Image display device including an optical laminate and an optical film of the optical laminate.

Abstract

Provided is an optical laminate in which defective peeling when a surface protection film is peeled from a deformation-processed portion is significantly suppressed. An optical laminate according to an embodiment of the present invention comprises an optical film, a surface protection film peelably temporarily attached to one side of the optical film, an adhesive layer disposed on the other side of the optical film, and a separator peelably temporarily attached to the adhesive layer. The optical laminate has a deformed shape other than a rectangular shape. The lower end of the surface protection film extends further outward than the upper end thereof, the length of a straight line connecting outer edges of the optical laminate in a direction orthogonal to a peeling direction at a position 1 mm away in the peeling direction from a peeling starting point when the surface protection film is peeled from the deformed shape is 2 mm or more, and the bending load of the surface protection film is 0.5 g or less.

Description

[Technical Field]

[0001] The present invention relates to an optical laminate and an image display device including an optical film of the optical laminate. [Background technology]

[0002] Various optical laminates (e.g., polarizing plates) are used in image display devices such as mobile phones and notebook personal computers to realize image display and / or enhance the performance of said image display. Typically, an adhesive layer is provided as the outermost layer of the optical laminate, allowing it to be bonded to an image display cell. In practice, a separator is temporarily attached to the adhesive layer in a removable manner to protect the adhesive layer until actual use. Furthermore, in practice, a surface protective film is temporarily attached to the side of the optical laminate opposite the adhesive layer in a removable manner to protect the optical laminate during the manufacturing process and transportation. In recent years, it has been desirable to process optical films into shapes other than rectangles (irregular shapes: for example, R-shaped chamfering of corners, notches, and / or the formation of through holes). However, when peeling the surface protective film from the irregularly shaped parts, peeling defects may occur. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-022140 [Patent Document 2] Japanese Patent Publication No. 2017-203167 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The main objective of the present invention is to provide an optical laminate in which peeling defects when peeling the surface protective film from the irregularly shaped processed portion are significantly suppressed. [Means for solving the problem]

[0005] An optical laminate according to an embodiment of the present invention comprises an optical film, a surface protection film peelably attached to one side of the optical film, an adhesive layer disposed on the other side of the optical film, and a separator peelably attached to the adhesive layer. The optical laminate has a shape other than a rectangle. The lower end of the surface protection film extends outward more than the upper end, and the length of the straight line connecting the outer edges of the optical laminate in a direction perpendicular to the peeling direction at a position 1 mm away from the peeling starting point in the peeling direction when peeling the surface protection film from the irregular shape is 2 mm or more, and the bending load of the surface protection film is 0.5 g or less. In one embodiment, the above-mentioned shape includes a rounded chamfer at the corner. In one embodiment, the initial peeling force when peeling off the surface protective film is 1.0 N or less. In one embodiment, the thickness of the surface protective film is 80 μm or less. In one embodiment, the extension length is 1 μm to 50 μm. In one embodiment, the optical film includes a polarizer. According to another aspect of the present invention, an image display device is provided. This image display device includes the optical film of the optical laminate described above. [Effects of the Invention]

[0006] According to an embodiment of the present invention, in an optical laminate having a surface protective film, an optical film, and a separator, and having a shaped processing portion, when the lower end of the surface protective film extends outward beyond the upper end, and the length of the straight line connecting the outer edge of the optical laminate in a direction perpendicular to the peeling direction at a position 1 mm away from the peeling starting point in the peeling direction when peeling the surface protective film from the shaped processing portion is 2 mm or more, an optical laminate can be realized in which peeling defects when peeling the surface protective film from the shaped processing portion are significantly suppressed by setting the bending load of the surface protective film to 0.5 g or less. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. [Figure 2] This is a schematic plan view illustrating an example of a deformed or deformed part in an optical laminate according to an embodiment of the present invention. [Figure 3] This is a schematic plan view illustrating a modified example of a deformed or deformed portion in an optical laminate according to an embodiment of the present invention. [Figure 4] This is a schematic plan view illustrating further modifications of the irregular shape or irregularly shaped processed portion in an optical laminate according to an embodiment of the present invention. [Figure 5] This is a schematic diagram illustrating the relationship between the shape or shape-processed portion and the peeling characteristics in an optical laminate according to an embodiment of the present invention. [Figure 6] This is a schematic diagram illustrating a method for measuring the bending load of a surface protective film that can be used in an optical laminate according to an embodiment of the present invention. [Modes for carrying out the invention]

[0008] Specific embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Note that the drawings are schematic representations for clarity, and the ratios of lengths, widths, thicknesses, angles, etc., shown in the drawings differ from actual dimensions.

