Laminated optical film and image display device

Abstract

Provided is a laminated optical film in which at least an acrylic film and a first optical film are laminated via an adhesive layer, the adhesive layer being formed from a cured product layer of an adhesive composition containing at least a polymerizable compound, the acrylic film and the adhesive layer having a structure in which the acrylic film and the adhesive layer are in direct contact with each other, the HSP distance between the acrylic film and the adhesive layer is 1.9 or more and 5.0 or less, and the elastic modulus of the adhesive layer is 108 Pa or more and 3 * 109 Pa or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a laminated optical film in which at least an acrylic film and a first optical film are laminated via an adhesive layer. The laminated optical film can form an image display device such as a mobile phone, a car navigation device, a monitor for a personal computer, a television, or the like. BACKGROUND

[0002] In an image display device such as a mobile phone, a car navigation device, a monitor for a personal computer, a television, or the like, a laminated optical film in which a plurality of optical films are laminated via an adhesive layer, a binder layer, or the like is provided. As the optical film, a transparent resin film such as a polarizer, an acrylic film, or the like has been used.

[0003] Regarding the acrylic film, since there is almost no functional group or the like that can contribute to an increase in the adhesive force with the film surface, there is a risk that the adhesive force between the acrylic film and other optical films when the laminated optical film is produced is insufficient. In order to address this problem, in Patent Document 1 described below, an optical film laminate in which a (meth)acrylic resin layer and a thermoplastic resin film such as a cyclic olefin resin film are adhered with sufficient adhesive force by a active energy ray-curable adhesive, is light in weight and realizes thin filmization, is described as an object, and the optical film laminate is one in which the adhesive layer is formed of an active energy ray-curable adhesive, and in the active energy ray-curable adhesive, 2 to 35 parts by weight of a polymerizable monomer that dissolves the (meth)acrylic resin layer and 30 to 60 parts by weight of a polymerizable multifunctional acrylate compound are contained with respect to 100 parts by weight of the total amount of an active energy ray-curable compound including the polymerizable monomer that dissolves the (meth)acrylic resin layer and the polymerizable multifunctional acrylate compound.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENT

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-232251 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] On the other hand, in recent years, as a durability test required for a laminated optical film for a vehicle-mounted use, there is, for example, a humidity durability test in which exposure to an environment of 65°C - 95% humidity is performed for 1000 hours. Here, the present inventors and the like have conducted detailed studies on the appearance state of the laminated optical film after the humidity durability test, and as a result, it has been found that, in particular, a bright spot originating from a white, fog-like foreign matter is generated at the end portion of the laminated optical film, and from the viewpoint of the appearance characteristics, the product becomes defective. Such a phenomenon has been observed for the first time after the durability test in a high-temperature and high-humidity environment, and in order to solve this new problem, further studies are required.

[0009] The present application has been developed in view of the above-described circumstances, and aims to provide a laminated optical film which at least has an acrylic film, generation of bright spots originating from impurities is suppressed even after a humidification durability test, appearance characteristics are excellent, and adhesion between laminated optical films is excellent.

[0010] Method for solving the problem

[0011] The above-described problem can be solved by the following means. That is, the present application relates to a laminated optical film (1) which is a laminated optical film in which at least an acrylic film and a first optical film are laminated via an adhesive layer, the adhesive layer is formed of a cured product layer of an adhesive composition containing at least a polymerizable compound, the acrylic film has a structure in which it directly contacts the adhesive layer, the HSP distance between the acrylic film and the adhesive layer is 1.9 or greater and 5.0 or less, the elastic modulus of the adhesive layer is 10 8 Pa or greater and 3 x 10 9 Pa or less.

[0012] In the laminated optical film (1) described above, it is preferable that the laminated optical film (2) be one in which the first optical film is a liquid crystal film or a phase difference film.

[0013] In the laminated optical film (1) or (2) described above, it is preferable that the laminated optical film (3) be one in which the thickness of the adhesive layer is 0.1 to 10 μm.

[0014] In any one of the laminated optical films (1) to (3) described above, it is preferable that the laminated optical film (4) be one in which a second optical film is further laminated via an adhesive layer on a face of the first optical film which is opposite to the face on which the acrylic film is laminated.

[0015] In any one of the laminated optical films (1) to (4) described above, it is preferable that the laminated optical film (5) be one in which the second optical film is a liquid crystal film or a phase difference film.

[0016] In any one of the laminated optical films (1) to (5) described above, it is preferable that the laminated optical film (6) be one in which the adhesive composition contains a polymerizable compound A, the HSP distance between the polymerizable compound A and the acrylic film is 0.0 or greater and 4.0 or less, and the content of the polymerizable compound A is 20 parts by mass or greater and 60 parts by mass or less when the total amount of the polymerizable compound contained in the adhesive composition is taken as 100 parts by mass.

[0017] In any one of the above-described laminated optical films (1) to (6), preferably the laminated optical film (7) in which the above-described adhesive composition contains a polymerizable compound B, the above-described polymerizable compound B is a compound having at least two or more polymerizable groups, and the content of the above-described polymerizable compound B is 20 parts by mass or more and 50 parts by mass or less when the total amount of the polymerizable compounds contained in the above-described adhesive composition is taken as 100 parts by mass.

[0018] In the above-described laminated optical film (6) or (7), preferably the laminated optical film (8) in which the above-described adhesive composition contains a polymerizable compound C, the HSP distance of the above-described polymerizable compound C from the above-described acrylic film is greater than 4.0 and is 8.0 or less, and the content of the above-described polymerizable compound C is the blending amount of the above-described polymerizable compound A or less when the total amount of the polymerizable compounds contained in the above-described adhesive composition is taken as 100 parts by mass.

[0019] In any one of the above-described laminated optical films (1) to (8), preferably the laminated optical film (9) in which the above-described adhesive composition contains a polymerizable compound D, the above-described polymerizable compound D is a compound represented by the following general formula (1):

[0020] [Chemical Formula 1]

[0021]

[0022] (In the formula, X is a reactive group, Y is an alkylene group having 1 to 12 carbon atoms which optionally has a branch, or a phenylene group which optionally has a substituent, and R 1 and R 2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group which optionally has a substituent, an aryl group, or a heterocyclic group), and the content of the above-described polymerizable compound D is 1 part by mass or more and 10 parts by mass or less when the total amount of the polymerizable compounds contained in the above-described adhesive composition is taken as 100 parts by mass.

[0023] In the above-described laminated optical film (9), preferably the laminated optical film (10) in which the above-described adhesive composition contains a polymerizable compound E, the above-described polymerizable compound E is a polymerizable compound containing a hydroxyl group, and the content of the above-described polymerizable compound E is 1 or more and 15 or less when the content of the above-described polymerizable compound D is taken as 1.

[0024] In addition, the present application relates to an image display device (11) which has at least one piece of any one of the above-described laminated optical films (1) to (10).

[0025] Effects of the Invention

[0026] With respect to the acrylic film, as described above, there is a risk that the adhesion force is insufficient when the laminated optical film is produced, since there are almost no functional groups that can contribute to an increase in the adhesion force to the surface of the film, and the like. Here, with respect to the acrylic film, there is a method of increasing the adhesion force of the acrylic film to the adhesive layer by forming an easy-adhesion layer by applying an easy-adhesion agent containing a water-based urethane resin or the like to the acrylic film. However, due to limitations in the process, and the like, it is sometimes necessary to produce the laminated optical film in a structure in which the acrylic film is directly in contact with the adhesive layer, rather than forming an easy-adhesion layer on the acrylic film. In this case, there is still a risk that the adhesion force becomes insufficient due to the weak interaction between the acrylic film and the adhesive layer.

[0027] On the other hand, in laminated optical films for vehicle use and the like, it is required that the appearance properties be excellent, for example, even after a humidity durability test in which exposure to an environment of 65°C-95% humidity is performed for 1000 hours. As a component that adversely affects the appearance properties, particularly in a heating process using an oven, a heating device, or the like, a drying process, or a process in which a modification treatment of the surface of the film, such as corona treatment, plasma treatment, ITRO treatment, or the like, is performed, there is an oxalic acid bright spot that is generated due to oxalate that is present in the atmosphere. In the past, the oxalic acid bright spot has been a problem in the adhesive layer that is in contact with a polarizer containing a metal component such as zinc that is a cause of the oxalic acid bright spot. However, as a result of research by the present inventors and the like, it has been shown that even the adhesive layer that is not in contact with the polarizer, and specifically in the present application, the adhesive layer that is directly in contact with the acrylic film, suffers from deterioration in the appearance properties due to the oxalic acid bright spot.

[0028] As described above, with respect to a laminated optical film that includes an acrylic film, since there are almost no functional groups that can contribute to adhesion on the surface of the acrylic film, in the case where the configuration is such that the acrylic film is not treated with an easy-adhesion agent containing a water-based urethane resin or the like, that is, in the case where the structure is formed in which the acrylic film is directly in contact with the adhesive layer, there is the following problem that is unique to the acrylic film: it is difficult to increase the adhesion force of the acrylic film to the adhesive layer while suppressing the generation of the oxalic acid bright spot. However, in the laminated optical film of the present application, the generation of bright spots due to impurities is suppressed even after a humidity durability test, the appearance properties are excellent, and the adhesion force between the laminated optical films is excellent. The reason why such effects are obtained is not clear, but it is believed to be the following reason.

