Adhesive film and flexible device

Abstract

Provided is an adhesive film having an antistatic layer, a substrate layer, and an adhesive layer in this order, the adhesive film being disposed between an image display panel and a member such as an optical sensor disposed on the rear surface of the image display panel, it is possible to achieve both a reduction in visibility of a member such as an optical sensor on a display surface and a reduction in visibility of a non-uniform portion of an antistatic layer. Also provided is a flexible device provided with such an adhesive film. The adhesive film according to an embodiment of the present invention has an antistatic layer, a base material layer, and an adhesive layer in this order, the antistatic layer being a coating layer formed by applying an antistatic treatment liquid, the haze of the adhesive film being 3.0-7.5%, the Malangori 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] The present application relates to an adhesive film. The present application also relates to a flexible device provided with such an adhesive film. BACKGROUND

[0002] On the surface of optical members, electronic members, and the like typified by organic EL (Organic Electro-Luminescence) panels, LCD (Liquid Crystal Display) panels, touch panels, and the like, an adhesive film is sometimes attached for the purpose of imparting rigidity, impact resistance, surface protection, and the like. Such an adhesive film generally has an adhesive layer laminated on a base material layer.

[0003] In order to prevent the surface of optical devices, electronic devices, and the like from being damaged during processing, assembly, inspection, transportation, and the like, by attaching an adhesive film to the surface of the optical devices, electronic devices, or optical members, electronic members that constitute these devices, it is possible to suppress damage and breakage of the adherend (Patent Literature 1).

[0004] In recent years, the bezel-less design of displays is advancing, and a configuration in which an optical sensor such as a fingerprint sensor is disposed in the display region of a display has been proposed. For example, by disposing an optical sensor on the back surface of an organic EL panel as a display element, it is possible to realize a configuration in which the optical sensor is provided in the display region.

[0005] However, in such a configuration, the following problem can occur: when visually recognizing the screen in a bright place, the optical sensor or the like member disposed on the back surface of the image display panel is visually recognized.

[0006] As one method of solving such a problem, it is possible to cite a method in which a high-haze adhesive film is disposed on the back surface of the image display panel (between the image display panel and the optical sensor). Thereby, it is possible to reduce the degree of visual recognition of the optical sensor or the like member from the surface of the display.

[0007] On the other hand, the adhesive film, the optical member, and the electronic member have high electrical insulation, and static electricity is generated due to friction or peeling. In such a case, in a state in which static electricity remains, for example, if a voltage is applied to a liquid crystal, it is possible that the orientation of the liquid crystal molecules is lost, or the liquid crystal panel is damaged. In addition, the presence of static electricity can be a major cause of attracting dust or reducing workability.

[0008] In order to prevent such static electricity from being generated, a method of providing an antistatic layer on an adhesive film has been proposed. For example, it is reported that static electricity is generated by providing an antistatic layer on the back surface side (the surface on the opposite side from the adhesive layer) of the base material layer of an adhesive film. As such an antistatic layer, a coating layer formed by applying an antistatic treatment liquid is known (Patent Literature 2).

[0009] However, as described above, if a high-haze adhesive film is arranged 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 the optical sensor and the like, there is a problem that uneven portions (treatment unevenness, coating streaks, and the like) of the coating layer formed by applying the antistatic treatment liquid are visually recognized, and the yield is reduced.

[0010] Prior Art 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

[0014] Problems to be Solved by the Invention

[0015] The technical problem of the present application is to provide an adhesive film having an antistatic layer, a substrate layer, and an adhesive layer in this order, which can achieve both reduction in visual recognition of the optical sensor and the like from the surface of the display and reduction in visual recognition of uneven portions of the antistatic layer, in a case where the adhesive film is arranged between an image display panel and a member such as an optical sensor arranged on the back of the image display panel. Further, the technical problem of the present application is to provide a flexible device provided with such an adhesive film.

[0016] Solution to the Problem

[0017] [1] The adhesive film of the embodiment of the present application has an antistatic layer, a substrate layer, and an adhesive layer in this order, 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] The adhesive film according to the above [1] can be one in which the antistatic treatment liquid contains an electroconductive polymer.

[0019] [3] The adhesive film according to the above [1] or [2] can be one in which the adhesive layer is composed of an acrylic adhesive.

[0020] [4] The adhesive film according to the above [1] or [3] can be one in which the number of particles or agglomerates of particles having a Feret diameter of 0.5 μm or more observed per unit area (0.01 mm 2 ) is 10 to 110.

[0021] [5] The flexible device of the embodiment of the present application is provided with the adhesive film described in any one of the above-mentioned [1] to [4].

[0022] Effects of the Invention

[0023] According to the present application, it is possible to provide an adhesive film having an antistatic layer, a base material layer, and an adhesive layer in this order, which can achieve both reduction in visual recognition of an optical sensor or the like member from the surface of a display and reduction in visual recognition of uneven portions of the antistatic layer in a case where 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. In addition, it is possible to provide a flexible device provided with such an adhesive film. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic cross-sectional view showing one embodiment of the adhesive film of the present application. DETAILED DESCRIPTION

[0025] 《《A. Adhesive film》》

[0026] The adhesive film of the embodiment of the present application has an antistatic layer, a base material layer, and an adhesive layer in this order. The adhesive film of the present application can have any appropriate other layer as long as it has an antistatic layer, a base material layer, and an adhesive layer in this order, without impairing the effects of the present application.

[0027] The base material 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 is a schematic cross-sectional view showing one embodiment of the adhesive film of the present application. In Figure 1 , the adhesive film 100 of the present application has an antistatic layer 30, a base material layer 10, and an adhesive layer 20.

[0031] The adhesive film of the embodiment of the present application can be provided with any appropriate release liner on the surface on the opposite side of the base material layer of the adhesive layer, for protection before use or the like.

[0032] As the release liner, for example, a release liner in which the surface of a substrate (liner substrate) such as paper, a plastic film, or the like is treated with silicone; a release liner in which the surface of a substrate (liner substrate) such as paper, a plastic film, or the like is laminated with a polyolefin-based resin layer; and the like can be exemplified. As the plastic film serving as the liner substrate, for example, a polyethylene film, a polypropylene film, a polybutylene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a chlorovinyl copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, and the like can be exemplified.

