness of the adhesive layer can be appropriately determined according to the intended use, adhesive strength, etc., and is typically 1 to 500 μm, preferably 1 to 200 μm, and particularly preferably 1 to 100 μm.

[0147] For the exposed surface of the adhesive layer, to prevent contamination, a diaphragm can be temporarily applied to cover it until it is put into actual use. This prevents contact with the adhesive layer under normal handling conditions. As the diaphragm, suitable diaphragms as previously specified can be used, in addition to the thickness conditions mentioned above, which are prepared by coating suitable thin materials such as plastic films, rubber sheets, paper, cloth, non-woven fabrics, meshes, foam sheets, metal foils, and their laminates with appropriate release agents such as silicone, long-chain alkyl, fluorine, and molybdenum sulfide as needed.

[0148] The laminated optical film manufactured according to the present invention can be preferably used in the formation of various devices such as liquid crystal display devices. The formation of liquid crystal display devices can be performed in a conventional manner. That is, liquid crystal display devices are typically formed by appropriately assembling liquid crystal cells with polarizing films or laminated optical films, and components such as illumination systems used as needed, and incorporating driving circuitry. In the present invention, there are no particular limitations except for the use of the polarizing film or laminated optical film of the present invention, and conventional methods can be followed. Regarding the liquid crystal cells, any type of liquid crystal cell, such as TN type, STN type, or π type, can be used.

[0149] Suitable liquid crystal display devices, such as liquid crystal display devices with optical laminates arranged on one or both sides of the liquid crystal cell, and liquid crystal display devices using backlights or reflectors in the lighting system, can be formed. In this case, the optical laminate of the present invention can be provided on one or both sides of the liquid crystal cell. When optical laminates are provided on both sides, they can be the same or different. Furthermore, when forming the liquid crystal display device, one or more suitable components, such as diffuser plates, anti-glare layers, anti-reflective films, protective plates, prism arrays, lens arrays, light diffuser plates, and backlights, can be arranged at appropriate positions.

[0150] Example

[0151] The following describes embodiments of the present invention, but the implementation of the present invention is not limited thereto.

[0152] (Preparation of adhesive compositions for laminated optical films)

[0153] According to the formulation table shown in Table 1, the components shown below were mixed and stirred at 50°C for 1 hour to obtain the adhesive compositions for laminated optical films used in Examples 1-8 and Comparative Examples 1-2. The values ​​in the table represent the weight percentage when the total amount of the composition is set to 100% by mass.

[0154] The materials constituting the adhesive composition for laminated optical films are shown below.

[0155] (i) Metal oxide particles

[0156] Zirconia dispersion 1: A dispersion of phenoxybenzyl acrylate containing zirconium oxide with an average particle size of 100 nm (particle concentration 50% by weight).

[0157] • Zirconia dispersion 2: A dispersion of phenoxybenzyl acrylate containing zirconia with an average particle size of 20 nm (particle concentration 50% by weight).

[0158] Zirconia dispersion 3: A dispersion of phenoxybenzyl acrylate containing zirconia with an average particle size of 8 nm (particle concentration 50% by weight).

[0159] Zirconia dispersion 4: A phenoxydiethylene glycol acrylate dispersion of zirconia with an average particle size of 8 nm (particle concentration 50% by weight).

[0160] Zirconia dispersion 5: A phenoxyethyl acrylate dispersion of zirconium oxide with an average particle size of 8 nm (particle concentration 50% by weight).

[0161] • Titanium dioxide dispersion 1: A dispersion of phenoxybenzyl acrylate titanium dioxide with an average particle size of 20 nm (particle concentration 30% by weight).

[0162] (ii) (meth)acrylates containing an aromatic ring skeleton

[0163] • Phenoxybenzyl acrylate: Trade name "LIGHT ACRYLATE POB-A", manufactured by Kyoei Chemical Co., Ltd.

[0164] • Phenoxyethyl acrylate: Trade name "LIGHT ACRYLATE PO-A", manufactured by Kyoei Chemical Co., Ltd.