[0029] The laminated optical film of the present application is a laminated optical film in which at least an acrylic film and a first optical film are laminated via an adhesive layer, the adhesive layer is formed from a cured product layer of an adhesive composition containing at least a polymerizable compound, and the acrylic film has a structure in which it is directly in contact with the above-mentioned adhesive layer. Furthermore, it is designed so that (i) the HSP distance of the acrylic film to the adhesive layer is 1.9 or greater and 5.0 or less, (ii) the elastic modulus of the adhesive layer is 10 8Pa or higher and 3×10 9 Pa or less. As described above, oxalic acid, a component that adversely affects appearance characteristics, may be mixed into the adhesive layer from the atmosphere during various manufacturing processes. However, since the present invention specifically possesses the structure described in (ii), the adhesive layer is sufficiently elastic to suppress the mixing of oxalic acid into the adhesive layer, thereby suppressing the generation of oxalic acid bright spots that cause deterioration of appearance characteristics. On the other hand, it can be considered that when a structure is formed in which the acrylic film and the adhesive layer are directly bonded, it is difficult to improve the adhesion between the acrylic film and the adhesive layer, which also makes it more difficult to improve the adhesion when the adhesive layer is highly elastic. However, since the laminated optical film of the present invention possesses the structure described in (i), a compatible layer is formed between the acrylic film and the adhesive layer, thereby improving the adhesion due to the anchoring effect. As a result, in the laminated optical film of the present invention, even after the humidification durability test, the generation of bright spots originating from impurities is suppressed, the appearance characteristics are excellent, and the adhesion between the laminated optical films is excellent.

[0030] When the adhesive layer of the laminated optical film of the present invention contains at least one of the specific polymeric compounds A to E, especially when it contains polymeric compounds A, B, D and / or E, the adhesion of the acrylic film or its adhesion to the first optical film or its effect of suppressing the generation / diffusion of oxalic acid bright spots is further improved. Attached Figure Description

[0031] Figure 1 This is an example of a cross-sectional schematic diagram of a stacked optical film according to one embodiment of the present invention. Detailed Implementation

[0032] Figure 1 This diagram shows an example of a cross-sectional view of a laminated optical film according to one embodiment of the present invention. In this embodiment, the laminated optical film 10 is laminated with an acrylic film 1 and a first optical film 2 via an adhesive layer 3. No easy-to-bond layer or similar is inserted between the acrylic film 1 and the adhesive layer 3, resulting in a structure where the acrylic film 1 and the adhesive layer 3 are directly bonded. Details regarding the acrylic film 1, the first optical film 2, and the adhesive layer 3 will be explained separately. In this embodiment, on the side of the acrylic film 1 opposite to the side where the first optical film 2 is laminated, a cellulose triacetate film 6 serving as a transparent protective film is further laminated via an aqueous adhesive layer 7. On the side of the first optical film 2 opposite to the side where the acrylic film 1 is laminated, a second optical film 4 is further laminated via an adhesive layer 5. Details regarding the adhesive layer 5 and the second optical film 4 will be explained separately. In this embodiment, the side of the second optical film 4 opposite to the side where the first optical film 2 is stacked is bonded to the image display device via an adhesive layer 8. Figure 1(Not shown in the image). The following is a description of each component.

[0033] <Acrylic film>

[0034] Acrylic films contain (meth)acrylic resins. (meth)acrylic resin films can be obtained, for example, by extruding a molding material containing a resin component with (meth)acrylic resin as the main component.

[0035] As for the aforementioned (meth)acrylic resin, the glass transition temperature (Tg) is preferably 70°C or higher, more preferably 110°C or higher, even more preferably 115°C or higher, and particularly preferably 120°C or higher. The aforementioned (meth)acrylic resin film, by comprising a (meth)acrylic resin with a Tg (glass transition temperature) of 70°C or higher as the main component, can become a resin film with excellent durability. The upper limit of the Tg of the aforementioned (meth)acrylic resin is not particularly limited, but from the viewpoint of moldability, it is preferably 170°C or lower.

[0036] As the aforementioned (meth)acrylic resin, any suitable (meth)acrylic resin can be used. Examples include: poly(meth)acrylic esters such as polymethyl methacrylate, methyl methacrylate-(meth)acrylic acid copolymers, methyl methacrylate-(meth)acrylic acid copolymers, methyl methacrylate-acrylate-(meth)acrylic acid copolymers, methyl methacrylate-styrene copolymers (MS resin, etc.), and polymers having alicyclic hydrocarbon groups (e.g., methyl methacrylate-cyclohexyl methacrylate copolymers, methyl methacrylate-norborneol methacrylate copolymers, etc.). Poly(meth)acrylic acid C1-6 alkyl esters such as poly(meth)acrylic acid are preferred. More preferably, methyl methacrylate resins with methyl methacrylate as the main component (50-100% by weight, preferably 70-100% by weight) are preferred.

[0037] In this invention, from the viewpoint of having high heat resistance, high transparency, and high mechanical strength, the above-mentioned (meth)acrylic resin is preferably a (meth)acrylic resin having a glutaric anhydride structure, a (meth)acrylic resin having a lactone ring structure, or a (meth)acrylic resin having a glutarimide structure.

[0038] Examples of (meth)acrylic resins having a glutaric anhydride structure include those described in Japanese Patent Application Publication No. 2006-283013, Japanese Patent Application Publication No. 2006-335902, and Japanese Patent Application Publication No. 2006-274118.

[0039] Examples of (meth)acrylic resins with a lactone ring structure include those described in Japanese Patent Application Publication No. 2000-230016, Japanese Patent Application Publication No. 2001-151814, Japanese Patent Application Publication No. 2002-120326, Japanese Patent Application Publication No. 2002-254544, and Japanese Patent Application Publication No. 2005-146084.

[0040] Examples of (meth)acrylic resins having a glutarimide structure include those described in Japanese Patent Application Publication Nos. 2006-309033, 2006-317560, 2006-328329, 2006-328334, 2006-337491, 2006-337492, 2006-337493, 2006-337569, and 2007-009182.

[0041] The content of the (meth)acrylic resin in the (meth)acrylic resin film is preferably 50-100% by weight, more preferably 50-99% by weight, even more preferably 60-98% by weight, and particularly preferably 70-97% by weight. When the content of the (meth)acrylic resin in the (meth)acrylic resin film is less than 50% by weight, there is a risk that the high heat resistance and high transparency originally possessed by the (meth)acrylic resin may not be fully reflected.

[0042] The content of the aforementioned (meth)acrylic resin in the molding material used in molding (meth)acrylic resin films is preferably 50-100% by weight, more preferably 50-99% by weight, even more preferably 60-98% by weight, and particularly preferably 70-97% by weight. When the content of the aforementioned (meth)acrylic resin in the molding material used in molding (meth)acrylic resin films is less than 50% by weight, there is a risk that the high heat resistance and high transparency inherent in the (meth)acrylic resin may not be adequately reflected.

[0043] In addition to the (meth)acrylic resins mentioned above, (meth)acrylic resin films may also contain other thermoplastic resins. Other thermoplastic resins include, for example: olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, and poly(4-methyl-1-pentene); halogenated vinyl polymers such as vinyl chloride, vinylidene chloride, and chlorinated vinyl resins; acrylic polymers such as polymethyl methacrylate; styrene polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, and acrylonitrile-butadiene-styrene block copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon 6, nylon 66, and nylon 610; polyacetal; polycarbonate; polyphenylene ether; polyphenylene sulfide; polyetheretherketone; polysulfone; polyethersulfone; polyoxybenzylene; polyamide imide; and rubbery polymers such as ABS resin and ASA resin formulated with polybutadiene rubber and acrylic rubber.

[0044] The content of other thermoplastic resins in the (meth)acrylic resin film is preferably 0-50% by weight, more preferably 0-40% by weight, even more preferably 0-30% by weight, and particularly preferably 0-20% by weight.

[0045] (Meth)acrylic resin films may contain additives. Examples of additives include: hindered phenolic, phosphorus, and sulfur antioxidants; light stabilizers, weather stabilizers, and heat stabilizers; reinforcing materials such as glass fiber and carbon fiber; ultraviolet absorbers such as phenyl salicylate, (2,2'-hydroxy-5-methylphenyl)benzotriazole, and 2-hydroxybenzophenone; near-infrared absorbers; flame retardants such as tris(dibromopropyl) phosphate, triallyl phosphate, and antimony oxide; antistatic agents such as anionic, cationic, and nonionic surfactants; colorants such as inorganic pigments, organic pigments, and dyes; organic and inorganic fillers; resin modifiers; organic and inorganic fillers; plasticizers; lubricants; antistatic agents; flame retardants; and phase difference reducers.

[0046] The additive content in the (meth)acrylic resin film is preferably 0-5% by weight, more preferably 0-2% by weight, and even more preferably 0-0.5% by weight.

[0047] There are no particular limitations on the method for manufacturing (meth)acrylic resin films. For example, a thermoplastic resin composition can be prepared in advance by thoroughly mixing (meth)acrylic resin with other polymers, additives, etc., using any suitable mixing method, and then the composition can be film-formed. Alternatively, the (meth)acrylic resin with other polymers, additives, etc., can be prepared into separate solutions and then mixed to form a homogeneous mixture before film-forming.

[0048] To manufacture the above-mentioned thermoplastic resin composition, for example, after premixing the above-mentioned film raw materials using any suitable mixer such as an OMNI Mixer, the resulting mixture is extruded and compounded. In this case, the mixer used in the extrusion compounding is not particularly limited; for example, any suitable mixer such as a single-screw extruder, a twin-screw extruder, or a pressure kneader can be used.

[0049] Examples of film forming methods include solution casting, melt extrusion, calendering, compression molding, and any suitable film forming method. Among these methods, solution casting and melt extrusion are preferred.

[0050] Solvents used in the above-mentioned solution casting method (solution casting method) include, for example: aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as cyclohexane and decahydronaphthalene; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve, and butyl cellosolve; ethers such as tetrahydrofuran and dimethyl ether; halogenated hydrocarbons such as dichloromethane, chloroform, and carbon tetrachloride; dimethylformamide; and dimethyl sulfoxide. These solvents can be used alone or in combination of two or more.

[0051] Examples of apparatuses for performing the above-mentioned solution casting method (solution casting method) include drum casting machines, belt casting machines, spin coating machines, etc.

[0052] Examples of melt extrusion methods include T-die molding and blow molding. The molding temperature is preferably 150-350°C, more preferably 200-300°C.

