Cover film with protective film

Abstract

To provide a cover film with a protective film that has high adhesion between an anti-fouling surface and a first protective film of a cover film, has no decrease of the anti-fouling property after release, and does not generate peeling of the first protective film when peeling a second protective film.SOLUTION: In a cover film with a protective film, the cover film has a base film and an antifouling layer having a contact angle of water of 100° or more, a front side is an antifouling treated surface and a back side is a non-antifouling treated surface, a first adhesive layer of a first protective film is bonded to the antifouling treated surface, a second adhesive layer of the second protective film is bonded to the non-antifouling treated surface, and the peeling force (P1) against the antifouling treated surface of the first adhesive layer and the peeling force (P2) against the non-antifouling treated surface of the second adhesive layer satisfy the relationship P1>P2. Further, the first adhesive layer is a cured product of an adhesive composition containing a (meth)acrylic copolymer having a molecular weight distribution (Mw / Mn) of 3.0 or less and a crosslinking agent in a predetermined ratio.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cover film that is placed on the surface of a display, and which has protective films attached to both sides thereof. [Background technology]

[0002] A cover window, made of a glass or plastic substrate, is placed on the outermost surface of an image display device. Furthermore, displays in smartphones and tablet devices are equipped with touch panels, and fingerprints, sweat, and other contaminants can adhere to the display surface during use. Therefore, to suppress the adhesion of contaminants or to make them easier to wipe away, an anti-fouling layer may be provided on the cover window.

[0003] Furthermore, the cover window is fitted with a removable protective film to prevent dirt from adhering to it and scratches from occurring during transport. However, when a cover window has an anti-fouling layer formed on it, the protective film adheres poorly due to the properties of the anti-fouling layer, making it prone to peeling off. Therefore, a technology has been proposed to improve the adhesion of the protective film to the anti-fouling layer.

[0004] For example, Patent Document 1 discloses an optical film with a protective film, comprising an optical film having an antifouling layer as the outermost surface layer on a first main surface of a first film substrate, and a surface protection film temporarily attached to the antifouling layer of the optical film, wherein the surface protection film comprises an adhesive layer on a second film substrate, the thickness of the adhesive layer is 16 μm or more, the water contact angle of the antifouling layer is 100° or more, the antifouling layer and the adhesive layer are in contact, and the adhesive strength between the antifouling layer of the optical film and the adhesive layer of the surface protection film is less than 0.07 N / 50 mm (see Patent Document 1 (Claim 1)). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-52221 [Overview of the project] [Problems that the invention aims to solve]

[0006] In recent years, flexible displays have attracted attention in the field of image display devices. These displays can maintain their display function even when bent and can be repeatedly bent and used. Examples of flexible displays include foldable displays that can be folded and rollable displays that can be rolled into a cylindrical shape. For the cover window of such flexible displays, a cover film made of a flexible plastic film is used instead of glass as the substrate.

[0007] Cover films undergo processes such as printing, die-cutting, bonding to the display surface, and inspection while the protective film is attached. However, during these processes, the protective film may peel off from the anti-fouling layer. In particular, when used in flexible displays, there was a problem that the protective film tended to peel off from the anti-fouling layer when the cover film was bent or stretched. However, increasing the adhesion of the protective film to the anti-fouling layer tended to impair the anti-fouling performance, resulting in adhesive residue due to cohesive breakdown of the adhesive layer or contamination of the cover film surface due to migration of low molecular weight components.

[0008] Furthermore, because plastic films are more easily scratched than glass, cover films sometimes not only protect the surface with the anti-fouling layer with a first protective film, but also protect the surface without the anti-fouling layer with a second protective film. In this case, the second protective film needs to be peeled off immediately before printing on the cover film or bonding it to the display, but there was a problem in that when attempting to peel off the second protective film, the first protective film bonded to the anti-fouling layer would peel off first.

[0009] The present invention has been made in view of the above circumstances, and aims to provide a protective film-attached cover film having a cover film having an anti-fouling treated surface and a non-anti-fouling treated surface, a first protective film laminated to the anti-fouling treated surface, and a second protective film laminated to the non-anti-fouling treated surface, wherein the first protective film has appropriate adhesion to the anti-fouling treated surface, the anti-fouling properties of the anti-fouling treated surface are not impaired even after peeling, and the peeling of the first protective film is suppressed when peeling off the second protective film. [Means for solving the problem]

[0010] The protective film-attached cover film of the present invention, which has solved the above problems, comprises a cover film having an antifouling treated surface on the front side and a non-antifouling treated surface on the back side, a first protective film disposed on the antifouling treated surface side of the cover film, and a second protective film disposed on the non-antifouling treated surface side of the cover film, wherein the cover film has an antifouling layer disposed on the outermost surface side with the base film and having a water contact angle of 100° or more, the first protective film comprises a first base material and a first adhesive layer, the first adhesive layer is bonded to the antifouling treated surface, the second protective film comprises a second base material and a second adhesive layer, the second adhesive layer is bonded to the non-antifouling treated surface, and the peeling force (P1) of the first adhesive layer to the antifouling treated surface at 23°C and the peeling force (P2) of the second adhesive layer to the non-antifouling treated surface at 23°C satisfy the relationship P1 > P2. Furthermore, the first adhesive layer is a cured product of an adhesive composition containing a (meth)acrylic copolymer having a first reactive group and a crosslinking agent having a second reactive group that reacts with the first reactive group, wherein the molecular weight distribution (Mw / Mn) of the (meth)acrylic copolymer having the first reactive group is 3.0 or less, and the molar ratio of the second reactive group of the crosslinking agent to the first reactive group of the (meth)acrylic copolymer having the first reactive group (moles of the second reactive group / molars of the first reactive group) is 0.01 to 0.30. [Effects of the Invention]

[0011] The protective film-attached cover film of the present invention has a first protective film that adheres appropriately to the antifouling treated surface of the cover film, preventing the first protective film from peeling off even when the cover film is bent or stretched, and also preventing a decrease in the antifouling properties of the antifouling treated surface after the first protective film is removed. Furthermore, the protective film-attached cover film of the present invention allows the second protective film, which is attached to the non-antifouling treated surface, to be peeled off without causing the first protective film to peel or lift. Thus, the non-antifouling treated surface of the cover film can be protected while also reliably protecting the antifouling treated surface. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic cross-sectional view showing one embodiment of the protective film-attached cover film of the present invention. [Figure 2] This is a schematic cross-sectional view showing a test specimen for the second protective film peel test. [Modes for carrying out the invention]

[0013] <Cover film with protective film> The protective cover film of the present invention comprises a cover film having an anti-fouling treated surface on the front side and a non-fouling treated surface on the back side, a first protective film disposed on the anti-fouling treated side of the cover film, and a second protective film disposed on the non-fouling treated side of the cover film.

[0014] Figure 1 shows one embodiment of the protective film-attached cover film of the present invention. As shown in Figure 1, the protective film-attached cover film 1 according to one embodiment of the present invention comprises a cover film 10, a first protective film 20 disposed on the anti-fouling treated side of the cover film 10, and a second protective film 30 disposed on the non-anti-fouling treated side of the cover film 10.

[0015] The cover film 10 has at least a base film 11 and an antifouling layer 12 disposed on the outermost surface side with a water contact angle of 100° or more. Note that the surface side of the cover film becomes the outer surface side when installed on the display. The cover film 10 has a surface provided with the antifouling layer 12 as an antifouling treatment surface and a surface without the antifouling layer 12 as a non-antifouling treatment surface.

[0016] The first protective film 20 has a first base material 21 and a first adhesive layer 22, and the first adhesive layer 22 is bonded to the antifouling treatment surface (antifouling layer 12) of the cover film 10. The second protective film 30 has a second base material 31 and a second adhesive layer 32, and the second adhesive layer 32 is bonded to the non-antifouling treatment surface of the cover film 10.

[0017] In the cover film 1 with a protective film of the present invention, the peel force (P1) of the first adhesive layer 22 against the antifouling treatment surface at 23°C and the peel force (P2) of the second adhesive layer 32 against the non-antifouling treatment surface at 23°C satisfy the relationship P1 > P2.

[0018] If the peel force (P1) and the peel force (P2) satisfy the relationship P1 > P2, in the process of printing on the non-antifouling treatment surface of the cover film 10 or the process of bonding the cover film to a display or the like, while suppressing the lifting and peeling of the first protective film 20, the second protective film 30 can be peeled off.

[0019] The difference (P1-P2) between the peeling force (P1) of the first adhesive layer against the antifouling treated surface at 23°C and the peeling force (P2) of the second adhesive layer against the non-antifouling treated surface at 23°C is preferably 10 mN / 25 mm or more, more preferably 20 mN / 25 mm or more, even more preferably 30 mN / 25 mm or more, preferably 370 mN / 25 mm or less, more preferably 360 mN / 25 mm or less, and even more preferably 350 mN / 25 mm or less. If the difference (P1-P2) is 10 mN / 25 mm or more, the second protective film can be peeled off while suppressing the lifting and peeling of the first protective film, and if it is 370 mN / 25 mm or less, the first protective film and the second protective film can be easily peeled off from the cover film, making them easy to handle in processes such as printing and lamination with displays.

[0020] The peeling force (P1) is preferably 30 mN / 25 mm or more, more preferably 50 mN / 25 mm or more, even more preferably 70 mN / 25 mm or more, preferably 380 mN / 25 mm or less, more preferably 300 mN / 25 mm or less, and even more preferably 200 mN / 25 mm or less. If the peeling force (P1) is 30 mN / 25 mm or more, adhesion to the antifouling treated surface is further improved, and unexpected lifting and peeling in processes such as printing following the lamination of the first protective film is suppressed. If it is 380 mN / 25 mm or less, the first protective film can be peeled off from the antifouling treated surface more easily without leaving any adhesive residue.

[0021] The peeling force (P2) is preferably 10 mN / 25 mm or more, more preferably 20 mN / 25 mm or more, even more preferably 40 mN / 25 mm or more, preferably 300 mN / 25 mm or less, more preferably 200 mN / 25 mm or less, and even more preferably 100 mN / 25 mm or less. If the peeling force (P2) is 10 mN / 25 mm or more, the lifting and peeling of the second protective film is further suppressed, and if it is 300 mN / 25 mm or less, the lifting of the first protective film is further suppressed when peeling off the second protective film.

[0022] The protective cover film 1 can be manufactured by attaching the first protective film 20 to the antifouling treated surface of the cover film 10 and the second protective film 30 to the non-antifouling treated surface. The order in which the first protective film 20 and the second protective film 30 are attached to the cover film 10 is not particularly limited. The second protective film 30 may also be attached to the non-antifouling treated surface before the antifouling layer 12 is formed on the base film 11. However, it is preferable to attach the second protective film 30 to the non-antifouling treated surface after the antifouling layer 12 has been formed on the base film 11, in order to facilitate visual quality inspection of the antifouling layer 12.

