Adhesive films and flexible devices

Abstract

Provided is an adhesive film having, in order, an antistatic layer, a base material layer, and an adhesive layer, which can achieve both a reduction in the visual recognition of the optical sensor or the like from the surface of the display and a reduction in the visual recognition of unevenness of the antistatic layer when the adhesive film is arranged between the image display panel and a member such as an optical sensor arranged on the back surface of the image display panel. Further, provided is a flexible device having such an adhesive film. The adhesive film of the embodiment of the present invention has, in order, an antistatic layer, a base material layer, and an adhesive layer, the antistatic layer being a coating layer formed by applying an antistatic treatment liquid, the haze of the adhesive film being 3.0% to 7.5%, the Marangoni number of the antistatic treatment liquid being 10 or less, and the capillary number of the antistatic treatment liquid being 5 or less.

Description

Technical Field

[0001] This invention relates to an adhesive film. It also relates to a flexible device having such an adhesive film. Background Technology

[0002] On the surfaces of optical and electronic components, such as organic EL (Organic Electro-Luminescence) panels, LCD (Liquid Crystal Display) panels, and touch panels, adhesive films are sometimes laminated to impart rigidity, impact resistance, and surface protection. Such adhesive films typically consist of an adhesive layer layered on top of a substrate layer.

[0003] To prevent damage to the surfaces of optical and electronic devices during processing, assembly, inspection, and transportation, an adhesive film is applied to the surface of the optical or electronic device or the optical or electronic components constituting these devices, which can suppress damage to the adhered object (Patent Document 1).

[0004] In recent years, the advancement of borderless displays has led to the development of configurations that incorporate optical sensors, such as fingerprint sensors, within the display area. For example, by placing an optical sensor on the back of the organic EL panel, which serves as the display element, it is possible to achieve a configuration that includes an optical sensor within the display area.

[0005] However, this configuration presents the following problem: when visually recognizing the image in the light, the optical sensor and other components located on the back of the image display panel are visually recognized.

[0006] One approach to solving this problem is to place a high-haze adhesive film on the back of the image display panel (between the image display panel and the optical sensor). This reduces the visual visibility of components such as the optical sensor on the display surface.

[0007] On the other hand, adhesive films, optical components, and electronic components have high electrical insulation properties, and static electricity is generated due to friction and peeling. In such cases, if a voltage is applied to the liquid crystal while static electricity remains, the alignment of liquid crystal molecules may be lost, or the liquid crystal panel may be damaged. Furthermore, the presence of static electricity can attract dust or be a major cause of reduced workability.

[0008] To prevent the generation of such static electricity, an antistatic layer has been proposed for the adhesive film. For example, it has been reported that static electricity is generated by providing an antistatic layer on the back side (the side opposite to the adhesive layer) of the substrate layer of the adhesive film. As such an antistatic layer, a coating layer formed by applying an antistatic treatment liquid is known (Patent Document 2).

[0009] However, as mentioned above, if a high-haze adhesive film is placed on the back of the image display panel (between the image display panel and the optical sensor) in order to solve the problem of visual recognition of components such as optical sensors, the following problems exist: uneven parts of the coating layer formed by applying antistatic treatment liquid (uneven treatment, coating streaks, etc.) will be visually recognized, and the yield will be reduced.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 2020-41113

[0013] Patent Document 2: Japanese Patent Application Publication No. 2020-204010 Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] The technical problem of this invention is to provide an adhesive film comprising, in sequence, an antistatic layer, a substrate layer, and an adhesive layer, wherein when the adhesive film is disposed between an image display panel and a component such as an optical sensor disposed on the back side of the image display panel, it can simultaneously reduce the visual recognition of the component such as the optical sensor on the display surface and reduce the visual recognition of uneven portions of the antistatic layer. Furthermore, the technical problem of this invention is to provide a flexible device having such an adhesive film.

[0016] Solution for solving the problem

[0017] [1] The adhesive film of the embodiment of the present invention has an antistatic layer, a substrate layer and an adhesive layer in sequence. The antistatic layer is a coating layer formed by applying an antistatic treatment liquid. The haze of the adhesive film is 3.0% to 7.5%, the Marangoni number of the antistatic treatment liquid is 10 or less, and the capillary number of the antistatic treatment liquid is 5 or less.

[0018] [2] It may be the adhesive film according to [1] above, wherein the antistatic treatment liquid contains a conductive polymer.

[0019] [3] It may be an adhesive film according to [1] or [2] above, wherein the adhesive layer is composed of an acrylic adhesive.

[0020] [4] It can be an adhesive film according to [1] or [3] above, wherein the particles or particle aggregates in the adhesive film with a Fere diameter of 0.5 μm or more have a density of 0.01 mm per unit area. 2 The number of observed samples ranged from 10 to 110.

[0021] [5] The flexible device according to the embodiments of the present invention includes an adhesive film as described in any one of [1] to [4] above.

[0022] Invention Effects

[0023] According to the present invention, an adhesive film is provided, comprising an antistatic layer, a substrate layer, and an adhesive layer in sequence. When the adhesive film is disposed between an image display panel and a component such as an optical sensor disposed on the back side of the image display panel, it can simultaneously reduce the visual recognition of the component such as the optical sensor on the display surface and reduce the visual recognition of the uneven portions of the antistatic layer. Furthermore, a flexible device having such an adhesive film can be provided. Attached Figure Description

[0024] Figure 1 This is a schematic cross-sectional view illustrating one embodiment of the adhesive film of the present invention. Detailed Implementation

[0025] 《A. Adhesive Film》

[0026] The adhesive film of the present invention comprises an antistatic layer, a substrate layer, and an adhesive layer in sequence. The adhesive film of the present invention, as long as it comprises an antistatic layer, a substrate layer, and an adhesive layer in sequence, may have any other suitable layers without impairing the effects of the present invention.

[0027] The substrate layer can be one layer or two or more layers.

[0028] The adhesive layer can be one layer or two or more layers.

[0029] The antistatic layer can be one layer or two or more layers.

[0030] Figure 1 This is a schematic cross-sectional view illustrating one embodiment of the adhesive film of the present invention. Figure 1 In this invention, the adhesive film 100 has an antistatic layer 30, a substrate layer 10, and an adhesive layer 20.

[0031] The adhesive film of the present invention may have any suitable release liner on the surface opposite to the substrate layer of the adhesive layer for protection before use, etc.

[0032] Examples of release liner materials include: release liner materials whose surfaces (liner substrates) are treated with silicone; and release liner materials whose surfaces (liner substrates) are laminated with polyolefin resins. Regarding plastic films used as liner substrates, examples include: polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, and ethylene-vinyl acetate copolymer films.

[0033] The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, even more preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

[0034] The total thickness of the adhesive film, excluding the release liner, in embodiments of the present invention is preferably 1 μm to 500 μm, more preferably 5 μm to 200 μm, even more preferably 10 μm to 150 μm, and particularly preferably 20 μm to 100 μm. If the total thickness of the adhesive film, excluding the release liner, in embodiments of the present invention is within the above range, the effects of the present invention can be further demonstrated.

[0035] In the adhesive film of the embodiments of the present invention, the antistatic layer is a coating layer formed by applying an antistatic treatment liquid. The antistatic layer will be described later.

[0036] Regarding the adhesive film of the embodiments of the present invention, the haze of the adhesive film is 3.0% to 7.5%, the Marangoni number of the antistatic treatment liquid is 10 or less, and the capillary number of the antistatic treatment liquid is 5 or less. The adhesive film of the embodiments of the present invention, by ensuring that (1) the haze of the adhesive film, (2) the Marangoni number of the antistatic treatment liquid, and (3) the capillary number of the antistatic treatment liquid are each within the aforementioned specific ranges, can achieve the effects of the present invention. For example, when the adhesive film is disposed between an image display panel and a component such as an optical sensor disposed on the back of the image display panel, it can simultaneously reduce the visual recognition of the optical sensor and other components on the display surface and reduce the visual recognition of the uneven portions of the antistatic layer. If at least one of (1) the haze of the adhesive film, (2) the Marangoni number of the antistatic treatment liquid, and (3) the capillary number of the antistatic treatment liquid deviates from the aforementioned specific ranges, the effects of the present invention may not be achieved.

[0037] Regarding the adhesive film according to embodiments of the present invention, the haze of the adhesive film is as described above, ranging from 3.0% to 7.5%, preferably from 3.5% to 7.5%, more preferably from 4.0% to 7.5%, and even more preferably from 4.5% to 7.5%. If the haze of the adhesive film deviates from the above range and is too small, when the adhesive film is disposed between an image display panel and a component such as an optical sensor disposed on the back side of the image display panel, the component such as the optical sensor may be visually discernible from the display surface. If the haze of the adhesive film deviates from the above range and is too large, uneven portions of the antistatic layer (uneven processing, coating streaks, etc.) may be visually discernible, and the yield may decrease.

[0038] Regarding the adhesive film according to embodiments of the present invention, the Marangoni number of the antistatic treatment liquid is 10 or less, preferably 8 or less, more preferably 7 or less, and particularly preferably 6 or less, as described above. If the Marangoni number of the antistatic treatment liquid deviates from the above range and is too large, uneven treatment may easily occur in the antistatic layer. In practice, the lower limit value of the Marangoni number of the antistatic treatment liquid is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 1.0 or more. The method for calculating the Marangoni number of the antistatic treatment liquid will be described later.

[0039] Regarding the adhesive film according to embodiments of the present invention, the capillary count of the antistatic treatment liquid is 5 or less, as described above. If the capillary count of the antistatic treatment liquid deviates from the above range and is too large, coating streaks may easily occur in the antistatic layer. In practice, the lower limit value of the capillary count of the antistatic treatment liquid is preferably 0 or more. The method for calculating the capillary count of the antistatic treatment liquid will be described later.

[0040] The substrate layer of the adhesive film in embodiments of the present invention may contain particles (fillers) to prevent adhesion, etc. From the perspective of further demonstrating the effects of the present invention, the adhesive film in embodiments of the present invention contains particles or agglomerates with a Freret diameter of 0.5 μm or more, per unit area (0.01 mm²). 2 The number of particles observed in the image display panel is preferably 10 to 110, more preferably 20 to 100, further preferably 30 to 90, and particularly preferably 40 to 80. If the number deviates from the above range and is too small, for example, if the adhesive film is disposed between the image display panel and a component such as an optical sensor disposed on the back of the image display panel, the component such as the optical sensor may be visually identifiable from the display surface. If the number deviates from the above range and is too large, particles or particle aggregates may be easily identified as foreign objects during foreign object inspection, reducing productivity.

[0041] The Freret diameter is an indicator of the size of a particle or condensation of particles, also known as the directional diameter. It is the distance between parallel lines that enclose the particle's projected image, measured as a straight line. The Freret diameter can be observed and measured using digital microscopes and similar instruments. Particles or condensations of particles can take many shapes, including spherical, ellipsoidal, needle-like, various geometric shapes, and amorphous shapes.

[0042] A-1. Substrate Layer

[0043] As the substrate layer, a substrate formed of any suitable material may be used, depending on the purpose, without impairing the effects of the present invention. Examples of such materials include: resin sheets, nonwoven fabrics, paper, metal foils, woven fabrics, rubber sheets, foam sheets, and laminates thereof (especially laminates including resin sheets).

[0044] Examples of resins that constitute resin sheets include: acrylic resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polymethyl methacrylate (PMMA); polycarbonate, cellulose triacetate (TAC), polysulfone, polyarylate, polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), fully aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyvinyl acetate, polyphenylene sulfide (PPS), fluorinated resins, polyether ether ketone (PEEK), and cyclic olefin polymers.