[0053] When forming film using the T-die method described above, a T-die can be installed at the front end of a known single-screw extruder or twin-screw extruder, and the extruded film can be wound up to obtain a rolled film. At this time, unidirectional stretching can also be achieved by appropriately adjusting the temperature of the take-up roller and applying stretching in the extrusion direction. Alternatively, simultaneous bidirectional stretching or progressive bidirectional stretching can be performed by stretching the film in a direction perpendicular to the extrusion direction.

[0054] (Meth)acrylic resin films can be any type of unstretched or stretched film. When stretched, they can be either uniaxially stretched or biaxially stretched. When biaxially stretched, they can be either synchronously biaxially stretched or progressively biaxially stretched. Biaxial stretching improves mechanical strength and film performance. For (meth)acrylic resin films, by blending with other thermoplastic resins, the increase in phase difference can be suppressed even after stretching, maintaining optical isotropy.

[0055] The stretching temperature is preferably near the glass transition temperature of the thermoplastic resin composition used as the film raw material, specifically, preferably within the range of (glass transition temperature -30°C) to (glass transition temperature +100°C), and more preferably within the range of (glass transition temperature -20°C) to (glass transition temperature +80°C). If the stretching temperature is lower than (glass transition temperature -30°C), there is a risk that a sufficient stretch ratio cannot be obtained. Conversely, if the stretching temperature exceeds (glass transition temperature +100°C), there is a risk that the resin composition will flow and cannot be stretched stably.

[0056] The stretch ratio, defined by area ratio, is preferably 1.1 to 25 times, more preferably 1.3 to 10 times. If the stretch ratio is less than 1.1 times, there is a risk that the increased toughness accompanying the stretching may not be achieved. If the stretch ratio exceeds 25 times, there is a risk that the full effect of increasing the stretch ratio may not be observed.

[0057] The stretching speed in one direction is preferably 10~20000% / min, more preferably 100~10000% / min. If the stretching speed is lower than 10% / min, there is a risk that it will take more time to obtain the required stretch ratio and that manufacturing costs will increase. If the stretching speed exceeds 20000% / min, there is a risk that the stretched film may break.

[0058] For (meth)acrylic resin films, in order to achieve optical isotropy and stabilize mechanical properties, heat treatment (annealing) can be performed after stretching. Any suitable conditions can be used for heat treatment.

[0059] The thickness of the (meth)acrylic resin film is preferably 20-60 μm, more preferably 20-30 μm. If the thickness is less than 20 μm, not only will the strength decrease, but there is also a risk of shrinkage during durability tests of the laminated optical film. If the thickness exceeds 60 μm, there is a risk of decreased transparency.

[0060] The laminated optical film of the present invention comprises an acrylic film and a first optical film laminated together via an adhesive layer, wherein the acrylic film and the adhesive layer are in direct contact. That is, the acrylic film does not have an easily bondable layer. The surface of the acrylic film in contact with the adhesive layer can be subjected to a surface modification treatment. Examples of surface modification treatments include corona treatment, plasma treatment, and ITRO treatment, with corona treatment being particularly preferred.

[0061] <First Optical Film>

[0062] The laminated optical film of the present invention comprises at least an acrylic film and a first optical film laminated via an adhesive layer. The first optical film is preferably a liquid crystal film or a retardation film. Examples of liquid crystal films include alignment films of liquid crystal polymers and films formed by an alignment layer of a liquid crystal polymer supported by a film. Examples of retardation films include retardation films 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 in the range of 40 to 200 nm, and the thickness-direction phase difference is typically controlled in the range of 80 to 300 nm. In addition to birefringent films formed by unidirectional or bidirectional stretching of polymer raw materials, retardation films can also be alignment films of liquid crystal polymers or films formed by an alignment layer of a liquid crystal polymer supported by a film. The thickness of the liquid crystal film and the retardation film is not particularly limited and is typically around 1 to 150 μm.

[0063] As a phase retardation film, a phase retardation film with reverse wavelength dispersion that satisfies the following equations (1) to (3) can be used:

[0064] 0.70<Re

[450] / Re

[550] <0.97···(1)

[0065] 1.5×10 -3 <Δn<6×10 -3 ···(2)

[0066] 1.13 < NZ < 1.50 ···(3)

[0067] (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).

[0068] <Adhesive layer>

[0069] The laminated optical film of the present invention comprises at least an acrylic film and a first optical film laminated together via an adhesive layer. The acrylic film and the adhesive layer have a structure in direct contact. That is, no easily bonded layer containing water-based urethane resin or the like is provided between the acrylic film and the adhesive layer.

[0070] In the laminated optical film of the present invention, the adhesive layer has the following characteristics.

[0071] (i) The HSP distance between the acrylic film and the adhesive layer is greater than 1.9 and less than 5.0.

[0072] (ii) The elastic modulus of the adhesive layer is 10. 8 Pa or higher and 3×10 9 Below Pa.

[0073] Regarding (i) above, it is more preferable that the HSP distance between the acrylic film and the adhesive layer is 1.9 or more and 4.9 or less.

[0074] (Calculation method of solubility parameter (HSP distance))

[0075] In this invention, the solubility parameter (HSP distance) of the adhesive layer is calculated using Hansen's method [using HSPPversion 5.4.04 calculation software], that is, the Hansen solubility parameter is a value for predicting the solubility of substances published by Chares M. Hansen in 1967.

[0076] The Hansen solubility parameter consists of the following three parameters.

[0077] ·δD: Energy based on intermolecular dispersion forces

[0078] ·δP: Energy based on intermolecular dipole interactions

[0079] ·δH: Energy based on intermolecular hydrogen bonds

[0080] These three parameters can be considered as coordinates in three-dimensional space. The affinity between two substances (e.g., an acrylic film and an adhesive layer) can be evaluated by the distance between the two HSPs (HSP distance). It can be assumed that if the HSP distance between the two substances is small, the affinity is large.

[0081] The HSP distance used as an indicator in this study is calculated by substituting the three Hansen components of the two substances into the following formula.

[0082] [Mathematical Expression 1]

[0083] HSP distance=√(4×(δD1-δD2)^2+2×(δP1-δP2)^2+2×(δH1-δH2)^2)

[0084] The adhesive layer will now be described in detail. The adhesive layer is a cured layer formed from an adhesive composition containing at least a polymerizable compound, and is particularly preferably a cured layer formed from an adhesive composition that is curable by active energy rays such as electron beam curing, ultraviolet curing, or visible light curing. From the viewpoint of improving the appearance characteristics and adhesion of the laminated optical film, the thickness of the dried adhesive layer is preferably 0.1 μm to 10 μm, more preferably 0.5 μm to 5 μm. Active energy ray curable adhesive compositions can be classified into free radical polymerization curable adhesive compositions and cationic polymerization adhesive compositions. In this invention, active energy rays with a wavelength range of 10 nm or more and less than 380 nm are referred to as ultraviolet light, and active energy rays with a wavelength range of 380 nm to 800 nm are referred to as visible light.

[0085] Examples of polymerizable compounds constituting free radical polymerizable adhesive compositions include free radical polymerizable compounds. Examples of free radical polymerizable compounds include compounds having carbon-carbon double bonds such as (meth)acryloyl or vinyl groups. These monomer components can be any compound from monofunctional free radical polymerizable compounds or polyfunctional free radical polymerizable compounds having two or more polymerizable functional groups. Furthermore, these free radical polymerizable compounds can be used alone or in combination of two or more. For example, compounds having a (meth)acryloyl group are preferred as these free radical polymerizable compounds. It should be noted that in this invention, (meth)acryloyl refers to acryloyl and / or methacryloyl, and "(meth)" has the same meaning below.

[0086] Examples of monofunctional free radical polymerizable compounds include (meth)acrylamide derivatives having a (meth)acrylamide group. (Methacrylamide derivatives are preferred from the viewpoint of ensuring adhesion to polarizers and various transparent protective films, while also exhibiting fast polymerization speeds and excellent manufacturability. Specific examples of (meth)acrylamide derivatives include: N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, N-hexyl (meth)acrylamide, and other (meth)acrylamide derivatives containing N-alkyl groups; N-hydroxymethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, N-hydroxymethyl-N-propane (meth)acrylamide, and other (meth)acrylamide derivatives containing N-hydroxyalkyl groups; aminomethyl (meth)acrylamide, aminoethyl (meth)acrylamide, and other (meth)acrylamide derivatives containing N-aminoalkyl groups; N-methoxymethylacrylamide, N-ethoxymethylacrylamide, and other (meth)acrylamide derivatives containing N-alkoxy groups; mercaptomethyl (meth)acrylamide, mercaptoethyl (meth)acrylamide, and other (meth)acrylamide derivatives containing N-mercaptoalkyl groups; and so on. In addition, the nitrogen atom, which is a (meth)acrylamide group, forms heterocyclic (meth)acrylamide derivatives, such as N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine, etc.

[0087] Among the above-mentioned (meth)acrylamide derivatives, from the viewpoint of adhesion to polarizing mirrors and various transparent protective films, (meth)acrylamide derivatives containing N-hydroxyalkyl groups are preferred. In addition, as monofunctional free radical polymerizable compounds, various (meth)acrylic acid derivatives having (meth)acryloyloxy groups can be cited as examples. Specific 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).

[0088] In addition, examples of the above-mentioned (meth)acrylic acid derivatives include: cyclohexyl methacrylate, cyclopentyl methacrylate, and other cycloalkyl methacrylates; benzyl methacrylate and other aralkyl methacrylates; 2-isoborneol methacrylate, 2-norborneol methacrylate, 5-norborneol-2-yl methacrylate, 3-methyl-2-norborneol methacrylate, dicyclopentenyl methacrylate, dicyclopentenoxyethyl methacrylate, dicyclopentenyl methacrylate, and other polycyclic (meth)acrylic acid esters; 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-methoxymethoxyethyl methacrylate, 3-methoxybutyl methacrylate, ethyl carbitol methacrylate, phenoxyethyl methacrylate, alkylphenoxy polyethylene glycol methacrylate, and other (meth)acrylic acid esters containing alkoxy or phenoxy groups; and so on.