[0023] The protective film-attached cover film of the present invention can be used as a cover window for an image display device. In particular, since the peeling of the first protective film is suppressed when the protective film-attached cover film of the present invention is bent and stretched, it can be suitably used as a cover filter for a flexible display.

[0024] The following describes each component that constitutes the protective film-attached cover film of the present invention.

[0025] [Cover film] The cover film 10 comprises at least a base film 11 and an antifouling layer 12 positioned on the outermost surface. The side of the cover film 10 on which the antifouling layer 12 is positioned is the antifouling treated surface, and the side on which the antifouling layer 12 is not positioned is the non-antifouling treated surface.

[0026] (Base film) Examples of the base film 11 include polymer films and glass films, with flexible films being preferred. Examples of polymer materials constituting the polymer film include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene, polyethylene, polycycloolefins and cycloolefin copolymers, cellulosin resins such as triacetylcellulose and diacetylcellulose, polycarbonate, polyacrylate, polymethacrylate, polystyrene, polyamide, polyimide, polyacrylonitrile, polyphenylene sulfide, polyvinyl chloride, polyvinylidene chloride, and polyvinyl alcohol. The polymer film may be composed of only one polymer material or a combination of two or more materials.

[0027] From the viewpoint of mechanical strength and heat resistance, the aforementioned polymer film preferably contains at least one polymer component selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polymethyl methacrylate (PMMA), polycarbonate (PC), polyamide (PA), and polyphenylene sulfide (PPS) as a constituent component.

[0028] The polymer film is more preferably a polyimide-based film containing polyimide as a constituent component. In this case, in order to fully exhibit the physical properties of polyimide, the polyimide content in 100% by mass of the polymer material contained in the polyimide-based film is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. The polyimide-based film is particularly preferably composed solely of polyimide as the polymer material.

[0029] The polyimide film is suitable as a base film for cover films used in flexible displays that are repeatedly bent, as it has flexibility that allows it to withstand repeated bending. Furthermore, the polyimide film is suitable as a base film for cover films that have excellent pencil hardness, as it has excellent surface hardness. By using a polyimide film as the base film, it is possible to ensure the pencil hardness of the hard coat layer surface when a hard coat layer is laminated. For example, depending on the composition of the hard coat layer, the pencil hardness of the hard coat layer surface when a hard coat layer is laminated can be set to 3H or higher. In addition, the polyimide film also has excellent heat resistance.

[0030] The polymer film may contain additives other than polymer materials, such as antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, fillers, surfactants, and antistatic agents.

[0031] The base film 11 is preferably colorless and transparent. Colorless and transparent means that the total light transmittance in the visible light wavelength range, measured in accordance with JIS K7361-1 (1997), is 50% or more, and the yellowness (YI value), measured in accordance with JIS K 7373 (2006), is 20 or less. The total light transmittance is more preferably 70% or more, and even more preferably 85% or more. The yellowness (YI value) is more preferably 10 or less, and even more preferably 5 or less. If the base film 11 is colorless and transparent, a display that displays images with high transparency and high color reproducibility can be obtained.

[0032] The thickness of the base film 11 is not particularly limited, but from the viewpoint of handling and colorless transparency, it is preferably 12 μm or more, more preferably 25 μm or more, even more preferably 40 μm or more, preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 80 μm or less. In general, "film" refers to a material with a thickness of less than 0.25 mm, but even if the thickness is 0.25 mm or more, if it can be wound into a roll, it is also included as a "film".

[0033] (Anti-fouling layer) The anti-fouling layer 12 is positioned on the outermost surface of the cover film 10, and the side on which the anti-fouling layer 12 is positioned becomes the anti-fouling treated surface. The anti-fouling layer 12 suppresses the adhesion of dirt and fingerprints, facilitates the removal of dirt and fingerprints that have adhered, and further improves the slipperiness of fingers on the cover film. The anti-fouling layer 12 is formed directly on the surface side of the base film 11 or via an optical functional layer. Examples of the optical functional layer include an anti-reflective layer, an anti-glare layer, a polarizing layer, and a hard coat layer. Alternatively, an anti-fouling function may be imparted to the optical functional layer by blending it with an anti-fouling resin, thereby creating an anti-fouling layer.

[0034] The water contact angle of the anti-fouling layer 12 is 100° or more, preferably 102° or more, more preferably 105° or more, preferably 130° or less, more preferably 125° or less, and even more preferably 120° or less. If the water contact angle is 100° or more, the adhesion of dirt and fingerprints is suppressed and any dirt or fingerprints that do adhere can be easily removed, and if it is 130° or less, the adhesion of the first protective film is further improved.

[0035] The coefficient of dynamic friction of the anti-fouling layer 12 is preferably 0.14 or less, more preferably 0.13 or less, even more preferably 0.11 or less, and particularly preferably 0.10 or less. If the coefficient of dynamic friction is 0.14 or less, a smooth glide can be maintained when sliding a finger across the display surface.

[0036] A fluorine-containing compound is preferred as the material for the antifouling layer 12. The fluorine-containing compound not only provides antifouling properties but can also contribute to lowering the refractive index. A fluorine-based polymer containing a perfluoropolyether skeleton is preferred as the fluorine-containing compound. Using a fluorine-based polymer containing a perfluoropolyether skeleton further improves the water repellency of the antifouling layer and thus improves its antifouling properties.

[0037] The perfluoropolyether skeleton is preferably a perfluoroalkylene oxide which may have branched chains having 1 to 4 carbon atoms, for example, perfluoromethylene oxide (-CF2O-), perfluoroethylene oxide (-CF2CF2O-), perfluoropropylene oxide (-CF2CF2CF2O-), perfluoroisopropylene oxide (-CF(CF3)CF2O-), etc.

[0038] The antifouling layer 12 can be formed by wet methods such as reverse coating, die coating, and gravure coating, or by dry methods such as CVD (Chemical Vapor Deposition). The thickness of the antifouling layer is approximately 2 nm to 50 nm.

[0039] (Stain-resistant hard coat layer) The anti-fouling layer 12 is preferably a hard coat layer with anti-fouling properties. By making the anti-fouling layer 12 an anti-fouling hard coat layer, the cover film can be effectively given anti-fouling properties, pencil hardness, and scratch resistance.

[0040] The pencil hardness of the antifouling layer 12 is preferably 3H or higher, and more preferably 4H or higher. The pencil hardness of the antifouling layer 12 is the pencil hardness of the surface of the antifouling layer 12 formed on the base film 11. The pencil hardness of the antifouling layer 11 can be measured in accordance with JIS K 5600-5-4 (1999).

[0041] If the antifouling layer 12 is an antifouling hard coat layer, the thickness of the antifouling layer 12 is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 3.0 μm or more, preferably 10.0 μm or less, more preferably 8.0 μm or less, and even more preferably 6.0 μm or less. If the thickness of the antifouling layer 12 is 0.5 μm or more, the pencil hardness and scratch resistance of the antifouling layer are further improved, and if it is 10.0 μm or less, the antifouling layer has the flexibility to withstand repeated bending, and curling of the cover film 10 caused by the difference in thermal shrinkage between the antifouling layer 12 and the base film 11 is suppressed. The thickness of the antifouling layer 12 is the thickness in the smooth portion, and if the antifouling layer 12 contains particles, it is the thickness of the smooth portion in the thickness direction where there are no irregularities caused by the particles.

[0042] When the antifouling layer 12 is an antifouling hard coat layer, it is preferable that the antifouling layer 12 be composed of a cured product of a curable composition containing an antifouling agent and an ultraviolet-curable compound, from the viewpoint of high hardness, high flexibility, and productivity.

[0043] As the antifouling agent, a fluorine-containing compound is preferred. The fluorine-containing compound can suppress the adhesion of dirt and fingerprints and facilitate the removal of dirt and fingerprints. Examples of fluorine-containing compounds include those containing a perfluoropolyether structure. As the structural unit of the main chain skeleton of the perfluoropolyether, a perfluoroalkylene oxide having 1 to 4 carbon atoms is preferred (it may have branched chains), and examples include perfluoromethylene oxide (-CF2O-), perfluoroethylene oxide (-CF2CF2O-), perfluoropropylene oxide (-CF2CF2CF2O-), perfluoroisopropylene oxide (-CF(CF3)CF2O-), etc. Furthermore, in order to further enhance the antifouling properties, the fluorine-containing compound may have a linear or cyclic polysiloxane structure.

[0044] The fluorine-containing compound preferably has an ethylenically active carbon-carbon double bond. This allows the ethylenically active carbon-carbon double bond of the fluorine-containing compound to copolymerize with the ethylenically active carbon-carbon double bond (e.g., (meth)acryloyl group) of the UV-curable compound described later, resulting in the antifouling agent being covalently bonded to the cured product of the curable composition. As a result, the antifouling properties of the cured product are further improved. Examples of commercially available antifouling agents include Megafac® RS851, Megafac RS852, Megafac RS853, Megafac RS854 (manufactured by DIC Corporation), Opstar® TU2225, Opstar TU2224 (manufactured by Arakawa Chemical Industries, Ltd.), and KY-1203M (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0045] The content of the fluorine-containing compound is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.2% by mass or more, preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the solid content of the curable composition. If the content of the fluorine-containing compound is within the above range, the antifouling properties, antifingerprint properties, and scratch resistance of the antifouling layer are further improved. The solid content of the curable composition refers to the components other than the solvent contained in the curable composition.

[0046] Examples of UV-curable compounds include monomers, oligomers, and prepolymers having UV-reactive reactive groups. Examples of UV-reactive reactive groups include radical polymerization-type reactive groups having ethylenically unsaturated bonds, such as (meth)acryloyl groups, allyl groups, and vinyl groups, and cationic polymerization-type reactive groups, such as oxetanyl groups. Among these, (meth)acryloyl groups and oxetanyl groups are more preferred, and (meth)acryloyl groups are particularly preferred. In other words, (meth)acrylate-based monomers, oligomers, and polymers are particularly preferred as UV-curable compounds. In this specification, "(meth)acrylate" means "at least one of acrylate and methacrylate." "(meth)acryloyl" means "at least one of acryloyl and methacryloyl." "(meth)acrylic" means "at least one of acrylic and methacrylic."

[0047] Examples of the (meth)acrylate monomers include monofunctional (meth)acrylates having one UV-reactive group in the molecule, and polyfunctional (meth)acrylates having two or more UV-reactive groups in the molecule.