[0165] (iii) Curing components

[0166] • The compound represented by general formula (1) (3-methylacrylamidophenylboronic acid): trade name "MAPBA", manufactured by Junko Chemical Co., Ltd.

[0167] • Hydroxyl-containing (meth)acrylates (4-hydroxybutyl acrylate): Trade name "4HBA", manufactured by Mitsubishi Chemical Corporation

[0168] Acryloylmorpholine: Trade name "ACMO", manufactured by KJ Chemicals.

[0169] • Multifunctional free radical polymerizable compound (tripropylene glycol diacrylate): Trade name "Aronix M-220", manufactured by Toa Synthetic Co., Ltd.

[0170] (iv) Leveling agents (leveling agents containing modified isocyanurate compounds with (meth)acryloyl groups and modified polysiloxane compounds with (meth)acryloyl groups): Trade name "BYK UV-3505", manufactured by BYK Corporation.

[0171] (v) Acrylic oligomers synthesized from (meth)acrylic acid monomers: trade name "ARUFON UP-1190", manufactured by Toa Synthetic Co., Ltd.

[0172] (vi) Photopolymerization initiators

[0173] Photopolymerization initiator 1 (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide): trade name "Omnirad 819", manufactured by IGM Resins BV.

[0174] • Photopolymerization initiator 2 (1-hydroxycyclohexylphenyl ketone): Trade name "Omnirad 184", manufactured by IGM Resins B.V.

[0175] Photopolymerization initiator 3 (diethylthioxanthone): trade name "KAYACURE DETX-S", manufactured by Nippon Kayaku Co., Ltd.

[0176] It should be noted that the above-mentioned zirconia dispersion 1 to zirconia dispersion 5 and titanium dioxide dispersion 1 were manufactured by the following method.

[0177] (Synthesis of dispersant A)

[0178] 415 g (1 mol) of tristyrene-modified phenol and 1 g (0.018 mol) of potassium hydroxide were added to an autoclave and mixed thoroughly. Under the condition of 130 °C, 352 g (8 mol) of ethylene oxide (EO) was added dropwise to the reaction system. After the addition of ethylene oxide was complete, the system was aged at 130 °C with the pressure maintained at 0.1 MPa for 1 hour to obtain an 8-mol EO adduct of tristyrene-modified phenol.

[0179] 767 g (1 mol) of the above-mentioned 8 mol EO adduct of styrene-phenylphenol and 152 g (1.3 mol) of sodium monochloroacetate were added to the reactor and stirred until homogeneous. Then, 52 g of sodium hydroxide was added to the reaction system at 60°C, and the temperature was raised to 80°C for aging for 3 hours. After aging, the mixture was cooled to 50°C, and 117 g (1.2 mol) of 98% sulfuric acid was added dropwise at the same temperature, thus obtaining a white suspension. The white suspension was washed with distilled water, and the solvent was removed by vacuum distillation to obtain dispersant A.

[0180] (Preparation of Zirconia Dispersion 1)

[0181] An aqueous dispersion of zirconium oxide (manufactured by Sigma-Aldrich, average particle size 100 nm, zirconium oxide solids concentration: 10%) was concentrated using an ultrafiltration membrane. An equal volume of methanol as the filtrate was added to the concentrated dispersion, and the concentration and methanol-based dilution were performed continuously and simultaneously to maintain a zirconium oxide particle concentration of 10% by weight. The dispersion medium was then replaced with methanol to obtain a zirconium oxide particle concentration of 10% by weight. To 100 parts of the resulting methanol dispersion of zirconium oxide, 0.5 parts of dispersant A and 9.5 parts of m-phenoxybenzyl acrylate (manufactured by Kyoei Chemical Co., Ltd., trade name "LIGHT ACRYLATE POB-A"; hereinafter referred to as "POB-A") were added and mixed. The solvent was then removed under reduced pressure using a rotary evaporator to obtain zirconium oxide dispersion 1, which is a monomeric dispersion of zirconium oxide. This zirconium oxide dispersion A contains zirconium oxide / dispersant A / POB-A in a weight ratio of 50 / 2.5 / 47.5.