[0089] 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.; hydroxyalkyl (meth)acrylic acid esters such as [4-(hydroxymethyl)cyclohexyl]methyl acrylate, cyclohexanediol mono(meth)acrylic acid, and 2-hydroxy-3-phenoxypropyl (meth)acrylic acid; glycidyl (meth)acrylic acid, 4-hydroxybutyl (meth)acrylic acid glycidyl ether, etc., containing epoxy groups; 2,2,2-trifluoroethyl (meth)acrylic acid, etc. 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; oxy-heterocyclic butyl (meth)acrylates such as 3-oxetane butyl methyl (meth)acrylate, 3-methyloxetane butyl methyl (meth)acrylate, 3-ethyloxetane butyl methyl (meth)acrylate, 3-butyloxetane butyl methyl (meth)acrylate, and 3-hexyloxetane butyl 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.

[0090] 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.

[0091] In addition, examples of monofunctional free radical polymerizable compounds include: N-vinylpyrrolidone, N-vinyl-ε-caprolactam, methylvinylpyrrolidone and other lactam vinyl monomers; vinyl pyridine, vinyl piperidinone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl pyrazole, vinyl morpholine and other vinyl monomers with nitrogen-containing heterocycles.

[0092] 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)acryloyl 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: 2-acetylacetoxyethyl methacrylate, 2-acetylacetoxypropyl methacrylate, 2-acetylacetoxy-1-methylethyl methacrylate, and other acetylacetoxyalkyl methacrylates; 2-ethoxymalonyl ethyl methacrylate, 2-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 acetylacetoxyalkyl methacrylate.

[0093] In this invention, the adhesive composition is preferably a composition containing a polymerizable compound A. The HSP distance between the polymerizable compound A and the acrylic film is 0.0 or more and 4.0 or less. When the total amount of the polymerizable compound contained in the adhesive composition is set to 100 parts by mass, the content of the polymerizable compound A is preferably 20 parts by mass or more and 60 parts by mass or less, more preferably 30 parts by mass or more and 40 parts by mass or less. It should be noted that in this invention, the "HSP distance between the acrylic film and the polymerizable compound" is calculated based on the HSP value of the acrylic film (δD: 18.5, δP: 10.9, δH: 7.7). As the polymerizable compound A, the following compounds can be cited among the above-mentioned monofunctional free radical polymerizable compounds: vinylmethyl... The adhesive compositions used in this invention contain polymerizable compound A, which improves the adhesion between the acrylic film and the adhesive layer, thereby increasing the bonding strength. The compounds include N-acryloylmorpholine (HSP distance to acrylic film 3.2), N-isopropylacrylamide (HSP distance to acrylic film 1.9), N-isopropylacrylamide (HSP distance to acrylic film 3.2), N-ethylacrylamide (HSP distance to acrylic film 3.3), N-dimethylacrylamide (HSP distance to acrylic film 2.8), and N-vinylpyrrolidone (HSP distance to acrylic film 3.1).

[0094] Furthermore, in this invention, the adhesive composition is preferably a composition containing polymeric compound C. The HSP distance between polymeric compound C and the acrylic film is greater than 4.0 and less than 8.0. When the total amount of the polymeric compound contained in the adhesive composition is set to 100 parts by mass, the content of the polymeric compound C is preferably less than or equal to the amount of polymeric compound A, more preferably less than or equal to the amount of polymeric compound A. The adhesive composition used in this invention, by containing polymeric compound C, exhibits improved adhesive strength under humidification reliability testing, and is therefore preferred. In particular, from the viewpoint of improved adhesive strength under humidification reliability testing, when the total amount of the polymeric compound contained in the adhesive composition is set to 100 parts by mass, the content of the polymeric compound C is more preferably less than or equal to the amount of polymeric compound A and is 10 to 30 parts by mass. As polymeric compound C, the following compounds can be exemplified among the above-mentioned monofunctional free radical polymeric compounds. 4-Hydroxybutyl acrylate (HSP distance from membrane 6.4), (2-methyl-2-ethyl-1,3-dioxolane-4-yl)methyl acrylate (HSP distance from acrylic membrane 7.2), N (HSP distance from acrylic membrane 6.4), (2-methyl-2-ethyl-1,3-dioxolane-4-yl)methyl acrylate (HSP distance from membrane 7.2), diethylacrylamide (HSP distance from membrane 5.9), tert-butylcyclohexyl acrylate (HSP distance from membrane 5.4), ω-carboxylated polycaprolactone (n=2) monoacrylate (HSP distance from membrane 7.1), phenoxydiethylene glycol acrylate (HSP distance from membrane 6.5), phenoxybenzyl acrylate (HSP distance from membrane 7.8), phenoxyethyl acrylate (HSP distance from membrane 6.3).

[0095] Furthermore, in this invention, the adhesive composition is preferably a composition containing a polymerizable compound D. The polymerizable compound D is a compound represented by the following general formula (1):

[0096] [Chemical Formula 2]

[0097]

[0098] (In the formula, X is a reactive group, Y is an optional alkylene group with 1 to 12 carbon atoms having a branched chain, or an optional phenylene group with a substituent, R...) 1 and R 2 Each of the following groups (each independently representing a hydrogen atom, optionally an aliphatic hydrocarbon group with substituents, an aryl group, or a heterocyclic group) is used. When the total amount of the polymeric compound contained in the adhesive composition is set to 100 parts by mass, the content of polymeric compound D is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 5 parts by mass or less. By including polymeric compound D in the adhesive composition used in this invention, the adhesion between the acrylic film and the adhesive layer is improved, thereby increasing the adhesive strength, which is therefore preferred.

[0099] In the compounds represented by general formula (1), 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, groups containing at least one heteroatom and optionally substituented 5-membered or 6-membered rings. They can also be linked together to form a ring. In general formula (1), as R 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.

[0100] 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 make up 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 adhesive composition constituting 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 adhesive composition constituting 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 component in the adhesive layer, and is therefore more preferred. In addition, the (meth)acrylamide group has high polarity and excellent adhesive properties, and is therefore preferred from the perspective of effectively obtaining the effects of the present invention. When the curable adhesive composition constituting 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 adhesive layer has excellent adhesion to the adhered object, and is therefore preferred. When vinyl ether is present, the curability of the curable adhesive composition is excellent, and is therefore preferred.

[0101] 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.

[0102] [Chemical Formula 3]

[0103]

[0104] In addition to the compounds exemplified above, compounds represented by general formula (1) may also include esters formed from hydroxyethyl acrylamide and boric acid, esters formed from hydroxymethyl acrylamide and boric acid, esters formed from hydroxyethyl acrylate and boric acid, and esters formed from hydroxybutyl acrylate and boric acid, etc. (meth)acrylates formed from boric acid.

[0105] Furthermore, in this invention, the adhesive composition is preferably a composition containing a polymerizable compound E. The polymerizable compound E is a polymerizable compound containing hydroxyl groups. When the content of polymerizable compound D is set to 1, the content of polymerizable compound E is preferably 1 or more and 15 or less, more preferably 5 or more and 12 or less by mass. Examples of polymerizable compound D include: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl methacrylate, 10-hydroxydecyl methacrylate, 12-hydroxylauryl methacrylate, and other hydroxyalkyl methacrylates; methyl acrylate [4-(hydroxymethyl)cyclohexyl]acrylate; cyclohexanediol mono(meth)acrylate; and 2-hydroxy-3-phenoxypropyl methacrylate, and other hydroxyl-containing (meth)acrylates. By including the polymerizable compound E in the adhesive composition used in this invention, the adhesion between the acrylic film and the adhesive layer is improved, thereby increasing the adhesive strength, which is therefore preferred.

[0106] Examples of multifunctional free radical polymerizable compounds with two or more polymerizable functional groups include: tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-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 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 DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer Co., Ltd.), and CD-536 (manufactured by Sartomer Co., Ltd.). In addition, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, and various (meth)acrylate monomers can be cited as needed.

[0107] In this invention, the adhesive composition is preferably a composition containing a polymeric compound B. The polymeric compound B is a compound having at least two polymeric groups. When the total amount of the polymeric compound in the adhesive composition is set to 100 parts by mass, the content of the polymeric compound B is preferably 20 parts by mass or more and 50 parts by mass or less, more preferably 30 parts by mass or more and 40 parts by mass or less. The above-described multifunctional free radical polymeric compound can be used as an example of the polymeric compound B. By including the polymeric compound B in the adhesive composition used in this invention, the adhesive layer becomes sufficiently elastic, and the incorporation of oxalic acid into the adhesive layer can be suppressed, thereby suppressing the generation of oxalic acid bright spots, which are a cause of deterioration in appearance.

[0108] In this invention, the adhesive composition, which serves as the raw material for the adhesive layer of the laminated optical film, may contain, in addition to a free radical polymerizable compound, an acrylic oligomer formed by polymerizing (meth)acrylic acid monomers. By including the acrylic oligomer in the adhesive composition, curing shrinkage during irradiation with active energy rays and subsequent curing can be reduced, thereby reducing interfacial stress between the adhesive layer and the adhered objects such as polarizers and optical films. As a result, the reduction in adhesion between the adhesive layer and the adhered objects can be suppressed.

[0109] Considering workability and uniformity during application, the active energy radiation-cured adhesive is preferably low in viscosity; therefore, it is also preferable that the acrylic oligomer formed by polymerizing (meth)acrylic acid monomers is low in viscosity. As an acrylic oligomer with low viscosity that can prevent curing shrinkage of the adhesive layer, its weight-average molecular weight (Mw) is preferably 15,000 or less, more preferably 10,000 or less, and particularly preferably 5,000 or less. On the other hand, in order to sufficiently suppress 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), aralkyl methacrylates (e.g., benzyl methacrylate), and polycyclic methacrylates (e.g., 2-isobornyl methacrylate, 2-norberyl methacrylate). Fiber methyl esters, 5-norbornene-2-yl methyl ester (meth)acrylate, 3-methyl-2-norbornene-methyl ester (meth)acrylate, etc.), hydroxyl-containing (meth)acrylates (e.g., hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropyl methylbutyl (meth)acrylate, etc.), alkoxy or phenoxy (meth)acrylates (2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, etc.), These include ethyl carbitol methacrylate, phenoxyethyl methacrylate, etc.; epoxy-containing methacrylates (e.g., glycidyl methacrylate, etc.); 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, etc.). 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.

