Stacked optical films

Abstract

The laminated optical film (X) of the present invention comprises, in the thickness direction (H), an optical film (10), an adhesive layer (30), and an optical film (20), wherein the adhesive layer (30) is bonded to the optical film (10) and to the optical film (20), and the adhesive layer (30) has a side surface (31) that is more concave inward than the end edge (11) of the optical film (10) and the end edge (21) of the optical film (20) in a plane direction orthogonal to the thickness direction (H).

Description

Technical Field

[0001] This invention relates to laminated optical films. Background Technology

[0002] A display panel may have, for example, a stacked structure comprising a pixel panel, a touch panel, a surface protector, etc. This stacked structure of the display panel also includes various functional optical films having a given optical function. Examples of functional optical films include polarizing films and retardation films. These functional optical films are introduced into the stacked structure, for example, in a state where they are bonded to other optical films such as protective films via adhesives, i.e., in the form of a stacked optical film. Such a stacked optical film is described, for example, in Patent Document 1 below.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-147865 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] Long strips of laminated optical films are manufactured in a roll-to-roll manner and processed in roll form. On the other hand, with the thinning of display panels, the thinning of optical films has progressed. The thinner the optical films in the laminated optical films, the easier it is for adjacent laminated optical films to stick together at the ends of the roll of laminated optical films (laminated optical film roll), as described below.

[0008] For laminated optical film rolls, a load is applied in the film thickness direction (roll radial direction). Under a large load, at the ends of the laminated optical films, a portion of the adhesive layer (adhesive) overflows from between the optical films. When this adhesive extends beyond the aforementioned optical film to reach adjacent optical films at the roll end, these adjacent optical films are bonded together by the adhesive. The thinner the optical film, the easier it is for the adhesive overflowing from between the optical films to extend beyond that optical film to reach adjacent optical films. Therefore, the thinner the optical films in a laminated optical film, the easier it is for end adhesion to occur. In laminated optical films used for repeatedly bendable (foldable) display panels, the optical films and adhesive layers are soft, therefore, the aforementioned end adhesion is particularly prone to occur. Furthermore, in laminated optical films used for foldable display panels, the adhesive layer between the optical films is soft, therefore, end adhesion is also prone to occur during the shaping process of this laminated optical film. Furthermore, when such laminated optical films, which are prone to end adhesion, are mounted on flexible devices such as smartphones, long-term use in high-temperature environments can cause stress in the shear direction of the laminated optical films at the bonding interface, making them prone to peeling at the bonding interface.

[0009] The present invention provides a laminated optical film suitable for suppressing end adhesion in a laminated optical film containing an adhesive layer.

[0010] Problem Solving Methods

[0011] The present invention [1] relates to a laminated optical film, which comprises, in the thickness direction, a first optical film, an adhesive layer, and a second optical film in sequence.

[0012] The adhesive layer is bonded to the first optical film and to the second optical film. The adhesive layer has a side surface that is more concave inward than the first end edge of the first optical film and the second end edge of the second optical film in a plane direction orthogonal to the thickness direction.

[0013] In this laminated optical film, the adhesive layer sandwiched between the first and second optical films, as described above, has a side surface that is more concave inward than the first end edge of the first optical film and the second end edge of the second optical film. At the end edges of the laminated optical film, where the adhesive layer has such a concave side surface, even when a load is applied to the laminated optical film in the thickness direction, it is possible to prevent the adhesive layer from overflowing between the optical films at the ends of the laminated optical film. Therefore, this laminated optical film is suitable for suppressing end adhesion.

[0014] The present invention [2] includes the laminated optical film described in [1] above, wherein the recess length of the side surface located inside the end edge in the surface direction of the first end edge and the second end edge is 0.05 μm or more.

[0015] This configuration is preferred for preventing the adhesive layer from overflowing between the optical films, and therefore is preferred for preventing end adhesion. Suppression of end adhesion helps ensure the transportability / handlingability of the laminated optical films during processing.

[0016] The present invention [3] includes the laminated optical film described in [1] or [2] above, wherein the recess length of the side surface located inside the end edge in the surface direction of the first end edge and the second end edge is less than 1.0 μm.

[0017] This configuration is preferred for suppressing peeling between the first and second optical films at the ends of the laminated optical films. For example, this configuration is preferred for ensuring peeling suppression based on the adhesion of the adhesive layer between the optical films even in high temperature and high humidity environments. In addition, the above configuration is also preferred for ensuring the reinforcing function of the adhesive layer on both ends (first end and second end) of the first and second optical films and ensuring the impact resistance of the two ends. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of one embodiment of the stacked optical film of the present invention.

[0019] Figure 2 yes Figure 1 The enlarged cross-sectional view of the end of the stacked optical film shown.

[0020] Figure 3 yes Figure 1 An enlarged cross-sectional view of an end of a modified example of the stacked optical film is shown, in which the side of the adhesive layer has a curved recessed shape.

[0021] Figure 4 yes Figure 1 An enlarged cross-sectional view of the end of another variation of the stacked optical film is shown, in which the side of the adhesive layer has a partially recessed shape.

[0022] Symbol Explanation

[0023] X-Layered Optical Film

[0024] H Thickness direction

[0025] 10 Optical Films (First Optical Film)

[0026] 10a end

[0027] 11. End edge (first end edge)

[0028] 20 Optical Film (Second Optical Film)

[0029] 20a end

[0030] 21. End edge (second end edge)

[0031] 30 adhesive layers

[0032] Side views of 31, 31a, and 31B

[0033] 31a, 31b ends Detailed Implementation

[0034] like Figure 1 As shown, the stacked optical film X, as one embodiment of the stacked optical film of the present invention, includes an optical film 10 (first optical film), an optical film 20 (second optical film), and an adhesive layer 30. The stacked optical film X has a sheet shape of a given thickness and is unfolded in a direction orthogonal to the thickness direction H (planar direction). Specifically, the stacked optical film X has the optical film 10, the adhesive layer 30, and the optical film 20 sequentially arranged in the thickness direction H. The adhesive layer 30 bonds the optical films 10 and 20 together. The stacked optical film has an elongated shape in one direction and is processed in a roll form. Furthermore, the stacked optical film X is a composite film introduced into a stacked structure of a display panel.

