KR20240004227A - Laminated Optical Film - Google Patents

Abstract

The laminated optical film (X) of the present invention includes an optical film (10), an adhesive layer (30), and an optical film (20) in that order in the thickness direction (H). The adhesive layer 30 is bonded to the optical film 10 and is also bonded to the optical film 20 . The adhesive layer 30 has a side surface 31 that is concave inward from the end edge 11 of the optical film 10 and the end edge 21 of the optical film 20 in the direction perpendicular to the thickness direction H. has

Description

Laminated Optical Film

The present invention relates to laminated optical films.

The display panel has a laminated structure including, for example, a pixel panel, a touch panel, and a surface protective cover. The laminated structure of the display panel also includes various functional optical films that have certain optical functions. Examples of functional optical films include polarizer films and retardation films. The functional optical film is included in a laminated structure in a state in which it is bonded to another optical film, such as a protective film, through an adhesive, that is, in the form of a laminated optical film. Such a laminated optical film is described, for example, in Patent Document 1 below.

Japanese Patent Publication No. 2019-147865

Long-length laminated optical films are manufactured using a roll-to-roll method and are handled in the form of rolls. Meanwhile, as display panels become thinner, optical films are becoming thinner. The thinner the optical film in a laminated optical film is, the more likely it is for a phenomenon (end blocking) to occur where adjacent laminated optical films are stuck to each other at the end of the roll-shaped laminated optical film (laminated optical film roll). Specifically, it is as follows.

In a laminated optical film roll, a load is applied in the film thickness direction (roll diameter direction). When the load is large, a part of the adhesive layer (adhesive) is pushed out between the optical films at the end of the laminated optical film. When this adhesive passes over the optical film and reaches the adjacent optical film at the end of the roll, these adjacent optical films are attached to each other with the adhesive. The thinner the optical film, the easier it is for the adhesive extruded between the optical films to reach beyond the optical film and into adjacent optical films. Therefore, the thinner the optical film in a laminated optical film is, the more likely it is that edge blocking will occur. In a laminated optical film for a display panel that can be repeatedly bent (foldable), the above-described edge blocking is particularly likely to occur because the optical film and the adhesive layer are soft. Additionally, in the laminated optical film for a foldable display panel, since the adhesive layer between the optical films is soft, edge blocking is likely to occur even during external processing of the laminated optical film. Furthermore, when such a laminated optical film, which is prone to edge blocking, is mounted on a flexible device such as a smartphone and is used for a long period of time in a high temperature environment, stress in the laminated optical film is generated in the shear direction of the adhesive interface, and peeling occurs at the adhesive interface. It becomes easier to do.

The present invention provides a laminated optical film suitable for suppressing edge blocking in a laminated optical film including an adhesive layer.

The present invention [1] is a laminated optical film comprising a first optical film, an adhesive layer, and a second optical film in that order in the thickness direction, wherein the adhesive layer is bonded to the first optical film and further bonded to the second optical film. In the plane direction perpendicular to the thickness direction, the adhesive layer has a side surface that is concave inward than the first edge of the first optical film and the second edge of the second optical film.

In the present laminated optical film, as described above, the adhesive layer sandwiched between the first optical film and the second optical film has a side surface that is concave inward than the first end edge of the first optical film and the second end edge of the second optical film. has At the end edge of the laminated optical film, at a location where the adhesive layer has such a concave side, even when a load is applied in the thickness direction to the laminated optical film, the adhesive layer is pushed out between the optical films at the end edge of the laminated optical film. is suppressed. Therefore, the present laminated optical film is suitable for suppressing edge blocking.

The present invention [2] includes the laminated optical film according to the above [1], wherein the length of the concave portion of the side from the end edge located inside the plane direction among the first end edge and the second end edge is 0.05 μm or more. .

This configuration is desirable for suppressing extrusion of the adhesive layer between the optical films and, therefore, for suppressing edge blocking. Suppression of edge blocking is helpful in ensuring transportability and handleability during processing of the laminated optical film.

The present invention [3] is the laminate according to the above [1] or [2], wherein the length of the concave portion of the side from the end edge on the inside of the face direction among the first end edge and the second end edge is 1.0 μm or less. Includes optical films.

This configuration is preferable for suppressing peeling between the first and second optical films at the end of the laminated optical film. For example, the above configuration is desirable for ensuring bonding between optical films by the adhesive layer and suppressing peeling, even in a high temperature and high humidity environment. In addition, the above configuration is also preferable for ensuring impact resistance of both ends (first end, second end) of the first and second optical films by securing a reinforcing function by the adhesive layer.

1 is a cross-sectional schematic diagram of one embodiment of the laminated optical film of the present invention.
FIG. 2 is an enlarged cross-sectional view of the end of the laminated optical film shown in FIG. 1.
FIG. 3 is an enlarged cross-sectional view of the end portion of a variation of the laminated optical film shown in FIG. 1. In this modification, the side surface of the adhesive layer has a curved concave shape.
FIG. 4 is an enlarged cross-sectional view of an end portion of another modification of the laminated optical film shown in FIG. 1. In this modification, the side surface of the adhesive layer has a partially concave shape.

As shown in FIG. 1, the laminated optical film (X) as one embodiment of the laminated optical film of the present invention includes an optical film 10 (first optical film), an optical film 20 (second optical film), and , and is provided with an adhesive layer (30). The laminated optical film (X) has a sheet shape of a predetermined thickness and extends in a direction (plane direction) perpendicular to the thickness direction (H). Specifically, the laminated optical film (X) includes an optical film (10), an adhesive layer (30), and an optical film (20) in that order in the thickness direction (H). The adhesive layer 30 bonds the optical films 10 and 20 together. The laminated optical film has an elongated shape in one direction and is handled in the form of a roll. Additionally, the laminated optical film (X) is a composite film included in the laminated structure of the display panel.