[0110] The amount of acrylic oligomers in the composition is generally preferably 15 parts by weight or less, relative to the total amount of monomer components in the adhesive composition (100 parts by weight). If the content of acrylic oligomers in the composition is too high, the reaction rate when the composition is irradiated with active energy rays may decrease drastically, leading to poor curing. On the other hand, to sufficiently suppress the curing shrinkage of the adhesive layer, it is preferable to contain 3 parts by weight or more of acrylic oligomers in the composition.

[0111] In the case of using free radical polymerizable compounds, the photopolymerization initiator can be appropriately selected based on the active energy of the radiation. When curing by ultraviolet or visible light, a photopolymerization initiator that is pyrolyzed by ultraviolet or visible light 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, α-hydroxycyclohexylphenyl ketone, etc.; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one, etc.; 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.

[0112] When the total amount of the active energy ray curable adhesive composition is set to 100% by weight, the amount of the above-mentioned photopolymerization initiator is 20% by weight or less. The amount of the photopolymerization initiator is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, and even more preferably 0.1 to 5% by weight.

[0113] Furthermore, when using the curable adhesive for laminated optical films of the present invention in a visible light curable form containing a free radical polymerizable compound as a curing component, it is particularly preferable to use a photopolymerization initiator that is highly sensitive to light above 380 nm. The photopolymerization initiator that is highly sensitive to light above 380 nm will be explained later.

[0114] As the above-mentioned photopolymerization initiator, it is preferred to use the compound represented by the following general formula (1) alone, or to use the compound represented by the general formula (1) in combination with the photopolymerization initiator that is highly sensitive to light above 380 nm as described later.

[0115] [Chemical Formula 4]

[0116]

[0117] (where R is in the formula) 1 and R 2 Represents -H, -CH2CH3, -iPr, or Cl, R 1 and R 2 (Can be the same or different). When using compounds represented by general formula (1), the adhesion is superior compared to using photopolymerization initiators that are highly sensitive to light above 380 nm alone. Among the compounds represented by general formula (1), R is particularly preferred. 1 and R 2 Diethylthioxanthone of the form -CH2CH3. The composition ratio of the compound represented by general formula (1) in the adhesive composition is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, and even more preferably 0.9 to 3 parts by weight, relative to 100 parts by weight of the total amount of the curing component.

[0118] Furthermore, it is preferable to add a polymerization initiator 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, the amount added is typically 0 to 5 parts by weight relative to 100 parts by weight of the total amount of the curing component, preferably 0 to 4 parts by weight, and most preferably 0 to 3 parts by weight.

[0119] In addition, known photopolymerization initiators can be used in combination as needed. Since transparent protective films with UV absorption capabilities do not transmit light below 380 nm, it is preferable to use photopolymerization initiators that are highly sensitive to light above 380 nm. 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.

[0120] In particular, as a photopolymerization initiator, it is preferable to use a compound represented by the following general formula (2) in addition to the photopolymerization initiator of general formula (1).

[0121] [Chemical Formula 5]

[0122]

[0123] (where R is in the formula) 3 R 4 and R 5 Represents -H, -CH3, -CH2CH3, -iPr, or Cl, R 3 R 4 and R 5 (These may be the same or different). As compounds represented by general formula (2), 2,4,6-trimethylbenzoyl diphenylphosphine oxide (trade name: Omnirad 819, manufacturer: IGM Resins BV) and 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one (trade name: Omnirad 907, manufacturer: IGM Resins BV), which are also commercially available, are preferred due to their high sensitivity. In addition, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (trade name: Omnirad 369, manufacturer: IGM Resins BV) and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone (trade name: Omnirad 379, manufacturer: IGM Resins BV) are preferred due to their high sensitivity.

[0124] In this invention, a hydroxyl-containing photopolymerization initiator is preferably used among the aforementioned photopolymerization initiators. When the active energy ray-curable adhesive composition contains a hydroxyl-containing photopolymerization initiator as a polymerization initiator, the solubility of the adhesive layer with a higher concentration of component A on the polarizer side is improved, and the curing properties of the adhesive layer are improved. Examples of photopolymerization initiators containing hydroxyl groups include: 2-methyl-2-hydroxyphenylacetone (trade name "DAROCUR1173", manufactured by BASF), 1-hydroxycyclohexylphenyl ketone (trade name "IRGACURE184", manufactured by BASF), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one (trade name "IRGACURE2959", manufactured by BASF), and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanoyl)-benzyl]phenyl}-2-methyl-propane-1-one (trade name "IRGACURE127", manufactured by BASF). 1-hydroxycyclohexylphenyl ketone is particularly preferred due to its excellent solubility in adhesive layers with high concentrations of component A.

[0125] In this invention, a cationic polymerizable adhesive composition can be used as the adhesive composition that forms the adhesive layer of a laminated optical film. The cationic polymerizable compound used in the cationic polymerizable adhesive composition can be classified as a monofunctional cationic polymerizable compound having one cationic polymerizable functional group within its molecule, and a polyfunctional cationic polymerizable compound having two or more cationic polymerizable functional groups within its molecule. Monofunctional cationic polymerizable compounds have lower liquid viscosity; therefore, by including a monofunctional cationic polymerizable compound in the resin composition, the liquid viscosity of the resin composition can be reduced. Furthermore, monofunctional cationic polymerizable compounds often have functional groups exhibiting various functions; by including them in the cationic polymerizable adhesive composition, the cationic polymerizable adhesive composition and / or the cured cationic polymerizable adhesive composition can exhibit various functions. Polyfunctional cationic polymerizable compounds are preferably included in the cationic polymerizable adhesive composition because they can cause three-dimensional crosslinking in the cured cationic polymerizable adhesive composition. Regarding the ratio of monofunctional cationic polymeric compounds to polyfunctional cationic polymeric compounds, it is preferable to mix polyfunctional cationic polymeric compounds in the range of 10 to 1000 parts by weight relative to 100 parts by weight 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. Due to their excellent curability and adhesive properties, alicyclic epoxy compounds are particularly preferred as the cationic polymeric adhesive composition of the present invention. 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, CELLOXIDE 2021, CELLOXIDE 2021A, CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE 2083, CELLOXIDE 2085 (all manufactured by CELLOXIDE Chemical Industry Co., Ltd.), Cyracure UVR-6105, Cyracure UVR-6107, Cyracure 30, and R-6110 (all manufactured by Dow Chemical Japan Ltd.). Compounds containing oxocyclic 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 products include ARONOXETANE 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, pentaerythritol-type tetravinyl ether, etc.

[0126] The cationic polymerizable adhesive composition contains at least one compound selected from the above-described compounds having epoxy groups, oxetyl groups, and vinyl ether groups as a curing agent. 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 a photocationic polymerization initiator, a photoacid generator described later can be appropriately used. 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 are particularly preferred due to their excellent photosensitizing effect; 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 weight, more preferably 0.5% to 3% by weight.

[0127] Figure 1 The laminated optical film 10 shown further has a cellulose triacetate film 6, which serves as a transparent protective film, laminated on the opposite side of the acrylic film 1 where the first optical film 2 is laminated, via an aqueous adhesive layer 7. On the opposite side of the first optical film 2 where the acrylic film 1 is laminated, a second optical film 4 is further laminated via an adhesive layer 5.

[0128] <Adhesive layer>

[0129] There are no particular limitations on the adhesive used to form the adhesive layer; adhesives with polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorinated polymers, and rubbers as the base polymer can be appropriately selected. In particular, acrylic adhesives, which exhibit excellent optical transparency and moderate wetting, cohesiveness, and adhesion properties, as well as excellent weather resistance and heat resistance, are preferred.

[0130] For the exposed surface of the adhesive layer, it can be temporarily covered by an adhesive diaphragm to prevent contamination 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, 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.

[0131] <Second Optical Film>

[0132] In this invention, the second optical film is particularly preferably a liquid crystal film or a retardation film. As the liquid crystal film and retardation film, those same as those exemplified in the first optical film can preferably be used.

[0133] In addition to the acrylic film, the first optical film and the second optical film described above, the laminated optical film of the present invention may also have the optical film shown below.

[0134] The laminated optical film of the present invention can incorporate a polarizer as another optical film. As a material suitable for a polyvinyl alcohol film used in a polarizer, polyvinyl alcohol or its derivatives can be used. Examples of polyvinyl alcohol derivatives include polyvinyl formal and polyvinyl acetal; in addition, materials modified with olefins such as ethylene and propylene, acrylic acid, methacrylic acid, unsaturated carboxylic acids such as crotonic acid or their alkyl esters, acrylamide, etc., are also examples. Polyvinyl alcohol with a degree of polymerization of approximately 1000 to 10000 and a degree of saponification of approximately 80 to 100 mol% is typically used.

[0135] Polyvinyl alcohol (PVA) films may contain additives such as plasticizers. Examples of plasticizers include polyols and their condensates, such as glycerol, diglycerol, triglyceride, ethylene glycol, propylene glycol, and polyethylene glycol. There are no particular restrictions on the amount of plasticizer used, but less than 20% by weight is suitable in PVA films.

[0136] When manufacturing a polarizing lens, a dyeing process is performed to stain the polyvinyl alcohol film with iodine, and a stretching process is performed to stretch the polyvinyl alcohol film in at least one direction. Generally, the polyvinyl alcohol film is subjected to a series of processes including swelling, dyeing, crosslinking, stretching, washing, and drying.