[0035] In this embodiment, the optical film 10 is a functional optical film. Examples of functional optical films include polarizing films and phase refraction films.

[0036] Examples of polarizing film include hydrophilic polymer films that have undergone dyeing with a dichroic substance and subsequent stretching. Examples of dichroic substances include iodine and dichroic dyes. Examples of hydrophilic polymer films include polyvinyl alcohol (PVA) films, partially methyl acetalized PVA films, and partially saponified films of ethylene-vinyl acetate copolymers. Polyene-oriented films can also be used as polarizing film. Examples of materials for polyene-oriented films include dehydrated PVA and dehydrochlorinated polyvinyl chloride. From the perspective of excellent optical properties such as polarization characteristics, PVA films that have undergone dyeing with iodine and subsequent uniaxial stretching are preferred as polarizing film.

[0037] From the viewpoint of thinness, the thickness of the optical film 10, which serves as the polarizing lens film, is preferably 15 μm or less, more preferably 12 μm or less, even more preferably 10 μm or less, and particularly preferably 8 μm or less. Thin polarizing lenses have excellent visual clarity due to less thickness variation, and also exhibit excellent durability against thermal shock due to minimal dimensional changes caused by temperature variations. From the viewpoint of strength, the thickness of the optical film 10, which serves as the polarizing lens film, is preferably 3 μm or more, more preferably 5 μm or more.

[0038] Examples of phase retardation films include, for example, λ / 2 wavelength films, λ / 4 wavelength films, and viewing angle compensation films. Examples of materials for phase retardation films include, for example, polymer films that have undergone birefringence through stretching. Examples of polymer films include, for example, cellulose films and polyester films. Examples of cellulose films include, for example, cellulose triacetate films. Examples of polyester films include, for example, polyethylene terephthalate films and polyethylene naphthalate films. The thickness of the optical film 10, as a phase retardation film, is, for example, 20 μm or more, and for example, 150 μm or less. Furthermore, as a phase retardation film, a film having a substrate such as a cellulose film and an alignment layer of a liquid crystal compound such as a liquid crystal polymer on that substrate is preferably used.

[0039] In this embodiment, the optical film 20 is a transparent protective film. The transparent protective film is, for example, a flexible transparent resin film. Examples of materials for the transparent protective film include: polyolefins, polyesters, polyamides, polyimides, polyvinyl chloride, polyvinylidene chloride, cellulose, modified cellulose, polystyrene, and polycarbonate. Examples of polyolefins include: cyclic olefin polymers (COP), polyethylene, polypropylene, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, and ethylene-vinyl alcohol copolymers. Examples of polyesters include: polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. Examples of polyamides include: polyamide 6, polyamide 6,6, and some aromatic polyamides. Examples of modified cellulose include: cellulose triacetate. These materials can be used alone or in combination of two or more. From a cleanliness perspective, polyolefins are preferred as materials for the transparent protective film, and COPs are more preferred. Furthermore, the optical film 20 is preferably a uniaxially stretched film or a biaxially stretched film.

[0040] From the viewpoint of the strength of the stacked optical film X, 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 thinning the stacked optical film X, the thickness of the optical film 20 is preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less.

[0041] The adhesive layer 30 is a cured form of the adhesive composition. The adhesive layer 30 is directly bonded to the optical film 10 and also directly bonded to the optical film 20. The adhesive composition contains a curable resin, the specific components of which are described below.

[0042] From the viewpoint of bonding strength between optical films 10 and 20, the thickness of adhesive layer 30 is preferably 0.1 μm or more, more preferably 0.4 μm or more, further preferably 0.7 μm or more, and particularly preferably 0.8 μm or more. From the viewpoint of thinning the laminated optical film X, the thickness of adhesive layer 30 is preferably 5 μm or less, more preferably 3 μm or less, further preferably 1.5 μm or less, and particularly preferably 1 μm or less.

[0043] In the laminated optical film X, the adhesive layer 30 sandwiched between the optical films 10 and 20 has a side surface 31 that is more concave inward than the end edges 11 and 21 of the optical films 10 and 20 (an exemplary map shows the end edges 11 and 21 located at the same position in the planar direction). The location of the adhesive layer 30 with such a concave side surface 31 at the end edges of the laminated optical film X prevents the adhesive layer 30 from overflowing between the optical films 10 and 20 even when a load is applied to the laminated optical film X in the thickness direction H. Therefore, the laminated optical film X is adapted to suppress the aforementioned end adhesion. Suppression of end adhesion helps ensure the transportability / processability of the laminated optical film during processing.

[0044] The recess length L1 of the side surface 31 from the innermost end edge of the end edges 11 and 21 in the planar direction is preferably 0.05 μm or more, more preferably 0.1 μm or more, and even more preferably 0.2 μm or more. This configuration is preferred for suppressing the overflow of the adhesive layer 30 from between the optical films 10 and 20, and therefore is preferred for suppressing end adhesion. Specifically, the recess length L1 is the distance in the planar direction between the innermost end edge of the end edges 11 and 21 of the optical films 10 and 20 in the planar direction and the innermost end of the side surface 31 of the adhesive layer 30 in the planar direction.