[0048] The aforementioned monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Rate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, bornyl (meth)acrylate, tricyclodecanyl (meth)acrylate, Dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, 1-naphthylmethyl (meth)acrylate, 2-naphthylmethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxy-2-methylethyl (meth)acrylate, phenoxyethoxyethyl (meth)acrylate, 3-phenoxy-2-hydroxypropyl (meth)acrylate, 2-phenylphenoxyethyl (meth)acrylate, 4-phenylphenoxyethyl (meth)acrylate, 3-(2-phenylphenyl)-2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, methoxyethylene glycol (meth)acrylate,Examples include ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate.

[0049] Examples of the aforementioned polyfunctional (meth)acrylates include difunctional (meth)acrylates, trifunctional (meth)acrylates, tetrafunctional (meth)acrylates, etc. More specifically, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. Examples include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tetra(meth)acrylate, tripentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, and tripentaerythritol octa(meth)acrylate.

[0050] Examples of the (meth)acrylate oligomers and polymers mentioned above include urethane (meth)acrylate, silicone (meth)acrylate, the monofunctional (meth)acrylate described above, and / or polymers of polyfunctional (meth)acrylate.

[0051] The urethane (meth)acrylate is obtained by addition reaction with a polyol, polyisocyanate, and a (meth)acrylate having a hydroxyl group. The urethane (meth)acrylate is preferably a polyfunctional urethane (meth)acrylate having two or more UV-reactive reactive groups in its molecule.

[0052] Examples of the polyols include polyether polyols, polyester polyols, and polycarbonate polyols, which can be appropriately selected from viewpoints such as flexibility, heat resistance, and chemical resistance. The polyisocyanate can be, for example, aromatic diisocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate, xylylene diisocyanate (XDI), and tetramethylxylylene diisocyanate (TMXDI), or alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate (CDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, 1,3-diisocyanatomethylcyclohexane (hydrogenated XDI), and 4-methyl-1,3-cyclohexylene diisocyanate (hydrogenated TDI). Examples of (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate.

[0053] As the UV-curable compound, polyfunctional (meth)acrylate monomers, polyfunctional (meth)acrylate oligomers, and polyfunctional (meth)acrylate polymers are preferred. In particular, urethane (meth)acrylate is especially preferred from the viewpoint of being relatively flexible and improving the flexibility of the cover film 10, and it is preferable that the compound contains polyfunctional urethane (meth)acrylate.

[0054] The curable composition may contain a photopolymerization initiator. Examples of photopolymerization initiators include alkylphenone-based, acylphosphine oxide-based, and oxime ester-based photopolymerization initiators. Examples of alkylphenone-based photopolymerization initiators include 2,2'-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropane-1- Examples include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzylmethyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-(4-morpholinophenyl)-1-butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, and N,N-dimethylaminoacetophenone. Examples of acylphosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Examples of oxime ester-based photopolymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime). One photopolymerization initiator may be used alone, or two or more may be used in combination.

[0055] When the photopolymerization initiator is included, the content of the photopolymerization initiator is preferably 0.1% by mass or more, more preferably 1% by mass or more, preferably 10% by mass or less, and more preferably 5% by mass or less, based on 100% by mass of the solid content of the curable composition.

[0056] The curable composition may contain a non-UV-curable resin in addition to the UV-curable compound. Examples of the non-UV-curable resin include thermoplastic resins and thermosetting resins. Examples of the thermoplastic resin include polyester resins, polyether resins, polyolefin resins, and polyamide resins. Examples of the thermosetting resin include unsaturated polyester resins, epoxy resins, alkyd resins, and phenolic resins.

[0057] Furthermore, the curable composition may contain additives as needed. Examples of such additives include inorganic particles, resin particles, dispersants, leveling agents, defoamers, vibration modifiers, antibacterial agents, flame retardants, and slip agents.

[0058] Inorganic particles and resin particles are added to the antifouling hard coat layer for purposes such as preventing blocking, improving the hardness of the antifouling hard coat layer, or providing anti-glare properties.

[0059] Examples of the inorganic particles include metal oxide particles made from metal oxides such as silica, titanium, zirconium, tin, zinc, silicon, niobium, aluminum, chromium, magnesium, germanium, gallium, antimony, and platinum. One type of inorganic particle may be used alone, or two or more types may be used in combination. Titanium oxide, zirconium oxide, and tin oxide are particularly preferred as inorganic particles from the viewpoint of achieving both high hardness and transparency.

[0060] Examples of the resin particles include resins such as (meth)acrylic resin, styrene resin, styrene-(meth)acrylic resin, urethane resin, polyamide resin, silicone resin, epoxy resin, phenolic resin, polyethylene resin, and cellulose. The resin particles may be used individually or in combination of two or more types.

[0061] The curable composition may contain a solvent as needed. Examples of solvents for the curable composition include alcoholic solvents such as ethanol, isopropyl alcohol, n-butyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and acetone; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate (EtAc), propyl acetate, isopropyl acetate, and butyl acetate (BuAc); and amide solvents such as N-methylpyrrolidone, acetamide, and dimethylformamide. These solvents may be used individually or in combination of two or more.

[0062] The solid content concentration (concentration of components other than the solvent) of the curable composition is not particularly limited and may be determined appropriately considering the coating properties, film thickness, etc. The solid content concentration is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, even more preferably 2.0% by mass or more, preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less.

[0063] [First protective film] The first protective film 20 comprises a first substrate 21 and a first adhesive layer 22, the first adhesive layer 22 being bonded to the anti-fouling surface of the cover film 10.

[0064] The first protective film 20 prevents scratches on the surface of the anti-fouling treated surface (anti-fouling layer 12) during handling, such as continuous processing in a roll process or laminating the cover film 10 onto a flexible display.

[0065] The first protective film 20 is peeled off from the anti-fouling surface (anti-fouling layer 12) of the cover film after the cover film 10 has been attached to the display or the like. Therefore, the adhesive force between the first adhesive layer 22 and the first substrate 21 is stronger than the adhesive force between the anti-fouling surface of the cover film and the first adhesive layer 22, and the adhesive force is adjusted to allow for interfacial peeling between the anti-fouling surface and the first adhesive layer 22.

[0066] (1st base material) The material constituting the first substrate 21 is not particularly limited, but examples include polymer materials. Examples of polymer materials include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene, polyethylene, polycycloolefin, and cycloolefin copolymer, polycarbonate, polyacrylate, polymethacrylate, polystyrene, polyamide, polyimide, polyacrylonitrile, polyphenylene sulfide, polyvinyl chloride, polyvinylidene chloride, and polyvinyl alcohol. One polymer material may be used alone, or two or more may be used in combination. Among these, polyethylene terephthalate, polyimide, polycarbonate, polyacrylate, polymethacrylate, polycycloolefin, and cycloolefin copolymer are more preferred from the viewpoint of durability and other factors.

[0067] The first substrate 21 may consist of a single layer comprising one or more of the polymer materials, or it may consist of two or more layers, such as a layer comprising one or more of the polymer materials and a layer comprising one or more of polymer materials different from this layer.

[0068] The thickness of the first substrate 21 is not particularly limited, but from the viewpoint of handling ease during processing and material cost, it is preferably 19 μm or more, more preferably 22 μm or more, even more preferably 25 μm or more, preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 75 μm or less.

[0069] (1st adhesive layer) The first adhesive layer 22 is a cured product of an adhesive composition containing a (meth)acrylic copolymer having a first reactive group and a crosslinking agent having a second reactive group that reacts with the first reactive group. The adhesive composition contains (A) a (meth)acrylic copolymer having a first reactive group and (B) a crosslinking agent.

[0070] The thickness of the first adhesive layer 22 is not particularly limited and can be adjusted as appropriate according to the adhesion to the antifouling surface. The thickness of the first adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, and particularly preferably 15 μm or less. If the thickness is within the above range, the adhesion to the antifouling surface will be further improved and stop marks caused by zipping (slip-stick phenomenon) can be suppressed.

[0071] (A) (meth)acrylic copolymer having a primary reactive group The (meth)acrylic copolymer having the (A) first reactive group (hereinafter sometimes simply referred to as "(A) copolymer") is a (meth)acrylic copolymer having the first reactive group and having a molecular weight distribution (Mw / Mn) of 3.0 or less.

[0072] The (meth)acrylic copolymer mentioned above is any copolymer whose main component (50% by mass or more) is structural units derived from (meth)acrylic monomer, and may contain structural units derived from vinyl monomers other than (meth)acrylic monomer. The content of structural units derived from (meth)acrylic monomer in the copolymer (A) is preferably 80% by mass or more, and more preferably 90% by mass or more, out of 100% by mass of the entire copolymer. The copolymer (A) may also consist only of structural units derived from (meth)acrylic monomer.

[0073] The copolymer (A) is preferably a (meth)acrylate copolymer. A (meth)acrylate copolymer is any copolymer having structural units derived from (meth)acrylate as its main component (50% by mass or more), and may contain structural units derived from vinyl monomers other than (meth)acrylate. The (meth)acrylate is an ester compound in which a hydrogen atom of the carboxyl group of (meth)acrylic acid is replaced by an organic group. The content of structural units derived from (meth)acrylate in the copolymer (A) is preferably 80% by mass or more, and more preferably 90% by mass or more, out of 100% by mass of the entire copolymer.

[0074] The copolymer (A) has a first reactive group. The first reactive group is a functional group that can react with a second reactive group of the crosslinking agent (B) described later. The first reactive group can be, for example, one or more selected from the group consisting of a hydroxyl group, a carboxyl group, and an epoxy group, and is preferably a hydroxyl group and / or a carboxyl group.

[0075] The preferred combinations of the first reactive group of the copolymer (A) and the second reactive group of the crosslinking agent (B) are: (1) a combination in which the first reactive group is a hydroxyl group and the second reactive group is an isocyanate group; and (2) a combination in which the first reactive group is a carboxyl group and the second reactive group is an epoxy group.

[0076] The amount of the first reactive group per 100g of copolymer (A) is preferably 0.5 mmol / 100g or more, more preferably 5 mmol / 100g or more, even more preferably 10 mmol / 100g or more, particularly preferably 15 mmol / 100g or more, preferably 150 mmol / 100g or less, more preferably 100 mmol / 100g or less, and even more preferably 70 mmol / 100g or less. If the amount of the first reactive group is 0.5 mmol / 100g or more, the durability of the first adhesive layer is excellent, and if it is 150 mmol / 100g or less, the adhesion of the first adhesive layer to the antifouling surface of the cover film is excellent.

[0077] If the copolymer (A) has carboxyl groups, the amount of carboxyl groups per 100g of copolymer (A) is preferably 0.5 mmol / 100g or more, more preferably 5 mmol / 100g or more, even more preferably 10 mmol / 100g or more, particularly preferably 15 mmol / 100g or more, preferably 150 mmol / 100g or less, more preferably 100 mmol / 100g or less, and even more preferably 70 mol / 100g or less.