[0137] The swelling process is performed, for example, by immersing a polyvinyl alcohol (PVA) film in a swelling bath (water bath). This treatment removes stains and anti-blocking agents from the surface of the PVA film while simultaneously preventing uneven dyeing by swelling the film. Glycerin, potassium iodide, etc., may also be added to the swelling bath as appropriate. The temperature of the swelling bath is typically around 20–60°C, and the immersion time is usually around 0.1–10 minutes.

[0138] The dyeing process is carried out, for example, by immersing a polyvinyl alcohol film in an iodine solution. The iodine solution is typically an aqueous iodine solution containing iodine and potassium iodide as a dissolving agent. The iodine concentration is typically about 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight. The potassium iodide concentration is typically about 0.01 to 10% by weight, preferably 0.02 to 8% by weight.

[0139] In the iodine dyeing process, the temperature of the iodine solution is typically around 20-50°C, preferably 25-40°C. The immersion time is typically around 10-300 seconds, preferably in the range of 20-240 seconds. During the iodine dyeing treatment, it is preferable to adjust the concentration of the iodine solution, the immersion temperature of the polyvinyl alcohol film in the iodine solution, and the immersion time to ensure that the iodine and potassium content in the polyvinyl alcohol film falls within the aforementioned ranges.

[0140] The crosslinking process is performed, for example, by immersing a polyvinyl alcohol film, which has been iodine-dyed, in a treatment bath containing a crosslinking agent. Any suitable crosslinking agent can be used. Specific examples of crosslinking agents include boric acid, boron compounds such as borax, glyoxal, and glutaraldehyde. They can be used alone or in combination. The solvent used in the crosslinking bath solution is usually water, but an appropriate amount of an organic solvent compatible with water may also be added. The crosslinking agent is usually used at a ratio of 1 to 10 parts by weight relative to 100 parts by weight of the solvent. It is desirable that the crosslinking bath solution further contains auxiliaries such as iodides. The concentration of the auxiliaries is preferably 0.05 to 15% by weight, more preferably 0.5 to 8% by weight. The temperature of the crosslinking bath is usually around 20 to 70°C, preferably 40 to 60°C. The immersion time in the crosslinking bath is usually around 1 second to 15 minutes, preferably 5 seconds to 10 minutes.

[0141] The stretching process is the process of stretching a polyvinyl alcohol (PVA) film in at least one direction. Typically, the PVA film is unidirectionally stretched in the transport direction (length direction). There are no particular limitations on the stretching method; either wet stretching or dry stretching can be used. In the case of wet stretching, the PVA film is stretched to a given ratio in a treatment bath. Preferably, the solution used as the stretching bath is a solution containing various compounds required for the treatment, added to a solvent such as water or an organic solvent (e.g., ethanol). Examples of dry stretching methods include, for example, roller stretching, heated roller stretching, and compression stretching. In the manufacture of polarizing mirrors, the stretching process can be performed at any stage. Specifically, it can be performed simultaneously with swelling, dyeing, and crosslinking, or at any stage before or after these processes. Furthermore, stretching can also be performed in multiple stages. The cumulative stretch ratio of the PVA film is typically 5 times or more, preferably around 5 to 7 times.

[0142] In this invention, the polarizer preferably contains a metal component that can form a divalent metal cation in water, more preferably magnesium, calcium, copper, or zinc, and particularly preferably zinc. By containing zinc in the polarizer, the tendency for the transmittance of the stacked optical film to decrease and for color tone to deteriorate after heating tests can be suppressed. When the polarizer contains zinc, the zinc content in the polarizer is preferably 0.002 to 2% by weight, more preferably 0.01 to 1% by weight.

[0143] In this invention, the polarizer preferably contains sulfate ions. By including sulfate ions in the polarizer, the decrease in transmittance of the stacked optical film after heating is tended to be suppressed. When the polarizer contains sulfate ions, the sulfate ion content in the polarizer is preferably 0.02 to 0.45% by weight, more preferably 0.05 to 0.35% by weight, and even more preferably 0.1 to 0.25% by weight. It should be noted that the sulfate ion content in the polarizer can be calculated from the sulfur atom content.

[0144] To ensure the polarizer contains zinc, it is preferable to perform a zinc impregnation treatment during the polarizer manufacturing process. Furthermore, to ensure the polarizer contains sulfate ions, it is preferable to perform a sulfate ion treatment during the polarizer manufacturing process.

[0145] Zinc impregnation treatment can be carried out, for example, by impregnating a polyvinyl alcohol film with a zinc salt solution. The preferred zinc salts are inorganic salt compounds such as zinc chloride, zinc iodide, zinc sulfate, and zinc acetate in aqueous solution. Various zinc complex compounds can also be used in the zinc impregnation treatment. Furthermore, regarding the zinc salt solution, it is preferable to use an aqueous solution containing potassium and iodide ions, such as potassium iodide, to easily impregnate zinc ions. The concentration of potassium iodide in the zinc salt solution is preferably set to about 0.5 to 10% by weight, and more preferably 1 to 8% by weight.

[0146] Sulfate ion treatment can be carried out, for example, by immersing a polyvinyl alcohol membrane in an aqueous solution containing a metal sulfate salt. The preferred metal sulfate salt is one that is easily separable into sulfate ions and metal ions in the treatment solution, and which is readily introduced into the polyvinyl alcohol membrane in an ionic state. Examples of metals that can form the metal sulfate salt include: alkali metals such as sodium and potassium; alkaline earth metals such as magnesium and calcium; and transition metals such as cobalt, nickel, zinc, chromium, aluminum, copper, manganese, and iron.

[0147] In the manufacture of the polarizing mirror, the zinc impregnation treatment and sulfate ion treatment described above can be performed at any stage. That is, the zinc impregnation treatment and sulfate ion treatment can be performed before or after the dyeing process. The zinc impregnation treatment and sulfate ion treatment can also be performed simultaneously. In this invention, it is preferable to use zinc sulfate as both the zinc salt and the metal sulfate salt, and to immerse the polyvinyl alcohol film in a treatment bath containing zinc sulfate, thereby simultaneously performing the zinc impregnation treatment and sulfate ion treatment. Alternatively, the zinc salt and the metal sulfate salt can be pre-existing in the dyeing solution so that the zinc impregnation treatment and / or sulfate ion treatment are performed simultaneously with the dyeing process. The zinc impregnation treatment and sulfate ion treatment can be performed simultaneously with stretching.

[0148] In zinc immersion treatment and sulfate ion treatment, the zinc content and sulfate ion content in the polarizer are adjusted by modifying conditions such as the concentrations of the zinc salt solution and the metal sulfate solution, the immersion temperature of the polyvinyl alcohol film in the treatment bath, and the immersion time. In zinc immersion treatment and sulfate ion treatment, the temperature of the zinc salt solution and the metal sulfate solution is typically around 15~85°C, preferably 25~70°C. The immersion time is typically around 1~120 seconds, preferably in the range of 3~90 seconds. The concentrations of the zinc salt solution and the metal sulfate solution vary depending on the type of zinc salt and metal sulfate, typically around 0.5~20% by weight, preferably 1~10% by weight, and more preferably 2~7% by weight. By setting the zinc salt concentration and the metal sulfate concentration within this range, the zinc content and sulfate ion content in the polarizer can be made to reach the aforementioned preferred ranges.

[0149] The polyvinyl alcohol films (stretch films) after the above treatments are then subjected to water washing and drying processes according to conventional methods.

[0150] The washing process typically involves immersing a polyvinyl alcohol (PVA) membrane in a water bath. The water bath can be pure water or an aqueous solution of an iodide (e.g., potassium iodide, sodium iodide, etc.). The concentration of the iodide aqueous solution is preferably 0.1 to 10 by weight. Additives such as zinc sulfate or zinc chloride may be added to the iodide aqueous solution.

[0151] The washing temperature is typically 5~50℃, preferably 10~45℃, and more preferably 15~40℃. The immersion time is typically about 10~300 seconds, preferably 20~240 seconds. The washing process can be performed only once or multiple times as needed. When performing multiple washing processes, the type and concentration of additives in the water bath used in each treatment can be adjusted appropriately.

[0152] The drying process of the polyvinyl alcohol film can be carried out by any suitable method (e.g., natural drying, air drying, heat drying). The thickness of the polarizer after the drying process is preferably 3~20 μm.

[0153] In this invention, the surface of the obtained polarizer can be modified. Examples of surface modification treatments include corona treatment, plasma treatment, and ITRO treatment, with corona treatment being particularly preferred. By performing corona treatment, reactive functional groups such as carboxyl and amino groups are generated on the surface of the polarizer, thereby improving the adhesion to the durability improvement layer. In addition, surface impurities can be removed or surface unevenness can be reduced through ashing, thereby producing a laminated optical film with excellent appearance properties.

[0154] The laminated optical film of the present invention can also include a transparent protective film as other optical films. As a material constituting the transparent protective film, for example, a thermoplastic resin with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy can be used. Specific examples of such thermoplastic resins include: cellulose resins such as cellulose triacetate, 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, 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, even more 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 50% by weight or less, there is a risk that the high transparency originally possessed by the thermoplastic resin may not be fully manifested.

[0155] Furthermore, as the material for forming the transparent protective film, materials with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy are preferred; in particular, materials with a moisture permeability of 150 g / m² are more preferred. 2 Materials with a permeability of less than 24h, preferably with a moisture permeability of 140g / m².2 Materials with a permeability of less than 24h are preferred, with a further optimal permeability of 120g / m³. 2 Materials with a lifespan of less than 24 hours.

[0156] 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 transparent protective film. It should be noted that these functional layers, such as the hard coating layer, anti-reflective layer, anti-adhesion layer, diffusion layer, and anti-glare layer, can be used not only to protect the transparent protective film itself, but also as separate layers different from the transparent protective film.

[0157] 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 1~500μm, preferably 1~300μm, more preferably 5~200μm, further preferably 10~200μm, and even more preferably 20~80μm.

[0158] The laminated optical film of the present invention can be manufactured by, for example, the following manufacturing methods.