[0009] A. Optical laminate A-1. Schematic of an optical stack Figure 1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. The illustrated optical laminate 100 comprises an optical film 10, a surface protection film 20 peelably attached to one side of the optical film 10, an adhesive layer 30 disposed on the other side of the optical film 10, and a separator 40 peelably attached to the adhesive layer 30. When the optical laminate is applied to an image display device, typically the separator 40 is placed on the image display cell side. In actual use of the optical laminate (substantially an optical film), the separator 40 is peeled off, and the adhesive layer 30 can be used to bond the optical laminate (substantially an optical film) to an image display device (substantially an image display cell). The surface protection film 20 typically comprises a substrate 21 and an adhesive layer 22. Note that the adhesive layer 22 of the surface protection film may be referred to as the "PF adhesive layer" to distinguish it from the adhesive layer 30. The surface protective film 20 is also peeled off during actual use of the optical laminate.

[0010] In embodiments of the present invention, the optical laminate has a shape other than a rectangle. In this specification, "having a shape other than a rectangle" means that the plan view shape of the optical laminate is a shape other than a rectangle. The shape is typically a processed part that has been shaped. Therefore, an "optical laminate having a shape other than a rectangle" (hereinafter sometimes referred to as an "irregularly shaped optical laminate") includes not only cases where the entire irregularly shaped optical laminate (i.e., the outer edge that defines the plan view shape of the optical laminate) is not rectangular, but also cases where an irregularly shaped part is formed in a portion spaced inward from the outer edge of a rectangular optical laminate. When attempting to peel off a surface protective film from such an irregularly shaped part, peeling defects are likely to occur, but according to embodiments of the present invention, such peeling defects can be significantly suppressed. Examples of irregular shapes (irregularly shaped parts) include, for example, as shown in Figure 2, corners that are chamfered in an R shape, through holes, and machined parts that become recesses when viewed in plan. Typical examples of recesses include a shape similar to a boat (not shown), a rectangle, an R shape similar to a bathtub shape, a V-shaped notch, and a U-shaped notch. Another example of a non-standard shape (non-standard processed part) is a shape corresponding to an automobile's instrument panel, as shown in Figures 3 and 4. This shape includes a portion where the outer edge is formed in an arc shape along the rotation direction of the meter needle, and the outer edge is convex inward in the surface direction (including a rounded shape). Needless to say, the shape of the non-standard shape (non-standard processed part) is not limited to the illustrated example. For example, the shape of the through hole can be any appropriate shape (e.g., ellipse, triangle, square, pentagon, hexagon, octagon) depending on the purpose, in addition to the approximately circular shape shown in the illustrated example. Furthermore, the through hole can be provided at any appropriate position depending on the purpose. As shown in Figure 2, the through hole may be provided approximately in the center of the longitudinal end of the rectangular optical laminate, at a predetermined position on the longitudinal end, or at a corner of the optical laminate; although not shown, it may also be provided at the short end of the rectangular optical laminate; or as shown in Figure 3 or 4, it may be provided in the center of the non-standard optical laminate. Multiple through holes may be provided. Furthermore, the shapes of the illustrated examples may be appropriately combined depending on the purpose. For example, V-shaped notches and / or U-shaped notches may be formed at any appropriate position on the outer edge of the irregularly shaped optical stack shown in Figure 3 or Figure 4.Such a shaped optical laminate can be suitably used in an image display device such as an automotive meter panel, a smartphone, a tablet PC, or a smartwatch.

[0011] When the shape includes an R shape, the radius of curvature is, for example, 0.2 mm or more, and for example, 1 mm or more, and for example, 2 mm or more, and for example, 3 mm or more, and for example, 5 mm or more, and for example, 10 mm or more. On the other hand, the radius of curvature is, for example, 30 mm or less, and for example, 25 mm or less, and for example, 20 mm or less, and for example, 15 mm or less, and for example, 10 mm or less. When the shape is chamfered at the corners to an R shape, the radius of curvature of the corners is, for example, 3 μm to 30 μm, and for example, 5 μm to 25 μm, and for example, 10 μm to 25 μm. The radius of curvature of the corners may be, for example, 5 μm to 15 μm. In an optical laminate having a shaped portion with such a radius of curvature, the effects according to the embodiments of the present invention can be remarkable. Note that when the shape includes an R shape, it may include a plurality of R shapes. Also, one R shape may be a combination of a plurality of curvatures.