[0078] If the copolymer (A) has hydroxyl groups, the amount of hydroxyl groups per 100g of copolymer (A) is preferably 0.5 mmol / 100g or more, more preferably 5 mmol / 100g or more, even more preferably 10 mmol / 100g or more, particularly preferably 15 mmol / 100g or more, preferably 150 mmol / 100g or less, more preferably 100 mmol / 100g or less, and even more preferably 70 mmol / 100g or less.

[0079] The copolymer (A) has a first reactive group. That is, the copolymer (A) contains a structural unit (a-1) having a first reactive group in its structure. The structural unit (a-1) having a first reactive group may be one type or may consist of two or more types. The first reactive group may be present in structural units derived from (meth)acrylic monomers (preferably (meth)acrylate monomers and / or (meth)acrylic acid) or structural units derived from vinyl monomers other than (meth)acrylic monomers. That is, the structural unit (a-1) having a first reactive group may be a structural unit derived from a (meth)acrylic monomer (preferably (meth)acrylate monomers and / or (meth)acrylic acid) having a first reactive group, or a structural unit derived from vinyl monomers other than (meth)acrylic monomers having a first reactive group.

[0080] The content of structural units (structural units (a-1)) derived from vinyl monomers having a first reactive group in the copolymer (A) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, particularly preferably 3% by mass or more, preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and particularly preferably 8% by mass or less, based on 100% by mass of the entire copolymer. If the content of structural units (a-1) is within the above range, an adhesive layer with an excellent balance of adhesion and durability to the antifouling treated surface can be obtained. Note that vinyl monomers having a first reactive group include (meth)acrylic monomers having a first reactive group and vinyl monomers other than (meth)acrylic monomers having a first reactive group.

[0081] Examples of the (meth)acrylic monomer include (b1) a (meth)acrylic monomer that does not have a functional group that can act as a primary reactive group, and (b2) a (meth)acrylic monomer that has a functional group that can act as a primary reactive group. These monomers may be used individually or in combination of two or more. As the (b1) (meth)acrylic monomer, (b1-1) a (meth)acrylate monomer that does not have a functional group that can act as a primary reactive group is preferred. Examples of the (b2) (meth)acrylic monomer include (b2-1) a (meth)acrylate monomer that has a functional group that can act as a primary reactive group, and (meth)acrylic acid.

[0082] Examples of the (b1)(meth)acrylic monomer include (meth)acrylates having a linear alkyl group, (meth)acrylates having a branched alkyl group, (meth)acrylates having an alkoxy group, (meth)acrylates having a polyalkylene glycol structural unit, (meth)acrylates having an alicyclic hydrocarbon group, (meth)acrylates having an aromatic group, (meth)acrylates having a tertiary amino group, and (meth)acrylamides. Among these, at least one selected from the group consisting of (meth)acrylates having a linear alkyl group, (meth)acrylates having a branched alkyl group, (meth)acrylates having an alicyclic hydrocarbon group, (meth)acrylates having an aromatic group, and (meth)acrylamides is preferred.

[0083] The (meth)acrylate having a linear alkyl group is preferably one in which the linear alkyl group has 1 to 20 carbon atoms, and more preferably one in which the linear alkyl group has 1 to 10 carbon atoms. Examples of the (meth)acrylate having a linear alkyl group include linear alkyl esters of (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-lauryl (meth)acrylate, and n-stearyl (meth)acrylate.

[0084] The (meth)acrylate having a branched alkyl group is preferably a (meth)acrylate having a branched alkyl group having 3 to 20 carbon atoms, and preferably a (meth)acrylate having a branched alkyl group having 3 to 10 carbon atoms. Examples of the (meth)acrylate having a branched alkyl group include isopropyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and isodecyl (meth)acrylate, which are branched alkyl esters of (meth)acrylic acid.

[0085] Examples of (meth)acrylates having an alkoxy group include alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate.

[0086] Examples of (meth)acrylates having polyalkylene glycol structural units include polyethylene glycol (degree of polymerization = 2-10) methyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 2-10) ethyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 2-10) propyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 2-10) phenyl ether (meth)acrylate, and other (meth)acrylates having polyethylene glycol structural units; polypropylene glycol (degree of polymerization = 2-10) methyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2-10) ethyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2-10) propyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2-10) phenyl ether (meth)acrylate, and other (meth)acrylates having polypropylene glycol structural units.

[0087] Examples of (meth)acrylates having an alicyclic hydrocarbon group include (meth)acrylates having a cyclic alkyl group and (meth)acrylates having a polycyclic structure. Preferably, the (meth)acrylate having a cyclic alkyl group has 6 to 12 carbon atoms. Examples of cyclic alkyl groups include monocyclic alkyl groups (e.g., cycloalkyl groups), and may also have a chain-like portion. Specific examples of (meth)acrylates having a monocyclic cyclic alkyl group include cyclic alkyl esters of (meth)acrylic acid such as cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, and cyclododecyl (meth)acrylate.

[0088] The (meth)acrylate having the polycyclic structure is preferably a (meth)acrylate having a polycyclic structure with 6 to 12 carbon atoms. Examples of the polycyclic structure include cyclic alkyl groups having a cross-linking ring structure (e.g., adamantyl group, norvonyl group, isobornyl group), and may also have a chain portion. Specific examples of (meth)acrylates having a polycyclic structure include bornyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate.

[0089] The (meth)acrylate having an aromatic group is preferably one having an aromatic group with 6 to 12 carbon atoms. Examples of aromatic groups include aryl groups, and may also have a chain portion such as an alkylaryl group, aralkyl group, or aryloxyalkyl group. Examples of the (meth)acrylate having an aromatic group include compounds in which an aryl group is directly bonded to a (meth)acryloyloxy group, compounds in which an aralkyl group is directly bonded to a (meth)acryloyloxy group, and compounds in which an alkylaryl group is directly bonded to a (meth)acryloyloxy group. The number of carbon atoms in the aryl group is preferably 6 to 12. The number of carbon atoms in the aralkyl group is preferably 6 to 12. The number of carbon atoms in the alkylaryl group is preferably 6 to 12. Examples of (meth)acrylate having an aromatic group include benzyl (meth)acrylate, phenyl (meth)acrylate, and phenoxyethyl (meth)acrylate.

[0090] Examples of (meth)acrylates having a tertiary amino group include 2-(dimethylamino)ethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

[0091] Examples of the (meth)acrylamides include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-tert-butyl(meth)acrylamide, N-octyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-ethoxymethyl(meth)acrylamide, N-propoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, diacetone acrylamide, and N-(meth)acryloylmorpholine. The (meth)acrylamides are (meth)acrylic monomers but are not included in (meth)acrylate monomers.

[0092] Examples of monomers that can become (b2) (meth)acrylic monomers include (meth)acrylic monomers having a hydroxyl group (preferably (meth)acrylate monomers), (meth)acrylic monomers having a carboxyl group (preferably (meth)acrylic acid), and (meth)acrylic monomers having an epoxy group (preferably (meth)acrylate monomers). Among these, (meth)acrylic monomers having a hydroxyl group and / or (meth)acrylic monomers having a carboxyl group are preferred.

[0093] Examples of (meth)acrylic monomers having a hydroxyl group include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate; hydroxyalkylcycloalkane (meth)acrylates such as (4-hydroxymethylcyclohexyl)methyl (meth)acrylate; and caprolactone adducts of hydroxyalkyl (meth)acrylates. Among these, hydroxyalkyl (meth)acrylates are preferred, and (meth)acrylates having a hydroxyalkyl group with 1 to 5 carbon atoms are more preferred.

[0094] Examples of (meth)acrylic monomers having a carboxyl group include monomers obtained by reacting hydroxyl group-containing (meth)acrylates such as carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, and 2-(meth)acryloyloxyethyl phthalate with acid anhydrides such as maleic anhydride, succinic anhydride, and phthalic anhydride, as well as (meth)acrylic acid. Among these, (meth)acrylic acid is preferred.

[0095] Examples of (meth)acrylic acid esters having the epoxy group include glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0096] Examples of vinyl monomers other than the (meth)acrylic monomers mentioned above include (b3) vinyl monomers other than (meth)acrylic monomers that do not have a functional group that can act as a primary reactive group, and (b4) vinyl monomers other than (meth)acrylic monomers that have a functional group that can act as a primary reactive group. These monomers may be used individually or in combination of two or more.

[0097] Examples of the vinyl monomers in (b3) include aromatic vinyl monomers, vinyl monomers containing heterocyclic rings, vinyl carboxylates, vinyl monomers containing tertiary amino groups, vinyl monomers containing quaternary ammonium bases, vinyl amides, α-olefins, dienes, halogenated vinyl monomers, and the like.

[0098] Examples of the aromatic vinyl monomers include styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene, 2-hydroxymethylstyrene, and 1-vinylnaphthalene. Examples of vinyl monomers containing the heterocycle include 2-vinylthiophene, N-methyl-2-vinylpyrrole, 2-vinylpyridine, and 4-vinylpyridine. Examples of vinyl carboxylates include vinyl acetate, vinyl pivalate, and vinyl benzoate. Examples of vinyl monomers containing the aforementioned tertiary amino group include N,N-dimethylallylamine. Examples of vinyl monomers containing the quaternary ammonium base include N-methacryloylaminoethyl-N,N,N-dimethylbenzylammonium chloride. Examples of the aforementioned vinylamides include N-vinylformamide, N-vinylacetamide, 1-vinyl-2-pyrrolidone, and N-vinyl-ε-caprolactam. Examples of the α-olefins mentioned above include 1-hexene, 1-octene, and 1-decene. Examples of the aforementioned dienes include butadiene, isoprene, 4-methyl-1,4-hexadiene, and 7-methyl-1,6-octadiene. Examples of the aforementioned vinyl halogenated monomers include vinyl fluoride, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, tetrafluoropropylene, vinylidene chloride, vinyl chloride, 1-chloro-1-fluoroethylene, and 1,2-dichloro-1,2-difluoroethylene.

[0099] Examples of the vinyl monomers (b4) include vinyl monomers having a hydroxyl group, vinyl monomers having a carboxyl group, and vinyl monomers containing an epoxy group.

[0100] Examples of vinyl monomers having a hydroxyl group include p-hydroxystyrene and allyl alcohol. Examples of vinyl monomers having a carboxyl group include crotonic acid, maleic acid, itaconic acid, citraconic acid, and cinnamic acid. Examples of vinyl monomers containing the epoxy group include 2-allyloxirane, glycidyl vinyl ether, and 3,4-epoxycyclohexyl vinyl ether.

[0101] The copolymer (A) may be a random copolymer, a block copolymer, or a graft copolymer, and is preferably a random copolymer.