[0159] A method for manufacturing a laminated optical film, wherein the laminated optical film is a laminated optical film having at least an acrylic film and a first optical film laminated together via an adhesive layer, wherein...

[0160] The aforementioned adhesive layer is formed from a cured layer of an adhesive composition containing at least a polymerizable compound.

[0161] The manufacturing method of the above-mentioned stacked optical film includes:

[0162] A coating process in which at least one of the above-mentioned acrylic film and the above-mentioned first optical film is coated with the above-mentioned adhesive composition.

[0163] A bonding process in which the acrylic film and the first optical film are bonded together in such a manner that the acrylic film is directly bonded to the adhesive layer; and

[0164] An adhesive bonding process in which the acrylic film and the first optical film are bonded together by curing the adhesive composition by irradiating it with active energy rays from the acrylic film side or the first optical film side to form an adhesive layer, and the acrylic film and the first optical film are bonded together via the adhesive layer.

[0165] The following is a description of each process.

[0166] (Coating process)

[0167] The method for applying the adhesive composition to at least one of the acrylic film and the first optical film can be appropriately selected according to the viscosity of the composition and the target thickness. Examples include: reverse coaters, gravure coaters (direct, reverse, or offset), rod reverse coaters, roller coaters, die coaters, wire-wound rod coaters, and bar coaters. The viscosity of the easy-to-bond composition and the adhesive composition is preferably 0.1 to 200 mPa·s, more preferably 1 to 100 mPa·s, and most preferably 5 to 50 mPa·s. High viscosity of the composition results in insufficient surface smoothness after coating, leading to poor appearance, which is therefore undesirable. Therefore, coating can be performed after adjusting the viscosity of each composition to the preferred range by heating or cooling.

[0168] (Lamination process)

[0169] The acrylic film and the first optical film are bonded together in a manner that directly adheres the acrylic film and the adhesive layer. In the coating process, when the adhesive composition is applied to the acrylic film, it is not necessary to apply an easy-to-bond agent containing water-based urethane resin or the like to the acrylic film; instead, the acrylic film is directly bonded to the first optical film while the adhesive composition is applied. Furthermore, in the coating process, when the adhesive composition is applied to the first optical film, it is not necessary to use an easy-to-bond agent; instead, the adhesive composition-coated surface of the first optical film is directly bonded to the acrylic film. When bonding the acrylic film and the first optical film using the adhesive composition, a roller laminator or similar device is used for bonding.

[0170] (Adhesive bonding process)

[0171] An acrylic film and a first optical film are bonded together by an adhesive layer formed by curing the adhesive composition at least from the acrylic film side or the first optical film side by irradiating it with active energy rays. The irradiation direction of the active energy rays (electron beam, ultraviolet light, visible light, etc.) can be any suitable direction.

[0172] The irradiation conditions under electron beam irradiation are only required to cure the adhesive composition; 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 is greater than 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, resulting in reduced mechanical strength, yellowing, and failure to obtain the desired optical properties.

[0173] Electron beam irradiation is typically carried out in an inert gas, but it can also be performed in the atmosphere with a small amount of oxygen introduced, depending on the requirements. Although it depends on the materials of the first and second optical films, by appropriately introducing oxygen, the surfaces of the first and second optical films initially irradiated by the electron beam can be made to produce oxygen barriers, thereby preventing damage to the first and second optical films and allowing the electron beam to be effectively irradiated only on the adhesive.

[0174] In manufacturing the laminated optical film of the present invention, the active energy ray preferably includes visible light in the wavelength range of 380 nm to 450 nm, especially the 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 second optical film with ultraviolet absorption capability, such as an ultraviolet-proof transparent protective film, light with wavelengths shorter than about 380 nm is absorbed. Therefore, light with wavelengths shorter than 380 nm does not reach the adhesive composition and does not contribute to its polymerization reaction. Furthermore, the light with wavelengths shorter than 380 nm absorbed by the first and second optical films is converted into heat, causing the first and second optical films to heat up themselves, which becomes a cause of 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 generating device. 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, 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. Ultraviolet light with wavelengths shorter than 380 nm can also be blocked by a bandpass filter before use. To improve the adhesion performance of the adhesive layer between the first optical film and the second optical film and to prevent the stacked optical films from curling, it is preferable to use: active energy rays obtained by using a gallium-encapsulated metal halide lamp and a bandpass filter that can block light with wavelengths shorter than 380 nm, or active energy rays with a wavelength of 405 nm obtained by using an LED light source.

[0175] When manufacturing the laminated optical film of the present invention via a continuous production line, the linear speed varies depending on the curing time of the adhesive composition, but 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 or second optical film, making it impossible to produce a laminated optical film capable of withstanding durability tests, etc. If the linear speed is too high, the curing of the adhesive composition may sometimes be insufficient, and the desired adhesion may not be achieved.

[0176] (Layered optical film)

[0177] The laminated optical film of the present invention is preferably used in the formation of various image display devices, such as liquid crystal display devices. The formation of a liquid crystal display device can be performed in a conventional manner. That is, a liquid crystal display device is typically formed by appropriately assembling liquid crystal cells with polarizing films or 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 laminated optical film of the present invention, and it can be performed in a conventional manner. Regarding the liquid crystal cells, any type of liquid crystal cell, such as TN type, STN type, or π type, can be used.

[0178] 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.

[0179] Example

[0180] The following describes embodiments of the present invention, but the implementation of the present invention is not limited to these.

[0181] (Method for determining the storage modulus of the adhesive layer)

[0182] The storage modulus of the adhesive layer was measured using a Dva225 dynamic viscoelasticity measuring device manufactured by IT Measurement Control Co., Ltd., under the following measurement conditions.

[0183] Sample dimensions: 50mm wide, 30mm long;

[0184] Clamp distance: 20mm;

[0185] Measurement mode: tensile, frequency: 1Hz;

[0186] Heating rate: 5℃ / minute.

[0187] Dynamic viscoelasticity was measured, and the storage modulus was determined at 25°C.

[0188] <Estimation Method for HSP of Adhesive Compositions>

[0189] The HSP of the adhesive composition was determined by calculating the Hansen solubility parameter (HSP) of each constituent material of the composition using the Y-MB method of Hansen Solubility Parameter in Practice (HSPiP) and taking the average value based on their volume ratio in the composition.

[0190] <Method for determining HSP in acrylic films>

[0191] Acrylic films were immersed for 24 hours in five solvents with different solubilities: methyl ethyl ketone, methanol, n-hexane, trichlorobenzene, γ-butyrolactone, and mixtures thereof. The transparent protective films after 24 hours of immersion were classified into three categories: (1) dissolved, (2) swollen, and (3) insoluble. Based on the solubility information obtained in each solvent, the Hansen Solubility Parameter in Practice (HSPiP) ver. 5.4.04 (http: / / www.hansen-solubility.com / index.php) was used to calculate the Hansen Solubility Parameter (HSP).

[0192] <HSP distance between the HSP of the transparent protective film and the HSP of the adhesive composition>

[0193] When the dispersion term of the Hansen solubility parameter of the acrylic film is set as σd, the polarity term as σp, and the hydrogen bonding term as σh, and the dispersion term of the Hansen solubility parameter of the adhesive composition is set as σAd, the polarity term as σAp, and the hydrogen bonding term as σAh, the following mathematical formula is used as the definition of "the HSP distance between the HSP of the acrylic film and the HSP of the adhesive composition":

[0194] Ra=[4×(σd-σAd) 2 +2×(σp-σAp) 2 +2×(σh-σAh) 2 ] 1 / 2

[0195] The Hansen solubility parameters of the acrylic film and adhesive composition, calculated using the method described above, were used for calculation.

[0196] <Acrylic film>

[0197] As an acrylic film, it uses the trade name "RX420" manufactured by Nippon Shokubai Co., Ltd.

[0198] <Liquid crystal film>

[0199] Based on the following photopolymerizable liquid crystal composition, the following λ / 2 phase difference film was obtained as a liquid crystal film.

[0200] <Photopolymerizable Liquid Crystal Composition>

[0201] A photopolymerizable liquid crystal compound (BASF's "Paliocolor LC242") displaying a nematic liquid crystal phase was dissolved in cyclopentanone to prepare a solution with a solid content of 30% by weight. A surfactant (BYK-CHEMIE's "BYK-360") and a photopolymerization initiator (IGM Resins' "Omnirad 907") 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.

[0202] <λ / 2 phase difference film>

[0203] A biaxially stretched norbornene film (ZeonorFilm, Japan, thickness: 33 μm, front retardation: 135 nm) was used as the substrate. The aforementioned liquid crystal composition was applied to the substrate using a wire-wound bar coater to achieve a phase difference of λ / 2. The liquid crystal was oriented by heating at 100°C for 3 minutes. 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 with homogeneous alignment liquid crystal layers.

[0204] <Fabrication of Polarizing Film>

[0205] A polyvinyl alcohol (PVA) film with an average degree of polymerization of 2400, a saponification degree of 99.9 mol%, and a thickness of 45 μm was prepared. The PVA film was immersed for 30 seconds in a swelling bath (water bath) at 30°C between rollers with different peripheral speed ratios, while simultaneously swelling and stretching to 2.2 times its original length in the transport direction (swelling process). Next, it was immersed for 30 seconds in a dyeing bath at 30°C (an iodine aqueous solution prepared by mixing iodine and potassium iodide in a 1:7 weight ratio relative to 100 parts by weight of water), adjusting the iodine concentration to achieve a given transmittance for the polarizing film, while simultaneously stretching to 3.3 times its original length in the transport direction (dyeing process) based on the original PVA film (a completely unstretched PVA film in the transport direction). Next, the dyed polyvinyl alcohol (PVA) film was immersed in a crosslinking bath at 40°C (an aqueous solution of 3.5 wt% boric acid, 3.0 wt% potassium iodide, and 3.6 wt% zinc sulfate) for 28 seconds, and stretched to 3.6 times its original thickness in the transport direction (crosslinking process). Further, the resulting PVA film was immersed in a stretching bath at 64°C (an aqueous solution of 4.8 wt% boric acid, 5.0 wt% potassium iodide, and 5.0 wt% zinc sulfate) for 60 seconds, and stretched to 6.0 times its original thickness in the transport direction (stretching process), then immersed in a cleaning bath at 29°C (2.3 wt% potassium iodide) for 10 seconds (cleaning process). The cleaned PVA film was dried at 40°C for 30 seconds to produce a polarizing film. The thickness of the polarizing film was 18 μm.