[0012] In an embodiment of the present invention, as shown in FIG. 1, the lower end of the surface protection film 20 extends outward more than the upper end. Therefore, the cross-sectional shape of the surface protection film can be a trapezoid with the upper base shorter than the lower base. The inventors have found that such an extended portion is formed in the surface protection film due to the profiling process, and the extended portion can affect the peeling characteristics when peeling the surface protection film from the profiling portion. Furthermore, as a result of intensive studies on the relationship between the configuration of the optical laminate, the extended portion, and the peeling characteristics of the surface protection film, the inventors have found that by setting the bending load of the surface protection film described later to a predetermined value or less, peeling failure when peeling the surface protection film from the profiling portion can be significantly suppressed, and the present invention has been completed. Substantially, as shown in FIG. 1, the lower end of the PF adhesive layer 22 extends outward from the upper end of the surface protection film. Therefore, in this specification, the "extended length L" means the extended length of the lower end of the PF adhesive layer 22 starting from the upper end of the surface protection film, as shown in FIG. 1. The extended length L is, for example, 1 μm to 50 μm, and also for example, 5 μm to 50 μm, and also for example, 20 μm to 50 μm, and also for example, 24 μm to 48 μm, and also for example, 27 μm to 46 μm.

[0013] The profiling process can be performed in any suitable manner. Specific examples include laser light irradiation, cutting with an end mill, and punching with a Thomson blade or a Pinnacle (registered trademark) blade. The extended portion as shown in FIG. 1 can be formed, for example, by irradiating laser light from the surface protection film side of the optical laminate, or for example, by cutting with an end mill with the separator of the optical laminate facing up.

[0014] In embodiments of the present invention, as shown in Figure 5, the length of the straight line AB connecting the outer edge of the optical laminate in a direction perpendicular to the peeling direction at a position 1 mm away from the peeling starting point in the peeling direction when peeling the surface protective film from the irregularly shaped processed portion is 2 mm or more. The length of the straight line AB is, for example, 3 mm or more, or for example, 4 mm or more, or for example, 5 mm or more, or for example, 6 mm or more. On the other hand, the length of the straight line AB is, for example, 100 mm or less, or for example, 50 mm or less, or for example, 30 mm or less, or for example, 20 mm or less, or for example, 18 mm or less, or for example, 15 mm or less. The length of the straight line AB may be, for example, 5.5 μm to 9.5 μm, or for example, 5.8 μm to 9.0 μm. If the length of the straight line AB is greater than or equal to a predetermined value, it means that it is difficult to secure a starting point when peeling the surface protective film from the irregularly shaped processed portion. For example, in the case of irregularly shaped optical laminates as shown in Figures 3 and 4, peeling the surface protective film is extremely difficult because the force required for peeling, i.e., the stress, is dispersed. According to the embodiment of the present invention, even with such a configuration, the surface protective film can be easily peeled from the irregularly shaped processed portion without causing peeling defects.

[0015] In the embodiments of the present invention, the bending load of the surface protective film is 0.5g or less. If the bending load of the surface protective film is 0.5g or less, even in the case of irregularly shaped processed parts that have a shape that makes peeling difficult, peeling defects when peeling the surface protective film from the irregularly shaped processed part can be significantly suppressed. As described above, the surface protective film has a base material and an adhesive layer, but even if the thickness of the base material, the thickness of the adhesive layer, the overall thickness, the elastic modulus of the base material, the elastic modulus of the adhesive layer, etc. are adjusted individually, it is not possible to comprehensively suppress peeling defects. In other words, even if each component of the surface protective film is changed individually, no clear correlation can be obtained regarding when peeling defects are suppressed and when peeling defects occur. The inventors have found that by setting the bending load of the surface protective film to 0.5g or less, peeling defects when peeling the surface protective film from an irregularly shaped processed part can be comprehensively suppressed. The bending load can be measured as follows. As shown in Figure 6, a jig with a U-shaped cross section is prepared and placed at a position 30 mm away from the weighing platform so as to cover the weighing platform. A sample of surface protective film punched into a dumbbell-shaped multi-purpose test piece (150 mm in total length) according to JIS K 7139-A1 can be folded exactly in half and placed on a weighing platform. The load on the weighing platform can be measured as a bending load because the upper jig restricts the surface protective film from returning to its original shape.