[0045] Examples of nonwoven fabrics include: nonwoven fabrics made from heat-resistant natural fibers such as Manila hemp nonwoven fabrics; synthetic resin nonwoven fabrics such as polypropylene resin nonwoven fabrics, polyethylene resin nonwoven fabrics, and ester resin nonwoven fabrics; etc.

[0046] The thickness of the substrate layer can be any suitable thickness, depending on the purpose, without impairing the effects of the present invention. Preferably, the thickness is 4 μm to 500 μm; more preferably, 10 μm to 300 μm; even more preferably, 20 μm to 200 μm; particularly preferably, 30 μm to 150 μm; and most preferably, 40 μm to 100 μm. If the thickness of the substrate layer is within the above range, the effects of the present invention can be further realized.

[0047] The total light transmittance of the substrate layer is preferably 90% or more, more preferably 91% or more, even more preferably 92% or more, and particularly preferably 93% or more.

[0048] The substrate layer may contain an antistatic agent. For example, a resin sheet incorporating an antistatic agent can be used as the substrate layer containing the antistatic agent. Such a resin sheet can be formed from a composition comprising a resin and an antistatic agent for forming the substrate layer.

[0049] The substrate layer can also be surface-treated. Examples of surface treatments include: corona treatment, plasma treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage electric shock exposure, ionization radiation treatment, and coating treatment using a primer.

[0050] As organic coating materials, examples include those described in Plastic Hard Coating Materials II (CMC Publishing, (2004)). As such organic coating materials, urethane polymers are preferred, and polyurethane acrylate, polyester urethane, or their precursors are more preferred. This is because applying / coating to the substrate layer A1 is simple, and a variety of industrially available materials are readily available and inexpensive. Examples of such urethane polymers include polymers comprising a reaction mixture of an isocyanate monomer and a monomer containing an alcoholic hydroxyl group (e.g., a hydroxyl-containing acrylic compound or a hydroxyl-containing ester compound). Organic coating materials may also contain chain extenders such as polyamines, anti-aging agents, oxidation stabilizers, etc., as optional additives.

[0051] The substrate layer may contain any other suitable additives, depending on the purpose, without impairing the effects of the invention.

[0052] A-2. Adhesive Layer

[0053] The thickness of the adhesive layer is preferably 1 μm to 250 μm, more preferably 2 μm to 150 μm, further preferably 3 μm to 100 μm, particularly preferably 5 μm to 50 μm, and most preferably 10 μm to 35 μm. If the thickness of the adhesive layer is within the above range, the effects of the present invention can be further demonstrated.

[0054] The adhesive layer may be composed of any suitable adhesive without impairing the effects of the invention. Examples of such adhesives include acrylic adhesives, rubber adhesives, silicone adhesives, and urethane adhesives. Preferably, the adhesive layer is composed of an acrylic adhesive, considering that it further enhances the effects of the invention.

[0055] Acrylic adhesives are formed from acrylic adhesive compositions. Thus, acrylic adhesives can be defined as substances formed from acrylic adhesive compositions. This is because, in the case of adhesives, adhesive compositions typically undergo cross-linking reactions such as heating or irradiation with active energy rays, thereby becoming adhesives. Therefore, it is impossible to directly determine an adhesive based on its structure. Furthermore, there are generally impractical situations ("impossible / impractical situations"). Therefore, based on the definition of "substances formed from adhesive compositions," adhesives are appropriately defined as "substances."

[0056] The adhesive layer can be formed from an acrylic adhesive composition by any suitable method. For example, the adhesive layer can be formed by applying an acrylic adhesive composition onto any suitable substrate, subjecting it to heating, irradiation with active energy rays (such as ultraviolet light), drying, etc., as needed, and curing it as needed, thereby forming an adhesive layer on the substrate.

[0057] As a method for coating acrylic adhesive compositions, any suitable method may be employed without impairing the effects of the present invention. Examples of such coating methods include: roller coating, gravure roller coating, reverse roller coating, kiss roll coating, dip roller coating, bar coating, brush coating, spray coating, doctor blade coating, air knife coating, comma coating, direct coating, and mold coating.

[0058] The heating and drying of the acrylic adhesive composition can be carried out by any suitable method without impairing the effects of the present invention. Examples of such heating and drying methods include heating to 60°C to 180°C; for example, aging treatment at a temperature of around room temperature.

[0059] The curing of the acrylic adhesive composition can be carried out by any suitable method without impairing the effects of the present invention. Examples of such curing methods include: ultraviolet irradiation, laser irradiation, alpha irradiation, beta irradiation, gamma irradiation, X-ray irradiation, and electron beam irradiation.

[0060] Representative methods for forming acrylic adhesives from acrylic adhesive compositions include: (1) a method for forming a thermosetting acrylic adhesive by a crosslinking reaction of a thermosetting acrylic adhesive composition comprising an acrylic polymer, wherein the acrylic polymer is prepared by solution polymerization using a thermal polymerization initiator; and (2) a method for forming a photocurable acrylic adhesive by a photocuring reaction of a photocurable acrylic adhesive composition comprising an acrylic polymer, wherein the acrylic polymer (representatively, a partial acrylic polymer) is prepared by polymerization (representatively, partial polymerization) using a photopolymerization initiator. That is, as an acrylic adhesive, examples include: (1) a thermosetting acrylic adhesive formed by a crosslinking reaction of a thermosetting acrylic adhesive composition containing an acrylic polymer (P1), wherein the acrylic polymer (P1) is prepared by solution polymerization using a thermal polymerization initiator; and (2) a photocurable acrylic adhesive formed by a photocurable acrylic adhesive composition containing an acrylic polymer (P2), wherein the acrylic polymer (representatively, a partial acrylic polymer) (P2) is prepared by polymerization (representatively, partial polymerization) using a photopolymerization initiator.

[0061] <A-2-1. Acrylic polymers (P1)>

[0062] One embodiment of the acrylic polymer is an acrylic polymer (P1) prepared by solution polymerization using a thermal polymerization initiator. As a method for polymerization using a thermal polymerization initiator, any suitable method, such as conventionally known methods, can be employed without impairing the effects of the present invention.

[0063] Acrylic polymer (P1) is a substance obtained by polymerizing monomer component (M1). The monomer component (M1) mentioned herein does not contain the crosslinking agent described later, which may be included in acrylic adhesive compositions. When obtaining acrylic polymer (P1) by polymerization, in addition to using monomer component (M1) and a thermal polymerization initiator, any suitable additives may be used without impairing the effects of the present invention.

[0064] Acrylic polymers (P1) can be defined as substances obtained by polymerizing monomer components (M1). This is because, for acrylic polymers (P1), the monomer components (M1) undergo a polymerization reaction to become acrylic polymers (P1). It is not possible to directly identify acrylic polymers (P1) based on their structure alone; furthermore, there are generally impractical scenarios ("impossible / impractical scenarios"). Therefore, based on the definition of "substances obtained by polymerizing monomer components (M1), acrylic polymers (P1) are appropriately defined as "substances".

[0065] The Tg of the acrylic polymer (P1) is preferably -85℃ to -30℃, more preferably -80℃ to -40℃, even more preferably -75℃ to -50℃, and particularly preferably -70℃ to -60℃.

[0066] The Tg of an acrylic polymer (P1) is a value calculated using the Fox equation based on the Tg of the homopolymer of each monomer constituting the acrylic polymer (P1) and the weight fraction of that monomer (the copolymerization ratio on a weight basis).

[0067] Fox formula refers to the relationship between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer formed by homopolymerizing the monomers constituting the copolymer, as shown below.

[0068] 1 / Tg=Σ(Wi / Tgi)

[0069] In the above Fox formula, Tg represents the glass transition temperature of the copolymer (in K), Wi represents the weight fraction of monomer i in the copolymer (copolymerization ratio on a weight basis), and Tgi represents the glass transition temperature of the homopolymer of monomer i (in K). The Tg value for the homopolymer is adopted from publicly available sources.

[0070] For example, the Tg of a homopolymer can be expressed as the following values.

[0071] n-Butyl acrylate (BA): -55℃.

[0072] Lauryl acrylate (LA): -23℃.

[0073] 2-Ethylhexyl acrylate (2EHA): -70℃.

[0074] 2-Hydroxyethyl Acrylate (2HEA): -15℃.

[0075] 4-Hydroxybutyl acrylate (2HBA): -40℃.

[0076] N-vinyl-2-pyrrolidone (NVP): 80℃.

[0077] For the Tg of homopolymers other than those exemplified above, the values ​​described in the "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. If multiple values ​​are described in the "Polymer Handbook," the conventional value shall be used. For monomers not described in the "Polymer Handbook," the values ​​listed in the monomer manufacturer's catalog shall be used. For homopolymers of monomers not described in the "Polymer Handbook" and for which no manufacturer's catalog is provided, the Tg value shall be obtained using the determination method described in Japanese Patent Application Publication No. 2007-51271.

[0078] The monomer component (M1) preferably comprises an alkyl (meth)acrylate (a1) and a monomer containing a polar group (b1). The alkyl (meth)acrylate (a1) may be a single type or two or more types. The monomer containing a polar group (b1) may be a single type or two or more types.

[0079] [A-2-1-1.(Meth)alkyl acrylate (a1)]

[0080] The alkyl group of the ester portion of (meth)acrylate (a1) (hereinafter sometimes referred to as "alkyl group of the ester portion") does not include alkyl groups containing hydroxyl groups or alkyl groups containing polar groups other than hydroxyl groups. Therefore, (meth)acrylate (a1) can be clearly distinguished from monomers (b1) containing polar groups.

[0081] The content of alkyl methacrylate (a1) in the monomer component (M1) is preferably 70% to 99.9% by weight, more preferably 80% to 99.5% by weight, further preferably 90% to 99.2% by weight, even more preferably 93% to 99.2% by weight, particularly preferably 95% to 99% by weight, and most preferably 97% to 99% by weight.

[0082] The alkyl group of the ester portion is preferably an alkyl group with 1 to 20 carbon atoms, more preferably an alkyl group with 1 to 18 carbon atoms, even more preferably an alkyl group with 2 to 16 carbon atoms, particularly preferably an alkyl group with 3 to 14 carbon atoms, and most preferably an alkyl group with 4 to 14 carbon atoms.

[0083] The alkyl group of the ester moiety is preferably a chain alkyl group. Here, "chain" means including both straight-chain and branched chains.

[0084] Alkyl methacrylates (a1) in which the alkyl group of the ester moiety is a chain alkyl group having 1 to 20 carbon atoms, such as: methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, pentyl methacrylate, isoamyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, propyl methacrylate, etc. Isooctyl acrylate, nonyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate, undecyl acrylate, lauryl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, octadecyl acrylate, isostearyl acrylate, nonadecanyl acrylate, eicosyl acrylate.

[0085] The glass transition temperature (Tg) of the homopolymer of the alkyl methacrylate (a1) that may be included in the monomer component (M1) is preferably below -10°C, more preferably below -12°C, further preferably below -15°C, particularly preferably below -18°C, and most preferably below -20°C. The lower limit of the above-mentioned glass transition temperature Tg is preferably above -80°C.

[0086] Here, the glass transition temperature (Tg) of the homopolymer of alkyl methacrylate (a1), which may be included as a monomer component (M1), can be a value recorded in known sources, such as the value recorded in the "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989). It should be noted that if multiple values ​​are recorded in the aforementioned "Polymer Handbook," the conventional value is used. For alkyl methacrylates not recorded in the aforementioned "Polymer Handbook," the values ​​listed in the monomer manufacturer's catalog are used. For homopolymers of alkyl methacrylates not recorded in the aforementioned "Polymer Handbook" and for which no monomer manufacturer's catalog value is provided, the Tg is obtained using the measurement method described in Japanese Patent Application Publication No. 2007-51271.