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

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

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

[0036] In the adhesive film of the embodiment of the present application, the haze of the adhesive film is from 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 embodiment of the present application exhibits the effects of the present application by such 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 above specific ranges, and in particular, in the case where the adhesive film is disposed between an image display panel and a member such as an optical sensor disposed on the back surface of the image display panel, the reduction in the visibility of the optical sensor and the like from the surface of the display and the reduction in the visibility of the uneven portion of the antistatic layer can be both achieved. 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 above specific ranges, the effects of the present application can not be exhibited.

[0037] The haze of the adhesive film according to the embodiment of the present application is preferably 3.0% to 7.5%, more preferably 3.5% to 7.5%, further preferably 4.0% to 7.5%, and particularly preferably 4.5% to 7.5%. If the haze of the adhesive film deviates from the above range and is too small, in the case where the adhesive film is arranged between an image display panel and a member such as an optical sensor arranged on the back surface of the image display panel, the member such as the optical sensor can be visually recognized from the surface of the display. If the haze of the adhesive film deviates from the above range and is too large, unevenness of the antistatic layer (treatment unevenness, coating streaks, and the like) can be visually recognized, and the yield can decrease.

[0038] The Marangoni number of the antistatic treatment liquid according to the embodiment of the present application is preferably 10 or less, more preferably 8 or less, further preferably 7 or less, and particularly preferably 6 or less. If the Marangoni number of the antistatic treatment liquid deviates from the above range and is too large, treatment unevenness can 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 further preferably 1.0 or more. The method for calculating the Marangoni number of the antistatic treatment liquid will be described later.

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

[0040] The substrate layer of the adhesive film according to the embodiment of the present application can contain particles (fillers) for preventing blocking and the like. In the adhesive film according to the embodiment of the present application, the number of particles or agglomerates of particles having a Feret diameter of 0.5 μm or more observed per unit area (0.01 mm 2 ) 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, in the case where the adhesive film is arranged between an image display panel and a member such as an optical sensor arranged on the back surface of the image display panel, for example, the member such as the optical sensor can be visually recognized from the surface of the display. If the number deviates from the above range and is too large, particles or agglomerates of particles can be easily recognized as foreign matter in foreign matter inspection, and the productivity can decrease.

[0041] The Feret diameter is an index of the size of a particle or a conglomeration of particles as an object, and is also called a directional diameter. The Feret diameter is the distance between parallel lines sandwiching a projected image of the particle in a certain direction, and is the length of the longest portion in terms of straight-line distance. The Feret diameter can be observed and measured using a digital microscope or the like. The shape of a particle or a conglomeration of particles can adopt a variety of shapes such as a spherical shape, a shape of a rotational ellipsoid, a needle shape, various geometric shapes, various irregular shapes, and the like.

[0042] A-1. Substrate Layer

[0043] As the substrate layer, a substrate formed of any appropriate material can be used as appropriate without impairing the effects of the present application, in accordance with the purpose. As such a material, for example, a resin sheet, a nonwoven fabric, paper, a metal foil, a woven fabric, a rubber sheet, a foamed sheet, a laminate thereof (particularly, a laminate including a resin sheet), and the like can be exemplified.

[0044] As the resin constituting the resin sheet, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polymethyl methacrylate (PMMA), and the like acrylic resins; polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyethylene (PE), polypropylene (PP), an ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyvinyl acetate, polyphenylene sulfide (PPS), a fluorine-based resin, polyether ether ketone (PEEK), a cyclic olefin-based polymer, and the like can be exemplified.

[0045] As the nonwoven fabric, for example, a nonwoven fabric including abaca and the like nonwoven fabrics made of natural fibers having heat resistance; a polypropylene resin nonwoven fabric, a polyethylene resin nonwoven fabric, an ester-based resin nonwoven fabric, and the like synthetic resin nonwoven fabrics; and the like can be exemplified.

[0046] As the thickness of the substrate layer, any appropriate thickness can be used as appropriate without impairing the effects of the present application, in accordance with the purpose. As such a thickness, 4 μm to 500 μm is preferred, 10 μm to 300 μm is more preferred, 20 μm to 200 μm is further preferred, 30 μm to 150 μm is particularly preferred, and 40 μm to 100 μm is most preferred. If the thickness of the substrate layer is within the above range, the effects of the present application can be further exhibited.

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

[0048] The base material layer can contain an antistatic agent. As the base material layer containing an antistatic agent, for example, a resin sheet in which an antistatic agent is kneaded can be used. Such a resin sheet can be formed from a base material layer-forming composition containing a resin and an antistatic agent.

[0049] The base material layer can also be subjected to surface treatment. As the surface treatment, for example, corona treatment, plasma treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage electric shock exposure, ionized radiation treatment, coating treatment using a primer, and the like can be exemplified.

[0050] As the organic coating material, for example, materials described in Plastic Hard Coat Materials II (CMC Publishing, (2004)) can be exemplified. As such an organic coating material, a urethane-based polymer can be preferably exemplified, and a polyacryl urethane, a polyester urethane, or a precursor thereof can be more preferably exemplified. The reason for this is that coating / application to the base material layer Al is easy, and a variety of substances are industrially available, and can be obtained at low cost. Such a urethane-based polymer can be exemplified by, for example, a polymer of a reaction mixture containing an isocyanate monomer and a monomer containing an alcoholic hydroxyl group (for example, a hydroxyl group-containing acryl compound or a hydroxyl group-containing ester compound). The organic coating material can also contain a chain extender such as a polyamine, an anti-aging agent, an oxidation stabilizer, and the like as an arbitrary additive.

[0051] In the base material layer, an arbitrary appropriate other additive can be contained within a range not impairing the effects of the present application, as necessary.

[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 application can be further exhibited.

[0054] The adhesive layer is composed of an arbitrary appropriate adhesive within a range not impairing the effects of the present application. As such an adhesive, for example, an acrylic adhesive, a rubber-based adhesive, a silicone-based adhesive, a urethane-based adhesive can be exemplified, and the adhesive layer is preferably composed of an acrylic adhesive in terms of further exhibiting the effects of the present application.

[0055] The acrylic adhesive is formed from the acrylic adhesive composition. Thus, the acrylic adhesive can be defined as a substance formed from the acrylic adhesive composition. The reason for this is that, in the case of an adhesive, the adhesive composition typically undergoes a cross-linking reaction or the like by heating, active energy ray irradiation, or the like, thereby becoming an adhesive, and thus the adhesive cannot be directly determined by its structure, and furthermore, there are generally impractical cases ("impossible / impractical cases"), and thus the adhesive is appropriately determined as a "substance" in accordance with the definition of "a substance formed from an adhesive composition".