In this embodiment, the optical film 10 is a functional optical film. Examples of functional optical films include polarizer films and retardation films.

Examples of the polarizer film include hydrophilic polymer films that have been dyed with a dichroic substance and subsequently subjected to stretching. Examples of dichroic substances include iodine and dichroic dyes. Examples of hydrophilic polymer films include polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified films of ethylene/vinyl acetate copolymer. As a polarizer film, a polyene orientation film is also listed. Examples of materials for the polyene orientation film include dehydrated PVA and dehydrochlorinated polyvinyl chloride. As a polarizer film, a PVA film that has been dyed with iodine and subsequently uniaxially stretched is preferred because it has excellent optical properties such as polarization properties.

From the viewpoint of thinning, the thickness of the optical film 10 as a polarizer film is preferably 15 μm or less, more preferably 12 μm or less, further preferably 10 μm or less, and particularly preferably 8 μm or less. A thin polarizer film has excellent visibility because it has little thickness unevenness, and also has excellent durability against thermal shock because dimensional changes due to temperature changes are small. The thickness of the optical film 10 as a polarizer film is preferably 3 μm or more, more preferably 5 μm or more from the viewpoint of strength.

Examples of retardation films include λ/2 wavelength film, λ/4 wavelength film, and viewing angle compensation film. Examples of materials for the retardation film include polymer films birefringent through stretching treatment. Examples of polymer films include cellulose films and polyester films. Examples of the cellulose film include triacetylcellulose film. Examples of the polyester film include polyethylene terephthalate film and polyethylene naphthalate film. The thickness of the optical film 10 as a retardation film is, for example, 20 μm or more, for example, 150 μm or less. Additionally, as a retardation film, a film comprising a substrate such as a cellulose film and an alignment layer of a liquid crystal compound such as a liquid crystal polymer on the substrate can also be preferably used.

The optical film 20 is a transparent protective film in this embodiment. The transparent protective film is, for example, a flexible transparent resin film. Examples of materials for the transparent protective film include polyolefin, polyester, polyamide, polyimide, polyvinyl chloride, polyvinylidene chloride, cellulose, modified cellulose, polystyrene, and polycarbonate. Examples of polyolefins include cycloolefin polymer (COP), polyethylene, polypropylene, ethylene/propylene copolymer, ethylene/vinyl acetate copolymer, and ethylene/vinyl alcohol copolymer. Examples of polyester include polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. Examples of polyamides include polyamide 6, polyamide 6,6, and partially aromatic polyamide. Examples of modified cellulose include triacetylcellulose. These materials may be used individually, or two or more types may be used together. As a material for the transparent protective film, from the viewpoint of cleanliness, polyolefin is preferably used, and COP is more preferably used. Additionally, the optical film 20 is preferably a uniaxially stretched film or a biaxially stretched film.

The thickness of the optical film 20 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more from the viewpoint of the strength of the laminated optical film (X). From the viewpoint of reducing the thickness of the laminated optical film

The adhesive layer 30 is a cured product of an adhesive composition. The adhesive layer 30 is directly bonded to the optical film 10 and is also bonded directly to the optical film 20 . The adhesive composition contains a curable resin. The components of the adhesive composition are specifically as described below.

The thickness of the adhesive layer 30 is preferably 0.1 μm or more, more preferably 0.4 μm or more, further preferably 0.7 μm or more, particularly preferably 0.8 μm or more, from the viewpoint of bonding strength between the optical films 10 and 20. It is more than ㎛. From the viewpoint of reducing the thickness of the laminated optical film It is as follows.

In the laminated optical film The case where the end edges 11 and 21 are at the same position in the direction is shown as an example). At the end edge of the laminated optical film At the end of the laminated optical film Therefore, the laminated optical film (X) is suitable for suppressing the above-described edge blocking. Suppression of edge blocking is helpful in ensuring transportability and handleability during processing of the laminated optical film.

Among the end edges 11 and 21, the length L1 of the concave portion of the side surface 31 from the end edge located on the inner side in the plane direction is preferably 0.05 μm or more, more preferably 0.1 μm or more, and still more preferably 0.2 μm or more. . This configuration is desirable to suppress the adhesive layer 30 from being pushed out between the optical films 10 and 20, and thus to suppress edge blocking. Specifically, the concave length L1 is the distance between the end edges 11 and 21 of the optical films 10 and 20, which are on the inner side in the in-plane direction, and the side surface 31 of the adhesive layer 30 in the in-plane direction. It is the distance in the plane direction between the innermost end.

The concave length L1 is preferably 1.0 μm or less, more preferably 0.8 μm or less, and even more preferably 0.6 μm or less. This configuration is preferable for suppressing peeling between the optical films 10 and 20 at the end of the laminated optical film X. For example, the above configuration ensures adhesion between the optical films 10 and 20 by the adhesive layer 30 even in a high temperature and high humidity environment, so that peeling (heat shrinkage of the adhesive layer 30 during processing of the laminated optical film) is prevented. It is desirable to suppress peeling due to large size. In addition, the above configuration is also desirable to secure the reinforcing function of the adhesive layer 30 for the ends 10a and 20a of the optical films 10 and 20, thereby ensuring the impact resistance of the ends 10a and 20a.