[0087] The monomer component (M1) may contain alkyl methacrylates (a1), preferably alkyl methacrylates (a1-1) in which the glass transition temperature Tg of the homopolymer is in the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C).

[0088] As an alkyl ester (a1-1) of (meth)acrylate, lauryl acrylate (LA) can be listed as an example (its homopolymer has a glass transition temperature Tg = -23°C).

[0089] The proportion of alkyl methacrylate (a1-1) in the total amount of alkyl methacrylate (a1) that may be contained in the monomer component (M1) is preferably 1% to 30% by weight, more preferably 2% to 20% by weight, further preferably 4% to 15% by weight, particularly preferably 5% to 12% by weight, and most preferably 6% to 10% by weight.

[0090] The proportion of alkyl methacrylate (a1-1) in the total amount of monomer component (M1) is preferably 1% to 30% by weight, more preferably 2% to 20% by weight, further preferably 4% to 15% by weight, particularly preferably 5% to 12% by weight, and most preferably 6% to 10% by weight.

[0091] The monomer component (M1) may contain alkyl methacrylates (a1), preferably alkyl methacrylates (a1-2) whose glass transition temperature (Tg) is in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C).

[0092] As an alkyl ester (a1-2) of (meth)acrylate, 2-ethylhexyl acrylate (2EHA) (whose homopolymer has a glass transition temperature Tg = -70°C) can be cited as an example.

[0093] The proportion of alkyl methacrylates (a1-2) in the total amount of alkyl methacrylates (a1) that may be included in the monomer component (M1) is preferably 40% to 95% by weight, more preferably 50% to 90% by weight, further preferably 55% to 85% by weight, particularly preferably 60% to 80% by weight, and most preferably 65% ​​to 75% by weight.

[0094] The proportion of alkyl (meth)acrylate (a1-2) in the total amount of monomer component (M1) is preferably 40% to 95% by weight, more preferably 50% to 90% by weight, further preferably 55% to 85% by weight, particularly preferably 60% to 80% by weight, and most preferably 65% ​​to 75% by weight.

[0095] The monomer component (M1) may contain alkyl methacrylates (a1), preferably alkyl methacrylates (a1-3) with a glass transition temperature (Tg) in the range of greater than -60°C and less than -40°C.

[0096] As an alkyl methacrylate (a1-3), examples include n-butyl acrylate (BA) (whose homopolymer has a glass transition temperature Tg = -55°C).

[0097] The proportion of alkyl methacrylates (a1-3) in the total amount of alkyl methacrylates (a1) that may be included in the monomer component (M1) is preferably 1% to 50% by weight, more preferably 5% to 35% by weight, further preferably 10% to 30% by weight, particularly preferably 13% to 28% by weight, and most preferably 15% to 25% by weight.

[0098] The proportion of alkyl methacrylate (a1-3) in the total amount of monomer component (M1) is preferably 1% to 50% by weight, more preferably 5% to 35% by weight, further preferably 10% to 30% by weight, particularly preferably 13% to 28% by weight, and most preferably 15% to 25% by weight.

[0099] [A-2-1-2. Monomer containing polar groups (b1)]

[0100] The content of the monomer (b1) containing a polar group in the monomer component (M1) is preferably 0.1% to 30% by weight, more preferably 0.5% to 20% by weight, even more preferably 0.8% to 10% by weight, even more preferably 0.8% to 7% by weight, particularly preferably 1% to 5% by weight, and most preferably 1% to 3% by weight.

[0101] The monomer (b1) containing a polar group preferably includes at least one selected from the group consisting of a hydroxyl-containing monomer (b1-1) and a monomer (b1-2) having a polar group other than a hydroxyl group, and more preferably includes both the hydroxyl-containing monomer (b1-1) and the monomer (b1-2) having a polar group other than a hydroxyl group.

[0102] The hydroxyl-containing monomer (b1-1) can be only one type or two or more types.

[0103] Examples of hydroxyl-containing monomers (b1-1) include: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, and other hydroxyalkyl methacrylates; polypropylene glycol mono(meth)acrylate; and N-hydroxyethyl(meth)acrylamide.

[0104] The glass transition temperature (Tg) of the homopolymer of the hydroxyl-containing monomer (b1-1) is preferably -60°C to -10°C, more preferably -55°C to -10°C, and even more preferably -45°C to -10°C.

[0105] Regarding the glass transition temperature Tg of homopolymers of hydroxyl-containing monomers (b1-1), the description of the glass transition temperature Tg of homopolymers of (meth)acrylates (a1) that may be included in the monomer component (M1) can be referenced in the section [1-2-1-1. Alkyl methacrylates (a1)].

[0106] As a hydroxyl-containing monomer (b1-1), hydroxyalkyl methacrylate is preferably listed, more preferably, hydroxyalkyl methacrylate is listed as a straight-chain alkyl group in which the alkyl part of the hydroxyalkyl group has 2 to 4 carbon atoms, and even more preferably, 2-hydroxyethyl acrylate (HEA) (the glass transition temperature of its homopolymer is Tg = -15°C), 4-hydroxybutyl acrylate (4HBA) (the glass transition temperature of its homopolymer is Tg = -40°C), and particularly preferably 4-hydroxybutyl acrylate (4HBA) (the glass transition temperature of its homopolymer is Tg = -40°C).

[0107] The proportion of hydroxyl-containing monomer (b1-1) in the monomer (b1) containing polar groups is preferably 1% to 99% by weight, more preferably 20% to 90% by weight, further preferably 40% to 80% by weight, particularly preferably 45% to 75% by weight, and most preferably 50% to 70% by weight.

[0108] The proportion of hydroxyl-containing monomer (b1-1) in the monomer component (M1) is preferably 0.001% to 10% by weight, more preferably 0.01% to 5% by weight, further preferably 0.05% to 3% by weight, particularly preferably 0.1% to 2% by weight, and most preferably 0.5% to 1.5% by weight.

[0109] Monomers (b1-2) containing polar groups other than hydroxyl groups can be only one type or two or more types.

[0110] Examples of monomers (b1-2) that have polar groups other than hydroxyl groups include: N-vinyl-2-pyrrolidone, nitrogen-containing monomers other than N-vinyl-2-pyrrolidone, carboxyl-containing monomers, sulfonic acid-containing monomers, phosphate-containing monomers, cyano-containing monomers, acid anhydride-containing monomers, vinyl esters (e.g., vinyl acetate (VAc), vinyl propionate, vinyl laurate), aromatic vinyl compounds, amide-containing monomers, epoxy-containing monomers, (meth)acryloylmorpholine, and vinyl ethers.

[0111] Examples of monomers containing carboxyl groups include: acrylic acid (AA), methacrylic acid (MAA), carboxyethyl methacrylate, carboxypentyl methacrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

[0112] Nitrogen-containing monomers other than N-vinyl-2-pyrrolidone include, for example: methyl vinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazolium, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinylcarboxylic acid amides, N-vinylcaprolactam, etc.; and acrylic monomers containing cyano groups such as acrylonitrile and methacrylonitrile.

[0113] In view of aspects that can further demonstrate the effects of the present invention, the glass transition temperature Tg of the homopolymer of monomers (b1-2) having polar groups other than hydroxyl groups is preferably -30°C to 100°C, more preferably -20°C to 95°C, and even more preferably -10°C to 90°C.

[0114] As monomers (b1-2) having polar groups other than hydroxyl groups, preferably examples are monomers having polar groups other than hydroxyl groups whose homopolymers have a glass transition temperature (Tg) of 50°C to 100°C. The glass transition temperature (Tg) of the homopolymer of this monomer is preferably 60°C to 95°C, more preferably 70°C to 90°C.

[0115] Regarding the glass transition temperature Tg of homopolymers of monomers (b1-2) having polar groups other than hydroxyl groups, the description of the glass transition temperature Tg of homopolymers of (meth)acrylates (a1) that may be included in the monomer component (M1) can be referenced in the section [1-2-1-1. Alkyl methacrylates (a1)].

[0116] As monomers (b1-2) having polar groups other than hydroxyl groups, N-vinyl-2-pyrrolidone (whose homopolymer has a glass transition temperature Tg = 80°C) is preferably listed.

[0117] The proportion of monomers (b1-2) containing polar groups other than hydroxyl groups in the monomer (b1) containing polar groups is preferably 1% to 99% by weight, more preferably 10% to 80% by weight, further preferably 20% to 60% by weight, particularly preferably 25% to 55% by weight, and most preferably 30% to 50% by weight.

[0118] The monomer (b1-2) containing polar groups other than hydroxyl groups in the monomer component (M1) is preferably 0.0001% to 10% by weight, more preferably 0.005% to 5% by weight, further preferably 0.01% to 3% by weight, particularly preferably 0.05% to 2% by weight, and most preferably 0.1% to 1% by weight.

[0119] The monomer component (M1) preferably comprises at least one of the group consisting of alkyl (meth)acrylate (a1) and monomers selected from the group consisting of hydroxyl-containing monomers (b1-1) and monomers having polar groups other than hydroxyl groups (b1-2), more preferably comprising alkyl (meth)acrylate (a1), hydroxyl-containing monomers (b1-1), and monomers having polar groups other than hydroxyl groups (b1-2), and even more preferably comprising a homopolymer with a glass transition temperature Tg in the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C). Alkyl methacrylate (a1-1), alkyl methacrylate (a1-2) with a glass transition temperature (Tg) in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), alkyl methacrylate (a1-3) with a glass transition temperature (Tg) in the range of greater than -60°C and less than -40°C, hydroxyl-containing monomers (b1-1), and monomers having polar groups other than hydroxyl groups (b1-2).

[0120] The homopolymer in the monomer component (M1) has a glass transition temperature (Tg) in the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C) for alkyl methacrylate (a1-1), and a homopolymer has a glass transition temperature (Tg) in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C) for alkyl methacrylate (a1-2), and a homopolymer (h The total content of alkyl methacrylate (a1-3), hydroxyl-containing monomer (b1-1), and monomer having polar groups other than hydroxyl groups (b1-2) in the methacrylate (a methacrylate polymer) having a glass transition temperature Tg in the range of greater than -60°C and less than -40°C is preferably 60% to 100% by weight, more preferably 70% to 100% by weight, further preferably 80% to 100% by weight, particularly preferably 90% to 100% by weight, and most preferably 95% to 100% by weight.

[0121] Specifically, the monomer component (M1) preferably includes lauryl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, n-butyl acrylate, and N-vinyl-2-pyrrolidone.

[0122] [A-2-1-3. Other monomers (c1)]

[0123] The monomer component (M1) may contain other monomers (c1) that do not correspond to either the alkyl methacrylate (a1) or the monomer containing a polar group (b1). These other monomers (c1) may be used, for example, to adjust the glass transition temperature (Tg) of the acrylic polymer (P1) or to adjust adhesive properties. There may be only one or more other monomers.

[0124] The proportion of other monomers (c1) in the monomer component (M1) is preferably 20% by weight or less, more preferably 10% by weight or less, further preferably 5% by weight or less, particularly preferably 3% by weight or less, and most preferably 1% by weight or less.

[0125] [A-2-1-4. Thermal polymerization initiator]

[0126] As a thermal polymerization initiator, it can be appropriately selected from any suitable thermal polymerization initiator depending on the type of polymerization method. There can be only one thermal polymerization initiator, or two or more.