[0016] The bending load of the surface protective film is, for example, 0.5g or less, 0.3g or less, 0.2g or less, 0.1g or less, 0.07g or less, 0.05g or less, 0.04g or less, and 0.03g or less. The lower limit of the bending load may be, for example, 0.005g. If the bending load of the surface protective film is within this range, peeling defects when removing the surface protective film can be prevented very well.

[0017] In embodiments of the present invention, the initial peeling force when peeling the surface protective film is, for example, 1.0 N or less, 0.9 N or less, 0.8 N or less, 0.7 N or less, 0.6 N or less, and 0.5 N or less. The lower limit of the initial peeling force may be, for example, 0.05 N. If the initial peeling force is within this range, the surface protective film can be easily peeled off, and peeling defects can be significantly suppressed. The initial peeling force can be measured, for example, in accordance with JIS Z 0237. Specifically, a pickup tape can be attached to the surface protective film of a test sample (optical laminate) along the peeling direction, and the peeling force when peeling at a 90° tensile angle using the pickup tape can be measured as the initial peeling force. The width of the pickup tape may be, for example, 10 mm, and the tensile speed may be, for example, 300 mm / min.

[0018] A-2. Optical film The optical film 10 may be a single-layer film or a laminate. Specific examples of a single-layer optical film include a window film, a polarizer, and a phase difference film. Specific examples of an optical film configured as a laminate include a polarizer (typically a laminate of a polarizer and a protective film), a conductive film for touch panels, a surface treatment film, and a laminate obtained by appropriately laminating these single-layer optical films and / or optical films configured as a laminate according to the purpose (for example, an anti-reflective circular polarizer or a polarizer with a conductive layer for touch panels).

[0019] A-3. Surface protective film As described above, the surface protective film 20 typically comprises a base material 21 and a PF adhesive layer 22. The base material 21 can be made of any suitable material as long as it can achieve the desired bending load. Specific examples of constituent materials include polyester polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); cellulosic polymers such as diacetylcellulose and triacetylcellulose; polycarbonate polymers; (meth)acrylic polymers such as polymethyl methacrylate; and cycloolefin polymers such as polynorbornene. These may be used individually or in combination of two or more. Polyester polymers are preferred, and among them, it is preferable to use those with excellent properties such as optical properties (e.g., transparency), mechanical strength, thermal stability, moisture shielding, isotropy, flexibility, and dimensional stability. In particular, polyester films that are not too stiff may easily achieve the desired bending load. The properties of the polyester film can be controlled by adjusting the type and combination of polycarboxylic acid and polyol components. For example, polyethylene terephthalate and polybutylene terephthalate may be used in combination as constituent materials for the base material.

[0020] Other examples of constituent materials for the base material include styrene polymers such as polystyrene and acrylonitrile-styrene copolymers; vinyl chloride polymers; amide polymers such as nylon 6, nylon 6,6, and aromatic polyamides; imide polymers; sulfone polymers; polyethersulfone polymers; polyetheretherketone polymers; polyphenylene sulfide polymers; vinyl alcohol polymers; vinylidene chloride polymers; vinyl butyral polymers; arylate polymers; polyoxymethylene polymers; and epoxy polymers. These may be used individually or in combination of two or more.

[0021] In one embodiment, the substrate may have a laminated structure of resin layer / adhesive layer / resin layer. The constituent materials of the resin layer include those described above as constituent materials of the substrate. The constituent materials of the adhesive layer include adhesives, tacks, and anchor coating agents. The adhesive layer may have a laminated structure of an adhesive layer or tack layer and an anchor coating layer. By interposing an adhesive layer having predetermined properties (e.g., elastic modulus) between two resin layers, the elastic modulus (e.g., tensile modulus) can be reduced to a desired degree depending on the purpose. As a result, the desired bending load may be easily achieved.

[0022] The tensile modulus of the base material 21 is, for example, 2.3 × 10⁻⁶. 9 It is less than or equal to Pa, preferably 1.5 × 10⁻⁶. 9 It is less than or equal to Pa, and more preferably 1.3 × 10⁻⁶. 9 Pa or less, and more preferably 1.0 × 10⁻⁶ 7 Pa~1.3×10 9 Pa is particularly preferred, and 1.0 × 10 8 Pa~1.3×10 9 The value is Pa. If the tensile modulus of the base material is within this range, the desired bending load can be easily achieved. The tensile modulus is measured in accordance with JIS K 7161.