[0045] The recess 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 preferred for suppressing peeling between optical films 10 and 20 at the ends of the laminated optical film X. For example, this configuration is preferred for ensuring the adhesion of the adhesive layer 30 between the optical films 10 and 20 even in high temperature and high humidity environments, thereby suppressing peeling (peeling caused by the large thermal shrinkage of the adhesive layer 30 during the processing of the laminated optical films). In addition, this configuration is also preferred for ensuring the reinforcing function of the adhesive layer 30 on the ends 10a and 20a of the optical films 10 and 20, thereby ensuring the impact resistance of the ends 10a and 20a.

[0046] The aforementioned side 31 in Figure 2 The section shown in the thickness direction has a generally straight shape at the point where it recedes from the end edges 11, 21 in the surface direction. However, as... Figure 3 As shown, the adhesive layer 30 may also have a curved, recessed side surface 31A (an exemplary map shows the case where the ends 31a, 31a in the thickness direction H of the side surface 31A are located at the same position as the end edges 11, 21 in the surface direction). The side surface 31A in... Figure 3The cross-section shown has a curved, roughly V-shaped profile, specifically, it has a shape that gradually concaves inward from both ends (ends 31a, 31a) in the thickness direction H toward the middle portion (deepest portion 31b) toward the surface direction. The concavity length L1 of the side surface 31A is the distance in the surface direction between the end edge 11, 21 of the optical films 10, 20 located inward in the surface direction and the innermost end (deepest portion) 31b of the side surface 31A. The adhesive layer 30 having side surface 31A also achieves the aforementioned technical effects (suppression of end adhesion, suppression of peeling between optical film ends, and assurance of impact resistance of optical film ends) in the same way as the adhesive layer 30 having side surface 31.

[0047] Adhesive layer 30 can be as Figure 4 The side surface 31B has a partially concave shape as shown (the exemplary map shows the case where the outermost end 31a of the side surface 31B is located at the same position as the end edges 11, 21 in the surface direction). Additionally... Figure 4 The side surface 31B shown has an end face F and an inclined surface D. The end face F is located on the side of the optical film 10 and is coplanar with the end edge 11. The inclined surface D is located on the side of the optical film 20 and is inclined inward in the planar direction from the end face F toward the optical film 20 (the more inward the inclined surface D is in the planar direction, the closer it is to the optical film 20). As an alternative to such a partially recessed shape, the side surface 31B may also have a partially recessed shape or an inclined surface on the side of the optical film 10 (not shown), and the middle part in the thickness direction H may also have a partially recessed shape (not shown). The recess length L1 of the side surface 31B is the distance in the planar direction between the end edge 11, 21 of the optical films 10, 20 located inward in the planar direction and the innermost end 31b of the side surface 31B in the planar direction. The adhesive layer 30 having side surface 31B also achieves the same technical effects as the adhesive layer 30 having side surface 31 (suppression of end adhesion, suppression of peeling between optical film ends, and assurance of impact resistance of optical film ends).

[0048] The first indentation modulus of the adhesive layer 30, measured by nanoindentation at 25°C, is preferably 0.01 GPa or more, more preferably 0.03 GPa or more, further preferably 0.05 GPa or more, and particularly preferably 0.07 GPa or more (the first indentation modulus is set as the indentation modulus under the first measurement conditions. The first measurement conditions are as described in the following examples, in which the maximum indentation depth of the indenter on the test sample during the load application process is 200 nm). This configuration is preferred from the viewpoint of ensuring the bonding force between the optical films 10 and 20. In addition, this configuration helps to ensure the aforementioned impact resistance of the optical films 10 and 20. Furthermore, the first indentation modulus is preferably 5 GPa or less, more preferably 3 GPa or less, and further preferably 1 GPa or less. This configuration is preferred for ensuring the flexibility of the adhesive layer 30 when using laminated optical films X in repeatedly bendable (foldable) display panels. As a method for adjusting the compressive elastic modulus of the adhesive layer 30, one example is adjusting the composition of the adhesive composition. Specifically, as a method for adjusting the compressive elastic modulus of the adhesive layer 30, adjusting the number of functional groups of the polymeric compound (described later) in the adhesive composition forming the adhesive layer 30, i.e., adjusting the acrylic equivalent and epoxy equivalent of the polymeric compound, is effective.

[0049] Nanoindentation is a technique for measuring various physical properties of a sample at the nanoscale. In this embodiment, nanoindentation is performed based on ISO 14577. In nanoindentation, the process of pressing an indenter into a sample placed on a stage (load application process) and then removing the indenter from the sample (load release process) is performed. During this series of processes, the load acting between the indenter and the sample, and the relative displacement of the indenter relative to the sample are measured (load-displacement measurement), thereby obtaining a load-displacement curve. Based on this load-displacement curve, various physical properties of the sample can be determined based on nanoscale measurements. For example, the load-displacement measurement of the adhesive layer cross-section using nanoindentation can be performed using a nanoindenter (trade name "Triboindenter", manufactured by Hysitron Corporation), as described in the examples below.

[0050] The second indentation modulus of the adhesive layer 30, measured by nanoindentation at 25°C, is preferably 0.5 GPa or more, more preferably 1 GPa or more, further preferably 1.5 GPa or more, and particularly preferably 2 GPa or more (the second indentation modulus is set as the indentation modulus under the second measurement conditions. The second measurement conditions are as described in the later examples, in which the maximum indentation depth of the indenter to the test sample during the load application process is 50 nm). This configuration is preferred from the viewpoint of ensuring the bonding force between the optical films 10 and 20. In addition, this configuration helps to ensure the aforementioned impact resistance of the optical films 10 and 20. Furthermore, the second indentation modulus is preferably 7 GPa or less, more preferably 5 GPa or less, and further preferably 3 GPa or less. This configuration is preferred for ensuring the flexibility of the adhesive layer 30 when using the laminated optical film X in a repeatedly bendable (foldable) display panel.