[0127] Examples of azo initiators used in thermal polymerization include: 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl ester, 4,4'-azobis-4-cyanopentanoic acid, azobisisovalerate, 2,2'-azobis(2-amidinylpropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis(2-methylpropimidazolium) disulfate, 2,2'-azobis(N,N'-dimethyleneisobutylimidazolium), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropimidazolium] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.), etc.; and persulfates such as potassium persulfate and ammonium persulfate. Peroxide-based initiators include: di(2-ethylhexyl) peroxide dicarbonate, di(4-tert-butylcyclohexyl) peroxide dicarbonate, disec-butyl peroxide dicarbonate, tert-butyl peroxynedecanoate, tert-hexyl peroxynepentanoate, dilauroyl peroxide, dioctanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxide-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, dibenzoyl peroxide, tert-butyl peroxyisobutyrate, 1,1-di(tert-hexylperoxy)cyclohexane, tert-butyl hydroperoxide, and hydroperoxide; redox initiators composed of peroxides and epoxy agents, such as combinations of persulfates and sodium bisulfite, and combinations of peroxides and sodium ascorbate; substituted ethane initiators, such as phenyl-substituted ethanes; and aromatic carbonyl compounds.

[0128] The amount of thermal polymerization initiator used can be set to any appropriate amount without impairing the effects of the present invention. The amount of thermal polymerization initiator used relative to 100 parts by weight of monomer component (M1) is preferably 0.001 parts by weight to 10 parts by weight, more preferably 0.005 parts by weight to 5 parts by weight, further preferably 0.007 parts by weight to 3 parts by weight, and particularly preferably 0.01 parts by weight to 1 part by weight.

[0129] <A-2-2. Thermosetting Acrylic Adhesive Compositions and Thermosetting Acrylic Adhesives>

[0130] One embodiment of an acrylic adhesive is a thermosetting acrylic adhesive, which, in particular, is formed by a crosslinking reaction of a thermosetting acrylic adhesive composition comprising an acrylic polymer (P1).

[0131] The thermosetting acrylic adhesive is formed from a thermosetting acrylic adhesive composition by any suitable method. Representative examples of such a method include: applying the thermosetting acrylic adhesive composition onto any suitable substrate, heating / drying as needed, curing as needed, and forming the thermosetting acrylic adhesive into a sheet on the substrate. Any coating method can be used without impairing the effects of the invention. Examples of such coating methods include: roller coating, gravure roller coating, reverse roller coating, roller licking coating, dip roller coating, bar coating, roller brush coating, spraying, doctor blade coating, air knife coating, comma coating, direct coating, and mold coating.

[0132] The heating / drying of the thermosetting acrylic adhesive composition can be carried out by any suitable method without impairing the effects of the present invention. Examples of such heating / drying methods include heating to approximately 60°C to 180°C. The curing of the acrylic adhesive composition can be carried out by any suitable method without impairing the effects of the present invention. Examples of such curing methods include ultraviolet irradiation, laser irradiation, alpha irradiation, beta irradiation, gamma irradiation, X-ray irradiation, and electron beam irradiation.

[0133] When forming thermosetting acrylic adhesives, aging can be performed as needed to adjust the transfer of components within the thermosetting acrylic adhesive, to carry out crosslinking reactions, and to relax the strain that may exist in the photocurable acrylic adhesive.

[0134] [A-2-2-1. Crosslinking agent (L1)]

[0135] The thermosetting acrylic adhesive composition preferably includes a crosslinking agent (L1). The crosslinking agent (L1) may be only one type or two or more types.

[0136] By using a crosslinking agent (L1), thermosetting acrylic adhesives can be given appropriate cohesive strength. The crosslinking agent (L1) can be included in thermosetting acrylic adhesives in various forms, including post-crosslinking, pre-crosslinking, partially crosslinked, intermediate, or composite forms. Typically, the crosslinking agent (L1) is included in thermosetting acrylic adhesives in its post-crosslinking form.

[0137] The crosslinking agent (L1) in the thermosetting acrylic adhesive composition is preferably 0.005 parts by weight to 10 parts by weight of the acrylic polymer (P1), more preferably 0.01 parts by weight to 5 parts by weight, even more preferably 0.01 parts by weight to 3 parts by weight, even more preferably 0.01 parts by weight to 1 part by weight, even more preferably 0.01 parts by weight to 0.7 parts by weight, even more preferably 0.01 parts by weight to 0.5 parts by weight, particularly preferably 0.01 parts by weight to 0.4 parts by weight, and most preferably 0.01 parts by weight to 0.3 parts by weight.

[0138] Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, organosilicon-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents, alkyl etherified melamine-based crosslinking agents, metal chelate-based crosslinking agents, and peroxides. In terms of further enhancing the effects of the present invention, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and peroxides are preferred, and isocyanate-based crosslinking agents and peroxides are more preferred.

[0139] Isocyanate-based crosslinking agents can be compounds having two or more isocyanate groups in one molecule (including isocyanate-regenerated polar groups whose isocyanate groups are temporarily protected by end-capping agents or polymerization). Examples of isocyanate-based crosslinking agents include: aromatic isocyanates such as toluene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate.

[0140] Examples of isocyanate-based crosslinking agents include: lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; aromatic diisocyanates such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, phenyl diisocyanate, and polymethylene polyphenyl isocyanate; trimethylolpropane / toluene diisocyanate trimer adducts (e.g., manufactured by TOSOH, trade name CORONATE L), trimethylolpropane / hexamethylene diisocyanate trimer adducts (e.g., manufactured by TOSOH, trade name: CORONATE HL), and isocyanurate forms of hexamethylene diisocyanate (e.g., manufactured by TOSOH, trade name: CORONATE). Isocyanate adducts such as HX); trimethylolpropane adducts of phenyl diisocyanate (e.g., manufactured by Mitsui Chemicals, trade name: TAKENATE D110N), trimethylolpropane adducts of phenyl diisocyanate (e.g., manufactured by Mitsui Chemicals, trade name: TAKENATED 120N), trimethylolpropane adducts of isophorone diisocyanate (e.g., manufactured by Mitsui Chemicals, trade name: TAKENATE D140N), trimethylolpropane adducts of hexamethylene diisocyanate (e.g., manufactured by Mitsui Chemicals, trade name: TAKENATE D160N); polyether polyisocyanates, polyester polyisocyanates, and their adducts with various polyols; and polyisocyanates with multifunctionalized isocyanurate bonds, biuret bonds, urethane bonds, etc. Among these, aromatic isocyanates and alicyclic isocyanates are preferred, considering a good balance between deformability and cohesiveness.

[0141] As epoxy crosslinking agents, polyfunctional epoxy compounds having two or more epoxy groups in one molecule can be used. Examples of epoxy crosslinking agents include: N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidyl-aniline, 1,3-bis(N,N-diglycidyl-aminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and sorbitol polycondensate. Glyceryl ether, glyceryl polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, triglycidyl-tris(2-hydroxyethyl) isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins with two or more epoxy groups within the molecule. Commercially available epoxy crosslinking agents include, for example, those manufactured by MITSUBISHI GAS CHEMICAL under the trade names "TETRAD-C" and "TETRAD-X".

[0142] Examples of peroxides include: benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, di-tert-butyl peroxide-3,3,5-trimethylcyclohexane, tert-butyl hydrogen peroxide, tert-butyl isopropyl peroxide, 2,5-dimethyl-2,5-di(tert-butyl peroxide)hexyn-3, 2,5-dimethyl-2,5-di(benzoyl peroxide)hexane, 2,5-dimethyl-2,5-mono(tert-butyl peroxide)hexane, α,α'-bis(tert-butyl peroxide-m-isopropyl)benzene, di(2-ethylhexyl) peroxide dicarbonate, di(4-tert-butylcyclohexyl) peroxide, and peroxide... Di-sec-butyl dicarbonate, tert-butyl peroxynedecanoate, tert-hexyl peroxynepentanoate, tert-butyl peroxynepentanoate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxide-2-ethylhexanoate, di(4-methylbenzoyl peroxide), tert-butyl peroxyisobutyrate, 1,1-di(tert-hexylperoxy)cyclohexane, 1,1-di(tert-butylperoxy)cyclohexane, tert-butyl peroxynedecanoate-2-ethylhexyl carbonate, tert-pentyl peroxynedecanoate, 3,5,5-trimethylhexanoyl peroxide, tert-butyl peroxynedecanoate, tert-butyl peroxynepentanoate, tert-hexyl peroxynepentanoate. Commercially available peroxides include, for example, the "NYPER BMT" and "NYPER BW" series manufactured by Nippon Oils & Fats Co., Ltd.

[0143] [A-2-2-2. Acrylic oligomer]

[0144] Thermosetting acrylic adhesive compositions may contain acrylic oligomers. There may be only one type of acrylic oligomer or two or more.

[0145] The content of acrylic oligomers in the thermosetting acrylic adhesive composition can be set to any appropriate amount without impairing the effects of the present invention. The content of acrylic oligomers in the thermosetting acrylic adhesive composition is preferably 0.1 to 20 parts by weight relative to 100 parts by weight of the acrylic polymer (P1), more preferably 1 to 15 parts by weight, further preferably 2 to 10 parts by weight, and particularly preferably 3 to 8 parts by weight.

[0146] The weight-average molecular weight of the acrylic oligomer is preferably 1,000 to 30,000, more preferably 1,000 to 20,000, even more preferably 1,500 to 10,000, and particularly preferably 2,000 to 8,000.

[0147] It should be noted that the weight-average molecular weight (Mw) can be calculated from polystyrene using the GPC method. For example, it can be determined using the high-speed GPC apparatus "HPLC-8120GPC" manufactured by TOSOH Corporation under the following conditions.

[0148] Column: TSKgel SuperHZM-H / HZ4000 / HZ3000 / HZ2000.

[0149] Solvent: Tetrahydrofuran.

[0150] Flow rate: 0.6 ml / min.

[0151] The glass transition temperature (Tg) of the acrylic oligomer is preferably 20°C to 300°C, more preferably 30°C to 300°C, and even more preferably 40°C to 300°C.

[0152] The Tg of acrylic oligomers refers to the value calculated using the Fox equation, based on the Tg of the homopolymer of each monomer constituting the acrylic oligomer and the weight fraction of that monomer (copolymerization ratio on a weight basis). For information on the Fox equation and the Tg of various homopolymers, please refer to the section <A-2-1. Acrylic Polymers (P1)>.

[0153] As acrylic oligomers, acrylic oligomers obtained from monomer compositions having (meth)acrylates having an intramolecular cyclic structure as an essential component are preferred, and acrylic oligomers obtained from monomer compositions having (meth)acrylates having an intramolecular cyclic structure and (meth)acrylate alkyl esters having straight-chain or branched alkyl groups as essential components are more preferred.

[0154] (Meth)acrylates with intramolecular cyclic structures can be of one type or more types.

[0155] Alkyl (meth)acrylates having straight-chain or branched alkyl groups can be one or more.

[0156] The cyclic structure in (meth)acrylates, which have an intramolecular cyclic structure, can be either an aromatic ring or a non-aromatic ring.

[0157] Examples of aromatic rings include: aromatic carbon rings (such as monocyclic carbon rings like benzene rings, condensed carbon rings like naphthalene rings, etc.), and various aromatic heterocycles.

[0158] Examples of non-aromatic rings include: non-aromatic aliphatic rings (non-aromatic alicyclic rings) (e.g., cyclopentane, cyclohexane, cycloheptane, cyclooctane, etc., cycloalkanes; cyclohexene, etc., cycloalkenes), non-aromatic bridged rings (e.g., bicyclic hydrocarbon rings in pinane, pinene, camphene, norcamphene, norbornene; tricyclic or more aliphatic hydrocarbon rings (bridged hydrocarbon rings) in adamantane, etc.), and non-aromatic heterocycles (e.g., epoxy rings, oxacyclopentane rings, oxacyclobutane rings, etc.). Examples of tricyclic or more aliphatic hydrocarbon rings (bridged hydrocarbon rings with more than three rings) include: dicyclopentyl, dicyclopentenyl, adamantyl, tricyclopentyl, tricyclopentenyl, etc.