[0056] The adhesive layer can be formed from the acrylic adhesive composition by any appropriate method. For example, in the case of an adhesive layer, the following methods can be listed: the acrylic adhesive composition is applied to any appropriate substrate, heating or the like, active energy ray (ultraviolet ray or the like) irradiation, drying, or the like is performed as necessary, it is cured as necessary, and the adhesive layer is formed on the substrate.

[0057] As the method of applying the acrylic adhesive composition, any appropriate method can be employed within a range that does not impair the effects of the present application. As such a method of application, for example, roll coating, gravure roll coating, reverse roll coating, kiss roll coat, dip roll coating, bar coating, roll brush coating, spray coating, blade coating, air knife coating, comma coating, direct coating, and die coating can be listed.

[0058] The heating, drying of the acrylic adhesive composition can employ any appropriate method within a range that does not impair the effects of the present application. As such a method of heating, drying, for example, heating to 60°C to 180°C; aging treatment at a temperature of, for example, around room temperature can be listed.

[0059] The curing of the acrylic adhesive composition can employ any appropriate method within a range that does not impair the effects of the present application. As such a method of curing, for example, ultraviolet ray irradiation, laser ray irradiation, α-ray irradiation, β-ray irradiation, γ-ray irradiation, X-ray irradiation, and electron beam irradiation can be listed.

[0060] As representative methods of forming an acrylic adhesive from an acrylic adhesive composition, the following methods can be cited: (1) a method of forming a thermally cured acrylic adhesive by cross-linking reaction of a thermally cured acrylic adhesive composition containing an acrylic polymer prepared by solution polymerization using a thermal polymerization initiator; and (2) a method of forming a photocured acrylic adhesive by photocuring reaction of a photocured acrylic adhesive composition containing an acrylic polymer (typically, an acrylic partial polymer) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator. That is, as the acrylic adhesive, typically, the following can be cited: (1) a thermally cured acrylic adhesive formed by cross-linking reaction of a thermally cured acrylic adhesive composition containing an acrylic polymer (P1) prepared by solution polymerization using a thermal polymerization initiator; and (2) a photocured acrylic adhesive formed by photocuring reaction of a photocured acrylic adhesive composition containing an acrylic polymer (typically, an acrylic partial polymer) (P2) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator.

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

[0062] One embodiment of the acrylic polymer is an acrylic polymer (P1) prepared by solution polymerization using a thermal polymerization initiator. As the method of polymerization using a thermal polymerization initiator, for example, any appropriate method known in the art can be employed without impairing the effects of the present application.

[0063] The acrylic polymer (P1) is a substance obtained by polymerizing a monomer component (M1). The monomer component (M1) does not contain the cross-linking agent described later that can be contained in the acrylic adhesive composition. When the acrylic polymer (P1) is obtained by polymerization, in addition to the use of the monomer component (M1), a thermal polymerization initiator, any appropriate additive can be used without impairing the effects of the present application.

[0064] The acrylic polymer (P1) can be appropriately defined as a substance obtained by polymerizing the monomer component (M1). The reason for this is that, in the case of the acrylic polymer (P1), the monomer component (M1) undergoes a polymerization reaction, thereby becoming the acrylic polymer (P1), and the acrylic polymer (P1) cannot be directly determined by its structure, and furthermore, there are cases where it is substantially impractical ("impossible / impractical cases"), and thus the acrylic polymer (P1) is appropriately determined as a "substance" in accordance with the definition of "a substance obtained by polymerizing the monomer component (M1)".

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

[0066] The Tg of the acrylic polymer (P1) refers to a value calculated according to the Fox equation, based on the Tg of a homopolymer of each monomer that constitutes the acrylic polymer (P1) and the weight fraction (copolymerization ratio on a weight basis) of the monomer.

[0067] The Fox equation refers to a relationship between the Tg of a copolymer and the glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each monomer that constitutes the copolymer, as shown below.

[0068] 1 / Tg = ∑(Wi / Tgi)

[0069] In the above Fox equation, Tg represents the glass transition temperature of the copolymer (unit: K), Wi represents the weight fraction (copolymerization ratio on a weight basis) of the monomer i in the copolymer, and Tgi represents the glass transition temperature of the homopolymer of the monomer i (unit: K). As the Tg of the homopolymer, a value described in a publicly known document is used.

[0070] As the Tg of the homopolymer, for example, the following values can be used specifically.

[0071] n-Butyl acrylate (BA): -55°C.

[0072] Lauryl acrylate (LA): -23°C.

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

[0074] 2-Hydroxyethyl acrylate (2HEA): -15°C.

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

[0076] N-Vinyl-2-pyrrolidone (NVP): 80°C.

[0077] As for the Tg of the homopolymer other than those exemplified above, the value described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. In the case where a plurality of values are described in the above-mentioned "Polymer Handbook", the conventional value is adopted. As for the monomer not described in the above-mentioned "Polymer Handbook", the catalog value of the monomer manufacturing company is adopted. As for the Tg of the homopolymer of the monomer not described in the above-mentioned "Polymer Handbook" and for which no catalog value of the monomer manufacturing company is provided, the value obtained by the measurement method described in Japanese Patent Application Laid-Open No. 2007-51271 is used.

[0078] The monomer component (M1) preferably contains an alkyl (meth)acrylate (al) and a polar group-containing monomer (bl). The alkyl (meth)acrylate (al) can be only one kind, or two or more kinds. The polar group-containing monomer (bl) can be only one kind, or two or more kinds.

[0079] [A-2-1-1. Alkyl (meth)acrylate (al)]

[0080] The alkyl group of the ester moiety of the alkyl (meth)acrylate (al) (hereinafter, sometimes referred to as "alkyl group of the ester moiety") does not include an alkyl group containing a hydroxyl group and an alkyl group containing a polar group other than a hydroxyl group. Thus, the alkyl (meth)acrylate (al) can be clearly distinguished from the polar group-containing monomer (bl).

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

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

[0083] The alkyl group of the ester moiety is preferably a chain alkyl group. Here, the chain means to include a straight chain and a branched chain.

[0084] As the alkyl group of the alkyl (meth)acrylate (al) which is the ester moiety, a chain alkyl group having 1 to 20 carbon atoms can be exemplified, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, arachidyl (meth)acrylate.