[0051] In the laminated optical film X, the 90° peel strength between optical film 20 and optical film 10 at 25°C is preferably 1 N / 15 mm or more, more preferably 1.2 N / 15 mm or more, and even more preferably 1.5 N / 15 mm or more. This configuration is preferred for achieving good adhesion between optical films 10 and 20, and is particularly preferred for ensuring adhesion between optical films 10 and 20 for foldable display panels. The 90° peel strength is, for example, 10 N / 15 mm or less. The 90° peel strength can be measured, for example, using a Tensilon universal testing machine (trade name "RTC", manufactured by A&D Corporation). In this measurement, the measurement temperature is set to 25°C, the peel angle is set to 90°, and the peel speed is set to 1000 mm / min. In addition, as a method for adjusting the 90° peel strength, for example, a method of adjusting the composition of the adhesive composition can be cited. As a method for adjusting the 90° peel strength, specific examples include adjusting the number of functional groups of the polymeric compound in the adhesive composition (described later), that is, adjusting the acrylic equivalent and epoxy equivalent of the polymeric compound.

[0052] The ratio of 90° peel strength (N / 15mm) to the first indentation modulus (GPa) described above is preferably 5 or more, more preferably 10 or more, and even more preferably 15 or more; furthermore, it is preferably 30 or less, and even more preferably 25 or less. The ratio of 90° peel strength (N / 15mm) to the second indentation modulus (GPa) described above is preferably 0.2 or more, more preferably 0.3 or more, and even more preferably 0.4 or more; furthermore, it is preferably 5 or less, even more preferably 3 or less, and even more preferably 2 or less. These configurations are preferred for suppressing peeling between optical films 10 and 20 when the laminated optical film X is repeatedly bent.

[0053] The adhesive layer 30 is, for example, a cured product of an adhesive composition (an active energy ray-curable composition) containing an active energy ray-curable resin. Examples of active energy ray-curable compositions include electron beam curable compositions, ultraviolet curable compositions, and visible light curable compositions. In this embodiment, the active energy ray-curable composition is either a free radical polymerization composition or a cationic polymerization composition, or both.

[0054] When the active energy ray curable composition is a free radical polymerizable composition, the composition contains a free radical polymerizable compound as a monomer. A free radical polymerizable compound is a compound having a free radical polymerizable functional group. Examples of free radical polymerizable functional groups include groups containing olefinic unsaturated bonds. Examples of groups containing olefinic unsaturated bonds include (meth)acryloyl, vinyl, and allyl. (Methacryl)acryloyl refers to acryloyl and / or methacryloyl. From the viewpoint of the curability of the active energy ray curable composition, the active energy ray curable composition preferably contains a free radical polymerizable compound having a (meth)acryloyl group as a main component; the main component refers to the component with the highest content by mass percentage. The proportion of the free radical polymerizable compound containing a (meth)acryloyl group 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. Furthermore, examples of free radical polymerizable compounds include monofunctional free radical polymerizable compounds and polyfunctional free radical polymerizable compounds with two or more functions.

[0055] Examples of monofunctional free radical polymerizable compounds include (meth)acrylamide derivatives having a (meth)acrylamide group. Examples of (meth)acrylamide derivatives include: N-alkyl (meth)acrylamide derivatives, N-hydroxyalkyl (meth)acrylamide derivatives, N-aminoalkyl (meth)acrylamide derivatives, N-alkoxy (meth)acrylamide derivatives, and N-mercaptoalkyl (meth)acrylamide derivatives. Examples of N-alkyl (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, and N-hexyl (meth)acrylamide, with N,N-diethylacrylamide being preferred. Examples of N-hydroxyalkyl (meth)acrylamide derivatives include N-hydroxymethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, and N-hydroxymethyl-N-propyl (meth)acrylamide, with N-hydroxyethylacrylamide being preferred. The (meth)acrylamide derivatives can be used alone or in combination of two or more.

[0056] Examples of monofunctional free radical polymerizable compounds include (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Examples of such (meth)acrylic acid derivatives include alkyl (meth)acrylates and other (meth)acrylic acid derivatives. (Methacryl)acrylic acid derivatives can be used alone or in combination of two or more.

[0057] Examples of alkyl methacrylates include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, 2,2-dimethylbutyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, 4-methyl-2-propylpentyl methacrylate, and n-octadecyl methacrylate.

[0058] Examples of (meth)acrylic acid derivatives other than alkyl (meth)acrylates include: cycloalkyl (meth)acrylates, aralkyl (meth)acrylates, hydroxyl-containing (meth)acrylic acid derivatives, alkoxy (meth)acrylic acid derivatives, and phenoxy (meth)acrylic acid derivatives. Examples of cycloalkyl (meth)acrylates include: cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate. Examples of aralkyl (meth)acrylates include: benzyl (meth)acrylate and 3-phenoxybenzyl (meth)acrylate. Examples of hydroxyl-containing (meth)acrylic acid derivatives include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, [4-(hydroxymethyl)cyclohexyl]methyl acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate. Examples of alkoxy (meth)acrylic acid derivatives include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, and 3-methoxybutyl (meth)acrylate. Examples of phenoxy (meth)acrylic acid derivatives include phenoxyethyl (meth)acrylate and phenoxydiethylene glycol (meth)acrylate. As a (meth)acrylic acid derivative other than alkyl (meth)acrylates, at least one selected from 3-phenoxybenzyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and phenoxydiethylene glycol acrylate is preferred.