[0206] <Fabrication of Polarizing Film>

[0207] As an adhesive, an aqueous solution containing polyvinyl alcohol resin with acetylacetyl groups (average degree of polymerization of 1200, degree of saponification of 98.5 mol%, degree of acetylacetylation of 5 mol%) and hydroxymethyl melamine in a weight ratio of 3:1 was used. Using this adhesive, a 39 μm thick cellulose triacetate film (manufactured by KONICA MINOLTA, trade name "KC4UY") with a hard coating was laminated to one side of the polarizing film obtained above via an aqueous adhesive layer 7, and a 30 μm thick acrylic film (RX420) was laminated to the other side via an aqueous adhesive layer 3. Then, the film was further dried in an oven (temperature of 60°C for 4 minutes) to produce polarizing film 1.

[0208] <Active Energy Rays>

[0209] Visible light (a gallium-encapsulated metal halide lamp) was used as the active energy beam. Irradiation device: Light HAMMER10, manufactured by FusionUV Systems, Inc.; Valve: V-valve; Peak illuminance: 1600 mW / cm². 2Cumulative exposure dose 1000 mJ / cm 2 (Wavelength 380~440nm). It should be noted that the illuminance of visible light was measured using the Sola-Check system manufactured by Solatell.

[0210] Examples 1-4 and Comparative Examples 1-2

[0211] For polarizing film 1, using an MCD coating machine (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roller line count: 700 lines / inch, rotation speed 140% / pair line speed), the adhesive composition adjusted to the proportions listed in Table 1 was applied to the acrylic film surface of the polarizing film and the parallel-aligned liquid crystal layer of the liquid crystal film (a laminate of biaxially oriented norbornene film and parallel-aligned liquid crystal layer), such that the adhesive layer thickness reached 2 μm. The layers were then bonded using a roller press. Next, the adhesive composition was cured by irradiating the biaxially oriented norbornene film side with visible light through an active energy irradiation device. The biaxially oriented norbornene film was then peeled off, resulting in a laminated optical film.

[0212] The materials constituting the adhesive composition are described below.

[0213] • Polymer compound A: Acryloylmorpholine (trade name "ACMO", manufactured by KJ Chemicals) (HSP distance from acrylic film: 1.9)

[0214] • Polymer compound B: Tripropylene glycol diacrylate (trade name "ARONIX M-220", manufactured by Toa Synthetic Co., Ltd.) (HSP distance from the acrylic film: 8.9)

[0215] • Polymer compound C: Phenoxy diethylene glycol acrylate (trade name "LIGHT ACRYLATE P2H-A", manufactured by Kyoei Chemical Co., Ltd.) (HSP distance from the acrylic film: 6.5)

[0216] • Polymerizable compound D: 3-Methylacrylamidophenylboronic acid (trade name "MAPBA", manufactured by Junki Chemical Co., Ltd.) (HSP distance from acrylic film: 15.7)

[0217] • Polymer compound E: 4-Hydroxybutyl acrylate (trade name "4HBA", manufactured by Mitsubishi Chemical Corporation) (HSP distance from the acrylic film: 6.4)

[0218] • Polymer compound F: 1,9-Nonadiol diacrylate (trade name "LIGHT ACRYLATE 1,9ND-A", manufactured by Kyoei Chemical Co., Ltd.) (HSP distance from acrylic film 8.5)

[0219] • Initiator 1 (2-Methyl-1-(4-methylthiophenyl)-2-morpholinylpropane-1-one): (Trade name: Omnirad 907, Manufacturer: IGM Resins BV)

[0220] • Initiator 2 (Diethylthioxanthone): (Trade name "KAYACURE DETX-S", manufactured by Nippon Kayaku Co., Ltd.)

[0221] Examples 5-6

[0222] As the first optical film, an acrylic film was used instead of a liquid crystal film (i.e., a laminated structure of acrylic film-acrylic film). The formulation of the adhesive composition was further changed to the formulation described in Table 1. Otherwise, the laminated optical film was manufactured by the same method as in Examples 1-4 and Comparative Examples 1-2.

[0223] (Appearance evaluation (evaluation of the presence or absence of oxalic acid highlights))

[0224] A sample for evaluating humidification durability was prepared by bonding the manufactured laminated optical film to one side of 0.7 mm thick alkali-free glass via an adhesive layer (20 μm thick). The sample was placed in an environment of 85°C–85% humidity and then subjected to a 500-hour humidification durability test. Using a differential interference microscope at 5x magnification, 760 μs exposure time, and 1x gain, with the orthogonal Nicol polarizing plate perpendicular to the transmission axes of the laminated optical film, a 2 mm × 3 mm area with the highest number of oxalic acid bright spots was trimmed within 5 mm of the sample end face. The number of bright spots was counted using ImageJ ver. 1.8.0. Cases with fewer than 15 bright spots were marked "○", cases with 15–30 bright spots were marked "△", and cases with more than 30 bright spots were marked "×". The results are shown in Table 1.

[0225] (Initial peel force (initial adhesive force))

[0226] The obtained laminated optical film was cut into 200mm × 15mm pieces and adhered to a glass plate. Then, a cut was made between the acrylic film and the first optical film using a cutter. Using a Tensilon peeler, the acrylic film and the first optical film were peeled at a 90-degree angle at a peeling speed of 10000mm / min, and the peel strength (N / 15mm) was measured. Cases where the acrylic film or the first optical film broke, or where the peel strength exceeded 1.5N, were marked with "◎"; cases where the peel strength was 1~1.5N were marked with "○"; cases where the peel strength was 0.5N or more but less than 1N were marked with "△"; and cases where the peel strength was less than 0.5N were marked with "×". The results are shown in Table 1.

[0227] (Moisturized peel strength (Moisturized adhesive strength))

[0228] The obtained laminated optical film was placed in an oven at 20℃ and 98% humidity for 240 hours. Then, a 200mm × 15mm piece of the laminated optical film was cut and adhered to a glass plate. Next, a cut was made between the acrylic film and the first optical film using a cutter. Using a Tensilon peeler, the acrylic film and the first optical film were peeled at a 90-degree angle at a peeling speed of 10000mm / min, and the peel strength (N / 15mm) was measured. Cases where the acrylic film or the first optical film broke, or where the peel strength exceeded 1.5N, were marked with "◎"; cases where the peel strength was 1~1.5N were marked with "○"; cases where the peel strength was 0.5N or more but less than 1N were marked with "△"; and cases where the peel strength was less than 0.5N were marked with "×". The results are shown in Table 1.

[0229]

[0230] As shown in Table 1, the laminated optical films of Examples 1 to 6 exhibited excellent appearance characteristics, even after the humidification durability test, with the generation of bright spots originating from impurities suppressed, and the adhesion between the laminated optical films was also excellent.

Claims

1. A laminated optical film, comprising at least an acrylic film and a first optical film laminated together via an adhesive layer, wherein, The adhesive layer is formed from a cured layer of an adhesive composition containing at least a polymeric compound. The acrylic film and the adhesive layer have a structure in direct contact. The HSP distance between the acrylic film and the adhesive layer is greater than 1.9 and less than 5.

0. The elastic modulus of the adhesive layer is 10. 8 Pa or higher and 3×10 9 Below Pa.

2. The stacked optical film according to claim 1, wherein, The first optical film is a liquid crystal film or a phase difference film.

3. The stacked optical film according to claim 1 or 2, wherein, The thickness of the adhesive layer is 0.1~10μm.

4. The laminated optical film according to any one of claims 1 to 3, wherein, On the side opposite to the side of the first optical film on which the acrylic film is stacked, a second optical film is further stacked via an adhesive layer.

5. The stacked optical film according to claim 4, wherein, The second optical film is a liquid crystal film or a phase difference film.

6. The laminated optical film according to any one of claims 1 to 5, wherein, The adhesive composition contains polymeric compound A. The distance between the polymeric compound A and the HSP of the acrylic film is greater than 0.0 and less than 4.

0. When the total amount of the polymeric compound contained in the adhesive composition is set to 100 parts by mass, the content of polymeric compound A is 20 parts by mass or more and 60 parts by mass or less.

7. The laminated optical film according to any one of claims 1 to 6, wherein, The adhesive composition contains polymeric compound B. The polymerizable compound B is a compound having at least two polymerizable groups. When the total amount of the polymeric compound contained in the adhesive composition is set to 100 parts by mass, the content of the polymeric compound B is 20 parts by mass or more and 50 parts by mass or less.

8. The stacked optical film according to claim 6, wherein, The adhesive composition contains polymeric compound C. The distance between the polymeric compound C and the HSP of the acrylic film is greater than 4.0 and less than 8.

0. When the total amount of the polymeric compound contained in the adhesive composition is set to 100 parts by mass, the content of the polymeric compound C is less than or equal to the amount of the polymeric compound A.

9. The laminated optical film according to any one of claims 1 to 8, wherein, The adhesive composition contains polymeric compound D. The polymerizable compound D is 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, an aliphatic hydrocarbon group, an aryl group, or a heterocyclic group with substituents. When the total amount of the polymeric compound contained in the adhesive composition is set to 100 parts by mass, the content of the polymeric compound D is more than 1 part by mass and less than 10 parts by mass.

10. The stacked optical film according to claim 9, wherein, The adhesive composition contains a polymeric compound E. The polymeric compound E is a polymeric compound containing hydroxyl groups. When the content of the polymeric compound D is set to 1, the content of the polymeric compound E is 1 or more and 15 or less.

11. An image display device comprising at least one laminated optical film as described in any one of claims 1 to 10.

Images