[0085] The glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (al) which can be contained in the monomer component (Ml) is preferably -10°C or lower, more preferably -12°C or lower, further preferably -15°C or lower, particularly preferably -18°C or lower, and most preferably -20°C or lower. The lower limit of the glass transition temperature Tg is preferably -80°C or higher.

[0086] Here, the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (al) which can be contained in the monomer component (Ml) can be adopted from the values described in the publicly known documents, and for example, the values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. Note that in the case where a plurality of values are described in the above-mentioned "Polymer Handbook", a conventional value is adopted. For the alkyl (meth)acrylate which is not described in the above-mentioned "Polymer Handbook" and for which no catalog value of the monomer manufacturing company is provided, the value obtained by the measurement method described in Japanese Patent Application Publication No. 2007-51271 is used.

[0087] The (meth)alkyl acrylate (a1) that can be contained in the monomer component (M1) preferably contains a (meth)alkyl acrylate (a1-1) having a glass transition temperature Tg of the homopolymer in the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C).

[0088] As the (meth)alkyl acrylate (a1-1), for example, lauryl acrylate (LA) (Tg of the homopolymer = -23°C) can be exemplified.

[0089] The content ratio of the (meth)alkyl acrylate (a1-1) in the total amount of the (meth)alkyl acrylate (a1) that can be contained in the monomer component (M1) is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, further preferably 4% by mass or more and 15% by mass or less, particularly preferably 5% by mass or more and 12% by mass or less, most preferably 6% by mass or more and 10% by mass or less.

[0090] The content ratio of the (meth)alkyl acrylate (a1-1) in the total amount of the monomer component (M1) is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, further preferably 4% by mass or more and 15% by mass or less, particularly preferably 5% by mass or more and 12% by mass or less, most preferably 6% by mass or more and 10% by mass or less.

[0091] The (meth)alkyl acrylate (a1) that can be contained in the monomer component (M1) preferably contains a (meth)alkyl acrylate (a1-2) having a glass transition temperature Tg of the homopolymer in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C).

[0092] As the (meth)alkyl acrylate (a1-2), for example, 2-ethylhexyl acrylate (2EHA) (Tg of the homopolymer = -70°C) can be exemplified.

[0093] The content ratio of the (meth)alkyl acrylate (a1-2) in the total amount of the (meth)alkyl acrylate (a1) that can be contained in the monomer component (M1) is preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, further preferably 55% by mass or more and 85% by mass or less, particularly preferably 60% by mass or more and 80% by mass or less, most preferably 65% by mass or more and 75% by mass or less.

[0094] The content ratio of the (meth)acrylic acid alkyl ester (a1-2) in the total amount of the monomer component (M1) is preferably from 40% by mass to 95% by mass, more preferably from 50% by mass to 90% by mass, further preferably from 55% by mass to 85% by mass, particularly preferably from 60% by mass to 80% by mass, and most preferably from 65% by mass to 75% by mass.

[0095] The (meth)acrylic acid alkyl ester (a1) that can be contained in the monomer component (M1) preferably contains a (meth)acrylic acid alkyl ester (a1-3) whose homopolymer has a glass transition temperature Tg in the range of greater than -60°C and less than -40°C.

[0096] As the (meth)acrylic acid alkyl ester (a1-3), for example, n-butyl acrylate (BA) (homopolymer thereof has a glass transition temperature Tg = -55°C) can be exemplified.

[0097] The content ratio of the (meth)acrylic acid alkyl ester (a1-3) in the total amount of the (meth)acrylic acid alkyl ester (a1) that can be contained in the monomer component (M1) is preferably from 1% by mass to 50% by mass, more preferably from 5% by mass to 35% by mass, further preferably from 10% by mass to 30% by mass, particularly preferably from 13% by mass to 28% by mass, and most preferably from 15% by mass to 25% by mass.

[0098] The content ratio of the (meth)acrylic acid alkyl ester (a1-3) in the total amount of the monomer component (M1) is preferably from 1% by mass to 50% by mass, more preferably from 5% by mass to 35% by mass, further preferably from 10% by mass to 30% by mass, particularly preferably from 13% by mass to 28% by mass, and most preferably from 15% by mass to 25% by mass.

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

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

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

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

[0103] As the hydroxyl group-containing monomer (b1-1), for example, there can be mentioned (meth)acrylic acid 2-hydroxyethyl ester, (meth)acrylic acid 2-hydroxypropyl ester, (meth)acrylic acid 3-hydroxypropyl ester, (meth)acrylic acid 2-hydroxybutyl ester, (meth)acrylic acid 4-hydroxybutyl ester, and the like (hydroxyalkyl (meth)acrylate); polypropylene glycol mono(meth)acrylate; N-hydroxyethyl (meth)acrylamide.

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

[0105] As to the glass transition temperature Tg of the homopolymer of the hydroxyl group-containing monomer (b1-1), the description on the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (a1) which can be contained in the monomer component (M1) in the item of [1-2-1-1. Alkyl (meth)acrylate (a1)] can be referred to.

[0106] As the hydroxyl group-containing monomer (b1-1), preferably there can be mentioned hydroxyalkyl (meth)acrylate, and more preferably there can be mentioned (meth)acrylic acid hydroxyalkyl ester in which the alkyl moiety of the hydroxyalkyl group is a linear alkyl group having 2 to 4 carbon atoms, and further preferably there can be mentioned 2-hydroxyethyl acrylate (HEA) (homopolymer thereof: glass transition temperature Tg = -15°C), 4-hydroxybutyl acrylate (4HBA) (homopolymer thereof: glass transition temperature Tg = -40°C), and particularly preferably 4-hydroxybutyl acrylate (4HBA) (homopolymer thereof: glass transition temperature Tg = -40°C).

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

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

[0109] The monomer (b1-2) having a polar group other than a hydroxyl group can be only one or two or more.

[0110] As the monomer (b1-2) having a polar group other than a hydroxyl group, for example, N-vinyl-2-pyrrolidone, a nitrogen-containing monomer other than N-vinyl-2-pyrrolidone, a carboxyl-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, a cyano group-containing monomer, an acid anhydride group-containing monomer, vinyl esters (for example, vinyl acetate (VAc), vinyl propionate, vinyl laurate), aromatic vinyl compounds, an amide group-containing monomer, an epoxy group-containing monomer, (meth)acryloyl morpholine, vinyl ethers can be exemplified.