The above-mentioned side surface 31 has a substantially straight shape at a position retracted from the end edges 11 and 21 in the plane direction in the thickness direction cross section shown in FIG. 2. However, the adhesive layer 30 may have a curved concave side surface 31A, as shown in FIG. 3 (ends 31a and 31a in the thickness direction H on the side surface 31A). The case where (11, 21) are at the same position in the plane direction is shown as an example). The side surface 31A has a curved approximately V-shape in the thickness direction cross section shown in FIG. 3, and specifically, the middle portion (ends 31a, 31a) from both ends in the thickness direction H. It has a shape that gradually becomes concave inward in the surface direction toward the deepest part (31b). The length L1 of the concave portion on the side surface 31A is the innermost edge in the plane direction among the edge edges 11 and 21 of the optical films 10 and 20 and the innermost edge in the plane direction of the side surface 31A. It is the distance in the plane direction between the ends (deepest part) 31b. In the case where the adhesive layer 30 has the side surface 31A, the same as the case where the adhesive layer 30 has the side surface 31, the technical effects described above (suppression of end blocking, suppression of peeling between the ends of the optical film, optical Securing impact resistance at the end of the film) is demonstrated.

The adhesive layer 30 may have a partially concave side surface 31B, as shown in FIG. 4 (in the surface direction, the outermost end 31a and the end edge 11 of the side surface 31B, 21) is shown as an example in the same position). Additionally, the side surface 31B shown in FIG. 4 has an end surface F and an inclined surface D. The end surface F is on the side of the optical film 10 on the side surface 31B and is flush with the end edge 11. The inclined surface D is on the side of the optical film 20 on the side surface 31B, and is inclined inward in the plane direction as it goes from the end surface F toward the optical film 20 (the inclined surface D is closer to the inner surface of the optical film 20). ) is close to ). Instead of this partial concave shape, the side surface 31B may have a partial concave shape or an inclined surface (not shown) on the optical film 10 side, and the middle portion in the thickness direction H may have a partially concave shape (not shown). You can have it. The concave length L1 on the side surface 31B is the innermost edge of the end edges 11 and 21 of the optical films 10 and 20 and the innermost edge in the surface direction of the side surface 31B. It is the distance in the plane direction between the ends (31b). In the case where the adhesive layer 30 has the side surface 31B, the same as the case where the adhesive layer 30 has the side surface 31, the technical effects described above (suppression of end blocking, suppression of peeling between the ends of the optical film, optical Securing impact resistance at the end of the film) is demonstrated.

The first indentation elastic modulus of the adhesive layer 30 at 25°C measured by the nanoindentation method is preferably 0.01 GPa or more, more preferably 0.03 GPa or more, further preferably 0.05 GPa or more, especially preferably is 0.07 GPa or more (the first indentation elastic modulus is the indentation elastic modulus under the first measurement conditions. The first measurement conditions are as described later with respect to the examples, and in the first measurement conditions, the measurement sample during the load application process The maximum indentation depth of the indenter is 200 nm). This configuration is desirable from the viewpoint of securing adhesion between the optical films 10 and 20. Furthermore, this configuration helps ensure the above-described impact resistance in the optical films 10 and 20. Additionally, the first indentation elastic modulus is preferably 5 GPa or less, more preferably 3 GPa or less, and even more preferably 1 GPa or less. This configuration is desirable for ensuring the flexibility of the adhesive layer 30 when the laminated optical film (X) is used in a display panel that can be repeatedly bent (foldable). Examples of methods for adjusting the press-fit elastic modulus of the adhesive layer 30 include adjusting the composition of the adhesive composition. Specifically, adjustment of the number of functional groups of the polymerizable compound described later in the adhesive composition forming the adhesive layer 30, that is, adjustment of the acrylic equivalent or epoxy equivalent of the polymerizable compound is a method of adjusting the indentation elastic modulus of the adhesive layer 30. It is effective as

Nanoindentation is a technology that measures all physical properties of a sample on a nanometer scale. In this embodiment, the nanoindentation method is performed based on ISO14577. In the nanoindentation method, a process of indenting an indenter into a sample set on a stage (load application process) and later a process of pulling the indenter from the sample (unloading process) are performed. Among the series of processes, the indenter- The load acting between the samples and the relative displacement of the indenter with respect to the sample are measured (load-displacement measurement). By this, it is possible to obtain a load-displacement curve. From this load-displacement curve, it is possible to obtain, for the measurement sample, all physical properties based on nanometer scale measurements. For load-displacement measurement of the cross section of the adhesive layer by the nanoindentation method, for example, a nano indenter (trade name "Triboindenter", manufactured by Hysitron) can be used. Specifically, examples will be described later.

The second indentation elastic modulus of the adhesive layer 30 at 25°C measured by the nanoindentation method is preferably 0.5 GPa or more, more preferably 1 GPa or more, further preferably 1.5 GPa or more, especially preferably It is 2GPa or more (the second indentation elastic modulus is the indentation elasticity modulus under the second measurement condition. The second measurement condition is as described later with respect to the examples, and in the second measurement condition, the indentation elasticity modulus for the measurement sample during the load application process The maximum indentation depth of the indenter is 50 nm). This configuration is desirable from the viewpoint of securing adhesion between the optical films 10 and 20. Furthermore, this configuration helps ensure the above-described impact resistance in the optical films 10 and 20. Additionally, the second indentation elastic modulus is preferably 7 GPa or less, more preferably 5 GPa or less, and even more preferably 3 GPa or less. This configuration is desirable for ensuring the flexibility of the adhesive layer 30 when the laminated optical film (X) is used in a display panel that can be repeatedly bent (foldable).