[0023] The thickness of the substrate is, for example, 20 μm to 70 μm, or for example, 25 μm to 60 μm, or for example, 25 μm to 50 μm. If the thickness of the substrate is within this range, peeling defects when removing the surface protective film can be prevented very effectively.

[0024] As the PF adhesive layer 22, any suitable configuration can be adopted as long as the desired bending load can be realized. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination, and blending ratio of the monomers forming the base resin of the adhesive, as well as the blending amount of the crosslinking agent, reaction temperature, reaction time, etc., an adhesive having desired properties according to the purpose can be prepared. The base resin of the adhesive may be used alone or in combination of two or more. The base resin is preferably an acrylic resin (that is, the PF adhesive layer is preferably composed of an acrylic adhesive). The adhesive constituting the PF adhesive layer has the characteristic that the base resin contains a polymer having an active hydrogen-containing functional group (for example, a hydroxyl group). With such a base resin, a PF adhesive layer having a desired storage modulus can be obtained. The details of the adhesive constituting the PF adhesive layer are described, for example, in JP-A-2018-123281, and the description of this publication is incorporated herein by reference.

[0025] The thickness of the PF adhesive layer 22 is, for example, 5 μm to 50 μm, or for example, 10 μm to 40 μm, or for example, 10 μm to 30 μm. If the thickness of the PF adhesive layer is within such a range, it may be easy to realize the above-mentioned desired bending load.

[0026] The storage modulus G' of the PF adhesive layer 22 at 25°C is, for example, 0.5×10 6 (Pa) to 3.0×10 6 (Pa). If the storage modulus is within such a range, it may be easy to realize the above-mentioned desired bending load. Furthermore, an adhesive layer (and as a result, a surface protection film) having an excellent balance between adhesiveness and peelability can be obtained. The storage modulus can be obtained, for example, from dynamic viscoelasticity measurement.

[0027] The thickness of the surface protective film 20 is, for example, 80 μm or less, or for example, 30 μm to 80 μm, or for example, 35 μm to 70 μm, or for example, 40 μm to 60 μm. If the thickness of the surface protective film is within this range, it may be easy to achieve the desired bending load described above. Furthermore, peeling defects when removing the surface protective film can be prevented very effectively. Note that the thickness of the surface protective film refers to the total thickness of the substrate and the PF adhesive layer.

[0028] A-4.Adhesive layer Any suitable configuration can be adopted for the adhesive layer 30. Specific examples of adhesives constituting the adhesive layer include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination, and blending ratio of monomers forming the base resin of the adhesive, as well as the amount of crosslinking agent, reaction temperature, reaction time, etc., an adhesive with desired properties according to the purpose can be prepared. The base resin of the adhesive may be used alone or in combination of two or more types. From the viewpoint of transparency, processability, and durability, acrylic adhesives are preferred. Details of the adhesives constituting the adhesive layer are described, for example, in Japanese Patent Application Publication No. 2014-115468, and the description in said publication is incorporated herein by reference. The thickness of the adhesive layer 30 may be, for example, 10 μm to 100 μm. The storage modulus G' of the adhesive layer 30 at 25°C is, for example, 1.0 × 10⁻⁶. 4 (Pa) ~ 1.0 × 10 6 (Pa) is possible.

[0029] A-5. Separator Any suitable separator can be used as the separator 40. Specific examples include plastic films, nonwoven fabrics, or paper coated with a release agent. Specific examples of release agents include silicone-based release agents, fluorine-based release agents, and long-chain alkyl acrylate-based release agents. Specific examples of plastic films include polyethylene terephthalate (PET) film, polyethylene film, and polypropylene film. The thickness of the separator may be, for example, 10 μm to 100 μm.

[0030] B. Image display device An optical laminate (substantially an optical film) according to an embodiment of the present invention can be suitably applied to an image display device. Therefore, an image display device including an optical laminate (substantially an optical film) is also included in the embodiments of the present invention. An image display device typically includes an image display cell and an optical film bonded to the image display cell via an adhesive layer. Examples of image display devices include liquid crystal displays, organic electroluminescent (EL) displays, and quantum dot displays. [Examples]

[0031] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The evaluation items in the examples are as follows. Unless otherwise specified, "parts" and "%" in the examples are based on weight.