[0111] As the carboxyl-containing monomer, for example, acrylic acid (AA), methacrylic acid (MAA), (meth)acrylic acid carboxyethyl ester, (meth)acrylic acid carboxypentyl ester, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid can be exemplified.

[0112] As the nitrogen-containing monomer other than N-vinyl-2-pyrrolidone, for example, methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, (meth)acryloyl morpholine, N-vinyl carboxylic acid amides, N-vinyl caprolactam, and the like nitrogen-containing vinyl monomers; acrylonitrile, methacrylonitrile, and the like cyano group-containing acrylic monomers can be exemplified.

[0113] In terms of aspects in which the effects of the present application can be further exhibited, the glass transition temperature Tg of the homopolymer of the monomer (b1-2) having a polar group other than a hydroxyl group is preferably -30°C to 100°C, more preferably -20°C to 95°C, and further preferably -10°C to 90°C.

[0114] As the monomer (b1-2) having a polar group other than a hydroxyl group, preferably, a monomer having a polar group other than a hydroxyl group whose homopolymer has a glass transition temperature Tg of 50°C to 100°C can be exemplified. The homopolymer of this monomer has a glass transition temperature Tg of preferably 60°C to 95°C, and further preferably 70°C to 90°C.

[0115] As for the glass transition temperature Tg of the homopolymer of the monomer (b1-2) having a polar group other than a hydroxyl group, the description in the item of [1-2-1-1. (Meth)acrylic acid alkyl ester (a1)] regarding the glass transition temperature Tg of the homopolymer of the (meth)acrylic acid alkyl ester (a1) which can be contained in the monomer component (M1) can be cited.

[0116] As the monomer (b1-2) having a polar group other than a hydroxyl group, N-vinyl-2-pyrrolidone (the glass transition temperature Tg of the homopolymer thereof = 80°C) can be preferably cited.

[0117] The content ratio of the monomer (b1-2) having a polar group other than a hydroxyl group in the monomer (b1) having a polar group is preferably 1% by mass or more and 99% by mass or less, more preferably 10% by mass or more and 80% by mass or less, further preferably 20% by mass or more and 60% by mass or less, particularly preferably 25% by mass or more and 55% by mass or less, most preferably 30% by mass or more and 50% by mass or less.

[0118] The content ratio of the monomer (b1-2) having a polar group other than a hydroxyl group in the monomer component (M1) is preferably 0.0001% by mass or more and 10% by mass or less, more preferably 0.005% by mass or more and 5% by mass or less, further preferably 0.01% by mass or more and 3% by mass or less, particularly preferably 0.05% by mass or more and 2% by mass or less, most preferably 0.1% by mass or more and 1% by mass or less.

[0119] The monomer component (M1) preferably contains the (meth)acrylic acid alkyl ester (a1) and at least one selected from the group consisting of the monomer (b1-1) having a hydroxyl group and the monomer (b1-2) having a polar group other than a hydroxyl group, more preferably contains the (meth)acrylic acid alkyl ester (a1), the monomer (b1-1) having a hydroxyl group, and the monomer (b1-2) having a polar group other than a hydroxyl group, further preferably contains the (meth)acrylic acid alkyl ester (a1-1) of which the glass transition temperature Tg of the homopolymer is in the range of -40°C or more and -10°C or less (preferably -35°C or more and -15°C or less, more preferably -30°C or more and -20°C or less), the (meth)acrylic acid alkyl ester (a1-2) of which the glass transition temperature Tg of the homopolymer is in the range of -80°C or more and -60°C or less (preferably -75°C or more and -60°C or less, more preferably -75°C or more and -65°C or less), the (meth)acrylic acid alkyl ester (a1-3) of which the glass transition temperature Tg of the homopolymer is in the range of more than -60°C and less than -40°C, the monomer (b1-1) having a hydroxyl group, and the monomer (b1-2) having a polar group other than a hydroxyl group.

[0120] The content ratio of the total amount of the (meth)acrylic acid alkyl ester (al-1) of which the homopolymer 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), the (meth)acrylic acid alkyl ester (al-2) of which the 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), the (meth)acrylic acid alkyl ester (al-3) of which the homopolymer has a glass transition temperature Tg in the range of more than -60°C and less than -40°C, the hydroxyl group-containing monomer (bl-1), and the monomer (bl-2) having a polar group other than a hydroxyl group in the monomer component (Ml) is preferably 60% by weight or more, more preferably 70% by weight or more, further preferably 80% by weight or more, particularly preferably 90% by weight or more, and most preferably 95% by weight or more.

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

[0122] [A-2-1-3. Other monomer (cl)]

[0123] The monomer component (Ml) can contain an other monomer (cl) that does not correspond to any of the (meth)acrylic acid alkyl ester (al) and the polar group-containing monomer (bl). The other monomer (cl) can be used, for example, for the purpose of adjusting the glass transition temperature (Tg) of the acrylic polymer (Pl), adjusting the adhesion properties, and the like. The other monomer can be only one, or two or more.

[0124] The content ratio of the other monomer (cl) in the monomer component (Ml) 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] The thermal polymerization initiator can be appropriately selected from any appropriate thermal polymerization initiator according to the type of the polymerization method. The thermal polymerization initiator can be only one, or two or more.

[0127] As the thermal polymerization initiator, for example, the following can be mentioned: azo initiators such as 2,2'-azobisizobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl ester, 4,4'-azobis-4-cyanopentanoic acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazoline-2-yl)propane] dihydrochloride, 2,2'-azobis(2-methylimidazole) disulfate, 2,2'-azobis(N,N'-dimethyleneisobutyl imide), 2,2'-azobis[N-(2-carboxyethyl)-2-methylimidazole] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.), and the like; persulfate salts such as potassium persulfate, ammonium persulfate, and the like; peroxide initiators such as di(2-ethylhexyl) peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyneopentanoate, tert-butyl peroxyneopentanoate, dilauryl peroxydicarbonate, di-n-octyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, dibenzoyl peroxide, tert-butyl peroxyisobutyrate, 1,1-di(tert-hexylperoxy)cyclohexane, tert-butyl hydroperoxide, hydrogen peroxide, and the like; combinations of a persulfate salt and sodium bisulfite, combinations of a peroxide and sodium ascorbate, and the like, which are redox initiators combining a peroxide and an epoxy agent; substituted ethane initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds.