In the laminated optical film More preferably, it is 1.5N/15mm or more. This configuration is desirable for realizing good bonding strength between the optical films 10 and 20, and is particularly desirable for ensuring good bonding strength between the optical films 10 and 20 for the foldable display panel. The 90° peel strength is, for example, 10 N/15 mm or less. The 90° peel strength can be measured using, for example, a Tensilon universal testing machine (product name “RTC”, manufactured by A&D Company, Limited). In this measurement, the measurement temperature is 25°C, the peeling angle is 90°, and the peeling speed is 1000 mm/min. Additionally, as a method of adjusting the 90° peel strength, for example, adjusting the composition of the adhesive composition is listed. Specific examples of the method for adjusting the 90° peel strength include adjusting the number of functional groups of the polymerizable compound described later in the adhesive composition, that is, adjusting the acrylic equivalent or epoxy equivalent of the polymerizable compound.

The ratio of the 90° peel strength (N/15 mm) to the above-mentioned first indentation elastic modulus (GPa) is preferably 5 or more, more preferably 10 or more, further preferably 15 or more, and also preferably 30. or less, more preferably 25 or less. The ratio of the 90° peel strength (N/15 mm) to the above-mentioned second indentation elastic modulus (GPa) is preferably 0.2 or more, more preferably 0.3 or more, further preferably 0.4 or more, and further preferably 5 or less. , more preferably 3 or less, even more preferably 2 or less. These configurations are preferable in that they suppress peeling between the optical films 10 and 20 when the laminated optical film X is repeatedly bent.

The adhesive layer 30 is, for example, a cured product of an adhesive composition containing an active energy ray-curable resin (active energy ray-curable composition). Examples of the active energy ray curable composition include electron beam curable composition, ultraviolet ray curable composition, and visible ray curable composition. In addition, in this embodiment, the active energy ray-curable composition is one or both of a radical polymerization type composition and a cation polymerization type composition.

When the active energy ray-curable composition is a radically polymerizable composition, the composition contains a radically polymerizable compound as a monomer. A radically polymerizable compound is a compound having a radically polymerizable functional group. Examples of radically polymerizable functional groups include ethylenically unsaturated bond-containing groups. Examples of ethylenically unsaturated bond-containing groups include (meth)acryloyl group, vinyl group, and allyl group. (meth)acryloyl group means acryloyl group and/or methacryloyl group. From the viewpoint of curability of the active energy ray-curable composition, it is preferable that the active energy ray-curable composition contains a radically polymerizable compound having a (meth)acryloyl group as a main component. The main component refers to the component that has the largest proportion by mass. The proportion of the (meth)acryloyl group-containing radically polymerizable compound in the active energy ray-curable composition is, for example, 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more. Additionally, examples of the radically polymerizable compounds include monofunctional radically polymerizable compounds and bifunctional or more polyfunctional radically polymerizable compounds.

Examples of monofunctional radically polymerizable compounds include (meth)acrylamide derivatives having a (meth)acrylamide group. As (meth)acrylamide derivatives, (meth)acrylamide derivatives containing an N-alkyl group, (meth)acrylamide derivatives containing an N-hydroxyalkyl group, (meth)acrylamide derivatives containing an N-aminoalkyl group, (meth)acrylamide derivatives containing an N-alkoxy group ( Meth)acrylamide derivatives, and N-mercaptoalkyl group-containing (meth)acrylamide derivatives are listed. Examples of N-alkyl group-containing (meth)acrylamide derivatives include N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and N- Isopropyl(meth)acrylamide, N-butyl(meth)acrylamide, and N-hexyl(meth)acrylamide are listed, and N,N-diethylacrylamide is preferably used. Examples of N-hydroxyalkyl group-containing (meth)acrylamide derivatives include N-methylol (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, and N-methylol-N-propane (meth)acrylamide. ) Acrylamides are listed, and N-hydroxyethyl acrylamide is preferably used. The (meth)acrylamide derivative may be used individually, or two or more types may be used together.

Examples of monofunctional radically polymerizable compounds include (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Examples of the (meth)acrylic acid derivatives include (meth)acrylic acid alkyl esters and (meth)acrylic acid derivatives other than (meth)acrylic acid alkyl esters. The (meth)acrylic acid derivative may be used individually, or two or more types may be used together.

Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and n-butyl (meth)acrylate. Acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, 4-methyl-2-propylpentyl(meth)acrylate, and n-octadecyl(meth)acrylate are listed.

Examples of (meth)acrylic acid derivatives other than (meth)acrylic acid alkyl esters include (meth)acrylic acid cycloalkyl ester, (meth)acrylic acid aralkyl ester, hydroxyl group-containing (meth)acrylic acid derivative, and alkoxy group-containing (meth)acrylic acid. Derivatives, and phenoxy group-containing (meth)acrylic acid derivatives are listed. Examples of (meth)acrylic acid cycloalkyl esters include cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate. Examples of (meth)acrylic acid aralkyl esters include benzyl (meth)acrylate and 3-phenoxybenzyl (meth)acrylate. Examples of hydroxyl group-containing (meth)acrylic acid derivatives include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxy. Butyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, [4-(hydroxymethyl)cyclohexyl]methyl acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate. are listed. Examples of alkoxy group-containing (meth)acrylic acid derivatives include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, and 3-methoxybutyl (meth)acrylate. . Examples of phenoxy group-containing (meth)acrylic acid derivatives include phenoxyethyl (meth)acrylate and phenoxydiethylene glycol (meth)acrylate. (meth)acrylic acid derivatives other than (meth)acrylic acid alkyl esters are preferably selected from the group consisting of 3-phenoxybenzyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and phenoxydiethylene glycol acrylate. At least one selected is used.

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

Monofunctional radically polymerizable compounds also include lactam-based vinyl monomers. Examples of lactam-based vinyl monomers include N-vinyl-2-pyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone.

Examples of monofunctional radically polymerizable compounds include vinyl monomers having a nitrogen-containing heterocycle. Examples of the monomer include vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, and vinyl morpholine.