[0059] Monofunctional free radical polymerizable compounds can also include carboxyl-containing monomers. Examples of carboxyl-containing monomers include: (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, butenoic acid, and isobutenoic acid.

[0060] Examples of monofunctional free radical polymerizable compounds include lactam vinyl monomers. Examples of lactam vinyl monomers include N-vinyl-2-pyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone.

[0061] Examples of monofunctional radical polymerizable compounds include vinyl monomers having nitrogen-containing heterocycles. Examples of such monomers include: vinylpyridine, vinylpiperidinone, vinylpyrimidine, vinylpiperazine, vinylpyrrazine, vinylpyrrole, vinylimidazolium, and vinylpyrrole. Azole and vinylmorpholine.

[0062] As multifunctional free radical polymerizable compounds, for example, 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, neopentyl glycol di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, cyclotrimethylolpropane methyl acetal (meth)acrylate, di... Alkanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate, with tripropylene glycol diacrylate being preferred. The multifunctional radical polymerizable compound can be used alone or in combination of two or more. The multifunctional radical polymerizable compound functions as a crosslinking agent.

[0063] When the active energy ray curable composition is an ultraviolet curable composition or a visible light curable composition, the active energy ray curable composition preferably contains a photopolymerization initiator. Examples of photopolymerization initiators include: benzophenone compounds, benzoin ether compounds, and thioxanone compounds. Examples of benzophenone compounds include: benzoyl, 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 thioxanone compounds include: thioxanone, 2-chlorothioxanone, 2-methylthioxanone, 2,4-dimethylthioxanone, isopropylthioxanone, 2,4-dichlorothioxanone, 2,4-diethylthioxanone, 2,4-diisopropylthioxanone, and dodecylthioxanone.

[0064] When the active energy ray curable composition is obtained as a visible light curable composition, it is preferable to use a photopolymerization initiator that is highly sensitive to light above 380 nm. Examples of such photopolymerization initiators include: 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 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(n5-2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium.

[0065] 2,4-Diethylthioxanone and / or 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one are preferred as photopolymerization initiators.

[0066] In the active energy ray curing composition, the content of photopolymerization initiator is preferably 0.1 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, and 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, relative to 100 parts by mass of curing component (free radical polymerizable compound).

[0067] In the case of an active energy ray curable composition that is a cationic polymeric composition, the composition contains a cationic polymerizable compound as a monomer. A cationic polymerizable compound is a compound having a cationic polymerizable functional group, including monofunctional cationic polymeric compounds having one cationic polymerizable functional group and polyfunctional cationic polymeric compounds having two or more cationic polymerizable functional groups. Monofunctional cationic polymeric compounds have relatively low liquid viscosity; by incorporating such a monofunctional cationic polymeric compound into a resin composition, the viscosity of the resin composition can be reduced. Furthermore, monofunctional cationic polymeric compounds generally possess functional groups exhibiting various functions. By incorporating such a monofunctional cationic polymeric compound into a resin composition, the resin composition and / or the cured resin composition can exhibit various functions. On the other hand, by curing a resin composition incorporating a polyfunctional cationic polymeric compound, a cured product with a 3D cross-linked portion can be obtained (where the polyfunctional cationic polymeric compound functions as a cross-linking agent). From this viewpoint, the use of a polyfunctional cationic polymeric compound is preferred. When a monofunctional cationic polymeric compound is used in combination with a polyfunctional cationic polymeric compound, the amount of the polyfunctional cationic polymeric compound relative to 100 parts by mass of the monofunctional cationic polymeric compound is, for example, 10 parts by mass or more, and, for example, 1000 parts by mass or less. Examples of cationic polymeric functional groups include epoxy groups, oxetyl groups, and vinyl ether groups. Examples of compounds containing epoxy groups include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds. From the viewpoint of the curability and adhesion of the cationic polymeric composition, alicyclic epoxy compounds are preferred as compounds containing epoxy groups. Examples of alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, or caprolactone-modified, trimethylcaprolactone-modified, and valproicone-modified versions of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate. Commercially available alicyclic epoxy compounds include, for example, CELLOXIDE 2021, CELLOXIDE 2021A, CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE 2083, and CELLOXIDE 2085 (all manufactured by CELLOXIDE Chemical Co., Ltd.), and Cyracure UVR-6105, Cyracure UVR-6107, Cyracure 30, and R-6110 (all manufactured by Dow Chemical Japan Ltd.). From the viewpoint of improving the curability and reducing the viscosity of cationic polymeric compositions, compounds having oxocyclic butyl groups and / or compounds having vinyl ether groups are preferred.Examples of compounds containing oxetane include: 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetane)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, di[(3-ethyl-3-oxetane)methyl] ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, and phenolic varnish oxetane. Commercially available examples of compounds containing oxetane include: ARON OXETANE OXT-101, ARON OXETANE OXT-121, ARON OXETANE OXT-211, ARON OXETANE OXT-221, and ARON OXETANE OXT-212 (all manufactured by Toa Synthetic Co., Ltd.). 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, cyclohexanediethanol divinyl ether, cyclohexanediethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, and pentaerythritol-type tetravinyl ether.