[0159] As meth)acrylates with intramolecular cyclic structures, specific examples include: cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, cyclooctyl methacrylate, and other cycloalkyl methacrylates; isobornyl methacrylate and other meth)acrylates with bicyclic aliphatic hydrocarbon rings; dicyclopentyl methacrylate, dicyclopentoxyethyl methacrylate, tricyclopentyl methacrylate, 1-adamantyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate, and other meth)acrylates with tricyclic or more aliphatic hydrocarbon rings; phenyl methacrylate and other aryl methacrylates, phenoxyethyl methacrylate and other aryloxyalkyl methacrylates, benzyl methacrylate and other arylalkyl methacrylates, and other meth)acrylates with aromatic rings; etc.

[0160] As (meth)acrylates having an intramolecular cyclic structure, (meth)acrylates containing non-aromatic rings are preferably included in consideration of further demonstrating the effects of the present invention. More preferably, cyclohexyl acrylate (CHA), cyclohexyl methacrylate (CHMA), dicyclopentyl acrylate (DCPA), and dicyclopentyl methacrylate (DCPMA) are included. Even more preferably, dicyclopentyl acrylate (DCPA) and dicyclopentyl methacrylate (DCPMA) are included.

[0161] In view of aspects that can further demonstrate the effects of the present invention, the proportion of (meth)acrylates with intramolecular cyclic structures in all monomers that can be used to constitute acrylic oligomers is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, relative to 100 parts by weight of all monomers.

[0162] Examples of alkyl (meth)acrylates having straight-chain or branched alkyl groups include: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and so on. Alkyl methacrylates, such as nonyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate, undecyl acrylate, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, octadecyl acrylate, nonadecanyl acrylate, and eicosyl acrylate, are alkyl methacrylates with 1 to 20 carbon atoms. Among these, methyl methacrylate (MMA) is preferred in terms of further enhancing the effects of the present invention.

[0163] The proportion of (meth)acrylate alkyl esters having linear or branched alkyl groups in all monomers that can be used to form acrylic oligomers is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, and even more preferably 20 to 60 parts by weight relative to 100 parts by weight of all monomers.

[0164] The monomers (monomer compositions) that can be used to constitute acrylic oligomers may include, in addition to (meth)acrylates having an intramolecular cyclic structure and (meth)acrylates having linear or branched alkyl groups, other monomers (copolymeric monomers) that can copolymerize with these monomers. The content of other monomers (copolymeric monomers) in the monomer compositions (monomer compositions) that can be used to constitute acrylic oligomers is preferably less than 50 parts by weight relative to 100 parts by weight of all monomers, more preferably 40 parts by weight or less, further preferably 30 parts by weight or less, and particularly preferably 20 parts by weight or less.

[0165] Other monomers (copolymeric monomers) that can be listed include, for example: alkoxyalkyl esters of (meth)acrylate (e.g., 2-methoxyethyl ester, 2-ethoxyethyl ester, methoxytriethylene glycol ester, 3-methoxypropyl ester, 3-ethoxypropyl ester, 4-methoxybutyl ester, 4-ethoxybutyl ester, etc.), carboxyl-containing monomers (e.g., (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, maleic anhydride, etc.), hydroxyl-containing monomers (e.g., 2-hydroxyethyl ester, 3-hydroxypropyl ester, 4-hydroxybutyl ester, 6-hydroxyhexyl ester, etc.); vinyl alcohol; allyl acrylate. Alcohols; etc.), amide-containing monomers (e.g., (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, etc.), amino-containing monomers (e.g., (meth)acrylate aminoethyl ester, (meth)acrylate dimethylaminoethyl ester, (meth)acrylate tert-butylaminoethyl ester, etc.), cyano-containing monomers (e.g., acrylonitrile, methacrylonitrile, etc.), sulfonic acid-containing monomers (e.g., sodium vinyl sulfonate, etc.), phosphate-containing monomers (e.g., 2-hydroxyethylacryloyl phosphate, etc.), isocyanate-containing monomers (e.g., 2-methacryloyloxyethyl isocyanate, etc.), imide-containing monomers (e.g., cyclohexylmaleimide, isopropylmaleimide, etc.), etc.

[0166] The monomers (monomer composition) that can be used to form the acrylic oligomers particularly preferably include (1) at least one monomer selected from dicyclopentyl acrylate, dicyclopentyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate, and (2) methyl methacrylate. In this case, relative to 100 parts by weight of the monomers (monomer composition) that can be used to form the acrylic oligomers, the content of monomer (1) is preferably 30 to 70 parts by weight, and the content of monomer (2) is preferably 30 to 70 parts by weight.

[0167] Acrylic oligomers can be manufactured by any suitable polymerization without impairing the effects of the present invention. Examples of such polymerization methods include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization based on active energy radiation (active energy radiation polymerization). Bulk polymerization and solution polymerization are preferred, and solution polymerization is more preferred.

[0168] Examples of solvents that can be used in polymerization include: esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; ketones such as methyl ethyl ketone and methyl isobutyl ketone; and other organic solvents. There may be only one solvent or two or more.

[0169] In the polymerization process, any suitable polymerization initiator (e.g., thermal polymerization initiator, photopolymerization initiator, etc.) can be used without impairing the effects of the present invention. There may be only one polymerization initiator or two or more. It should be noted that, in the case of solution polymerization, oil-soluble polymerization initiators are preferred.

[0170] As a thermal polymerization initiator, any suitable thermal polymerization initiator may be used without impairing the effects of the present invention. There may be only one thermal polymerization initiator, or there may be two or more. Specific examples of such thermal polymerization initiators can be found in the description of item [A-2-1-4. Thermal Polymerization Initiators].

[0171] The content of the thermal polymerization initiator is preferably 0.1 to 15 parts by weight, for example, relative to 100 parts by weight of all monomers (monomer compositions) that can be used to form acrylic oligomers.

[0172] As a photopolymerization initiator, any suitable photopolymerization initiator can be used without impairing the effects of the present invention. There may be only one photopolymerization initiator, or there may be two or more.

[0173] Examples of photopolymerization initiators include: benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-keto alcohol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzoyl-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanone-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators.

[0174] As benzoin ether-based photopolymerization initiators, specific examples include: benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one (as a commercially available product, for example, under the trade name "OMNIRAD651", manufactured by IGM Resins BV), anisole methyl ether, etc.

[0175] As acetophenone-based photopolymerization initiators, specific examples include: 1-hydroxycyclohexylphenyl ketone (commercially available, for example, under the trade name "OMNIRAD184", manufactured by IGM Resins BV), 4-phenoxydichloroacetophenone, 4-tert-butyldichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one (commercially available, for example, under the trade name "OMNIRAD2959", manufactured by IGM Resins BV), 2-hydroxy-2-methyl-1-phenyl-propane-1-one, methoxyacetophenone, etc.

[0176] As α-keto alcohol photopolymerization initiators, examples include 2-methyl-2-hydroxyphenylacetone and 1-[4-(2-hydroxyethyl)-phenyl]-2-hydroxy-2-methylpropane-1-one.

[0177] As an aromatic sulfonyl chloride photopolymerization initiator, specifically, 2-naphthalenesulfonyl chloride can be listed as an example.

[0178] As photoactive oxime photopolymerization initiators, examples include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime.

[0179] As a benzoin-based photopolymerization initiator, specifically, benzoin and the like can be listed as examples.

[0180] As a benzoyl-based photopolymerization initiator, specifically, benzoyl and the like can be listed as examples.

[0181] As benzophenone-based photopolymerization initiators, specific examples include: benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenyl ketone, etc.

[0182] As a photopolymerization initiator for ketal systems, examples include benzoyl dimethyl ketal.

[0183] As photopolymerization initiators for thioxanthone, specific examples include: thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, etc.

[0184] As acylphosphine-based photopolymerization initiators, examples include 2,4,6-trimethylbenzoyl diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0185] The content of the photopolymerization initiator is preferably 0.001 to 0.5 parts by weight, for example, relative to 100 parts by weight of all monomers (monomer compositions) that can be used to form acrylic oligomers.

[0186] In the polymerization of acrylic oligomers, chain transfer agents can be used to adjust the molecular weight (preferably to adjust the weight-average molecular weight to 1000-30000). Examples of chain transfer agents include: 2-mercaptoethanol, α-thioglycerol, 2,3-dimercapto-1-propanol, octylthiol, tert-nonylthiol, dodecylthiol (laurylthiol), tert-dodecylthiol, glycidylthiol, thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, tert-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, thioglycolate of ethylene glycol, thioglycolate of neopentyl glycol, thioglycolate of pentaerythritol, α-methylstyrene dimer, etc. From the viewpoint of suppressing the whitening of the adhesive film of the present invention, α-thioglycerol and methyl thioglycolate are preferred, and α-thioglycerol is particularly preferred. The chain transfer agent may be only one type or may be two or more types.

[0187] The content of the chain transfer agent is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 15 parts by weight, and even more preferably 0.3 to 10 parts by weight, relative to 100 parts by weight of all monomers (monomer compositions) that can be used to form acrylic oligomers.

[0188] [A-2-2-3. Other ingredients]

[0189] The thermosetting acrylic adhesive composition may contain any suitable other components without impairing the effects of the present invention. Such other components include, for example: tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, foils, softeners, anti-aging agents, conductive agents, ultraviolet absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, other crosslinking agents, solvents, catalysts, crosslinking catalysts, delayed crosslinking agents, etc.

[0190] <A-2-3. Acrylic polymers (P2)>

[0191] Another embodiment of the acrylic polymer is an acrylic polymer (P2) prepared by polymerization (representatively, partial polymerization) using a photoinitiator. As a method for polymerization using a photoinitiator, any suitable method, such as conventionally known methods, can be used without impairing the effects of the present invention. In polymerization using a photoinitiator, for example, irradiation with UV light is employed.

[0192] Acrylic polymer (P2) is a substance obtained by polymerizing monomer component (M2). The monomer component (M2) mentioned herein does not contain the crosslinking agent described later, which may be included in acrylic adhesive compositions. When obtaining acrylic polymer (P2) by polymerization, in addition to using monomer component (M2) and a photopolymerization initiator, any suitable additives may be used without impairing the effects of the present invention.

[0193] Acrylic polymers (P2) can be defined as substances obtained by polymerizing monomer components (M2). This is because, for acrylic polymers (P2), the monomer components (M2) undergo a polymerization reaction to become acrylic polymers (P2), and it is impossible to directly determine acrylic polymers (P1) based on their structure. Furthermore, there are generally impractical scenarios ("impossible / impractical scenarios"). Therefore, based on the definition of "substances obtained by polymerizing monomer components (M2), acrylic polymers (P2) are appropriately defined as "substances".

[0194] The monomer component (M2) preferably comprises an alkyl (meth)acrylate (a2) and a monomer containing a polar group (b2). The alkyl (meth)acrylate (a2) may be a single type or two or more types. The monomer containing a polar group (b2) may be a single type or two or more types.

[0195] [A-2-3-1. (Meth)alkyl acrylate (a2)]

[0196] The alkyl group of the ester moiety of (meth)acrylate (a2) does not include alkyl groups containing hydroxyl groups or alkyl groups containing polar groups other than hydroxyl groups. Therefore, (meth)acrylate (a2) can be clearly distinguished from monomer (b2) containing polar groups.