Examples of polyfunctional radically polymerizable compounds include tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanedi. Old-(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecane dimethanol di( Meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol Tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate are used, and tripropylene glycol diacrylate is preferably used. The polyfunctional radically polymerizable compound may be used individually, or two or more types may be used together. The polyfunctional radically polymerizable compound functions as a crosslinking agent.

When the active energy ray curable composition is an ultraviolet ray curable composition or a visible ray curable composition, the active energy ray curable composition preferably contains a photopolymerization initiator. Examples of the photopolymerization initiator include benzophenone compounds, benzoin ether compounds, and thioxanthone compounds. Examples of benzophenone compounds include benzyl, benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone. Examples of benzoin ether compounds include benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin butyl ether. Examples of thioxanthone compounds include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, and 2,4-dichlorothioxanthone. Santhone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone are listed.

When the active energy ray-curable composition is a visible ray-curable composition, a photopolymerization initiator that is highly sensitive to light of 380 nm or more is preferably used. Examples of such photopolymerization initiators include 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholino Phenyl)-butanone-1,2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and bis(η5-2,4-cyclopentadien-1-yl)-bis(2 ,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium are listed.

As a photopolymerization initiator, 2,4-diethylthioxanthone and/or 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one is preferably used.

The content of the photopolymerization initiator in the active energy ray-curable composition is preferably 0.1 part by mass or more, more preferably 0.05 part by mass or more, and still more preferably 0.1 part by mass, based on 100 parts by mass of the curable component (radically polymerizable compound). parts or more, and is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less.

When the active energy ray-curable composition is a cationically polymerizable composition, the composition contains a cationically polymerizable compound as a monomer. Cationically polymerizable compounds are compounds having a cationically polymerizable functional group, and include monofunctional cationically polymerizable compounds having one cationically polymerizable functional group and polyfunctional cationically polymerizable compounds having two or more cationically polymerizable functional groups. Monofunctional cationic polymerizable compounds have relatively low liquid viscosity. By blending such a monofunctional cationically polymerizable compound into the resin composition, the viscosity of the resin composition is reduced. In addition, monofunctional cationic polymerizable compounds often have functional groups that express various functions. By blending such a monofunctional cationically polymerizable compound into a resin composition, various functions are expressed in the resin composition and/or a cured product of the resin composition. On the other hand, by curing a resin composition containing a polyfunctional cationically polymerizable compound, a cured product having a three-dimensional crosslinked portion is obtained (the polyfunctional cationically polymerizable compound functions as a crosslinking agent). From this point of view, the use of polyfunctional cationically polymerizable compounds is desirable. When using a monofunctional cationic polymerizable compound and a polyfunctional cationic polymerizable compound together, the amount of the polyfunctional cationic polymerizable compound relative to 100 parts by mass of the monofunctional cationic polymerizable compound is, for example, 10 parts by mass or more. For example, it is 1000 parts by mass or less. Examples of cationically polymerizable functional groups include epoxy group, oxetanyl group, and vinyl ether group. Examples of compounds having an epoxy group include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds. As the compound having an epoxy group, an alicyclic epoxy compound is preferably used from the viewpoint of curability and adhesiveness of the cationically polymerizable composition. Examples of the alicyclic epoxy compound include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate or 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate. Caprolactone denatures, trimethyl caprolactone denatures, and valerolactone denatures are listed. Examples of commercially available alicyclic epoxy compounds include Celoxide 2021, Celoxide 2021A, Celoxide 2021P, Celoxide 2081, Celoxide 2083, and Celoxide 2085 (manufactured by Daicel Chemical Industries, Ltd.). , Also listed are Cyracure UVR-6105, Cyracure UVR-6107, Cyracure 30, and R-6110 (manufactured by Dow Chemical Japan Limited). From the viewpoint of improving the curability and lowering the viscosity of the cationically polymerizable composition, it is preferable to use a compound having an oxetanyl group and/or a compound having a vinyl ether group. Examples of compounds having an oxetanyl group include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]benzene, and 3-ethyl. -3-(phenoxymethyl)oxetane, di[(3-ethyl-3-oxetanyl)methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, and phenolnovoloxe. Setan is listed. Commercially available compounds having an oxetanyl group include, for example, Aaronoxetane OXT-101, Aaronoxetane OXT-121, Aaronoxetane OXT-211, Aaronoxetane OXT-221, and Aaronoxetane OXT-212 (above , manufactured by Toagosei Co., Ltd.) are listed. Examples of compounds having a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, and cyclohexane. Dimethanol divinyl ether, cyclohexanedimethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, and pentaerythritol type tetravinyl ether are listed.

When the active energy ray curable composition is an ultraviolet ray curable composition or a visible ray curable composition, the active energy ray curable composition contains a photo cationic polymerization initiator. The photo cationic polymerization initiator generates cationic species or Lewis acids when irradiated with active energy rays (visible rays, ultraviolet rays, As photocationic polymerization initiators, photoacid generators and photobase generators are listed, and photoacid generators are preferably used. When the active energy ray-curable composition is a visible ray-curable composition, it is preferable to use a photo cationic polymerization initiator that is particularly sensitive to light of 380 nm or more. Additionally, when using a photo cationic polymerization initiator, it is preferable to use together a photosensitizer that exhibits maximum absorption for light with a wavelength longer than 380 nm. Since the photo cationic polymerization initiator is generally a compound that shows maximum absorption in the vicinity of 300 nm or shorter wavelength region, it can effectively absorb light with a wavelength longer than 380 nm by using it together with a photosensitizer that shows maximum absorption in light with a wavelength longer than 380 nm. When used, the generation of cationic species or Lewis acids from a photocationic polymerization initiator can be promoted. Examples of the photosensitizer include anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo compounds, diazo compounds, halogen compounds, and photoreducible dyes. These may be used individually, or two or more types may be used together. In particular, anthracene compounds are preferred because they have excellent light sensitization effects. Commercially available anthracene compounds as photosensitizers include, for example, Anthracure UVS-1331 and Anthracene UVS-1221 (manufactured by Kawasaki Kasei Chemicals Ltd.). The content of the photosensitizer in the composition is, for example, 0.1 to 5% by weight.