[0068] When the active energy ray curable composition is an ultraviolet curable composition or a visible light curable composition, the active energy ray curable composition contains a photocationic polymerization initiator. The photocationic polymerization initiator generates cationic species or Lewis acids upon irradiation by active energy rays (visible light, ultraviolet light, X-rays, electron beams, etc.), thereby initiating a polymerization reaction of cationic polymerizable functional groups. Examples of photocationic polymerization initiators include photoacid generators and photoalkali generators, with photoacid generators being preferred. When the active energy ray curable composition is a visible light curable composition, a photocationic polymerization initiator with high sensitivity to light above 380 nm is particularly preferred. Furthermore, when using a photocationic polymerization initiator, it is preferable to combine it with a photosensitizer that exhibits significant absorption for wavelengths longer than 380 nm. 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 photosensitizers that exhibit maximum absorption under light with wavelengths longer than 380 nm, it is possible to effectively utilize light with wavelengths longer than 380 nm to promote the generation of cationic species or Lewis acids from the photocationic polymerization initiator. Examples of photosensitizers include anthracene compounds, pyrene compounds, carbonyl compounds, organosulfur compounds, persulfides, redox compounds, azo compounds, diazo compounds, halogen compounds, and photoreducing pigments. These can be used alone or in combination of two or more. Anthracene compounds are particularly preferred due to their excellent photosensitizing effect. Commercially available anthracene compounds used as photosensitizers include, for example, Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Chemical Co., Ltd.). The content of the photosensitizer in the composition is, for example, 0.1 to 5% by weight.

[0069] The active energy ray-curable composition may contain oligomers. Examples of oligomers include acrylic oligomers, fluoro oligomers, and silicone oligomers, with acrylic oligomers being preferred. The inclusion of oligomers in the active energy ray-curable composition helps to suppress shrinkage during curing. Suppression of curing shrinkage in the active energy ray-curable composition is preferred for reducing interfacial stress between the formed adhesive layer 30 and the optical films 10, 20, and suppression of interfacial stress helps to ensure adhesion between the optical films 10, 20.

[0070] Examples of (meth)acrylic acid monomers that form acrylic acid oligomers include, for example, alkyl (meth)acrylic acid esters, cycloalkyl (meth)acrylic acid esters, aralkyl (meth)acrylic acid esters, polycyclic (meth)acrylic acid esters, hydroxyl-containing (meth)acrylic acid esters, and halogen-containing (meth)acrylic acid esters. Examples of alkyl methacrylates 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, and n-octadecyl methacrylate. Examples of cycloalkyl methacrylates include: cyclohexyl methacrylate and cyclopentyl methacrylate. Examples of aralkyl methacrylates include: benzyl methacrylate. Examples of polycyclic (meth)acrylates include: 2-isoborneol (meth)acrylate, 2-norborneol methyl (meth)acrylate, 5-norbornen-2-yl methyl (meth)acrylate, and 3-methyl-2-norborneol methyl (meth)acrylate. Examples of hydroxyl-containing (meth)acrylates include: hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2,3-dihydroxypropyl methylbutyl (meth)acrylate. Examples of halogen-containing (meth)acrylates include: 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethyl ethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, and heptadecafluorodecyl (meth)acrylate. These (meth)acrylates can be used alone or in combination of two or more.

[0071] The weight-average molecular weight (Mw) of the acrylic oligomer is preferably 15,000 or less, more preferably 10,000 or less, and even more preferably 5,000 or less. The Mw of the acrylic oligomer is preferably 500 or more, more preferably 1,000 or more, and even more preferably 1,500 or more.

[0072] The content of acrylic oligomers 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.

[0073] The active energy ray curable composition may contain other components. Examples of other components include silane coupling agents, leveling agents, surfactants, plasticizers, and ultraviolet absorbers. The amount of these other components relative to 100 parts by weight of the curable component is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, even more preferably 3 parts by weight or less, and, for example, 0.01 parts by weight or more.

[0074] From the viewpoint of coatability in the coating process described later, 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 even more preferably 10 mPa·s or more. Furthermore, it is 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 measured using an E-type viscometer (cone-plate viscometer).

[0075] The laminated optical film X can be manufactured, for example, as described below.

[0076] First, an active energy ray curable composition is coated onto one side (the pre-bonding surface) of an optical film (optical film 10 or optical film 20) to form a coating of the composition (coating step). Prior to this coating step, the pre-bonding surface of the optical film may undergo surface modification treatment. Examples of surface modification treatments include corona treatment, plasma treatment, excimer laser treatment, and flame treatment. Examples of coating methods used in this step include, for example, reverse coating, gravure coating, bar reverse coating, roll coating, die coating, wire rod coating, and bar coating.

[0077] Next, one optical film (optical film 20 or optical film 10) is laminated to another optical film through a coating of the composition. The lamination can be performed using, for example, a roller laminator.

[0078] Next, the composite coating between optical films 10 and 20 is irradiated with active energy rays to cure the coating (active energy ray curable composition), thereby forming an adhesive layer 30 (the adhesive layer 30 is not a pressure-sensitive adhesive layer). Thus, optical films 10 and 20 are bonded together through the adhesive layer 30 to obtain a raw material film for the laminated optical film X. In this process, from the viewpoint of suppressing the deterioration of the optical film 10 as a functional optical film, it is preferable to irradiate from the optical film 30 side with active energy rays. Electron beams, ultraviolet light, and visible light can be used as active energy rays. For example, an electron beam accelerator can be used as an electron beam irradiation device. Examples of sources of ultraviolet and visible light include LED lamps, gallium-encapsulated 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, wavelength blocking filters for blocking a portion of the wavelength range of ultraviolet and / or visible light emitted from the light source can be used as needed.

[0079] Next, at least a portion of the peripheral end of the raw material film is shaped (shape forming process), for example, one end of the rolled raw material film in the length direction is trimmed, for example, the rolled raw material film is cut into single sheets. Examples of such shape forming methods include: laser processing using CO2 laser irradiation, cutting using a cutting tool, cutting using a punching tool, and vertical milling.