[0182] (Preparation of Zirconia Dispersion 2)

[0183] 100 parts of a methyl ethyl ketone dispersion of zirconium oxide (manufactured by Nissan Chemical Industries, Ltd., grade "OZ-S40K-AC", average particle size (D50) based on dynamic light scattering: 20 nm, zirconium oxide solid content concentration: 30%) were mixed with 1.5 parts of dispersant A and 28.5 parts of m-phenoxybenzyl acrylate (manufactured by Kyoei Chemical Co., Ltd., trade name "LIGHTACRYLATE POB-A"; hereinafter referred to as "POB-A"). The solvent was then removed under reduced pressure using a rotary evaporator to obtain zirconium oxide dispersion 2, which is a monomeric dispersion of zirconium oxide. This zirconium oxide dispersion A contains zirconium oxide / dispersant A / POB-A in a weight ratio of 50 / 2.5 / 47.5.

[0184] (Preparation of Zirconia Dispersion 3)

[0185] 100 parts of a methanol dispersion of zirconium oxide (manufactured by Sakai Chemical Industry Co., Ltd., grade "SZR-CM", average particle size (D50) based on dynamic light scattering: 8 nm, zirconium oxide solid content concentration: 30%) were mixed with 1.5 parts of dispersant A and 28.5 parts of m-phenoxybenzyl acrylate (manufactured by Kyoei Chemical Co., Ltd., trade name "LIGHT ACRYLATE POB-A"; hereinafter referred to as "POB-A"). The solvent was then removed under reduced pressure using a rotary evaporator to obtain zirconium oxide dispersion A, which is a monomeric dispersion of zirconium oxide. This zirconium oxide dispersion A contains zirconium oxide / dispersant A / POB-A in a weight ratio of 50 / 2.5 / 47.5.

[0186] (Preparation of Zirconia Dispersion 4)

[0187] 100 parts of a methanol dispersion of zirconium oxide (manufactured by Sakai Chemical Industry Co., Ltd., grade "SZR-CM", average particle size (D50) based on dynamic light scattering: 8 nm, zirconium oxide solid content concentration: 30%) were mixed with 1.5 parts of dispersant A and 28.5 parts of phenoxy diethylene glycol acrylate (manufactured by Kyoei Chemical Co., Ltd., trade name "LIGHT ACRYLATE P2H-A"; hereinafter referred to as "P2H-A"). The solvent was then removed under reduced pressure using a rotary evaporator to obtain zirconium oxide dispersion 4, which is a monomeric dispersion of zirconium oxide. This zirconium oxide dispersion A contains zirconium oxide / dispersant A / P2H-A in a weight ratio of 50 / 2.5 / 47.5.

[0188] (Preparation of Zirconia Dispersion 5)

[0189] 100 parts of a methanol dispersion of zirconium oxide (manufactured by Sakai Chemical Industry Co., Ltd., grade "SZR-CM", average particle size (D50) based on dynamic light scattering: 8 nm, zirconium oxide solid content concentration: 30%) were mixed with 1.5 parts of dispersant A and 28.5 parts of phenoxyethyl acrylate (manufactured by Kyoei Chemical Co., Ltd., trade name "LIGHT ACRYLATE PO-A"; hereinafter referred to as "PO-A"). The solvent was then removed under reduced pressure using a rotary evaporator to obtain zirconium oxide dispersion 5, which is a monomeric dispersion of zirconium oxide. This zirconium oxide dispersion A contains zirconium oxide / dispersant A / PO-A in a weight ratio of 50 / 2.5 / 47.5.

[0190] (Preparation of titanium dioxide dispersion 1)

[0191] 100 parts of a methanol dispersion of titanium dioxide (manufactured by Nissan Chemical Industries, Ltd., grade name "OT-RA305M7-20", average particle size (D50) based on dynamic light scattering method: 20 nm, titanium dioxide solid content concentration: 30%) were mixed with 1.5 parts of dispersant A and 68.5 parts of m-phenoxybenzyl acrylate (manufactured by Kyoei Chemical Co., Ltd., trade name "LIGHTACRYLATE POB-A"; hereinafter referred to as "POB-A"). The solvent was then removed under reduced pressure using a rotary evaporator to obtain zirconia dispersion A, which is a monomeric dispersion of zirconia. This zirconia dispersion A contains zirconia / dispersant A / POB-A in a weight ratio of 30 / 1.5 / 68.5.