The active energy ray-curable composition may contain an oligomer. As oligomers, acrylic oligomers, fluorine oligomers, and silicone oligomers are listed, and acrylic oligomers are preferably used. The incorporation of oligomers into the active energy ray-curable composition helps suppress shrinkage during curing of the composition. Suppression of curing shrinkage of the active energy ray-curable composition is desirable for reducing the interfacial stress between the formed adhesive layer 30 and the optical films 10 and 20. Suppression of interfacial stress helps secure adhesion between the optical films 10 and 20.

Examples of (meth)acrylic monomers forming acrylic oligomers include (meth)acrylic acid alkyl esters having 1 to 20 carbon atoms, cycloalkyl (meth)acrylates, aralkyl (meth)acrylates, and polycyclic (meth)acrylates. esters, hydroxyl group-containing (meth)acrylic acid esters, and halogen-containing (meth)acrylic acid esters are listed. Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and 2-methyl-2-nitro. Propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, S-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate , t-pentyl (meth)acrylate, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, and N-octadecyl (meth)acrylate. Examples of cycloalkyl (meth)acrylate include cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate. Examples of aralkyl (meth)acrylate include benzyl (meth)acrylate. Polycyclic (meth)acrylates include, for example, 2-isobornyl (meth)acrylate, 2-norbornylmethyl (meth)acrylate, and 5-norbornen-2-yl-methyl (meth)acrylate. nitrate, and 3-methyl-2-norbornylmethyl(meth)acrylate. Examples of hydroxyl-containing (meth)acrylic acid esters include hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate. are listed. Halogen-containing (meth)acrylic acid esters include, for example, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethyl ethyl (meth)acrylate, and tetrafluoropropyl ( Meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, and heptadecafluorodecyl (meth)acrylate are listed. These (meth)acrylates may be used individually, or two or more types may be used together.

The weight average molecular weight (Mw) of the acrylic oligomer is preferably 15,000 or less, more preferably 10,000 or less, and still more preferably 5,000 or less. The Mw of the acrylic oligomer is preferably 500 or more, more preferably 1000 or more, and still more preferably 1500 or more.

The content of acrylic oligomer in the active energy ray-curable composition is preferably 2% by mass or more, more preferably 4% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less.

The active energy ray-curable composition may contain other components. Other ingredients include silane coupling agents, leveling agents, surfactants, plasticizers, and ultraviolet absorbers. The blending amount of the other components is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, with respect to 100 parts by mass of the curable component, and for example, 0.01 parts by mass or more. am.

The viscosity of the active energy ray-curable composition at 25°C is preferably 3 mPa·s or more, more preferably 5 mPa·s or more, and still more preferably 10 mPa·s or more from the viewpoint of applicability in the later application process. , and is also preferably 100 mPa·s or less, more preferably 50 mPa·s or less, and even more preferably 30 mPa·s or less. The viscosity of the composition is a value measured with an E-type viscometer (corn plate type viscometer).

The laminated optical film (X) can be manufactured, for example, as follows.

First, an active energy ray curable composition is applied to one side (the surface to be bonded) of one optical film (optical film 10 or optical film 20) to form a coating film of the composition (application process). Before this application process, the surface to be bonded to the optical film may be subjected to surface modification treatment. Surface modification treatments include corona treatment, plasma treatment, excimer treatment, and frame treatment. Examples of coating methods in this process include reverse coater, gravure coater, variverse coater, roll coater, die coater, bar coater, and rod coater.

Next, the other optical film (optical film 20 or optical film 10) is bonded to one optical film via the composition coating film. For joining, for example, a roll laminator can be used.

Next, active energy rays are irradiated to the composition film between the optical films 10 and 20, and the film (active energy ray-curable composition) is cured to form the adhesive layer 30 (the adhesive layer 30 is formed under reduced pressure). not an adhesive layer). From this, the optical films 10 and 20 are bonded via the adhesive layer 30, and a raw film of the laminated optical film X is obtained. In this process, it is preferable to irradiate active energy rays from the optical film 30 side from the viewpoint of suppressing deterioration of the optical film 10 as a functional optical film. As active energy rays, electron beams, ultraviolet rays, and visible rays can be used. Examples of the electron beam irradiation means include electron beam accelerators. Light sources of ultraviolet rays and visible rays include, for example, LED lights, gallium-filled metal halide lamps, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, and gallium lamps. In this process, a wavelength cut filter for cutting a partial wavelength range in the ultraviolet rays and/or visible rays emitted from the light source may be used as needed.

Next, at least a portion of the peripheral edge of the raw film is subjected to external shape processing (outer shape processing process). For example, one longitudinal end of a roll-shaped raw film is trimmed. For example, a roll-shaped raw film is cut and processed into a sheet shape. Examples of these external processing methods include laser processing using CO ₂ laser irradiation, cutting with a cutting blade, cutting with a punching blade, and end mill processing.