[0197] The preferred proportion of alkyl (meth)acrylate (a2) in the monomer component (M2) is 50% to 99% by weight.

[0198] The alkyl group of the ester moiety is preferably an alkyl group having 1 to 20 carbon atoms. The alkyl group of the ester moiety is preferably a chain alkyl group. Here, "chain" refers to both straight-chain and branched chains. The alkyl group of the ester moiety is preferably a chain alkyl group having 1 to 20 carbon atoms.

[0199] Example compounds of (meth)acrylate alkyl esters (a2) in which the alkyl group of the ester moiety is a chain alkyl group having 1 to 20 carbon atoms can be cited as example compounds of (meth)acrylate alkyl esters (a1) in the section [A-2-1-1. (meth)acrylate alkyl esters (a1)].

[0200] [A-2-3-2. Monomer containing polar groups (b2)]

[0201] The preferred proportion of the monomer (b2) containing a polar group in the monomer component (M2) is 1% to 50% by weight.

[0202] The monomer (b2) containing a polar group preferably includes at least one selected from the group consisting of a hydroxyl-containing monomer (b2-1) and a monomer (b2-2) having a polar group other than a hydroxyl group, and more preferably includes both the hydroxyl-containing monomer (b2-1) and the monomer (b2-2) having a polar group other than a hydroxyl group.

[0203] The hydroxyl-containing monomer (b2-1) can be only one type or two or more types.

[0204] As an example compound of a hydroxyl-containing monomer (b2-1), the example compound of a hydroxyl-containing monomer (b1-1) in the section [A-2-1-2. Monomers containing polar groups (b1)] can be cited.

[0205] As a hydroxyl-containing monomer (b2-1), hydroxyalkyl methacrylate is preferably listed, more preferably a straight-chain hydroxyalkyl methacrylate in which the alkyl part of the hydroxyalkyl group has 2 to 4 carbon atoms, and even more preferably 2-hydroxyethyl acrylate (HEA) (the glass transition temperature of its homopolymer is Tg = -15°C), 4-hydroxybutyl acrylate (4HBA) (the glass transition temperature of its homopolymer is Tg = -40°C), and particularly preferably 4-hydroxybutyl acrylate (4HBA) (the glass transition temperature of its homopolymer is Tg = -40°C).

[0206] Monomers (b2-2) containing polar groups other than hydroxyl groups can be either one or two or more.

[0207] As an example compound of a monomer (b2-2) having a polar group other than a hydroxyl group, the example compound of a monomer (b1-2) having a polar group other than a hydroxyl group in the section [A-2-1-2. Monomers containing polar groups (b1)] can be cited.

[0208] As a monomer (b2-2) having polar groups other than hydroxyl groups, N-vinyl-2-pyrrolidone (whose homopolymer has a glass transition temperature Tg = 80°C) is preferably listed.

[0209] The monomer component (M2) preferably comprises at least one of the group consisting of alkyl (meth)acrylate (a2) and monomers selected from the group consisting of hydroxyl-containing monomers (b2-1) and monomers having polar groups other than hydroxyl groups (b2-2), more preferably comprising alkyl (meth)acrylate (a2), hydroxyl-containing monomers (b2-1), and monomers having polar groups other than hydroxyl groups (b2-2), and even more preferably comprising a homopolymer with a glass transition temperature Tg of -40°C to -10°C. Alkyl methacrylate (a2-1) with a glass transition temperature (Tg) in the range of -35℃ to -15℃, more preferably -30℃ to -20℃, alkyl methacrylate (a2-2) with a glass transition temperature (Tg) in the range of -80℃ to -60℃ (preferably -75℃ to -60℃, more preferably -75℃ to -65℃), hydroxyl-containing monomers (b2-1), and monomers having polar groups other than hydroxyl groups (b2-2).

[0210] Specifically, the monomer component (M2) preferably includes lauryl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, and N-vinyl-2-pyrrolidone.

[0211] [A-2-3-3. Other monomers (c2)]

[0212] The monomer component (M2) may contain other monomers (c2) that do not correspond to either the (meth)acrylate alkyl ester (a2) or the monomer containing a polar group (b2). These other monomers (c2) may be used, for example, to adjust the glass transition temperature (Tg) of the acrylic polymer (P2) or to adjust adhesive properties. There may be only one or more other monomers.

[0213] [A-2-3-4. Photopolymerization initiator]

[0214] As a photopolymerization initiator, it can be appropriately selected from any suitable photopolymerization initiator depending on the type of polymerization method. There can be only one photopolymerization initiator, or two or more.

[0215] As an example compound for a photopolymerization initiator, the example compound for a photopolymerization initiator under the item [A-2-2-2. Acrylic oligomers] can be cited.

[0216] The amount of photopolymerization initiator used can be set to any appropriate amount without impairing the effects of the present invention. The amount of photopolymerization initiator used relative to 100 parts by weight of monomer component (M2) is preferably 0.001 parts by weight to 10 parts by weight, more preferably 0.005 parts by weight to 5 parts by weight, further preferably 0.007 parts by weight to 3 parts by weight, and particularly preferably 0.01 parts by weight to 1 part by weight.

[0217] <A-2-4. UV-curable acrylic adhesive compositions and UV-curable acrylic adhesives>

[0218] Another embodiment of acrylic adhesives is a photocurable acrylic adhesive, which, in particular, is formed by a photocuring reaction of a photocurable acrylic adhesive composition comprising an acrylic polymer (P2).

[0219] A UV-curable acrylic adhesive is formed from a UV-curable acrylic adhesive composition by any suitable method. A representative method for such formation is to apply the UV-curable acrylic adhesive composition to any suitable substrate, then place another suitable substrate on the surface of the adhesive layer formed by coating, and cure it by ultraviolet irradiation. Examples of substrates include, for example, the release liner described above. As for the method of applying the UV-curable acrylic adhesive composition, any suitable method can be listed without impairing the effects of the present invention. Examples of such methods include: roller coating, gravure roller coating, reverse roller coating, roller licking coating, dip roller coating, bar coating, roller brush coating, spraying, doctor blade coating, air knife coating, comma coating, direct coating, and mold coating.

[0220] Heating can be performed as needed during the formation of UV-curable acrylic adhesives. Furthermore, aging can be performed to adjust component transfer within the formed UV-curable acrylic adhesive, facilitate cross-linking reactions, and relax any strain that may exist within the UV-curable acrylic adhesive.

[0221] [A-2-4-1. Crosslinking agent (L2)]

[0222] The photocurable acrylic adhesive composition preferably includes a crosslinking agent (L2). The crosslinking agent (L2) may be one type or two or more types.

[0223] The content of the crosslinking agent (L2) in the UV-curable acrylic adhesive composition can be set to any appropriate amount without impairing the effects of the present invention. The content of the crosslinking agent (L2) in the UV-curable acrylic adhesive composition is preferably 0.001 to 0.5 parts by weight relative to 100 parts by weight of the acrylic polymer (P2), more preferably 0.005 to 0.3 parts by weight, further preferably 0.01 to 0.2 parts by weight, and particularly preferably 0.05 to 0.1 parts by weight.

[0224] As the crosslinking agent (L2), any suitable crosslinking agent can be used without impairing the effects of the present invention. Polyfunctional (meth)acrylates are preferably examples of such crosslinking agents (L2).

[0225] As a polyfunctional (meth)acrylate, any suitable polyfunctional (meth)acrylate can be used without impairing the effects of the present invention. There may be only one polyfunctional (meth)acrylate, or there may be two or more. Specifically, examples of such multifunctional (meth)acrylates include: polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, neopentyl glycol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, 1,2-ethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,12-dodecanediol dimethacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane trimethacrylate, and other polyol esters with (meth)acrylate; allyl (meth)acrylate; vinyl (meth)acrylate; divinylbenzene; epoxy acrylate; polyester acrylate; urethane acrylate; butyl (meth)acrylate; and hexyl (meth)acrylate.

[0226] [A-2-4-2. Acrylic oligomer]

[0227] UV-curable acrylic adhesive compositions may contain acrylic oligomers. There may be only one type of acrylic oligomer or two or more.

[0228] The content of acrylic oligomers in the UV-curable acrylic adhesive composition can be set to any appropriate amount without impairing the effects of the present invention. The content of acrylic oligomers in the UV-curable acrylic adhesive composition is preferably 0.1 to 20 parts by weight relative to 100 parts by weight of the acrylic polymer (P2), more preferably 1 to 15 parts by weight, further preferably 2 to 10 parts by weight, and particularly preferably 3 to 8 parts by weight.

[0229] For details on acrylic oligomers, please refer to the description in section [A-2-2-2. Acrylic Oligomers].

[0230] [A-2-4-3. Other ingredients]

[0231] The UV-curable acrylic adhesive composition may contain any suitable other components without impairing the effects of the present invention. Examples of such other components include, for instance: tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, foils, softeners, anti-aging agents, conductive agents, UV absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, other crosslinking agents, solvents, catalysts, crosslinking catalysts, delayed crosslinking agents, etc.

[0232] A-3. Antistatic Layer

[0233] The thickness of the antistatic layer can be any suitable thickness without impairing the effects of the present invention. From the perspective of further enhancing the effects of the present invention, the thickness of the antistatic layer is preferably 3 nm to 500 nm, more preferably 3 nm to 100 nm, even more preferably 3 nm to 60 nm, and particularly preferably 8 nm to 55 nm.

[0234] The antistatic layer is a coating layer formed by applying an antistatic treatment liquid.

[0235] As a method for forming the antistatic layer, any suitable method can be used without impairing the effects of the present invention. For example, one such method is to apply an antistatic treatment liquid to a substrate (substrate layer) and allow it to dry or cure.

[0236] For example, antistatic treatment solutions contain conductive polymers. These conductive polymers can be one type or two or more.

[0237] As a conductive polymer, any suitable antistatic layer can be used without impairing the effects of the present invention. Examples of such conductive polymers include water-soluble conductive polymers and water-dispersible conductive polymers.

[0238] Examples of water-soluble conductive polymers include polyaniline sulfonic acid, poly(isothioindene dimethyl sulfonate) compounds, and (meth)acrylate polymers containing quaternary ammonium salts, with polyaniline sulfonic acid being the most preferred.

[0239] Examples of water-dispersible conductive polymers include polythiophene and polyaniline doped with polyanionic polymers, with polythiophene doped with polyanionic polymers being preferred.

[0240] Examples of polythiophenes that can be used as water-dispersible conductive polymers include: polythiophene, poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), poly(3-butylthiophene), poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3-octadecylthiophene), poly(3-bromothiophene), and poly(3-... 3-chlorothiophene), poly(3-iodothiophene), poly(3-cyanothiophene), poly(3-phenylthiophene), poly(3,4-dimethylthiophene), poly(3,4-dibutylthiophene), poly(3-hydroxythiophene), poly(3-methoxythiophene), poly(3-ethoxythiophene), poly(3-butoxythiophene), poly(3-hexyloxythiophene), poly(3-heptoxythiophene), poly(3-octoxythiophene), poly(3-decoxythiophene), poly( 3-Dodecyloxythiophene), poly(3-octadecyloxythiophene), poly(3,4-dihydroxythiophene), poly(3,4-dimethoxythiophene), poly(3,4-diethoxythiophene), poly(3,4-dipropoxythiophene), poly(3,4-dibutoxythiophene), poly(3,4-dihexyloxythiophene), poly(3,4-diheptyloxythiophene), poly(3,4-dioctyloxythiophene), poly(3,4-didecyloxythiophene) Poly(3,4-bis(dodecyloxythiophene), poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), poly(3,4-butyritedioxythiophene), poly(3-methyl-4-methoxythiophene), poly(3-methyl-4-ethoxythiophene), poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), poly(3-methyl-4-carboxybutylthiophene). In view of further embodying the effects of the present invention, the degree of polymerization of the polythiophene is preferably 2 to 1000, more preferably 5 to 100.