[0080] Under CO2 laser irradiation, the adhesive layer 30 undergoes significant thermal shrinkage at the processing area of ​​the raw material film, forming a side surface 31 (or side surface 31A) that is more concave inward than the end edges 11, 21 of the optical films 10, 20. Specifically, the end shrinkage of the adhesive layer 30 causes the entirety or a portion of the side surface 31 of the adhesive layer 30 to recede from the end edges 11, 21 of the optical films 10, 20 to the inward direction at the end of the raw material film, thereby forming a concave side surface 31 (or side surface 31A). The length of the end shrinkage of the adhesive layer 30, i.e., the concave length L1, can be adjusted, for example, by adjusting the composition of the adhesive layer 30 and the CO2 laser irradiation conditions.

[0081] By partially removing the end of the adhesive layer 30 using a cutting tool, a side surface 31 (or side surfaces 31a, 31B) that is more concave inward than the end edges 11, 21 of the optical films 10, 20 can be formed. Methods for adjusting the position and extent of partial removal include, for example, adjusting the difference in elastic modulus between the optical films 10, 20 and the adhesive layer 30, adjusting the thermal shrinkage rate and thickness of the adhesive layer 30, and adjusting the frictional force generated between the cutting tool and the adhesive layer 30 during cutting. This frictional force can be adjusted, for example, by adjusting the composition of the adhesive layer 30.

[0082] For example, a laminated optical film X can be manufactured as described above.

[0083] Example

[0084] The present invention will be specifically described below with reference to embodiments, but the present invention is not limited to the embodiments. In addition, the specific numerical values ​​of the amount (content), physical property value, parameter, etc. described below can be replaced with the upper limit (a value defined in the form of "less than" or "less than") or lower limit (a value defined in the form of "more than" or "exceeds") of the amount (content), physical property value, parameter, etc. described in the "Specific Embodiments" above.

[0085] [Example 1]

[0086] An adhesive composition was prepared by mixing the following components at 25°C for 1 hour.

[0087] 45 parts by weight of 3-phenoxybenzyl acrylate (trade name "LIGHT ACRYLATE POB-A", monomer, manufactured by Kyoei Chemical Co., Ltd.)

[0088] 25 parts by weight of phenoxy diethylene glycol acrylate (trade name "LIGHT ACRYLATE P2H-A", monomer, manufactured by Kyoei Chemical Co., Ltd.)

[0089] 5 parts by weight of tripropylene glycol diacrylate (trade name "Aronix M-220", monomer, manufactured by Toa Synthetic Co., Ltd.)

[0090] 10 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate (trade name "Aronix M-5700", monomer, manufactured by Toa Synthetic Co., Ltd.)

[0091] 5 parts by weight of hydroxyethyl acrylamide (trade name "HEAA", monomer, manufactured by KJ Chemical Co., Ltd.)

[0092] 5 parts by weight of diethylacrylamide (trade name "DEAA", monomer, manufactured by KJ Chemical Co., Ltd.)

[0093] 3 parts by weight of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one (trade name "OMINIRAD907", photopolymerization initiator, manufactured by IGM Resins).

[0094] 3 parts by weight of 2,4-diethylthioxanone (trade name "KAYACURE DETX-S", photopolymerization initiator, manufactured by Nippon Kayaku Co., Ltd.)

[0095] 5 parts by weight of acrylic oligomer (trade name "Arufon 1190", viscosity 6000 mPa·s (25°C), Mw 1700, Tg -50°C, manufactured by Toa Gosei Co., Ltd.)

[0096] 0.5 parts by weight of acryloyl-modified polydimethylsiloxane (trade name "BYK-UV3505", leveling agent, manufactured by BYK Corporation)

[0097] Next, an adhesive composition was applied to a 23 μm thick COP film (trade name "ZEONOR Film ZF14", manufactured by Zeon Corporation, Japan) serving as a transparent protective film, forming an adhesive coating film with a thickness of 1 μm. Coating was performed using an MCD coating machine (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roller line count 1000 lines / inch, rotation speed 140% / pair line speed). Next, a polarizing lens film was bonded to the transparent protective film through the adhesive coating film. Then, the adhesive coating film between the films was cured by irradiating it with ultraviolet light from the transparent protective film side. Ultraviolet irradiation was performed using an ultraviolet irradiation device equipped with a gallium-encapsulated metal halide lamp as the light source (trade name "Light HAMMER10", valve: V valve, manufactured by Fusion UV Systems, Inc.). During ultraviolet irradiation, the peak illuminance was set to 1600 mW / cm². 2 Set the cumulative exposure dose to 1000 mJ / cm². 2 (Wavelength 380–440 nm) (Illuminance was measured using a Solatell "Sola-Check system"). Thus, a laminated optical film was obtained by bonding a transparent protective film to a polarizing lens film. Next, the laminated optical film was shaped. Specifically, the laminated optical film was cut along its thickness direction by CO2 laser irradiation to obtain a laminated optical film with a given top-view shape. During CO2 laser irradiation, the wavelength was set to 9.4 μm, the output power to 48 W, and the scanning speed to 500 mm / s. The laminated optical film was then left at room temperature for 24 hours.

[0098] The laminated optical film of Example 1 was fabricated as described above. The laminated optical film of Example 1 comprises, in the thickness direction, a polarizing film (thickness 5 μm), an adhesive layer, and a transparent protective film (thickness 23 μm).

[0099] [Example 2]

[0100] The amount of "Aronix M-220", one of the monomer components, was set to 2 parts by mass instead of 5 parts by mass. Otherwise, the laminated optical film (polarizing film / adhesive layer / transparent protective film) of Example 2 was made in the same manner as the laminated optical film of Example 1.

[0101] [Example 3]

[0102] The amount of "Aronix M-220", one of the monomer components, was set to 1 part by mass instead of 5 parts by mass. Otherwise, the laminated optical film (polarizing film / adhesive layer / transparent protective film) of Example 3 was prepared in the same manner as the laminated optical film of Example 1.