[0192] The materials constituting the laminated optical film and the manufacturing method of the laminated optical film are shown below.

[0193] <Manufacturing of Polarizing Filters>

[0194] A stretched laminate containing a 9 μm thick PVA layer on an amorphous PET substrate is generated by assisted stretching in a gas atmosphere at a stretching temperature of 130°C. Next, a colored laminate is generated from the stretched laminate by dyeing. Finally, the colored laminate is stretched integrally with the amorphous PET substrate at a total stretching ratio of 5.94 times by stretching in a boric acid aqueous solution at a stretching temperature of 65°C to generate an optical film laminate containing a 5 μm thick PVA layer. This results in an optical film laminate containing a 5 μm thick PVA layer constituting a thin polarizer. The thin polarizer is formed by the two-stage stretching process described above, which causes the PVA molecules in the PVA layer formed on the amorphous PET substrate to achieve a higher-order orientation, and causes the iodine adsorbed through dyeing to achieve a higher-order orientation in one direction in the form of a polyiodide ion complex.

[0195] <Transparent Protective Film>

[0196] “TAC”; Cellulose triacetate (TAC) film (trade name “TJ25UL”, thickness 25μm, manufactured by Fujifilm Corporation)

[0197] <Photopolymerizable Liquid Crystal Composition>

[0198] A photopolymerizable liquid crystal compound exhibiting a nematic liquid crystal phase (Paliocolor LC242, manufactured by BASF) was dissolved in cyclopentanone to prepare a solution with a solid content concentration of 30% by weight. A surfactant (BYK-360, manufactured by BYK-Chemie) and a photopolymerization initiator (Omnirad 907, manufactured by IGM Resins) were added to this solution to prepare a liquid crystal composition solution. The amount of leveling agent and polymerization initiator added was set to 0.01 parts by weight and 3 parts by weight, respectively, relative to 100 parts by weight of the photopolymerizable liquid crystal compound.

[0199] <λ / 2 phase difference film>

[0200] A biaxially stretched norbornene film (ZeonorFilm, manufactured by Zeon Corporation, Japan, thickness: 33 μm, front-side retardation: 135 nm) was used as the substrate. The aforementioned liquid crystal composition was coated onto the substrate using a rod coater with a retardation of λ / 2. The substrate was then heated to 100°C for 3 minutes to align the liquid crystals. After cooling to room temperature, the mixture was irradiated in a nitrogen atmosphere with a cumulative light intensity of 400 mJ / cm². 2 UV light was used for photocuring to obtain a laminate containing a homogeneous oriented liquid crystal layer.

[0201] <λ / 4 phase difference film>

[0202] A biaxially stretched norbornene film (ZeonorFilm, manufactured by Zeon Corporation, Japan, thickness: 33 μm, front-side phase difference: 135 nm) was used as the substrate. The aforementioned liquid crystal composition was coated onto the substrate using a rod coater with a phase difference of λ / 4. The substrate was then heated to 100°C for 3 minutes to align the liquid crystals. After cooling to room temperature, the mixture was irradiated in a nitrogen atmosphere with a cumulative light intensity of 400 mJ / cm². 2 UV light was used for photocuring to obtain a laminate containing a surface-oriented liquid crystal layer.