[0241] As a water-dispersible conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) is preferred in terms of further demonstrating the effects of the present invention.

[0242] Polyanionic polymers are polymers with anionic structural units that function as dopants for polythiophenes. Examples of polyanionic polymers include: polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polyacrylic acid sulfonic acid, polymethacrylic acid sulfonic acid, poly(2-acrylamide-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, polysulfonyl methacrylate, poly(4-sulfobutyl methacrylate), polymethallyloxybenzene sulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacrylic acid carboxylic acid, polymethacrylic acid carboxylic acid, poly(2-acrylamide-2-methylpropane carboxylic acid), polyisoprene carboxylic acid, polyacrylic acid, and polysulfonated phenylacetylene. Polyanionic polymers can be homopolymers of these polymers or copolymers of two or more polymers. Considering excellent doping and dispersibility with polythiophenes, the weight-average molecular weight (Mw) of the polyanionic polymer is preferably 10 million to 1 million, more preferably 20 million to 500,000.

[0243] As a polyanionic compound, polystyrene sulfonic acid (PSS) is preferred in terms of further demonstrating the effects of the present invention.

[0244] As an antistatic layer, for example, when poly(3,4-ethylenedioxythiophene) (PEDOT) is used as a polythiophene and polystyrene sulfonic acid (PSS) is used as a polyanionic agent that can dope polythiophene, PEDOT and PSS interact and exist at a very close distance. As a result, electrons of PEDOT are taken away by PSS, which can demonstrate the excellent conductivity of the antistatic layer.

[0245] Commercially available polythiophene products doped with polyanionic compounds include, for example, poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS) manufactured by HCStark under the trade name "Bytron P", manufactured by Shin EtsuPolymer under the trade name "SEPLEGYDA", and manufactured by Soken Chemical under the trade name "VERAZOL".

[0246] In view of further demonstrating the effects of the present invention, the weight-average molecular weight (Mw) of polyaniline sulfonic acid, which can be used as a water-soluble conductive polymer component, converted from polystyrene, is preferably 1 × 10⁻⁶. 3 ~5×10 5 More preferably 5×10 3 ~3×10 5 .

[0247] Commercially available products of polyaniline sulfonic acid include, for example, the product "aquaPASS" manufactured by MITSUBISHI RAYON.

[0248] The antistatic treatment liquid preferably contains an adhesive. The adhesive may be a single type or two or more. To further enhance the effects of the invention, the adhesive content in the overall antistatic layer is preferably 50% to 95% by weight, more preferably 60% to 90% by weight.

[0249] As an adhesive, any suitable resin may be used without impairing the effects of the present invention. Examples of such adhesives include polyester resins, acrylic resins, polyvinyl resins, urethane resins, melamine resins, and epoxy resins.

[0250] In view of further demonstrating the effects of the present invention, the adhesive preferably comprises a polyester resin. The polyester resin comprises polyester as a main component, preferably in a proportion of 50% to 100% by weight, more preferably 70% to 100% by weight, further preferably 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably substantially 100% by weight. Here, "substantially" means free from any intended added components, excluding accidental contamination, byproduct impurities, etc.

[0251] If polyester resin is used as an adhesive, the surface free energy of polyester resin is small. Therefore, even without the addition of additives such as lubricants, edge shrinkage can be suppressed when the antistatic agent composition is applied to the substrate to form a film.

[0252] The polyester preferably has a structure formed by the condensation of at least one compound (polycarboxylic acid component) selected from polycarboxylic acids (representatively dicarboxylic acids) and their derivatives (anhydrides, esters, halides, etc. of polycarboxylic acids) having two or more carboxyl groups in one molecule and at least one compound (polyol component) selected from polyols (representatively diols) having two or more hydroxyl groups in one molecule.

[0253] Examples of compounds that can be used as polycarboxylic acid components include: oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±)-malic acid, meso-tartaric acid, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, pentenic acid, adipic acid, dithioadipic acid, methyl adipic acid, dimethyl adipic acid, tetramethyl adipic acid, methylene adipic acid, mucoconic acid, galactosic acid, pimelic acid, octanoic acid, perfluorooctanoic acid, 3,3,6,6-tetramethyloctanoic acid, azelaic acid, sebacic acid, perfluorosebacic acid, tridecanoic acid, dodecyl dicarboxylic acid, tridecyl dicarboxylic acid, decadecyl dicarboxylic acid, etc. Aliphatic dicarboxylic acids such as tetraalkyl dicarboxylic acids; alicyclic dicarboxylic acids such as cycloalkyl dicarboxylic acids (e.g., 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), 1,4-(2-norbornene) dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid (nadic acid), adamantane dicarboxylic acid, spiroheptane dicarboxylic acid, etc.; phthalic acid, isophthalic acid, dithioisophthalic acid, methyl isophthalic acid, dimethyl isophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methyl terephthalic acid, dimethyl terephthalic acid, chloro terephthalic acid, bromoterephthalic acid, naphthalene dicarboxylic acid, fluorenone dicarboxylic acid, anthracene dicarboxylic acid, biphenyl dicarboxylic acid, biphenylene dicarboxylic acid Aromatic dicarboxylic acids, including dimethylbiphenyl dicarboxylic acid, dimethylbiphenyl dicarboxylic acid, 4,4”-p-p-phenylene dicarboxylic acid, 4,4”-p-tetraphenyl dicarboxylic acid, bibenzyl dicarboxylic acid, azobenzyl dicarboxylic acid, homophthalic acid, phenyl diacetic acid, phenyl dipropionic acid, naphthalene dicarboxylic acid, naphthalene dipropionic acid, biphenyl diacetic acid, biphenyl dipropionic acid, 3,3'-[4,4'-(methylene di-p-biphenylene)]dipropionic acid, 4,4'-bibenzyl diacetic acid, 3,3'(4,4'-bibenzyl)dipropionic acid, oxodi-p-phenylene diacetic acid, etc.; anhydrides of any of the above polycarboxylic acids; esters of any of the above polycarboxylic acids (e.g., alkyl esters, which can be monoesters, diesters, etc.); and acid halides (e.g., dicarboxylic acid chlorides) corresponding to any of the above polycarboxylic acids.

[0254] As compounds that can be used as polycarboxylic acid components, those that can further embody the effects of the present invention are preferably: aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalene dicarboxylic acid and their anhydrides; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, nadic acid, and 1,4-cyclohexanedicarboxylic acid and their anhydrides; and lower alkyl esters of said dicarboxylic acids (e.g., esters with monohydric alcohols having 1 to 3 carbon atoms).

[0255] Examples of compounds that can be used as polyol components include: ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylene glycol, hydrogenated bisphenol A, bisphenol A, and other diols. Other examples include alkylene oxide adducts of these compounds (e.g., ethylene oxide adducts, propylene oxide adducts, etc.).

[0256] In view of further demonstrating the effects of the present invention, regarding the molecular weight of the polyester resin, the weight-average molecular weight (Mw) converted from standard polystyrene as determined by gel permeation chromatography (GPC) is preferably 5 × 10⁻⁶. 3 ~1.5×10 5 More preferably 1×10 4 ~6×10 4 .

[0257] In view of aspects that can further demonstrate the effects of the present invention, the glass transition temperature (Tg) of the polyester resin is preferably 0°C to 120°C, more preferably 10°C to 80°C.

[0258] As a polyester resin, it can be commercially available under the trade name "VYLONAL" manufactured by Toyobo Co., Ltd.

[0259] As an adhesive, it may further contain resins other than polyester resins (e.g., acrylic resins, urethane acrylate resins, styrene acrylate resins, silicone acrylate resins, silicone resins, polysilazane resins, polyurethane resins, fluorinated resins, polyvinyl alcohol resins, polyolefin resins, etc.).

[0260] When the antistatic treatment solution contains an adhesive, the proportion of the conductive polymer to 100 parts by weight of the adhesive is preferably 10 to 200 parts by weight, more preferably 25 to 150 parts by weight, and even more preferably 40 to 120 parts by weight. If the proportion of the conductive polymer to 100 parts by weight of the adhesive deviates too much from the above range, the antistatic properties may decrease. If the proportion of the conductive polymer to 100 parts by weight of the adhesive deviates too much from the above range, the adhesion between the antistatic layer and adjacent layers may decrease, and the transparency may decrease.

[0261] The antistatic treatment solution preferably contains a crosslinking agent. The crosslinking agent can be one type or two or more.

[0262] As a crosslinking agent, a crosslinking agent commonly used for crosslinking resins can be used. Examples of such crosslinking agents include melamine-based crosslinking agents, isocyanate-based crosslinking agents, and epoxy-based crosslinking agents. The amount of crosslinking agent used can be adjusted appropriately according to the purpose.

[0263] The antistatic treatment liquid may contain any other suitable components without impairing the effects of the present invention. Such other components include, for example: solvents, other antistatic ingredients (organic conductive substances other than conductive polymers, inorganic conductive substances, other antistatic agents, etc.), surfactants, leveling agents, lubricants, antioxidants, colorants (pigments, dyes, etc.), flow modifiers (thixotropic agents, thickeners, etc.), film-forming aids, defoamers, preservatives, and PET oligomer sealants.

[0264] Examples of solvents include: organic solvents, water, or mixtures thereof. A solvent may be a single solvent or two or more. Examples of organic solvents include: esters such as ethyl acetate; ketones such as methyl ethyl ketone, acetone, and cyclohexanone; cyclic ethers such as tetrahydrofuran (THF) and dioxane; aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol, and cyclohexanol; and glycol ethers such as alkylene glycol monoalkyl ethers (e.g., ethylene glycol monomethyl ether and ethylene glycol monoethyl ether), and diallyl glycol monoalkyl ethers.

[0265] In view of aspects that can further demonstrate the effects of the present invention, as a solvent, a mixture of organic solvent and water is preferred, a mixture of aliphatic or alicyclic alcohol and water is more preferred, and a mixture of aliphatic alcohol and water is even more preferred.

[0266] When the solvent is a mixture of an organic solvent and water, one possible technical solution to further demonstrate the effects of the present invention is to adjust the mixing ratio of the organic solvent and water. By adjusting the mixing ratio of the organic solvent and water in this way, the Marangoni number of the antistatic treatment solution can be adjusted. For example, when the organic solvent is ethanol, the concentration of ethanol in the mixture of organic solvent and water is preferably 30% to 70% by weight, more preferably 40% to 60% by weight.

[0267] 《B. Flexible Devices》

[0268] The adhesive film of the present invention can be applied to various devices. For example, it can be applied to flexible devices such as bendable devices, foldable devices, and rollable devices with movable bending portions.

[0269] That is, the flexible device according to the embodiments of the present invention includes the adhesive film of the embodiments of the present invention. The flexible device according to the embodiments of the present invention can include any other suitable components as long as it includes the adhesive film of the present invention.

[0270] Example

[0271] The present invention will be described in more detail below with examples and comparative examples. However, the present invention is not limited thereto. It should be noted that, in the following description, "parts" and "%" are based on weight unless otherwise specified.

[0272] <Determination of Haze in Adhesive Films>

[0273] The haze of the adhesive film was measured using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute Co., Ltd.) in accordance with JIS-K-7136.

[0274] The haze level is calculated using the following formula.