According to CO ₂ laser irradiation, relatively large heat shrinkage occurs in the adhesive layer 30 at the external shape processing location of the raw material film, and the side surface 31 is concave inward from the end edges 11 and 21 of the optical film 10 and 20. ) (or side (31A)) can be formed. Specifically, the adhesive layer 30 is formed so that all or part of the side surface 31 of the adhesive layer 30 at the end of the raw film is retreated inward in the plane direction relative to the end edges 11 and 21 of the optical films 10 and 20. ) The end may be contracted to form a concave side 31 (or side 31A). The length at which the end of the adhesive layer 30 shrinks, that is, the concave length L1, can be adjusted, for example, by adjusting the composition of the adhesive layer 30 and the CO ₂ laser irradiation conditions.

By cutting with a cutting blade, the end of the adhesive layer 30 is partially removed, thereby forming a side 31 (or side 31A, 31B)) can be formed. Methods for adjusting the position and degree of partial removal include, for example, adjustment of the difference in elastic modulus between the optical films 10, 20 and the adhesive layer 30, adjustment of the thermal contraction rate of the adhesive layer 30, adjustment of thickness, and cutting. The adjustment of the friction force occurring between the cutting blade and the adhesive layer 30 is listed. The friction force can be adjusted, for example, by the composition of the adhesive layer 30.

For example, the laminated optical film (X) can be manufactured as described above.

Example

The present invention will be described in detail below by giving examples. The present invention is not limited to the examples. In addition, specific values such as mixing amount (content), physical property values, parameters, etc. described below are described in the above-mentioned "Specific Details for Carrying out the Invention", and the corresponding mixing amount (content), physical property values, and parameters It can be replaced with an upper limit (a numerical value defined as “less than” or “less than”) or a lower limit (a numerical value defined as “more than” or “exceeds”).

[Example 1]

The following components were mixed at 25°C for 1 hour to prepare an adhesive composition.

45 parts by mass of 3-phenoxybenzyl acrylate (product name “Light Acrylate POB-A”, monomer, manufactured by Kyoeisha Chemical Co., Ltd.)

25 parts by mass of phenoxydiethylene glycol acrylate (product name “Light Acrylate P2H-A”, monomer, manufactured by Kyoeisha Chemical Co., Ltd.)

5 parts by mass of tripropylene glycol diacrylate (product name “Aronix M-220”, monomer, manufactured by Toagosei Co., Ltd.)

10 parts by mass of 2-hydroxy-3-phenoxypropyl acrylate (product name “Aronics M-5700”, monomer, manufactured by Toagosei Co., Ltd.)

5 parts by mass of hydroxyethyl acrylamide (product name “HEAA”, monomer, manufactured by KJ Chemicals Corporation)

5 parts by mass of diethyl acrylamide (product name “DEAA”, monomer, manufactured by KJ Chemicals Corporation)

3 parts by mass of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (product name “OMINIRAD907”, photopolymerization initiator, manufactured by IGM Resins)

3 parts by mass of 2,4-diethylthioxanthone (product name “KAYACURE DETX-S”, photopolymerization initiator, manufactured by Nippon Kayaku Co., Ltd.)

5 parts by mass of acrylic oligomer (product name “Arupon 1190”, viscosity 6000 mPa·s (25°C), Mw 1700, Tg-50°C, manufactured by Toagosei Co., Ltd.)

0.5 parts by mass of modified polydimethylsiloxane having an acrylic group (product name “BYK-UV3505”, leveling agent, manufactured by BYK)

Next, the adhesive composition was applied onto a 23-μm-thick COP film (product name “Zeonor Film ZF14”, manufactured by Zeon Corporation) as a transparent protective film to form an adhesive film with a thickness of 1 μm. For coating, an MCD coater (manufactured by FUJI MACHINERY Co., Ltd.) (cell shape: honeycomb, number of gravure rolls 1000 pieces/inch, rotation speed 140%/line speed) was used. Next, the polarizer film was bonded to the transparent protective film through the adhesive coating film on the film. Next, the adhesive coating between the films was cured by irradiating ultraviolet rays to the adhesive coating from the transparent protective film side. For ultraviolet irradiation, an ultraviolet irradiation device (product name “Light HAMMER10”, valve: V valve, manufactured by Fusion UV Systems, Inc.) equipped with a gallium-encapsulated metal halide lamp as a light source was used. In ultraviolet irradiation, the peak irradiance was 1600 mW/cm ² and the accumulated irradiation amount was 1000 mJ/cm ² (wavelength 380 to 440 nm) (the illuminance was measured using the “Sola-Check system” manufactured by Solatell). In this way, the transparent protective film and the polarizer film were bonded together to obtain a laminated optical film. Next, the laminated optical film was subjected to external shape processing. Specifically, the laminated optical film was cut in the thickness direction by irradiation with a CO ₂ laser, and a laminated optical film with a predetermined planar view shape was obtained. In CO ₂ laser irradiation, the wavelength was 9.4 μm, the output was 48 W, and the scanning speed was 500 mm/sec. Next, the laminated optical film was left at room temperature for 24 hours.

As described above, the laminated optical film of Example 1 was produced. The laminated optical film of Example 1 includes a polarizer film (5 μm thick), an adhesive layer, and a transparent protective film (23 μm thick) in this order in the thickness direction.

[Example 2]

The laminated optical film of Example 2 (polarizer film/ Adhesive layer/transparent protective film) was produced.

[Example 3]

The laminated optical film of Example 3 (polarizer film/ Adhesive layer/transparent protective film) was produced.

[Comparative Example 1]

The laminated optical film of Comparative Example 1 (polarizer film/ Adhesive layer/transparent protective film) was produced.