[0203] <Polarizing film (1)>

[0204] The laminated optical film of Comparative Example 2 was coated with an adhesive composition using an MCD coating machine (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roller line count: 700 lines / inch, aperture ratio of cells formed on the gravure roller: 40%, rotational speed 140% / relative linear speed) (coating thickness 1.05 μm) and then treated with a corona treatment machine at a density of 50 W·min / m³. 2 The corona-treated surface of the PVA layer of the aforementioned polarizing mirror was subjected to corona treatment using a roller mill at a density of 50 W·min / m³. 2 The corona-treated surface of the TAC film was laminated (laminar speed was 15 m / min). It should be noted that the above coating thickness was measured using a spectroscopic interferometer (Ocean Optics: spectrometer "USB2000+", light source "HL-2000", fiber "OCF-103995"). Then, it was irradiated with visible light (Heraeus Light HAMMER10 Mark III, bulb: V bulb, peak illuminance: 1600 mW / cm²). 2 Cumulative radiation dose 1000 mJ / cm 2 The irradiance and cumulative irradiation of the active energy rays were measured using a Power Puck 2 (manufactured by EIT Corporation, UVV measurement value). The active energy rays were irradiated from the TAC film side to cure the adhesive composition for the laminated optical film, thereby creating a polarizing film (1) on which an amorphous PET substrate, a polarizer, and a TAC film were laminated via a cured layer of the adhesive composition for the laminated optical film. The thickness of the cured layer of the adhesive composition for the laminated optical film was 1 μm.

[0205] <Polarizing film (2)>

[0206] Next, the amorphous PET substrate of the polarizing film (1) was peeled off, and the polarizing mirror surface of the peeled surface was treated with a corona treatment machine at a density of 50 W·min / m. 2 Corona treatment was performed. The laminated optical film of Comparative Example 2 was coated (coating thickness 1.05 μm) onto a corona-treated polarizer using an MCD coating machine (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roller line count: 700 lines / inch, unit aperture ratio formed on the gravure roller: 40%, rotation speed 140% / relative linear speed). The treatment was carried out using a roller mill and the corona treatment machine at a density of 50 W·min / m³. 2The corona-treated λ / 2 retardation film was bonded to a surface-aligned liquid crystal layer, such that the slow axis of the λ / 2 retardation film was at a 15° angle to the transmission axis of the polarizer (the bonding linear velocity was 15 m / min). It should be noted that the above coating thickness was measured using a spectroscopic interferometer (Ocean Optics: spectrometer "USB2000+", light source "HL-2000", fiber "OCF-103995"). Then, it was irradiated with visible light (Heraeus Light HAMMER10 Mark III, bulb: V bulb, peak illuminance: 1600 mW / cm²). 2 Cumulative radiation dose 1000 mJ / cm 2 The irradiance and cumulative exposure of the active energy rays were measured using a Power Puck 2 (manufactured by EIT Corporation, UVV measurement value). The active energy rays were irradiated from the λ / 2 phase retardation film side to cure the adhesive composition for the laminated optical film, thereby creating a polarizing film (2) with the λ / 2 phase retardation film, a polarizer, and a TAC film laminated on the cured layer of the adhesive composition for the laminated optical film. The thickness of the cured layer of the adhesive composition for the laminated optical film was 1 μm.

[0207] (Example of manufacturing a laminated optical film)

[0208] The biaxially stretched norbornene film of the polarization film (2) was peeled off, and the λ / 2 phase difference film surface of the peeled surface was treated with a corona treatment machine at a density of 50 W·min / m. 2 Corona treatment was performed. An MCD coating machine (manufactured by Fuji Machinery Co., Ltd.) was used as a gravure coating machine (cell shape: honeycomb, gravure roller line count: 700 lines / inch, opening ratio of cells formed on the gravure roller: 40%, rotational speed 140% / relative linear speed). The adhesive compositions for laminated optical films of Examples 1-8 and Comparative Examples 1-2 as described in Table 1 were coated onto the λ / 2 phase difference film surface after corona treatment (coating process) (coating thickness 1.05 μm). The film was then processed using a roller mill at a density of 50 W·min / m². 2The corona-treated λ / 4 retardation film's surface-aligned liquid crystal layer was bonded to the λ / 2 retardation film, such that the slow axis of the λ / 4 retardation film was at a 75° angle to the transmission axis of the polarizer (the bonding linear velocity was 15 m / min). It should be noted that the coating thickness was measured using a spectroscopic interferometer (Ocean Optics: spectrometer "USB2000+", light source "HL-2000", fiber "OCF-103995"). Then, it was irradiated with visible light (Heraeus Light HAMMER10Mark III, bulb: V bulb, peak illuminance: 1600 mW / cm²). 2 Cumulative radiation dose 1000 mJ / cm 2 The irradiance and cumulative exposure of the active energy rays were measured using a Power Puck 2 (manufactured by EIT Corporation, UVV measurement value). The active energy rays were irradiated from the λ / 4 phase retardation film side, causing the adhesive compositions for laminated optical films of Examples 1-8 and Comparative Examples 1-2 to cure. This produced a laminated optical film (adhesive process) in which the λ / 4 phase retardation film, λ / 2 phase retardation film, polarizer, and TAC film were laminated via a cured layer of the adhesive composition for laminated optical films. The thickness of the cured layer of the adhesive composition for laminated optical films was 1 μm.