[0102] The weight-average molecular weight (Mw) of the copolymer (A) is preferably 200,000 or more, more preferably 400,000 or more, even more preferably 500,000 or more, preferably 2,000,000 or less, more preferably 1,500,000 or less, even more preferably 1,200,000 or less, and particularly preferably 1,000,000 or less. If the Mw of the copolymer (A) is 200,000 or more, the cohesive force is increased and the heat resistance of the adhesive layer is improved, and if it is 2,000,000 or less, the coating workability of the adhesive composition is improved. The method for measuring the weight-average molecular weight (Mw) will be described later.

[0103] The molecular weight distribution (Mw / Mn) of the copolymer (A) is 3.0 or less, preferably 2.5 or less, more preferably 2.3 or less, and particularly preferably 2.0 or less. The smaller the molecular weight distribution, the narrower the molecular weight distribution, resulting in a copolymer with uniform molecular weights, and the narrowest molecular weight distribution is achieved when the value is 1.0. If the molecular weight distribution is 3.0 or less, the content of molecules with smaller or larger molecular weights is lower compared to the molecular weight of the designed copolymer, resulting in an adhesive layer with less adhesive residue. In this invention, the molecular weight distribution is a value calculated by (weight-average molecular weight (Mw)) / (number-average molecular weight (Mn)), and the methods for measuring Mw and Mn will be described later.

[0104] The glass transition temperature (Tg) of the copolymer (A) is preferably -80°C or higher, more preferably -75°C or higher, preferably 0°C or lower, more preferably -20°C or lower, and even more preferably -50°C or lower. If the glass transition temperature is -80°C or higher, it provides sufficient cohesive force to the adhesive and improves the durability of the adhesive. If the glass transition temperature is 0°C or lower, it provides appropriate adhesion to the antifouling layer and suppresses zipping.

[0105] The glass transition temperature (Tg) of the copolymer (A) is the value calculated by the following FOX equation (Equation (1)). In Equation (1), Tg represents the glass transition temperature (°C) of the copolymer. Tgi represents the glass transition temperature (°C) when vinyl monomer i forms a homopolymer. Wi represents the mass ratio of vinyl monomer i to the total vinyl monomers forming the copolymer, where ΣWi = 1. i is a natural number from 1 to n.

[0106]

number

[0107] Table 1 shows the glass transition temperatures of typical homopolymers.

[0108] [Table 1]

[0109] The copolymer (A) is produced by polymerizing vinyl monomers. In particular, copolymer (A) is preferably polymerized by living radical polymerization. Living radical polymerization maintains the simplicity and versatility of conventional radical polymerization methods, while being less prone to termination reactions and chain transfer, and growing without being hindered by side reactions that deactivate the growth ends. Therefore, it is easy to precisely control the molecular weight distribution and produce polymers with a uniform composition.

[0110] Living radical polymerization methods include those that use compounds capable of generating nitroxide radicals (nitroxide method; NMP method), which differ in the method of stabilizing the polymerization growth ends; those that use metal complexes such as copper or ruthenium, with halogenated compounds as polymerization initiators, and polymerize them in a living manner (ATRP method); those that use dithiocarboxylic acid esters or xantate compounds (RAFT method); those that use organotellurium compounds (TERP method); those that use organiodine compounds (ITP method); and those that use iodine compounds as polymerization initiators and organic compounds such as phosphorus compounds, nitrogen compounds, oxygen compounds, or hydrocarbons as catalysts (reversible transfer catalytic polymerization; RTCP method, reversible catalyst-mediated polymerization; RCMP method). Among these methods, the TERP method is preferred from the viewpoint of the diversity of monomers that can be used, molecular weight control in the polymer range, uniform composition, and coloration.

[0111] The TERP method is a method for polymerizing radical polymerizable compounds (vinyl monomers) using an organotellurium compound as a chain transfer agent, and is described, for example, in International Publication Nos. 2004 / 14848, 2004 / 14962, 2004 / 072126, and 2004 / 096870.

[0112] Specific polymerization methods for the TERP method include the following (a) to (d). (a) A method for polymerizing vinyl monomers using an organotellurium compound represented by formula (1). (b) A method for polymerizing vinyl monomers using a mixture of an organic tellurium compound represented by formula (1) and an azo polymerization initiator. (c) A method for polymerizing vinyl monomers using a mixture of an organic tellurium compound represented by formula (1) and an organic diterlide compound represented by formula (2). (d) A method for polymerizing vinyl monomers using a mixture of an organic tellurium compound represented by formula (1), an azo polymerization initiator, and an organic diterlide compound represented by formula (2).

[0113] [ka] [In equation (1), R 1 R is an alkyl group, aryl group, or aromatic heterocyclic group having 1 to 8 carbon atoms. 2 and R 3 Each of these is independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. 4 These are alkyl groups, aryl groups, substituted aryl groups, aromatic heterocyclic groups, alkoxy groups, acyl groups, amide groups, oxycarbonyl groups, cyano groups, allyl groups, or propargyl groups having 1 to 8 carbon atoms. In equation (2), R 1 This is an alkyl group, aryl group, or aromatic heterocyclic group having 1 to 8 carbon atoms.

[0114] Specific examples of organotellurium compounds represented by formula (1) include ethyl=2-methyl-2-n-butylteranyl-propionate, ethyl=2-n-butylteranyl-propionate, (2-hydroxyethyl)=2-methyl-methylteranyl-propionate, and other organotellurium compounds described in International Publication Nos. 2004 / 14848, 2004 / 14962, 2004 / 072126, and 2004 / 096870. Specific examples of organoditerlide compounds represented by formula (2) include dimethylditerlide and dibutylditerlide. Any azo polymerization initiator used in normal radical polymerization can be used without particular restrictions, such as 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile) (ADVN), 1,1'-azobis(1-cyclohexanecarbonitride) (ACHN), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70).

[0115] The polymerization step involves mixing a vinyl monomer, an organic tellurium compound of formula (1), and, depending on the type of vinyl monomer, an azo polymerization initiator and / or an organic diterlide compound of formula (2) in a container purged with an inert gas, for purposes such as promoting the reaction, controlling the molecular weight and molecular weight distribution. Examples of inert gases used include nitrogen, argon, and helium. Argon and nitrogen are preferred. The amount of vinyl monomer used in (a), (b), (c), and (d) above may be adjusted as appropriate depending on the physical properties of the desired copolymer.

[0116] The coincidence reaction can be carried out without a solvent, but it may also be carried out by using an aprotic solvent or a protic solvent commonly used in radical polymerization and stirring the mixture. Examples of aprotic solvents that can be used include anisole, benzene, toluene, propylene glycol monomethyl ether acetate, ethyl acetate, tetrahydrofuran (THF), etc. Examples of protic solvents include water, methanol, 1-methoxy-2-propanol, etc. The solvent may be used alone or in combination of two or more. The amount of the solvent used may be adjusted as appropriate. For example, 0.01 ml to 50 ml is preferable with respect to 1 g of the vinyl monomer. The reaction temperature and reaction time may be adjusted as appropriate depending on the molecular weight or molecular weight distribution of the obtained copolymer, but usually, it is stirred at 0 °C to 150 °C for 1 minute to 100 hours. After completion of the polymerization reaction, the used solvent, residual vinyl monomer, etc. can be removed from the obtained reaction mixture by ordinary separation and purification means, and the target copolymer can be separated.

[0117] The growing end of the copolymer obtained by the polymerization reaction is -TeR derived from a tellurium compound 1 (where R 1 is the same as above) and is deactivated by an operation in air after completion of the polymerization reaction, but tellurium atoms may remain. Since the copolymer with tellurium atoms remaining at the end is colored or has poor thermal stability, it is preferable to remove the tellurium atoms. Examples of methods for removing tellurium atoms include a radical reduction method; a method of adsorbing with activated carbon or the like; a method of adsorbing a metal with an ion exchange resin or the like, and these methods can also be used in combination. The other end (the end opposite to the growing end) of the copolymer obtained by the polymerization reaction is -CR 2 R 3 R 4 (where R 2 , R 3 and R 4 are the same as R 2 , R 3 and R 4 in formula (1).). <​​((B) Crosslinking agent) The adhesive composition contains a (B) crosslinking agent. The (B) crosslinking agent is a compound having two or more second reactive groups in one molecule that can react with the first reactive group of the (A) copolymer described above. The (B) crosslinking agent is not particularly limited and examples include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, metal chelate crosslinking agents, melamine resin crosslinking agents, urea resin crosslinking agents, etc. Among these, isocyanate crosslinking agents, epoxy crosslinking agents, and aziridine crosslinking agents are preferred, and isocyanate crosslinking agents or epoxy crosslinking agents are more preferred from the viewpoint of being able to easily control the degree of progress of the crosslinking reaction and suppressing the migration of adhesive components to the antifouling layer.

[0119] (Isocyanate-based crosslinking agent) The isocyanate-based crosslinking agent is a compound having two or more isocyanate groups (including isocyanate-regenerating functional groups in which the isocyanate groups are temporarily protected by a blocking agent or quantification, etc.) as a second reactive group in one molecule. The isocyanate-based crosslinking agent may be used alone or in combination of two or more types.

[0120] Examples of the isocyanate-based crosslinking agents include aromatic polyisocyanates, alicyclic polyisocyanates, aliphatic polyisocyanates, and polyisocyanates polyfunctionalized by adducts of these with various polyols, isocyanurate bonds, biuret bonds, allophanate bonds, etc. More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic polyisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylylene diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, and polymethylene One or more of the following can be used: aromatic polyisocyanates such as polyphenyl isocyanates; isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adducts, trimethylolpropane / hexamethylene diisocyanate trimer adducts, and isocyanurate derivatives of hexamethylene diisocyanate; trimethylolpropane adducts of xylylene diisocyanate; trimethylolpropane adducts of hexamethylene diisocyanate; polyether polyisocyanates, polyester polyisocyanates, and adducts of these with various polyols, polyfunctionalized polyisocyanates with isocyanurate bonds, biuret bonds, allophanate bonds, etc. Of these, aliphatic polyisocyanates are preferred, and isocyanurate derivatives of aliphatic diisocyanates (for example, isocyanurate derivatives of hexamethylene diisocyanate) are more preferred.

[0121] (Epoxy crosslinking agent) The epoxy crosslinking agent refers to a compound having two or more epoxy groups as secondary reactive groups in one molecule. The epoxy crosslinking agent may be used alone or in combination of two or more types.

[0122] Examples of the epoxy crosslinking agent include bisphenol A, epichlorohydrin-type epoxy resins, ethylene glycidyl ether, N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, diamineglycidylamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether. Examples include lysidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate ester, diglycidyl o-phthalate ester, triglycidyl-tris(2-hydroxyethyl) isocyanurate, resorcinol diglycidyl ether, and bisphenol-S-diglycidyl ether.