[0032] (1) Extension length L Cross-sections of the optical laminates obtained in the examples and comparative examples were imaged using a scanning electron microscope, and measurements were taken from the obtained images. (2) Bending load of surface protective film As shown in Figure 6, a jig with a U-shaped cross-section was prepared and placed 30 mm away from the weighing platform. The surface protection film used in the examples and comparative examples was punched out into dumbbell-shaped multi-purpose test pieces (total length 150 mm) according to JIS K 7139-A1 as samples. This sample was folded exactly in half and placed on the weighing platform, and the load applied to the weighing platform as the sample (surface protection film) attempted to return to its original shape was measured as the bending load. (3) Peelability and initial peeling force Measurements were performed in accordance with JIS Z 0237. Specifically, a pickup tape was applied to the surface of the protective film of the optical laminate obtained in the examples and comparative examples, along the peeling direction (the direction perpendicular to the tangent to the R shape). The peeling force when peeling at a 90° tensile angle using the pickup tape was measured as the initial peeling force. For this measurement, Nitto Denko Corporation's polyester adhesive tape No. 315 was used as the pickup tape. The width of the pickup tape was 10 mm, the length of the bonded portion was 10 mm, and the tensile speed was 300 mm / min. Measurements were performed with n=6, and the average value of the remaining values ​​after excluding clearly deviant values ​​was taken as the initial peeling force.

[0033] <Manufacturing Example 1: Preparation of Acrylic Polymer A1> A monomer mixture containing 96 parts of 2-ethylhexyl acrylate and 4 parts of 2-hydroxyethyl acrylate was charged into a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser. Furthermore, 0.1 parts of 2,2'-azobisisobutyronitrile was added to 100 parts of this monomer mixture as a polymerization initiator along with 100 parts of ethyl acetate. After introducing nitrogen gas and purging the mixture with nitrogen while gently stirring, the polymerization reaction was carried out for 8 hours while maintaining the temperature of the liquid in the flask at around 55°C to prepare a solution of acrylic polymer A1 with a weight-average molecular weight (Mw) of 540,000.

[0034] <Manufacturing Example 2: Preparation of Acrylic Polymer A2> A solution of acrylic polymer A2 with a weight-average molecular weight (Mw) of 540,000 was prepared in the same manner as in Production Example 1, except that a monomer mixture containing 91 parts of 2-ethylhexyl acrylate and 9 parts of 4-hydroxybutyl acrylate was used.

[0035] <Manufacturing Example 3: Preparation of Adhesive Composition PSA1> To 100 parts of the solid content of the acrylic polymer A1 solution obtained in Production Example 1, 5 parts of an isocyanate crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate HX", isocyanurate of hexamethylene diisocyanate) and 0.3 parts of a reactive surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name "Aqualon HS-10") were added to prepare a solution of the acrylic adhesive composition PSA1.

[0036] <Manufacturing Example 4: Preparation of Adhesive Composition PSA2> A solution of acrylic adhesive composition PSA2 was prepared by blending 3.5 parts of an isocyanate crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate HX", isocyanurate of hexamethylene diisocyanate), 0.2 parts of a polyether-modified (oxyalkylene chain-containing) organopolysiloxane compound (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KF-353"), and 0.15 parts of a conductive agent (manufactured by Tokyo Chemical Industry Co., Ltd., lithium bis(trifluoromethanesulfonyl)imide: LiTFSI) with 100 parts of the solid content of the acrylic polymer A2 solution obtained in Production Example 2.

[0037] <Manufacturing Example 5: Preparation of Adhesive Composition PSA3> To 100 parts of the solid content of the acrylic polymer A2 solution obtained in Production Example 2, 12 parts of an isocyanate-based crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate L", trimethylolpropane / tolylene diisocyanate adduct) were added to prepare a solution of the acrylic adhesive composition PSA3.

[0038] <Manufacturing Example 6: Fabrication of Surface Protection Film SPV1> A polyethylene terephthalate (PET) film (thickness 38 μm) was coated with the adhesive composition PSA1 obtained in Production Example 3, so that the thickness after drying was 10 μm, and then dried to produce a surface protective film SPV1 having a substrate (PET film: 38 μm) / adhesive layer (10 μm) structure. The bending load of SPV1 was 0.025 g.

[0039] <Manufacturing Example 7: Fabrication of Surface Protection Film SPV2> Surface protective film SPV2 was prepared in the same manner as in manufacturing example 6, except that the thickness of the adhesive layer was set to 20 μm. The bending load of SPV2 was 0.027 g.