[0209] The details of each evaluation method are as follows.

[0210] <Viscosity of adhesive compositions for laminated optical films>

[0211] The viscosity of the adhesive compositions for laminated optical films in Examples 1-8 and Comparative Examples 1-2 was measured using an E-type viscometer TVE22LT manufactured by Toki Sangyo Co., Ltd.

[0212] <Determination of the refractive index of the adhesive layer>

[0213] The adhesive compositions for laminated optical films of Examples 1-8 and Comparative Examples 1-2 were coated (100 μm thick) onto a cyclic olefin polymer film (COP film). The COP film was then attached to the coated surface in the same manner. The film was irradiated with visible light using an active energy X-ray irradiation device to obtain cured layers (monomer films) of the adhesive compositions for laminated optical films of Examples 1-8 and Comparative Examples 1-2. The in-plane refractive index and the refractive index in the thickness direction of the obtained cured layers were measured using a prism coupler SPA-4000 (manufactured by Sairon Technology Co., Ltd.). The average value of these measurements was taken as the average refractive index of the adhesive layer. The measurement temperature was set to 23°C, and the measurement wavelength was set to 594 nm.

[0214] <Curing shrinkage rate of adhesive compositions for laminated optical films>

[0215] The curing shrinkage rate was measured using a CUSTRON EU201C resin curing shrinkage measuring device (manufactured by Acroedge) via a laser displacement meter, and the curing shrinkage rate was calculated using the method described in Japanese Patent Application Publication No. 2013-104869.

[0216] <Peeling force between stacked optical films>

[0217] The biaxially stretched norbornene film of the aforementioned laminated optical film was peeled off, and double-sided adhesive tape (No. 500, manufactured by Nitto Denko Corporation) was applied to the λ / 4 phase retardation film surface. Further, a 200mm × 15mm piece was cut, and a cutter was used to cut between the λ / 4 and λ / 2 phase retardation films. The release liner of the double-sided adhesive tape was then peeled off, and the adhesive side was adhered to a glass plate. The λ / 4 and λ / 2 phase retardation films were peeled off at a 90-degree angle using an angle-free adhesive / film peel analysis apparatus (VPA-2, manufactured by Kyowa Interface Chemicals Co., Ltd.), and the peel strength (N / 15mm) was measured.

[0218] <Degree of appearance defects caused by unevenness in the laminated optical film>

[0219] The biaxially stretched norbornene film of the aforementioned stacked optical film was peeled off, and samples were cut into 200mm × 200mm pieces and fixed in a flat state. The visual recognition of the stripes caused by the unevenness was evaluated by visual observation under fluorescent light, using the method of reflecting light onto the surface of the λ / 4 phase difference film. The evaluation was conducted according to the following criteria.

[0220] 0: Stripes caused by unevenness were not identified.

[0221] 1: The stripes caused by the unevenness were basically not discernible.

[0222] 2: The stripes caused by the unevenness can be slightly discerned.

[0223] 3: The stripes caused by the unevenness can be clearly identified.

[0224] Interference patterns of stacked optical films including polarizing films (at room temperature)

[0225] The biaxially stretched norbornene film of the laminated optical film obtained in the examples and comparative examples was peeled off, and a conventional acrylic adhesive was applied to the λ / 4 retardation film side. The film was then bonded to a V3 reflector (manufactured by NEODIS) using this acrylic adhesive to create a test sample. The test sample was observed visually under a 3-wavelength fluorescent lamp and evaluated according to the following criteria.