[0123] (Aziridine-based crosslinking agent) The aforementioned aziridine crosslinking agent refers to a compound having two or more aziridine groups as a secondary reactive group in one molecule. The aforementioned aziridine crosslinking agent may be used alone or in combination of two or more types.

[0124] Examples of the aziridine-based crosslinking agents include tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, tris[1-(2-methyl)-aziridinyl]phosphine oxide, and hexa[1-(2-methyl)-aziridinyl]triphosphatriazine.

[0125] The content of the second reactive group in the crosslinking agent (B) is preferably 0.5 mmol / g or more, more preferably 1.0 mmol / g or more, even more preferably 3.0 mmol / g or more, particularly preferably 5.0 mmol / g or more, preferably 20 mmol / g or less, more preferably 15.0 mmol / g or less, and even more preferably 12.0 mmol / g or less. When the content of the second reactive group in the crosslinking agent (B) is within this range, the cohesive force of the formed adhesive layer is desirable, and adhesive residue and the migration of adhesive components to the antifouling layer can be suppressed.

[0126] The content of (B) crosslinking agent in the adhesive composition is preferably 0.05 parts by mass or more, more preferably 0.06 parts by mass or more, even more preferably 0.08 parts by mass or more, preferably 7 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of (A) copolymer. If the content of (B) crosslinking agent is 0.05 parts by mass or more, the cohesive force of the formed adhesive layer is desirable, which can suppress adhesive residue and the migration of adhesive components to the antifouling layer, and if it is 7 parts by mass or less, appropriate adhesion to the antifouling treated surface can be obtained, which can suppress lifting and peeling of the first protective film.

[0127] The adhesive composition has a molar ratio (moles of second reactive groups / moles of first reactive groups) of (B) the crosslinking agent to the first reactive groups of (A) the copolymer, which is 0.01 or more, preferably 0.02 or more, more preferably 0.08 or more, and 0.30 or less, preferably 0.25 or less, and more preferably 0.20 or less. If the molar ratio is 0.01 or more, the cohesive force of the formed first adhesive layer is good, which can suppress adhesive residue and the transfer of adhesive components to the antifouling surface when peeled off. If the molar ratio is 0.30 or less, appropriate adhesion to the antifouling surface can be obtained, which can suppress lifting and peeling of the protective film.

[0128] (Other additives) In addition to (A) copolymer and (B) crosslinking agent, other additives may be added to the adhesive composition. Examples of other additives include crosslinking accelerators, crosslinking retarders, tackifiers, plasticizers, softeners, release aids, dyes, pigments, fluorescent whitening agents, antistatic agents, wetting agents, surfactants, thickeners, antifungal agents, preservatives, oxygen absorbers, ultraviolet absorbers, antioxidants, near-infrared absorbers, water-soluble quenchers, fragrances, metal deactivators, nucleating agents, alkylating agents, flame retardants, lubricants, and processing aids.

[0129] (Crosslinking promoter) The adhesive composition may optionally contain a crosslinking accelerator. Examples of crosslinking accelerators include organotin compounds and metal chelate compounds. The crosslinking accelerator may be used alone or in combination of two or more types.

[0130] Examples of the organotin compounds include dibutyltin dilaurate, dioctyolustin dilaurylate, and dibutyltin dioctylate. The metal chelate compound is a complex in which ligands having two or more coordinating atoms form a ring and are bonded to a central metal.

[0131] If the adhesive composition contains a crosslinking accelerator, the amount of the crosslinking accelerator is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, even more preferably 0.04 parts by mass or more, preferably 0.5 parts by mass or less, more preferably 0.4 parts by mass or less, and even more preferably 0.3 parts by mass or less, per 100 parts by mass of the copolymer (A). If the amount of the crosslinking accelerator is within the above range, it is possible to obtain an excellent crosslinking promoting effect.

[0132] (Crosslinking retarder) The adhesive composition may optionally contain a crosslinking retarder. A crosslinking retarder is a compound that can suppress an excessive increase in the viscosity of an adhesive composition containing a crosslinking agent by blocking the functional groups of the crosslinking agent. The type of crosslinking retarder is not particularly limited, but examples include β-diketones such as acetylacetone, hexane-2,4-dione, heptane-2,4-dione, and octane-2,4-dione; β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, butyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate; and benzoylacetone. The crosslinking retarder is preferably one that can act as a chelating agent, and β-diketones and β-ketoesters are preferred.

[0133] If the adhesive composition contains a crosslinking retarder, the content of the crosslinking retarder is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, even more preferably 0.5 parts by mass or more, preferably 4.0 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 1.5 parts by mass or less, per 100 parts by mass of copolymer (A). If the content of the crosslinking retarder is within the above range, after the crosslinking agent (B) is incorporated into the adhesive composition, excessive viscosity increase and gelation of the adhesive composition can be suppressed, and the storage stability (pot life) of the adhesive composition can be extended.

[0134] (Tackifier) The adhesive composition may optionally contain tackifiers other than the copolymer (A). The tackifiers are not particularly limited, but examples include rosin-based tackifiers, terpene-based tackifiers, phenol-based tackifiers, hydrocarbon-based tackifiers, and the like.

[0135] Examples of the rosin-based tackifying resins include unmodified rosin (raw rosin) such as gum rosin, wood rosin, and tall oil rosin, as well as modified rosin (polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, and other chemically modified rosin) obtained by polymerization, disproportionation, hydrogenation, etc., as well as various rosin derivatives.

[0136] Examples of the rosin derivatives include rosinphenol resins obtained by adding phenol to rosins (unmodified rosin, modified rosin) with an acid catalyst and then thermal polymerization; rosin ester resins such as ester compounds of rosin obtained by esterifying unmodified rosin with alcohols (unmodified rosin esters) and ester compounds of modified rosin obtained by esterifying modified rosin with alcohols (polymerized rosin esters, stabilized rosin esters, disproportionated rosin esters, fully hydrogenated rosin esters, partially hydrogenated rosin esters, etc.); unsaturated fatty acid modified rosin resins obtained by modifying unmodified rosin or modified rosin with unsaturated fatty acids; unsaturated fatty acid modified rosin ester resins obtained by modifying rosin ester resins with unsaturated fatty acids; rosin alcohol resins obtained by reducing the carboxyl groups in unmodified rosin, modified rosin, unsaturated fatty acid modified rosin resins, and unsaturated fatty acid modified rosin ester resins; and metal salts of rosin resins (especially rosin ester resins) such as unmodified rosin and modified rosin.

[0137] Examples of the terpene-based tackifying resins include terpene resins such as α-pinene polymers, β-pinene polymers, and dipentene polymers, and modified terpene resins obtained by modifying these terpene resins (phenol modification, aromatic modification, hydrogenation modification, hydrocarbon modification, etc.) (for example, terpene-phenol resins, styrene-modified terpene resins, aromatic-modified terpene resins, and hydrogenated terpene resins).

[0138] Examples of the phenolic tackifying resins include condensates of various phenols (e.g., phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcinol) and formaldehyde (e.g., alkylphenol resins, xyleneformaldehyde resins), resols obtained by addition reaction of the phenols and formaldehyde with an alkaline catalyst, and novolacs obtained by condensation reaction of the phenols and formaldehyde with an acid catalyst.

[0139] Examples of the hydrocarbon-based tackifying resins (petroleum-based tackifying resins) include aliphatic hydrocarbon resins [polymers of aliphatic hydrocarbons such as olefins and dienes with 4 to 5 carbon atoms (olefins such as butene-1, isobutylene, pentene-1; dienes such as butadiene, 1,3-pentadiene, isoprene, etc.)], aliphatic cyclic hydrocarbon resins [alicyclic hydrocarbon resins obtained by cyclizing and then polymerizing so-called "C4 petroleum fractions" or "C5 petroleum fractions", cyclic diene compounds (cyclopentadiene, dicyclopentadiene, ethylidene norbornene, Examples include polymers of dipentene (such as dipentene) or hydrogenated thereof, alicyclic hydrocarbon resins obtained by hydrogenating the aromatic rings of aromatic hydrocarbon resins and aliphatic-aromatic petroleum resins listed below, aromatic hydrocarbon resins [polymers of vinyl group-containing aromatic hydrocarbons with 8 to 10 carbon atoms (styrene, vinyltoluene, α-methylstyrene, indene, methylindene, etc.)], aliphatic-aromatic petroleum resins (styrene-olefin copolymers, etc.), aliphatic-alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone-indene resins, etc.

[0140] If the adhesive composition contains a tackifier, the content of the tackifier is preferably 0.5 parts by mass or more, more preferably 2 parts by mass or more, even more preferably 5 parts by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of copolymer (A). By adjusting the content of the tackifier to the above range, sufficient adhesion to the adherend can be ensured and lifting and peeling can be suppressed.

[0141] (Method for manufacturing adhesive composition) The adhesive composition can be produced by mixing the copolymer (A), the crosslinking agent (B), and other additives as needed. The adhesive composition may also contain a solvent derived from the production of the copolymer (A), or it may be further diluted with an appropriate solvent to achieve a viscosity suitable for forming an adhesive layer.

[0142] Examples of the aforementioned solvents include aliphatic hydrocarbons such as hexane and heptane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; cellosolve solvents such as ethyl cellosolve; and glycol ether solvents such as propylene glycol monomethyl ether. These solvents may be used individually or in mixtures of two or more.

[0143] The amount of solvent used is not particularly limited and can be adjusted as appropriate so that the adhesive composition has a viscosity suitable for coating. From the viewpoint of coating properties, the solvent content in the adhesive composition is preferably, for example, 1% to 90% by mass, more preferably 10% to 80% by mass, and even more preferably 20% to 70% by mass.

[0144] (Formation of the first adhesive layer) Methods for forming the first adhesive layer include: directly applying the adhesive composition to one surface of the first substrate; applying the adhesive composition to the surface of a release film to form the first adhesive layer, and then transferring it to one surface of the first substrate; and applying the adhesive composition to the surface of a first release film to form the first adhesive layer, then bonding a second release film, peeling off one of the release films, and transferring it to one surface of the first substrate.

[0145] The adhesive composition can be coated using various coating methods such as reverse gravure coating, direct gravure coating, die coating, bar coating, wire bar coating, roll coating, spin coating, dip coating, spray coating, knife coating, and kiss coating, as well as various printing methods such as inkjet printing, offset printing, screen printing, and flexographic printing.

[0146] The conditions for drying the coating film and curing the composition are not particularly limited, as long as the solvents and other substances contained in the adhesive composition are removed and curing is achieved. For example, it is preferable to perform heat treatment at a temperature of 60°C to 150°C for about 20 to 300 seconds. In particular, a drying temperature of 100°C to 130°C is preferred.

[0147] [Second protective film] The second protective film 30 comprises a second substrate 31 and a second adhesive layer 32, the second adhesive layer 32 being bonded to the non-fouling treated surface of the cover film 10.