[0275] Haze (%) = (Td / Tt) × 100

[0276] (Td: diffuse transmittance, Tt: total transmittance)

[0277] <Observations on particles or particle aggregates in adhesive membranes>

[0278] The adhesive film was observed using a digital microscope (OLYMPUS BX51, objective lens: UMPlanFI 50× / 0.75BD P), and the Freret diameter of the particles or particle aggregates in the adhesive film was measured. Then, for particles or particle aggregates with a Freret diameter greater than 0.5 μm, the diameter was measured per unit area (0.01 mm²). 2 The number of observed items in the sample is counted.

[0279] <Calculation of Marangoni Numbers>

[0280] The viscosity η of the antistatic treatment liquid at 20°C and the surface tension σ at 20°C and 40°C were measured, and the Marangoni number Mg was calculated according to (Equation 1). Viscosity η was measured using a viscometer (Toki Sangyo Co., Ltd., RE-85U) with a conical rotor (1°34'×R24) at a rotation speed of 100 rpm. Surface tension σ was measured using a static surface tension meter (Kyowa Interface Science Co., Ltd., DY-500). It should be noted that the thermal diffusivity α was calculated as 9.52 × 10⁻⁶ based on the density ρ, specific heat Cp, and thermal conductivity k of a 50% aqueous solution of ethanol at 20°C using (Equation 2). －8 m 2 / s. Film thickness L is set to 3.0 × 10⁻⁶. －8 m.

[0281] [Formula 1]

[0282]

[0283] <Calculation of Capillary Number>

[0284] The viscosity and surface tension σ of the antistatic treatment liquid at 20°C were measured, and the capillary number Ca was calculated according to (Equation 3). Viscosity μ was measured using a viscometer (Toki Sangyo Co., Ltd., RE-85U) with a conical rotor (1°34'×R24) at a rotation speed of 100 rpm. Surface tension σ was measured using a static surface tension meter (Kyowa Interface Science Co., Ltd., DY-500). It should be noted that the speed U was set to 20 m / min.

[0285] [Formula 2]

[0286] (Equation 3)

[0287]

[0288] <Counting the number of uneven items>

[0289] The adhesive film was cut into pieces 60mm wide and 120mm long, and placed on a black board with the antistatic treatment layer facing upwards. A three-wavelength lamp (Yamada Lighting Co., Ltd., Z-208) was used to illuminate the applied adhesive film, and the number of visually identifiable unevenness points was counted when visually inspected from above. It should be noted that unevenness can manifest as stripes, circles, ellipses, wavy patterns, etc.

[0290] <Counting the number of coating streaks>

[0291] The adhesive film was cut into pieces 60mm wide and 120mm long, and placed on a black board with the antistatic treatment layer facing upwards. The adhesive film was then illuminated with a three-wavelength lamp (Yamada Lighting Co., Ltd., Z-208), and the number of stripe-like appearance defects with a length of 30mm or more that were visually identified when viewed from above the adhesive film was counted.

[0292] <Methods for confirming visual recognition>

[0293] The adhesive film was cut into 50mm wide x 50mm long pieces. The release liner was peeled off and adhered to the antistatic layer of another adhesive film, resulting in a laminate of two adhesive films. The adhesive films were laminated in groups of 50. The release liner of the laminated adhesive film was then peeled off to create a test sample. The Nitto Denko Corporation logo was printed on a piece of paper 30mm long and 90mm wide. The test sample was placed 30cm above the paper, and the Nitto Denko logo was visually observed through the test sample from this position. The results were categorized into three stages: clearly legible logo (×), legible but difficult to read (△), and illegible logo (○). It should be noted that the Nitto Denko logo can be obtained from the Nitto Denko website.

[0294] [Manufacturing Example 1]: Manufacturing of Antistatic Treatment Solution

[0295] Prepare an aqueous solution (HCStark product, trade name "Baytron P") containing 0.5 wt% poly(3,4-dioxothiophene) (PEDOT) and 0.8 wt% polystyrene sulfonate (number average molecular weight 150,000) (PSS) as the conductive polymer.

[0296] Prepare a dispersion containing 25% by weight of polyester resin as a binder (Toyobo Co., Ltd. product, trade name "VYLONAL MD-1480" (aqueous dispersion of saturated copolyester resin)) (hereinafter also referred to as "binder dispersion").

[0297] Prepare an aqueous dispersion of carnauba wax (manufactured by Nippon Wax, trade name "Refined Carnauba Wax No. 2 Powder") (hereinafter also referred to as "lubricant dispersion") as a lubricant.

[0298] A conductive material aqueous solution was prepared by mixing 50 parts by weight of the above-mentioned conductive polymer aqueous solution, 100 parts by weight of the above-mentioned adhesive dispersion, and 30 parts by weight of the above-mentioned lubricant dispersion, based on the solid content. 20 parts by weight of a melamine-based crosslinking agent were added to 100 parts by weight of the prepared conductive material aqueous solution, and the solution was diluted with water in a 1:1 mixture with EKINEN F-6 (manufactured by Japan Alcohol Trading Co., Ltd.) to achieve a specified concentration of solid content, thereby preparing an antistatic treatment solution. The specified concentrations were set as 0.4% by weight, 0.6% by weight, 1.0% by weight, and 1.5% by weight.

[0299] [Manufacturing Example 2]: Manufacturing of Acrylic Polymers

[0300] To a four-necked flask equipped with a stirring blade, thermometer, nitrogen inlet pipe, and cooler, add 70.3 parts by weight of 2EHA (2-ethylhexyl acrylate), 8.0 parts by weight of LA (lauryl acrylate), 20.1 parts by weight of BA (n-butyl acrylate), 1.0 part by weight of 4HBA (4-hydroxybutyl acrylate), 0.6 parts by weight of NVP (N-vinyl-2-pyrrolidone), and 0.1 parts by weight of AIBN (2,2'-azobisisobutyronitrile) as a polymerization initiator, and add ethyl acetate to achieve a total concentration of 47% by weight. While stirring slowly, nitrogen replacement is carried out in the system over 1 hour. The liquid temperature in the flask is maintained at approximately 56°C for 6 hours for the polymerization reaction. After the reaction is complete, ethyl acetate is added to adjust the polymer concentration to 24% by weight, yielding a solution of acrylic polymer.

[0301] [Manufacturing Example 3]: Manufacturing of Acrylic Oligomers

[0302] 60 parts by weight of DCPMA (dicyclopentyl methacrylate) and 40 parts by weight of MMA (methyl methacrylate), 3.5 parts by weight of α-thioglycerol as a chain transfer agent, and 100 parts by weight of toluene as a polymerization solvent were mixed and stirred at 70°C for 1 hour under a nitrogen atmosphere. Then, 0.2 parts by weight of AIBN as a thermal polymerization initiator were added, and the mixture was reacted at 70°C for 2 hours. The temperature was then raised to 80°C, and the reaction was continued for another 2 hours to obtain an acrylic oligomer. The weight-average molecular weight (Mw) of the acrylic oligomer was 5100, and the glass transition temperature (Tg) was 130°C.

[0303] [Manufacturing Example 4]: Manufacturing of a coating solution for an acrylic adhesive composition

[0304] The acrylic polymer obtained in Manufacturing Example 2 (100 parts by weight), NYPER BMT-40SV (manufactured by Nippon Yushi Co., Ltd.) as a crosslinking agent (0.28 parts by weight), the acrylic oligomer obtained in Manufacturing Example 3 (3 parts by weight), and IRGANOX 1010 (manufactured by BASF) as an antioxidant (0.3 parts by weight) were mixed and stirred thoroughly. The mixture was then diluted with ethyl acetate to a total solid content of 17% by weight, thereby obtaining a coating solution of the acrylic adhesive composition.

[0305] [Example 1]

[0306] Using a Mayer rod, the 1.0% concentration of antistatic treatment solution obtained in Manufacturing Example 1 was applied to the side of a PET substrate (Lumirror S10#50, manufactured by Toray) opposite to the easily bonded treatment side. The substrate was dried at 130°C for 1 minute to remove the solvent and form an antistatic layer (thickness: 0.03 μm), thus producing a PET film with an antistatic layer.

[0307] The coating solution of the acrylic adhesive composition obtained in Manufacturing Example 4 was applied to the easily bonded surface of the obtained PET film with an antistatic layer to a thickness of 13 μm after drying, and dried at a drying temperature of 155°C for 2 minutes. Then, it was bonded to the surface of the obtained adhesive layer in such a way that it came into contact with the silicone-treated surface of a 50 μm thick release sheet made of polyester resin (product name: MRQ50T100J, manufactured by Mitsubishi Chemical Corporation), which had undergone silicone treatment on one side, to obtain an adhesive film (1).

[0308] The results are shown in Table 1.

[0309] [Example 2]

[0310] The PET substrate was changed to T100C50 manufactured by Mitsubishi Chemical Corporation, and the same procedure as in Example 1 was followed to obtain an adhesive film (2).

[0311] The results are shown in Table 1.

[0312] [Example 3]

[0313] Using the 0.6% antistatic treatment solution obtained in Manufacturing Example 1 as the antistatic treatment solution, the same procedure as in Example 1 was followed to obtain an adhesive film (3).

[0314] The results are shown in Table 1.

[0315] [Example 4]

[0316] Using the 0.6% antistatic treatment solution obtained in Manufacturing Example 1 as the antistatic treatment solution, the same procedure as in Example 2 was followed to obtain an adhesive film (4).

[0317] The results are shown in Table 1.

[0318] [Comparative Example 1]

[0319] The PET substrate was changed to Lumirror T60#50 manufactured by Toray Corporation, and otherwise the same procedure was followed as in Example 1 to obtain an adhesive film (C1).

[0320] The results are shown in Table 1.

[0321] [Comparative Example 2]

[0322] Using the 0.4% antistatic treatment solution obtained in Manufacturing Example 1 as the antistatic treatment solution, the same procedure as in Example 1 was followed to obtain an adhesive film (C2).

[0323] The results are shown in Table 1.

[0324] [Comparative Example 3]

[0325] The PET substrate was changed to T100C50 manufactured by Mitsubishi Chemical Corporation, and the same procedure was performed as in Comparative Example 2 to obtain an adhesive film (C3).

[0326] The results are shown in Table 1.

[0327] [Comparative Example 4]

[0328] The PET substrate was changed to Lumirror T60#50 manufactured by Toray Corporation, and otherwise the same procedure was performed as in Comparative Example 2 to obtain an adhesive film (C4).

[0329] The results are shown in Table 1.

[0330] [Comparative Example 5]

[0331] Using the 1.5% antistatic treatment solution obtained in Manufacturing Example 1 as the antistatic treatment solution, the same procedure as in Example 1 was followed to obtain an adhesive film (C5).

[0332] The results are shown in Table 1.

[0333] [Table 1]

[0334]

[0335] Industrial availability

[0336] The adhesive film of this invention can be applied to various devices. For example, it can be applied to flexible devices such as bendable devices, foldable devices, and rollable devices with movable bending portions.

Claims

1. An adhesive film comprising, in sequence, an antistatic layer, a substrate layer, and an adhesive layer, The antistatic layer is a coating layer formed by applying an antistatic treatment liquid. The haze of this adhesive film is 3.0%–7.5%. The Marangoni number of this antistatic treatment solution is below 10. The capillary count of this antistatic treatment solution is less than 5. The adhesive film contains particles or agglomerates with a Feretta diameter of 0.5 μm or larger, with a density of 0.01 mm per unit area. 2 The number of observed samples ranged from 10 to 110.

2. The adhesive film according to claim 1, wherein, The antistatic treatment liquid contains a conductive polymer.

3. The adhesive film according to claim 1, wherein, The adhesive layer is composed of an acrylic adhesive.

4. A flexible device comprising an adhesive film as described in any one of claims 1 to 3.

Images