[0226] 1: Even with careful observation, no interference patterns were identified.

[0227] 2: After careful observation, interference patterns were somewhat confirmed.

[0228] 3: Although interference patterns were slightly observed under normal conditions, they were within an acceptable range for practical use.

[0229] 4: Interference patterns of an unacceptable degree in practical use were confirmed under normal observation.

[0230] 5: The interference patterns are obvious under normal observation.

[0231] Interference patterns of stacked optical films including polarizing films (after heating test)

[0232] The biaxially stretched norbornene film of the laminated optical film obtained in the examples and comparative examples was peeled off, and a conventional acrylic adhesive was applied to the λ / 4 retardation film side. The film was then bonded to a V3 reflector (manufactured by NEODIS) using this acrylic adhesive to prepare a test sample. The test sample was heated in a hot air oven at 85°C for 500 hours, and then allowed to stand for 60 minutes in an environment of 23±2°C and 50±10%RH relative humidity. Afterward, it was observed visually under a 3-wavelength fluorescent lamp and evaluated according to the following criteria.

[0233] 1: Even with careful observation, no interference patterns were identified.

[0234] 2: After careful observation, interference patterns were somewhat confirmed.

[0235] 3: Although interference patterns were slightly observed under normal conditions, they were within an acceptable range for practical use.

[0236] 4: Interference patterns of an unacceptable degree in practical use were confirmed under normal observation.

[0237] 5: The interference patterns are obvious under normal observation.

[0238] <Transmittance change ΔY of a laminated optical film containing a polarizing film (after a humidification durability test at 85℃ for 500 hours)>

[0239] The biaxially stretched norbornene film of the laminated optical film obtained in the examples and comparative examples was peeled off, and a conventional acrylic adhesive was applied to the λ / 4 phase retardation film side. The film was then bonded to alkali-free glass (trade name: EAGLE XG, manufactured by Corning, 0.7 mm thick) using this acrylic adhesive to prepare test samples. After standing in a hot air oven at 85°C for 500 hours, the test samples were then placed in an environment of 23±2°C and 50±10%RH for 60 minutes. The monomer transmittance (ΔY) before and after heating was measured. The monomer transmittance was measured using a spectrophotometer (manufactured by Murakami Color Technology Research Institute Co., Ltd., product name "DOT-3") and evaluated according to the following criteria. This monomer transmittance is the Y value after visibility correction based on a 2-degree field of view (C light source) according to JlS Z 8701-1982. It should be noted that the measurement wavelength was 380~700nm (per 10nm). The results are shown in Table 1.

[0240] ΔY(%)=Y500-Y0

[0241] In the formula, Y0 is the monomer transmittance of the test sample before heating, and Y500 is the monomer transmittance of the test sample after 500 hours of heating.

[0242]

[0243]

[0244] It is evident that in Examples 1-8, where a gravure coating machine is used to apply shear force to the adhesive composition for laminated optical films containing curing components and metal oxide particles during coating, laminated optical films with reduced appearance defects and interference patterns caused by unevenness can be manufactured. Furthermore, it is evident that in Examples 1-8, laminated optical films with improved refractive index and adhesive strength balance of the adhesive layer and reduced curing shrinkage can be manufactured. It should be noted that in Comparative Examples 1-2, where an adhesive layer was formed using an adhesive composition for laminated optical films that does not contain metal oxide particles, it was thought that the occurrence of appearance defects, particularly those caused by unevenness, could be suppressed since the absence of metal oxide particles was not expected. However, contrary to expectations, appearance defects and interference patterns caused by unevenness occurred.

[0245] It should be noted that the laminated optical films manufactured by the manufacturing methods of the laminated optical films in Examples 1 to 8 include a polarizing film with at least a polarizing lens as an optical film. However, due to the excellent curing shrinkage rate and adhesive force of the adhesive layer, the expansion and contraction of the polarizing lens are suppressed. As a result, the change in transmittance of the laminated optical film (polarizing film) after the heat durability test can be suppressed.