[0148] The second protective film 30 prevents scratches on the non-fouling treated surface of the cover film 10 during continuous processing or storage, for example, in a roll process. The second protective film 30 is peeled off the non-fouling treated surface of the cover film 10 before the printing process on the non-fouling treated surface or before the cover film 10 is bonded to a display or the like. Therefore, the adhesive force between the second adhesive layer 32 and the second adhesive layer 32 is stronger than the adhesive force between the non-fouling treated surface of the cover film 10 and the second adhesive layer 32, and the adhesive force is adjusted to allow for interfacial peeling between the non-fouling treated surface and the second adhesive layer 32.

[0149] The material constituting the second substrate 31 is not particularly limited, but examples include polymer materials. Examples of polymer materials include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene, polyethylene, polycycloolefin, and cycloolefin copolymer, polycarbonate, polyacrylate, polymethacrylate, polystyrene, polyamide, polyimide, polyacrylonitrile, polyphenylene sulfide, polyvinyl chloride, polyvinylidene chloride, and polyvinyl alcohol. One polymer material may be used alone, or two or more may be used in combination. Among these, polyethylene terephthalate, polypropylene, and polyethylene are more preferred from the viewpoint of mechanical properties and material cost, and polyethylene terephthalate is particularly preferred from the viewpoint of transparency and mechanical strength.

[0150] The second substrate 31 may consist of a single layer comprising one or more of the polymer materials, or it may consist of two or more layers, such as a layer comprising one or more of the polymer materials and a layer comprising one or more of polymer materials different from this layer.

[0151] The thickness of the second substrate 31 is not particularly limited, but from the viewpoint of handling and other factors, it is preferably 19 μm or more, more preferably 22 μm or more, even more preferably 25 μm or more, preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 125 μm or less.

[0152] (2nd adhesive layer) The second adhesive layer 32 is for attaching the second protective film 30 to the non-fouling treated surface of the cover film 10.

[0153] The thickness of the second adhesive layer 32 is not particularly limited, but is preferably 1 μm or more, more preferably 2 μm or more, preferably 10 μm or less, and more preferably 7 μm or less. [Examples]

[0154] The present invention will be described in more detail below based on specific examples. The present invention is not limited in any way to the following examples, and can be implemented with appropriate modifications without changing its essence. The polymerization rate of the polymerization composition, the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polymer components, the thickness of each layer, the water contact angle of the antifouling layer, and the peeling force of the protective film were evaluated according to the methods described below.

[0155] The meanings of the abbreviations are as follows: EHA: 2-Ethylhexylacrylate BA: n-butyl acrylate AA: Acrylic acid HEA: 2-hydroxyethyl acrylate HBA: 4-hydroxybutyl acrylate BTEE: Ethyl 2-methyl-2-n-butylteranyl propionate V-70: 2,2'-Azobis(4-Methoxy-2,4-dimethylvaleronitrile) AIBN: Azobisisobutyronitrile AcOEt: Ethyl acetate

[0156] [Evaluation Method] (Polymerization rate) Using a nuclear magnetic resonance (NMR) spectroscopy system (Bruker BioSpin, model: AVANCE500 (frequency 500MHz)), 1 ¹H-NMR was measured (solvent: CDCl3, internal standard: trimethylsilane (TMS)). The integral ratio of the monomer-derived signal and the polymer-derived signal from the obtained NMR spectrum was determined to calculate the monomer polymerization rate.

[0157] (Weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn)) The molecular weight was determined by gel permeation chromatography (GPC) using a high-performance liquid chromatograph (Tosoh Corporation, model HLC-8320GPC). Two TSKgel Super Multipore HZ-H columns (Tosoh Corporation) were used, with tetrahydrofuran solution as the mobile phase and a differential refractometer as the detector. The measurement conditions were a column temperature of 40°C, a sample concentration of 10 mg / mL, a sample injection volume of 10 μm, and a flow rate of 0.2 mL / min. Calibration curves were created using polystyrene (molecular weights 2,890,000, 1,090,000, 775,000, 427,000, 190,000, 96,400, 37,900, 10,200, 2,630, 440) as standard substances, and the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were measured. The molecular weight distribution (Mw / Mn) was calculated from these measurements.

[0158] (Thickness of each layer) The thickness of the antifouling layer and adhesive layer was measured using a film thickness measurement system (Filmetrics F20) by spectral interferometry.

[0159] (water contact angle) The water contact angle of the antifouling layer was measured using a contact angle meter (DropMaster DMo-502, manufactured by Kyowa Interface Science). Specifically, 4 μL of pure water was dropped onto the surface of the antifouling layer under an atmosphere of room temperature (23°C) and relative humidity (50%), and the water contact angle was measured 60 seconds after dropping.

[0160] (Evaluation of peeling force and adhesive residue of the first adhesive layer against the antifouling layer) The release film of the first protective film was peeled from the first adhesive layer and bonded to the anti-fouling layer of the cover film, then cut to a size of 25 mm in width and 100 mm in length. Afterward, it was pressed down by rolling a 2 kg roller back and forth twice, and left to stand for 240 hours in a constant temperature and humidity chamber at 65°C and 95% relative humidity. Next, using a precision universal testing machine (Shimadzu Corporation, "AUTOGRAPH® AGS-1kNX, 50N load cell"), the peeling force of the first adhesive layer was measured under conditions of a peeling speed of 300 mm / min and a peeling angle of 180°, in an atmosphere of room temperature (23°C) and 50% relative humidity. Furthermore, the adhesive residue evaluation was performed by measuring the difference (θ1-θ2) between the water contact angle (θ1) of the antifouling layer before bonding the first adhesive layer and the water contact angle (θ2) of the antifouling layer after peeling off the bonded first adhesive layer. The evaluation was marked as "○" if the difference (θ1-θ2) was less than 2°, and "×" if it was 2° or more.

[0161] (Peel force of the second adhesive layer against the cover film substrate) The release film of the second protective film was peeled from the second adhesive layer and bonded to the base material of the cover film, then cut to a size of 25 mm in width and 100 mm in length. Afterward, a 2 kg roller was used to press the pieces together twice, and they were left standing for 240 hours in a constant temperature and humidity chamber at 65°C and 95% relative humidity. Next, using a precision universal testing machine (Shimadzu Corporation, "AUTOGRAPH® AGS-1kNX, 50N load cell"), the peeling force of the second adhesive layer was measured under conditions of a peeling speed of 300 mm / min and a peeling angle of 180°, in an atmosphere of room temperature (23°C) and 50% relative humidity.

[0162] (Peel test of the second protective film) A protective film-attached cover film was cut to a size of 25 mm in width and 150 mm in length. As shown in Figure 2, half of the adhesive side of a 30 mm long piece of cellophane tape (registered trademark, manufactured by Nichiban, 25 mm wide) 40 was attached to each of the first protective film 20 and second protective film 30 of the cut protective film-attached cover film 1, so as to face each other with the protective film-attached cover film 1 in between. The unattached portions of these cellophane tapes 40 were fixed to a precision universal testing machine (Shimadzu Corporation, "AUTOGRAPH® AGS-1kNX, 50N load cell") and peeled at a peeling speed of 300 mm / min and a peeling angle of 90°. The results were evaluated as follows: if the first protective film 20 could be peeled off the second protective film 30 without peeling off the cover film 10, it was evaluated as "○"; if the first protective film 20 peeled off or lifted from the cover film 10, it was evaluated as "×".

[0163] <Cover film preparation> (Preparation of compositions for stain-resistant hard coat layers) A fluorine-containing compound (Shin-Etsu Chemical Co., Ltd., "KY-1203", perfluoroalkyl group-containing (meth)acrylate, active ingredient 20% by mass) was added to an ultraviolet-curable resin composition (Aica Kogyo Co., Ltd., "Z-735-3L", composition: modified acrylate, photopolymerization initiator, solvent (methyl ethyl ketone, ethyl acetate), solids content 50% by mass) in an amount of 0.1% by mass relative to the total solids content of the composition for forming an antifouling hard coat layer. Then, propylene glycol monomethyl ether (PGM) was used to adjust the solids content to 37% by mass, thereby preparing a composition for forming an antifouling hard coat layer.

[0164] (Manufacturing of stain-resistant hard coat film) A polyimide film (manufactured by KOLON INDUSTRIES, "KOLON CPI® C_80_O", 80 μm thick) was coated with a composition for an antifouling hard coat layer so that the thickness after the formation of the antifouling layer (antifouling hard coat layer) would be 4 μm, and dried at 80°C for 60 seconds. Afterward, a light intensity of 110 mJ / cm² was applied using an electrodeless (microwave) lamp. 2 A stain-resistant hard coat film was manufactured by irradiating it with ultraviolet light. The water contact angle on the surface of the stain-resistant layer was 111°.

[0165] <Preparation of the first protective film> (Preparation of copolymers) Synthesis example 1: Copolymer No.A In a flask equipped with an argon gas inlet tube and a stirrer, BA (570.0g), HBA (30.0g), and AcOEt (452.6g) were charged. After purging with argon, BTEE (171.7μL) and V-70 (76.3mg) were added, and the mixture was reacted at 33°C for 24 hours to polymerize. The polymerization rate was 85%.

[0166] After the polymerization was stopped, AcOEt was added to the resulting solution to obtain a copolymer solution containing copolymer No. A. The obtained copolymer No. A had a weight-average molecular weight (Mw) of 670,000 and a molecular weight distribution (Mw / Mn) of 1.79.

[0167] Synthesis examples 2~4: Copolymers No.B~D Copolymers No. B to D were prepared in the same manner as copolymer No. A. Table 2 shows the raw material monomers, organotellurium compounds, azo polymerization initiators, solvents, reaction conditions, polymerization rate, weight-average molecular weight, molecular weight distribution, and glass transition temperature used. The content of each functional group in the copolymer was calculated from the charge ratio of the monomers used in the polymerization reaction.

[0168] [Table 2]

[0169] (Manufacturing of the first protective film) First protective film No. 1 To 100 parts by mass of copolymer component No. A obtained in Synthesis Example 1, 0.1 parts by mass of Duranate® TPA-100 was added, and butyl acetate was added to achieve a solid content concentration of 17% by mass to obtain an adhesive composition for the first adhesive layer.

[0170] Next, an adhesive composition for the first adhesive layer was applied to the corona-treated surface of a polyethylene terephthalate film (Toyobo Ester® Film E5101, manufactured by Toyobo, corona-treated on one side, 50 μm thick) using a Baker-type film applicator to the thickness shown in Table 3, and the first adhesive layer was formed by heating at 120°C for 1 minute. Next, the release side of a release film (PET film with a release treatment applied to the surface, Clean Sepa® HY-S10, manufactured by Higashiyama Film, 38 μm thick) was attached to the side of the first adhesive layer that was not covered by the polyethylene terephthalate film. After that, it was cured at 40°C for 3 days to produce the first protective film No. 1.