[0128] The amount of the thermal polymerization initiator used can be set to an arbitrary appropriate amount within a range that does not impair the effects of the present application. The amount of the thermal polymerization initiator used 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, relative to 100 parts by weight of the monomer component (M1).

[0129] The thermal curing type acrylic adhesive composition according to the present application is a composition for forming a thermal curing type acrylic adhesive, and contains the acrylic polymer (P1) and a thermal curing agent (A2-1).

[0130] One embodiment of the acrylic adhesive is a thermal curing type acrylic adhesive, and, as a representative example, the thermal curing type acrylic adhesive is formed by a crosslinking reaction of a thermal curing type acrylic adhesive composition containing the acrylic polymer (P1).

[0131] The thermosetting acrylic adhesive is formed from the thermosetting acrylic adhesive composition by any appropriate method. As such a forming method, representative examples include a method in which the thermosetting acrylic adhesive composition is applied to any appropriate substrate, heated / dried as necessary, cured as necessary, and the thermosetting acrylic adhesive is formed in sheet form on the substrate. As such an application method, any application method can be used within a range that does not impair the effects of the present application. As such an application method, for example, roll coating, gravure roll coating, reverse roll coating, roll kiss coating, dip roll coating, bar coating, roll brush coating, spray coating, blade coating, air knife coating, comma coating, direct coating, and die coating can be mentioned.

[0132] The heating / drying of the thermosetting acrylic adhesive composition can be performed by any appropriate method within a range that does not impair the effects of the present application. As such a heating / drying method, for example, heating to about 60°C to 180°C can be mentioned. The curing of the acrylic adhesive composition can be performed by any appropriate method within a range that does not impair the effects of the present application. As such a curing method, for example, ultraviolet irradiation, laser ray irradiation, α-ray irradiation, β-ray irradiation, γ-ray irradiation, X-ray irradiation, and electron beam irradiation can be mentioned.

[0133] In the formation of the thermosetting acrylic adhesive, aging can be performed as necessary for the purpose of adjustment of the transfer of components within the formed thermosetting acrylic adhesive, progress of crosslinking reaction, relaxation of strain that can exist within the photocurable acrylic adhesive, and the like.

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

[0135] The thermosetting acrylic adhesive composition preferably contains the crosslinking agent (L1). The crosslinking agent (L1) can be only one or two or more.

[0136] By using the crosslinking agent (L1), the thermosetting acrylic adhesive can be imparted with moderate cohesion. The crosslinking agent (L1) can be contained in the thermosetting acrylic adhesive in the form after crosslinking reaction, the form before crosslinking reaction, the form in which a part of the crosslinking reaction has been performed, an intermediate or a complex of these, and the like. Typically, the crosslinking agent (L1) is contained in the thermosetting acrylic adhesive in the form after crosslinking reaction.

[0137] The content ratio of the crosslinking agent (L1) in the heat-curable acrylic adhesive composition is preferably 0.005 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, further preferably 0.01 to 3 parts by weight, further preferably 0.01 to 1 part by weight, further preferably 0.01 to 0.7 parts by weight, further preferably 0.01 to 0.5 parts by weight, particularly preferably 0.01 to 0.4 parts by weight, and most preferably 0.01 to 0.3 parts by weight, relative to 100 parts by weight of the acrylic polymer (P1).

[0138] As the crosslinking agent, for example, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, silicone-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, peroxides, and the like can be exemplified, and, in terms of further exhibiting the effects of the present application, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and peroxides are preferred, and isocyanate-based crosslinking agents and peroxides are more preferred.

[0139] The isocyanate-based crosslinking agent can use a compound having two or more isocyanate groups (including isocyanate regenerable polar groups in which isocyanate groups are temporarily protected by a blocking agent or polymerization, etc.) in one molecule. As the isocyanate-based crosslinking agent, for example, aromatic isocyanates such as toluene diisocyanate, xylene diisocyanate, and the like; alicyclic isocyanates such as isophorone diisocyanate and the like; aliphatic isocyanates such as hexamethylene diisocyanate and the like can be exemplified.

[0140] As the isocyanate-based crosslinking agent, for example, lower aliphatic polyisocyanates such as butylene diisocyanate, hexamethylene diisocyanate, and the like; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, and the like; aromatic diisocyanates such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenyl isocyanate, and the like; isocyanate adducts such as trimethylolpropane / toluene diisocyanate trimer adduct (for example, manufactured by TOSOH Corporation, trade name: CORONATE L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (for example, manufactured by TOSOH Corporation, trade name: CORONATE HL), isocyanurate of hexamethylene diisocyanate (for example, manufactured by TOSOH Corporation, trade name: CORONATE HX), and the like; trimethylolpropane adducts of xylylene diisocyanate (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D110N), trimethylolpropane adducts of xylylene diisocyanate (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D120N), trimethylolpropane adducts of isophorone diisocyanate (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D140N), trimethylolpropane adducts of hexamethylene diisocyanate (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D160N); polyether polyisocyanates, polyester polyisocyanates, and adducts thereof with various polyols; and polyfunctional isocyanates having isocyanurate bonds, biuret bonds, allophanate bonds, and the like. Among these, aromatic isocyanates and alicyclic isocyanates are preferable in terms of balancing the deformability and the cohesiveness well.

[0141] As the epoxy-based crosslinking agent, a multifunctional epoxy compound having two or more epoxy groups in one molecule can be used. As the epoxy-based crosslinking agent, for example, N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidyl aniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, trisglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and an epoxy-based resin having two or more epoxy groups in one molecule can be listed. As the commercially available epoxy-based crosslinking agent, for example, "TETRAD-C" and "TETRAD-X" manufactured by MITSUBISHI GAS CHEMICAL Co., Ltd. can be listed.

[0142] As the peroxide, for example, dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, di-t-butyl peroxide-3,3,5-trimethylcyclohexane, t-butyl hydroperoxide, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-mono(t-butylperoxy)-hexane, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, dilauryl peroxide, di-n-octyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, t-butyl peroxy-2-ethylhexyl carbonate, t-amyl peroxyisopropyl carbonate, 3,5,5-trimethylhexanoyl peroxide, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate can be listed. As the commercially available peroxide, for example, "NYPER BMT" series and "NYPER BW" series manufactured by NOF Corporation can be listed.

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

[0144] The thermosetting acrylic adhesive composition can contain an acrylic oligomer. The acrylic oligomer can be only one or two or more.