<Indentation elastic modulus>

The indentation elastic modulus of the adhesive layer in each laminated optical film of Examples 1 to 3 and Comparative Example 1 was measured by the nanoindentation method. Specifically, first, a film piece (laminated optical film) with a size of 5 mm x 10 mm was cut from the laminated optical film. Next, the laminated optical film was cut by the cryomicrotome method. Specifically, the laminated optical film was cooled to -30°C, cut with a hard knife in the thickness direction of the film, and then returned to room temperature. As a result, a sample for measurement was obtained. Next, using a nano indenter (product name “TI950 Triboindenter”, manufactured by Hysitron), load-displacement measurement was performed on the exposed surface of the adhesive layer in the measurement sample in accordance with JIS Z 2255:2003, and the load -Displacement curve was obtained. In this measurement, the measurement mode is single indentation measurement, the measurement temperature is 25°C, the indenter used is a Berkovich (triangular pyramid) type diamond indenter, and the maximum indentation depth of the indenter to the measurement sample during the load application process is (Maximum displacement hmax) was set to 200 nm, the indentation speed of the indenter was set to 10 nm/sec, and the pulling speed of the indenter from the measurement sample in the unloading process was set to 10 nm/sec (first measurement condition). Then, the obtained measurement data was processed using “TI950 Triboindenter” dedicated analysis software (ver. 9.4.0.1). Specifically, based on the obtained load (f)-displacement (h) curve, the maximum load fmax (load acting on the indenter at the maximum displacement hmax) and the contact projection area S (contact between the indenter and the sample at the maximum load) The projected area of the area) and the slope D of the tangent line of the load-displacement curve at the start of the unloading process were obtained. Then, the indentation elastic modulus of the adhesive layer (=(π ^1/2 D)/(2S ^1/2 )) was calculated from the slope D and the contact projection area S.

Meanwhile, load-displacement measurement using a nano indenter was performed under the same measurement conditions (second measurement conditions) as the first measurement conditions except that the maximum indentation depth was changed from 200 nm to 50 nm. Then, the obtained measurement data was processed with "TI950 Triboindenter" dedicated analysis software (Ver. 9.4.0.1), and the indentation elastic modulus of the adhesive layer was calculated.

<Observation at the end>

For each laminated optical film of Examples 1 to 3 and Comparative Example 1, the longitudinal cross-sectional shape of the end portion was examined. Specifically, first, an arbitrarily selected location from the peripheral edge of the laminated optical film was cut in the thickness direction to form a longitudinal cross section for observation. Next, the longitudinal cross section was observed and photographed using an optical microscope. In addition, in the observation cross section of each laminated optical film of Examples 1 to 3, the end edge (side) of the adhesive layer is adjacent to the end edge (first end edge) of the polarizer film and the end edge of the transparent protective film in the film plane direction. It was confirmed that it was located on the inner side of the (second end edge). In the observation cross section of the laminated optical film of Comparative Example 1, the end edge (side) of the adhesive layer is the end edge of the polarizer film (first end edge) and the end edge of the transparent protective film (second end edge) in the film plane direction. ) was confirmed to be outside.

In addition, in each observation cross section, the planar retraction length d1 of the adhesive layer side surface from the end edge (first end edge) of the polarizer film, and the adhesive layer side surface from the end edge (second end edge) of the transparent protective film. The retreat length d2 in the plane direction was measured. The results are shown in Table 1. In addition, the length L1 of the concave portion on the side of the adhesive layer from the first edge and the second edge in the plane direction, which is on the inner side in the plane direction (corresponding to the longer of the retraction lengths d1 and d2) , shown in Table 1. When the concave length L1 takes a negative value, the end edge of the adhesive layer is outside the end edge of the polarizer film (first end edge) and the end edge of the transparent protective film (second end edge) in the film plane direction. there is. And, regarding the anti-blocking property of the edge of the laminated optical film, when the concave length L1 exceeded 0 μm, it was evaluated as “good”, and when it was 0 μm or less, it was evaluated as “poor.” The evaluation results are shown in Table 1.

<Impact resistance>

Regarding the impact resistance of each laminated optical film of Examples 1 to 3 and Comparative Example 1, the case where no damage (cracks, defects, etc.) occurred on both the polarizer film and the transparent protective film in the above observation cross section was considered "good." ", and the case in which at least one of the polarizer film and the transparent protective film was damaged was evaluated as "defect." The evaluation results are shown in Table 1.

Example 1 Example 2 Example 3 Comparative Example 1 Retreat length d1 (㎛) 0.1 0.95 1.2 -0.5 Retreat length d2 (㎛) 0.1 0.95 1.2 -0.5 Concave length L1 (㎛) 0.1 0.95 1.2 -0.5 Anti-blocking properties at the ends Good Good Good error impact resistance Good Good error Good

The laminated optical film of the present invention can be used, for example, as an element included in the laminated structure of a display panel such as a foldable display panel.

X Laminated Optical Film
H Thickness direction
10 Optical film (first optical film)
10a end
11 Last edge (1st last edge)
20 Optical film (second optical film)
20a end
21 Last Edge (2nd Last Edge)
30 adhesive layer
31, 31A, 31B sides
End of 31a, 31b

Claims (3)

A laminated optical film comprising a first optical film, an adhesive layer, and a second optical film in that order in the thickness direction,
The adhesive layer is bonded to the first optical film and also bonded to the second optical film,
The laminated optical film, wherein the adhesive layer has a side surface that is concave inward more than the first end edge of the first optical film and the second end edge of the second optical film in a plane direction perpendicular to the thickness direction. According to claim 1,
A laminated optical film, wherein the length of the concave portion of the side from the end edge located inside the plane direction of the first end edge and the second end edge is 0.05 μm or more. According to paragraph 1 or 2,
A laminated optical film, wherein the length of the concave portion of the side from the end edge located inside the plane direction among the first end edge and the second end edge is 1.0 μm or less.