[0171] First protective film No. 2-7 First protective films No. 2 to 7 were prepared in the same manner as first protective film No. 1, except that the composition of the adhesive was changed as shown in Table 3.

[0172] The peeling force of the first protective film prepared against the anti-fouling layer of the cover film was measured, and the amount of adhesive residue after peeling was evaluated. The results are shown in Table 3.

[0173] [Table 3] The materials used in the manufacture of the adhesive composition are as follows: TPA-100: Manufactured by Asahi Kasei Corporation, Duranate® TPA-100 (isocyanurate derivative of hexamethylene diisocyanate, isocyanate group content: 5.50 mmol / g) TC: Manufactured by Mitsubishi Gas Chemical Company, TETRAD®-C (1,3-bis(N,N-diglycidylaminoethyl)cyclohexane, epoxy group weight: 9.76 mmol / g)

[0174] The first protective films No. 1 to 4 are cured products of an adhesive composition in which the first adhesive layer contains a (meth)acrylic copolymer having a first reactive group and a crosslinking agent having a second reactive group that reacts with the first reactive group, the molecular weight distribution (Mw / Mn) of the (meth)acrylic copolymer having the first reactive group is 3.0 or less, and the molar ratio (moles of the second reactive group / molars of the first reactive group) is 0.01 to 0.30. These first protective films No. 1 to 4 have high peel strength (P1) against the antifouling layer (antifouling treated surface) of the cover film, excellent adhesion, and suppressed adhesive residue after peeling.

[0175] The first protective film No. 5 is the case where the molar ratio (moles of the second reactive group / molars of the first reactive group) in the adhesive composition forming the first adhesive layer is greater than 0.30. Although this first protective film No. 5 suppresses adhesive residue after peeling, it had a low peeling force (P1) against the anti-fouling layer (anti-fouling treated surface) of the cover film. The first protective film No. 6 is the case where the molar ratio (moles of the second reactive group / molars of the first reactive group) in the adhesive composition forming the first adhesive layer is less than 0.01. This first protective film No. 6 has a high peel strength (P1) from the antifouling layer (antifouling treated surface) of the cover film, but adhesive residue was left behind after peeling. The first protective film No. 7 is the case where the molecular weight distribution (Mw / Mn) of the (meth)acrylic copolymer having the first reactive group in the adhesive composition forming the first adhesive layer is greater than 3.0. This first protective film No. 7 has a low peeling force (P1) from the antifouling layer (antifouling treated surface) of the cover film, and adhesive residue is left behind after peeling.

[0176] <Preparing the second protective film> The following film was prepared as the second protective film. Second protective film No. 1: HPF01 (manufactured by Higashiyama Film, base material: polyester film (thickness 38 μm), adhesive layer: thickness 5 μm, peel strength against polyimide film: 20 mN / 25 mm) Second protective film No. 2: MU Masking (manufactured by Higashiyama Film, base material: polyester film (thickness 50 μm), adhesive layer: thickness 10 μm, peel strength against polyimide film: 40 mN / 25 mm) Second protective film No. 3: The first protective film No. 5 (peel strength against polyimide film of 100 mN / 25 mm) prepared above was used. Second protective film No. 4: HPF18 (manufactured by Higashiyama Film, base material: polyester film (thickness 38 μm), adhesive layer: thickness 10 μm, peel strength against polyimide film: 300 mN / 25 mm)

[0177] <Creation of a protective cover film> The release film of the first protective film was peeled off from the first adhesive layer, and the first adhesive layer was bonded to the antifouling layer (antifouling treated surface) of the cover film. A 2kg roller was then used to press it down twice. The release film of the second protective film was peeled off from the second adhesive layer, and the second adhesive layer was bonded to the substrate surface (non-antifouling treated surface) of the cover film opposite to the surface to which the first protective film was bonded. A 2kg roller was then used to press it down twice. The cover film with the first and second protective films attached was left to stand for 240 hours in a constant temperature and humidity chamber at 65°C and 95% relative humidity to produce a cover film with protective films. The first and second protective films used were those shown in Table 4. A peel test of the second protective film was performed on the obtained cover film with protective films, and the results are shown in Table 4.

[0178] [Table 4]

[0179] Cover films No. 1-6, 9-11, 13, and 14 with protective films satisfy the relationship P1 > P2 between peeling force (P1) and peeling force (P2), and the first adhesive layer is a cured product of an adhesive composition containing a (meth)acrylic copolymer having a first reactive group and a crosslinking agent having a second reactive group that reacts with the first reactive group, the molecular weight distribution (Mw / Mn) of the (meth)acrylic copolymer having the first reactive group is 3.0 or less, and the molar ratio (moles of the second reactive group / molars of the first reactive group) is 0.01 to 0.30. These cover films with protective films No. 1-6, 9-11, 13, and 14 have high peeling force (P1) against the antifouling layer (antifouling treated surface) of the cover film, excellent adhesion, and suppressed adhesive residue after peeling. Furthermore, the second protective film could be peeled off without causing peeling or lifting of the first protective film.

[0180] The present invention includes the following embodiments. (Embodiment 1) The device comprises a cover film having an anti-fouling treated surface on the front side and a non-anti-fouling treated surface on the back side, a first protective film disposed on the anti-fouling treated side of the cover film, and a second protective film disposed on the non-anti-fouling treated side of the cover film. The cover film comprises a base film and an anti-fouling layer located on the outermost surface, the water contact angle being 100° or more. The first protective film comprises a first substrate and a first adhesive layer, the first adhesive layer being bonded to the anti-fouling surface. The second protective film comprises a second substrate and a second adhesive layer, the second adhesive layer being bonded to the non-fouling treated surface. The peeling force (P1) of the first adhesive layer against the antifouling treated surface at 23°C and the peeling force (P2) of the second adhesive layer against the non-antifouling treated surface at 23°C satisfy the relationship P1 > P2. The first adhesive layer is a cured product of an adhesive composition containing a (meth)acrylic copolymer having a first reactive group and a crosslinking agent having a second reactive group that reacts with the first reactive group. The molecular weight distribution (Mw / Mn) of the (meth)acrylic copolymer having the first reactive group is 3.0 or less. A cover film with a protective film, characterized in that the molar ratio of the second reactive group of the crosslinking agent to the first reactive group of the (meth)acrylic copolymer having the first reactive group (moles of the second reactive group / molars of the first reactive group) is 0.01 to 0.30.

[0181] (Embodiment 2) A cover film with a protective film according to Embodiment 1, wherein the difference (P1-P2) between the peeling force (P1) of the first adhesive layer against the antifouling treated surface at 23°C and the peeling force (P2) of the second adhesive layer against the non-antifouling treated surface at 23°C is 10 mN / 25 mm or more.

[0182] (Embodiment 3) The peeling force (P1) of the first adhesive layer against the antifouling treated surface at 23°C is 30mN / 25mm to 380mN / 25mm. A cover film with a protective film according to Embodiment 1 or 2, wherein the peeling force (P2) of the second adhesive layer against the non-fouling treated surface at 23°C is 10 mN / 25 mm to 300 mN / 25 mm.

[0183] (Embodiment 4) A protective film-equipped cover film according to any one of Embodiments 1 to 3, wherein the base film of the cover film is a polyimide film.

[0184] (Embodiment 5) A protective film-equipped cover film according to any one of embodiments 1 to 4, wherein the anti-fouling layer of the cover film is an anti-fouling hard coat layer.

[0185] (Embodiment 6) A protective film-equipped cover film according to any one of Embodiments 1 to 5, wherein the (meth)acrylic copolymer having the first reactive group is obtained by living radical polymerization. [Industrial applicability]

[0186] The protective film-equipped cover film of the present invention can be used for the cover window of an image display device. [Explanation of symbols]

[0187] 1: Cover film with protective film, 10: Cover film, 11: Base material, 12: Anti-fouling layer, 20: First protective film, 21: First base material, 22: First adhesive layer, 30: Second protective film, 31: Second base material, 32: Second adhesive layer, 40: Cellophane tape

Claims

1. The device comprises a cover film having an anti-fouling treated surface on the front side and a non-fouling treated surface on the back side, a first protective film positioned on the anti-fouling treated side of the cover film, and a second protective film positioned on the non-fouling treated side of the cover film. The cover film comprises a base film and an anti-fouling layer located on the outermost surface, the water contact angle being 100° or more. The first protective film comprises a first substrate and a first adhesive layer, the first adhesive layer being bonded to the anti-fouling surface. The second protective film comprises a second substrate and a second adhesive layer, the second adhesive layer being bonded to the non-fouling treated surface. The peeling force (P1) of the first adhesive layer against the antifouling treated surface at 23°C and the peeling force (P2) of the second adhesive layer against the non-antifouling treated surface at 23°C satisfy the relationship P1 > P2. The first adhesive layer is a cured product of an adhesive composition containing a (meth)acrylic copolymer having a first reactive group and a crosslinking agent having a second reactive group that reacts with the first reactive group. The weight-average molecular weight (Mw) of the (meth)acrylic copolymer having the first reactive group is 200,000 or more and 1,000,000 or less, and the molecular weight distribution (Mw / Mn) is 3.0 or less. The amount of the first reactive group per 100 g of the (meth)acrylic copolymer having the first reactive group is 0.5 mmol / 100 g or more and 150 mmol / 100 g or less. A cover film with a protective film, characterized in that the molar ratio of the second reactive group of the crosslinking agent to the first reactive group of the (meth)acrylic copolymer having the first reactive group (moles of the second reactive group / molars of the first reactive group) is 0.01 to 0.

14.

2. The protective film-attached cover film according to claim 1, wherein the difference (P1-P2) between the peeling force (P1) of the first adhesive layer against the antifouling treated surface at 23°C and the peeling force (P2) of the second adhesive layer against the non-antifouling treated surface at 23°C is 10 mN / 25 mm or more.

3. The peeling force (P1) of the first adhesive layer against the antifouling treated surface at 23°C is 30 mN / 25 mm to 380 mN / 25 mm. The protective film-attached cover film according to claim 1 or 2, wherein the peeling force (P2) of the second adhesive layer against the non-fouling treated surface at 23°C is 10 mN / 25 mm to 300 mN / 25 mm.

4. The protective film-attached cover film according to claim 1 or 2, wherein the base film of the cover film is a polyimide film.

5. The protective film with cover film according to claim 1 or 2, wherein the anti-fouling layer of the cover film is an anti-fouling hard coat layer.

6. The protective film-equipped cover film according to claim 1 or 2, wherein the (meth)acrylic copolymer having the first reactive group is obtained by living radical polymerization.

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