[0145] The content of the acrylic oligomer in the thermosetting acrylic adhesive composition can be set to an arbitrary appropriate content within a range not impairing the effects of the present application. The content of the acrylic oligomer in the thermosetting acrylic adhesive composition is preferably 0.1 parts by weight to 20 parts by weight, more preferably 1 part by weight to 15 parts by weight, further preferably 2 parts by weight to 10 parts by weight, and particularly preferably 3 parts by weight to 8 parts by weight, relative to 100 parts by weight of the acrylic polymer (P1).

[0146] The weight average molecular weight of the acrylic oligomer is preferably 1000 to 30000, more preferably 1000 to 20000, further preferably 1500 to 10000, and particularly preferably 2000 to 8000.

[0147] Note that the weight average molecular weight (Mw) can be calculated by GPC method in terms of polystyrene. For example, a high-speed GPC device "HPLC-8120 GPC" manufactured by TOSOH CORPORATION can be used to measure under the following conditions.

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

[0149] Solvent: tetrahydrofuran.

[0150] Flow rate: 0.6 ml / minute.

[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 more preferably 40°C to 300°C.

[0152] The Tg of the acrylic oligomer is a value calculated according to the Fox equation based on the Tg of the homopolymer of each monomer constituting the acrylic oligomer and the weight fraction (copolymerization ratio on a weight basis) of the monomer. As to the Fox equation and the Tg of various homopolymers, the description in the item of <A-2-1. Acrylic polymer (P1)> can be referred to.

[0153] As the acrylic oligomer, an acrylic oligomer obtained from a monomer composition in which a (meth)acrylic ester having a cyclic structure in the molecule is a necessary component is preferred, and an acrylic oligomer obtained from a monomer composition in which a (meth)acrylic ester having a cyclic structure in the molecule and a (meth)acrylic alkyl ester having a linear or branched alkyl group are necessary components is more preferred.

[0154] The (meth)acrylate having a cyclic structure in the molecule can be one kind or two or more kinds.

[0155] The (meth)acrylate having a cyclic structure in the molecule can be one kind or two or more kinds.

[0156] As the cyclic structure in the (meth)acrylate having a cyclic structure in the molecule, any of an aromatic ring, a non-aromatic ring, and the like can be used.

[0157] As the aromatic ring, for example, an aromatic carbocyclic ring (e.g., a monocyclic carbocyclic ring such as a benzene ring, a condensed carbocyclic ring such as a naphthalene ring, and the like), various aromatic heterocyclic rings, and the like can be used.

[0158] As the non-aromatic ring, for example, a non-aromatic aliphatic ring (non-aromatic alicyclic ring) (e.g., a cycloalkane ring such as a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, and the like; a cycloalkene ring such as a cyclohexene ring, and the like), a non-aromatic bridged ring (e.g., a bicyclic hydrocarbon ring in pinane, pinene, bornane, norbornane, norbornene, and the like; a three or more ring aliphatic hydrocarbon ring (bridged hydrocarbon ring) in adamantane, and the like), a non-aromatic heterocyclic ring (e.g., an epoxy ring, an oxolane ring, an oxetane ring, and the like), and the like can be used. As the three or more ring aliphatic hydrocarbon ring (three or more ring bridged hydrocarbon ring), for example, a bicyclopentyl group, a bicyclopentenyl group, an adamantyl group, a tricyclopentyl group, a tricyclopentenyl group, and the like can be used.

[0159] As the (meth)acrylate having a cyclic structure in the molecule, specifically, for example, a (meth)acrylic acid cyclopentyl ester, a (meth)acrylic acid cyclohexyl ester, a (meth)acrylic acid cycloheptyl ester, a (meth)acrylic acid cyclooctyl ester, and the like (meth)acrylic acid cycloalkyl esters; a (meth)acrylic acid isobornyl ester and the like (meth)acrylates having a bicyclic aliphatic hydrocarbon ring; a (meth)acrylic acid dicyclopentyl ester, a (meth)acrylic acid dicyclopentyl oxyethyl ester, a (meth)acrylic acid tricyclopentyl ester, a (meth)acrylic acid 1-adamantyl ester, a (meth)acrylic acid 2-methyl-2-adamantyl ester, a (meth)acrylic acid 2-ethyl-2-adamantyl ester, and the like (meth)acrylates having a three or more ring aliphatic hydrocarbon ring; a (meth)acrylic acid phenyl ester and the like (meth)acrylic acid aryl esters, a (meth)acrylic acid phenoxyethyl ester and the like (meth)acrylic acid aryloxyalkyl esters, a (meth)acrylic acid benzyl ester and the like (meth)acrylic acid arylalkyl esters, and the like (meth)acrylates having an aromatic ring can be used.

[0160] As the (meth)acrylate having a cyclic structure in the molecule, (meth)acrylates containing a non-aromatic ring are preferable in terms of further embodying the effects of the present application, and more preferable are cyclohexyl acrylate (CHA), cyclohexyl methacrylate (CHMA), dicyclopentyl acrylate (DCPA), dicyclopentyl methacrylate (DCPMA), and further preferable are dicyclopentyl acrylate (DCPA), dicyclopentyl methacrylate (DCPMA).

[0161] The (meth)acrylate having a cyclic structure in the molecule can be contained in the total monomers constituting the acrylic oligomer at a ratio of preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, relative to 100 parts by weight of the total monomers, in terms of further embodying the effects of the present application.

[0162] As the (meth)acrylate having an alkyl group having a linear or branched chain, for example, there are mentioned (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid propyl ester, (meth)acrylic acid isopropyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid isobutyl ester, (meth)acrylic acid sec-butyl ester, (meth)acrylic acid tert-butyl ester, (meth)acrylic acid pentyl ester, (meth)acrylic acid isopentyl ester, (meth)acrylic acid hexyl ester, (meth)acrylic acid heptyl ester, (meth)acrylic acid octyl ester, (meth)acrylic acid 2-ethylhexyl ester, (meth)acrylic acid isooctyl ester, (meth)acrylic acid nonyl ester, (meth)acrylic acid isononyl ester, (meth)acrylic acid decyl ester, (meth)acrylic acid isodecyl ester, (meth)acrylic acid undecyl ester, (meth)acrylic acid dodecyl ester, (meth)acrylic acid tridecyl ester, (meth)acrylic acid tetradecyl ester, (meth)acrylic acid pentadecyl ester, (meth)acrylic acid hexadecyl ester, (meth)acrylic acid heptadecyl ester, (meth)acrylic acid octadecyl ester, (meth)acrylic acid nonadecyl ester, (meth)acrylic acid eicosyl ester, and the like, of which (meth)acrylic acid methyl ester (MMA) is preferable in terms of further embodying the effects of the present application.