[0103] [Comparative Example 1]

[0104] The amount of "Aronix M-220", one of the monomer components, was set to 3 parts by mass instead of 5 parts by mass. Otherwise, a composite optical film (polarizing film / adhesive layer / transparent protective film) of Comparative Example 1 was prepared in the same manner as the composite optical film of Example 1.

[0105] <Indented elastic modulus>

[0106] The indentation modulus of the adhesive layer in each of the laminated optical films of Examples 1-3 and Comparative Example 1 was determined by nanoindentation. Specifically, firstly, a 5mm × 10mm film (laminated optical film) was cut from the laminated optical film; next, the laminated optical film was cut by cryosectioning, specifically, the laminated optical film was cooled to -30°C, then cut along the thickness direction of the film with a hard blade, and then restored to room temperature, thereby obtaining the sample for testing. Next, the load-displacement of the exposed surface of the adhesive layer of the test sample was measured using a nanoindenter (trade name "TI950 Triboindenter", manufactured by Hysitron Corporation) based on JISZ 2255:2003, and the load-displacement curve was obtained. In this measurement, the measurement mode was set to single indentation measurement, the measurement temperature was set to 25℃, the indenter used was a Berkovich (triangular pyramid) diamond indenter, the maximum indentation depth (maximum displacement hmax) of the indenter to the test specimen during the load application process was set to 200nm, the indentation speed of the indenter was set to 10nm / s, and the withdrawal speed of the indenter from the test specimen during the load release process was set to 10nm / s (first measurement condition). Then, the obtained measurement data were processed using the dedicated analysis software (Ver. 9.4.0.1) of the "TI950Triboindenter". Specifically, based on the obtained load (f)-displacement (h) curve, the maximum load fmax (the load acting on the indenter at the maximum displacement hmax), the contact projection area S (the projected area of ​​the contact region between the indenter and the specimen at maximum load), and the slope D of the tangent line of the load-displacement curve at the beginning of the load release process were obtained. Then, the indentation elastic modulus of the adhesive layer (=(π)) was calculated based on the slope D and the contact projection area S.1 / 2 D) / (2S 1 / 2 )).

[0107] On the other hand, the maximum indentation depth was changed from 200 nm to 50 nm. Otherwise, load-displacement measurements were performed using a nanoindenter under the same conditions as the first measurement (the second measurement condition). The obtained measurement data were then processed using the dedicated analysis software (Ver. 9.4.0.1) of the "TI950Triboindenter" to calculate the indentation elastic modulus of the adhesive layer.

[0108] <Observation of the end>

[0109] The longitudinal cross-sectional shape of the ends of each of the laminated optical films of Examples 1-3 and Comparative Example 1 was investigated. Specifically, firstly, a section was cut along the thickness direction at an arbitrarily selected portion of the periphery of the laminated optical film to form a longitudinal cross-section for observation. Next, this longitudinal cross-section was observed and photographed using an optical microscope. Then, in the observation cross-sections of each of the laminated optical films of Examples 1-3, it was confirmed that the end edge (side surface) of the adhesive layer was closer to the inner side in the film surface direction than the end edge (first end edge) of the polarizing film and the end edge (second end edge) of the transparent protective film. In the observation cross-section of the laminated optical film of Comparative Example 1, it was confirmed that the end edge (side surface) of the adhesive layer was closer to the outer side in the film surface direction than the end edge (first end edge) of the polarizing film and the end edge (second end edge) of the transparent protective film.

[0110] In addition, in each observation section, the receding length d1 of the adhesive layer side surface in the face direction from the end edge (first end edge) of the polarizing lens film, and the receding length d2 of the adhesive layer side surface in the face direction from the end edge (second end edge) of the transparent protective film, were measured, and the results are shown in Table 1. Furthermore, the indentation length L1 (equivalent to the longer of the receding lengths d1 and d2) of the adhesive layer side surface in the face direction from the end edge located inside the face direction of the first and second end edges is also shown in Table 1. When the indentation length L1 is negative, the end edge of the adhesive layer is closer to the outer side in the film surface direction than the end edge (first end edge) of the polarizing lens film and the end edge (second end edge) of the transparent protective film. Moreover, regarding the end anti-adhesion of the laminated optical films, cases with an indentation length L1 exceeding 0 μm were evaluated as "good," and cases with an indentation length less than 0 μm were evaluated as "poor," and the evaluation results are shown in Table 1.

[0111] Impact resistance

[0112] Regarding the impact resistance of each layered optical film in Examples 1-3 and Comparative Example 1, the condition in which neither the polarizing lens film nor the transparent protective film is damaged (cracks, defects, etc.) in the above-mentioned observation section is evaluated as "good", and the condition in which at least one of the polarizing lens film and the transparent protective film is damaged is evaluated as "poor". The evaluation results are shown in Table 1.

[0113] Table 1

[0114]

[0115] Industrial applicability

[0116] The laminated optical film of the present invention can be used as an element in the laminated structure of a display panel, such as a foldable display panel.

Claims

1. A laminated optical film comprising, in order in a thickness direction, a first optical film, an adhesive layer, and a second optical film, the adhesive layer is joined to the first optical film and joined to the second optical film, the adhesive layer has a side surface that is more concave toward an inner side than a first end portion edge of the first optical film and a second end portion edge of the second optical film in a planar direction orthogonal to the thickness direction, a concave length of the side surface from the end portion edge located on an inner side in the planar direction among the first end portion edge and the second end portion edge is 1.0 μm or less.

2. The laminated optical film according to claim 1, wherein the concave length of the side surface from the end portion edge located on the inner side in the planar direction among the first end portion edge and the second end portion edge is 0.05 μm or more.

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