[0040] <Manufacturing Example 8: Fabrication of Surface Protection Film SPV3> Surface protective film SPV3 was prepared in the same manner as in Manufacturing Example 6, except that the thickness of the adhesive layer was set to 30 μm. The bending load of SPV3 was 0.022 g.

[0041] <Manufacturing Example 9: Fabrication of Surface Protection Film SPV4> Surface protective film SPV4 was prepared in the same manner as in manufacturing example 6, except that the thickness of the PET film was set to 50 μm. The bending load of SPV4 was 0.137 g.

[0042] <Manufacturing Example 10: Fabrication of Surface Protection Film SPV5> Surface protective film SPV5 was prepared in the same manner as in manufacturing example 6, except that the thickness of the PET film was set to 75 μm. The bending load of SPV5 was 0.624 g.

[0043] <Manufacturing Example 11: Fabrication of Surface Protection Film SPV6> Surface protective film SPV6 was prepared in the same manner as in Manufacturing Example 6, except that an adhesive layer with a thickness of 15 μm was formed using adhesive composition PSA2 instead of adhesive composition PSA1. The bending load of SPV6 was 0.027 g.

[0044] <Manufacturing Example 12: Fabrication of Surface Protection Film SPV7> Surface protective film SPV7 was prepared in the same manner as in Manufacturing Example 6, except that the thickness of the PET film was set to 125 μm and an adhesive layer with a thickness of 20 μm was formed using adhesive composition PSA3 instead of adhesive composition PSA1. The bending load of SPV7 was 3.092 g.

[0045] <Example 1> 1. Preparation of HC-coated TAC film A resin solution (manufactured by DIC Corporation, trade name: Unidick 17-806, solids content: 80%) in which a UV-curable resin monomer or oligomer mainly composed of urethane acrylate was dissolved in butyl acetate was prepared. Five parts of a photopolymerization initiator (manufactured by BASF Corporation, trade name: IRGACURE 907) and 0.1 parts of a leveling agent (manufactured by DIC Corporation, trade name: GRANDIC PC4100) were added per 100 parts of solids in the solution. Cyclopentanone and propylene glycol monomethyl ether were added to the solution in a ratio of 45:55 to adjust the solids content to 36% to prepare a hard coat layer forming material. This hard coat layer forming material was applied to a TAC film (thickness: 25 μm) to form a coating film with a hard coat layer thickness of 7 μm after curing. The coating film was dried at 90°C for 1 minute, and then exposed to a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm². 2 The coating film was cured by irradiation with ultraviolet light to form a hard coat layer and produce an HC-coated TAC film. The obtained HC-coated TAC film was subjected to saponification treatment.

[0046] 2. Fabrication of polarizing plates A 30 μm thick polyvinyl alcohol film was stretched to 3 times its original size while being stained for 1 minute in a 0.3% iodine solution at 30°C between rolls with different speed ratios. Then, it was stretched to a total stretch ratio of 6 times by immersion for 0.5 minutes in an aqueous solution containing 4% boric acid and 10% potassium iodide at 60°C. Next, it was washed by immersion for 10 seconds in an aqueous solution containing 1.5% potassium iodide at 30°C, and then dried at 50°C for 4 minutes to obtain a 12 μm thick polarizer. A polarizing plate was fabricated by laminating the HC-coated TAC film obtained above to one side of the polarizer and a cycloolefin resin (COP) film (manufactured by Nippon Zeon Co., Ltd., product name "ZF14") to the other side using a polyvinyl alcohol-based adhesive. The HC-coated TAC film was laminated so that the HC side was on the outside (opposite the polarizer).

[0047] 3. Fabrication of optical stacks The SPV1 obtained in Production Example 6 was bonded to the HC surface of the polarizing plate obtained above, via the adhesive layer of SPV1. Meanwhile, a 20 μm thick acrylic adhesive layer was formed on the release treatment surface of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Films, trade name "MRF38", separator film) treated with a silicone-based release agent. Next, the adhesive layer of the separator film / adhesive layer laminate was bonded to the COP film side of the polarizing plate obtained above. In this way, an optical laminate having the configuration of surface protection film / polarizing plate (optical film) / adhesive layer / separator was fabricated.