Claims

1. A method for manufacturing a laminated optical film, comprising: a method for manufacturing a laminated optical film having at least a first optical film and a second optical film laminated together via an adhesive layer; the method comprising: In the coating process, an adhesive composition for laminated optical films is applied to one or both of the bonding surfaces of the first optical film and the second optical film. The bonding process involves bonding the first optical film and the second optical film together. as well as In the bonding process, active energy rays are irradiated from either the first optical film surface or the second optical film surface to cure at least the laminated optical films using an adhesive composition, forming the adhesive layer. The first optical film and the second optical film are then bonded together via this adhesive layer. The adhesive composition for the laminated optical film contains curing components and metal oxide particles. The coating process is a process of applying shear force to the adhesive composition for the laminated optical film and then coating it.

2. The method for manufacturing a laminated optical film according to claim 1, wherein, The coating process is a process in which a laminated optical film is coated with an adhesive composition onto one or both of the bonding surfaces of the first optical film and the second optical film while the first optical film and the second optical film are being transported using a gravure coating machine.

3. The method for manufacturing a laminated optical film according to claim 1 or 2, wherein, The coating thickness of the adhesive composition for the laminated optical film in the coating process is 0.1~3.0 μm.

4. The method for manufacturing the laminated optical film according to any one of claims 1 to 3, wherein, The viscosity of the adhesive composition for the laminated optical film at 25°C is less than 100 [mPa·s].

5. The method for manufacturing a laminated optical film according to any one of claims 1 to 4, wherein, In the adhesive composition for the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the metal oxide particles is 10-50% by mass.

6. The method for manufacturing a laminated optical film according to any one of claims 1 to 5, wherein, The adhesive composition for the laminated optical film further comprises (meth)acrylate containing an aromatic ring backbone.

7. The method for manufacturing a stacked optical film according to claim 6, wherein, In the adhesive composition for laminated optical films, when the total amount of the composition is set to 100% by mass, the content of the (meth)acrylate containing an aromatic ring skeleton is 30-70% by mass.

8. The method for manufacturing a stacked optical film according to claim 6 or 7, wherein, The (meth)acrylate containing an aromatic ring skeleton comprises at least one selected from (meth)acrylates having a polycyclic aromatic ring skeleton and (meth)acrylates having two or more aromatic rings.

9. The method for manufacturing a laminated optical film according to any one of claims 6 to 8, wherein, The (meth)acrylate containing an aromatic ring skeleton is phenoxybenzyl (meth)acrylate.

10. The method for manufacturing a laminated optical film according to any one of claims 1 to 9, wherein, The adhesive composition for the laminated optical film further contains a compound represented by the following general formula (1). In the formula, X is a reactive group, Y is an alkylene group with 1 to 12 carbon atoms that is optionally branched, or a phenylene group that is optionally substituent, and R... 1 and R 2 Each can independently represent a hydrogen atom, optionally with a substituent, aliphatic hydrocarbon group, aryl or heterocyclic group.

11. The method for manufacturing a stacked optical film according to claim 10, wherein, In the adhesive composition for the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the compound represented by the general formula (1) is 0.1 to 10% by mass.

12. The method for manufacturing a laminated optical film according to any one of claims 1 to 11, wherein, The adhesive composition for the laminated optical film further contains hydroxyl-containing (meth)acrylates.

13. The method for manufacturing a stacked optical film according to claim 12, wherein, In the adhesive composition for the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the hydroxyl-containing (meth)acrylate is 1 to 30% by mass.

14. The method for manufacturing a laminated optical film according to any one of claims 1 to 13, wherein, The adhesive composition for the laminated optical film further comprises a leveling agent containing at least one selected from isocyanurate compounds and polysiloxane compounds.

15. The method for manufacturing a stacked optical film according to claim 14, wherein, In the adhesive composition for the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the isocyanurate compound is 0.05 to 10% by mass.

16. The method for manufacturing a stacked optical film according to claim 14 or 15, wherein, In the adhesive composition for the laminated optical film, when the total amount of the composition is set to 100% by mass, the content of the polysiloxane compound is 0.05~2.0% by mass.

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