[0048] 4. Fabrication of optical stacks The resulting optical laminate was punched out into a rectangle measuring 150 mm x 150 mm, and its four corners were chamfered (irregular shaping) into an R-shape. The irregular shaping was performed by laser irradiation. Specifically, the laser beam was irradiated from the surface protective film side under the following conditions. The radius of curvature of the chamfered portion (R-shape) was 5 mm. Equipment used: TLSM-301 (manufactured by Takei Electric Industry Co., Ltd.) Oscillator wavelength / power output: RF-excited CO2 laser (9.4 μm) Machining speed: 500mm / sec Number of passes: 1 Processing power: As shown in Table 1 The surface protective film in the obtained optical laminate extended outward at its lower end compared to its upper end, with an extension length of 29.4 μm. The obtained optical laminate was subjected to the evaluation described in (3) above. The results are shown in Table 1.

[0049] <Examples 2-3> An optical laminate with a modified shape was obtained in the same manner as in Example 1, except that the radius of curvature of the chamfered portion (R shape) was changed as shown in Table 1. In the obtained optical laminate, the surface protective film extended outward at the lower end than at the upper end. The extension length is shown in Table 1. Furthermore, the obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0050] <Examples 4-15 and Comparative Examples 1-6> An optical laminate with a modified shape was obtained in the same manner as in Example 1, except that the surface protective film shown in Table 1 was used, the chamfered portion (R-shape) was processed with the radius of curvature shown in Table 1, and the laser processing power was changed as shown in Table 1. In the obtained optical laminate, the lower end of the surface protective film extended outward beyond the upper end. The extension length is shown in Table 1. Furthermore, the obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0051] [Table 1]

[0052] The abbreviations in Table 1 are as follows. Furthermore, the amounts of each component in Table 1 are per 100 parts of polymer. Additionally, "poor peeling" in Table 1 means that when attempting to peel the surface protective film via the pickup tape, the surface protective film did not peel off, and only the pickup tape peeled off, resulting in a failure to peel properly. 2EHA:2-Ethylhexylacrylate HEA: 2-hydroxyethyl acrylate 4HBA: 4-Hydroxybutyl acrylate C / HX: Isocyanate-based crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate HX", isocyanurate derivative of hexamethylene diisocyanate) C / L: Isocyanate-based crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate L", trimethylolpropane / tolylene diisocyanate adduct) Aqualon HS-10: Reactive surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "Aqualon HS-10") KF-353: Polyether-modified (containing oxyalkylene chains) organopolysiloxane compound (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KF-353") LiTFSI: Conductive agent (manufactured by Tokyo Chemical Industry Co., Ltd., lithium bis(trifluoromethanesulfonyl)imide)

[0053] <Rating> As is clear from Table 1, according to the embodiment of the present invention, in an optical laminate having a predetermined irregularly shaped portion, by setting the bending load of the surface protective film to 0.5 g or less, peeling defects when peeling the surface protective film from the irregularly shaped portion can be significantly suppressed. [Industrial applicability]

[0054] The optical laminate of the present invention is suitably used in image display devices, and in particular suitably used in image display devices having irregularly shaped parts, such as instrument panels for automobiles, smartphones, tablet PCs, or smartwatches. [Explanation of Symbols]

[0055] 10 Optical film 20 Surface protective film 21 Base material 22 PF adhesive layer 30 Adhesive layer 40 Separators 100 Optical laminate

Claims

1. An optical laminate comprising an optical film, a surface protective film peelably attached to one side of the optical film, an adhesive layer disposed on the other side of the optical film, and a separator peelably attached to the adhesive layer, The optical laminate has a portion where the corners are chamfered in an R shape or a portion where the outer edge defining the plan view shape is formed in an arc shape, The lower end of the surface protective film extends outward beyond the upper end, with an extension length of 27 μm to 46 μm. When peeling the surface protective film from the irregularly shaped processed portion, the length of the straight line connecting the outer edges of the optical laminate in a direction perpendicular to the peeling direction at a position 1 mm away from the peeling starting point in the peeling direction is 6 mm or more. The bending load of the surface protective film is 0.5 g or less. The peeling initiation point is the point of contact between the deformed portion and a tangent line drawn in a direction perpendicular to the peeling direction. Optical laminate.

2. The optical laminate according to claim 1, wherein the irregularly shaped processing section is a laser processing section.

3. The optical laminate according to claim 1 or 2, wherein the trigger peeling force when peeling off the surface protective film is 1.0 N or less.

4. The optical laminate according to any one of claims 1 to 3, wherein the thickness of the surface protective film is 80 μm or less.

5. An optical laminate according to any one of claims 1 to 4, wherein the extension length is 1 μm to 50 μm.

6. The optical laminate according to any one of claims 1 to 5, wherein the optical film includes a polarizer.

Images