[0163] The (meth)acrylate having an alkyl group having a linear or branched chain can be contained in the total monomers constituting the acrylic oligomer at a ratio of preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, further preferably 20 to 60 parts by weight, relative to 100 parts by weight of the total monomers, in terms of further embodying the effects of the present application.

[0164] The total monomers (monomer composition) that can be used to constitute the acrylic oligomer can include, in addition to the (meth)acrylic acid ester having a cyclic structure within the molecule, the alkyl (meth)acrylic acid alkyl ester having a linear or branched alkyl group, other monomers (copolymerizable monomers) that can be copolymerized with these monomers. The content of the other monomers (copolymerizable monomers) in the total monomers (monomer composition) that can be used to constitute the acrylic oligomer is preferably less than 50 parts by weight, 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, relative to 100 parts by weight of the total monomers.

[0165] As such other monomers (copolymerizable monomers), for example, the following can be listed: (meth)acrylic acid alkoxyalkyl esters (e.g., (meth)acrylic acid 2-methoxyethyl ester, (meth)acrylic acid 2-ethoxyethyl ester, (meth)acrylic acid methoxytriethylene glycol ester, (meth)acrylic acid 3-methoxypropyl ester, (meth)acrylic acid 3-ethoxypropyl ester, (meth)acrylic acid 4-methoxybutyl ester, (meth)acrylic acid 4-ethoxybutyl ester, etc.), carboxyl group-containing monomers (e.g., (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, maleic anhydride, and other monomers containing anhydride group, etc.), hydroxyl group-containing monomers (e.g., (meth)acrylic acid 2-hydroxyethyl ester, (meth)acrylic acid 3-hydroxypropyl ester, (meth)acrylic acid 4-hydroxybutyl ester, (meth)acrylic acid 6-hydroxyhexyl ester, and other (meth)acrylic acid hydroxyalkyl esters; vinyl alcohol; allyl alcohol; etc.), amide group-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 group-containing monomers (e.g., (meth)acrylic acid aminoethyl ester, (meth)acrylic acid dimethylaminoethyl ester, (meth)acrylic acid tert-butylaminoethyl ester, etc.), cyano group-containing monomers (e.g., acrylonitrile, methacrylonitrile, etc.), sulfonic acid group-containing monomers (e.g., sodium vinyl sulfonate, etc.), phosphoric acid group-containing monomers (e.g., 2-hydroxyethyl acryloyl phosphate, etc.), isocyanate group-containing monomers (e.g., 2-methacryloyloxyethyl isocyanate, etc.), imide group-containing monomers (e.g., cyclohexyl maleimide, isopropyl maleimide, etc.), and the like.

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

[0167] The acrylic oligomer can be produced by any appropriate polymerization within a range not impairing the effects of the present application. As the method of such polymerization, for example, a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a polymerization method based on irradiation of active energy rays (active energy ray polymerization method), and the like can be exemplified. Among them, the bulk polymerization method, the solution polymerization method are preferred, and the solution polymerization method is more preferred.

[0168] As the solvent which can be used in the polymerization, for example, esters such as ethyl acetate, n-butyl acetate, and the like; aromatic hydrocarbons such as toluene, benzene, and the like; aliphatic hydrocarbons such as n-hexane, n-heptane, and the like; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, and the like; ketones such as methyl ethyl ketone, methyl isobutyl ketone, and the like; and the like organic solvents can be exemplified. The solvent can be only one, or two or more.

[0169] In the polymerization, any appropriate polymerization initiator (for example, a thermal polymerization initiator, a photopolymerization initiator, and the like) can be employed within a range not impairing the effects of the present application. The polymerization initiator can be only one, or two or more. Note that, in the case of performing solution polymerization, an oil-soluble polymerization initiator is preferably used.

[0170] As the thermal polymerization initiator, any appropriate thermal polymerization initiator can be employed within a range not impairing the effects of the present application. The thermal polymerization initiator can be only one, or two or more. As to specific examples of such thermal polymerization initiator, the description of the item of [A-2-1-4. Thermal polymerization initiator] can be referred to.

[0171] As the content of the thermal polymerization initiator, for example, 0.1 parts by weight to 15 parts by weight is preferable with respect to 100 parts by weight of the total monomers (monomer composition) which can be used for constituting the acrylic oligomer.

[0172] As the photopolymerization initiator, any appropriate photopolymerization initiator can be employed within a range not impairing the effects of the present application. The photopolymerization initiator can be only one, or two or more.

[0173] As the photopolymerization initiator, for example, a benzoin ether-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, an α-keto alcohol-based photopolymerization initiator, an aromatic sulfonyl chloride-based photopolymerization initiator, a photoactive oxime-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzil-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a ketal-based photopolymerization initiator, a thioxanthone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and the like can be exemplified.

[0174] As the benzoin ether-based photopolymerization initiator, specifically, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-l,2-diphenylethan-l-one (as a commercial product, for example, trade name "OMNIRAD 651", manufactured by IGM Resins B.V.), anisoin methyl ether, and the like can be exemplified.

[0175] As the acetophenone-based photopolymerization initiator, specifically, for example, 1-hydroxycyclohexyl phenyl ketone (as a commercial product, for example, trade name "OMNIRAD 184", manufactured by IGM Resins B.V.), 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, l-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-l-propane-l-one (as a commercial product, for example, trade name "OMNIRAD 2959", manufactured by IGM Resins B.V.), 2-hydroxy-2-methyl-l-phenyl-propane-l-one, methoxyacetophenone, and the like can be exemplified.

[0176] As the α-keto alcohol-based photopolymerization initiator, specifically, for example, 2-methyl-2-hydroxypropiophenone, l-[4-(2-hydroxyethyl)-phenyl]-2-hydroxy-2-methylpropane-l-one, and the like can be exemplified.

[0177] As the aromatic sulfonyl chloride-based photopolymerization initiator, specifically, for example, 2-naphthalenesulfonyl chloride, and the like can be exemplified.

[0178] As the photoactive oxime-based photopolymerization initiator, specifically, for example, l-phenyl-l,l-propanedione-2-(o-ethoxycarbonyl)-oxime, and the like can be exemplified.

[0179] As the benzoin-based photopolymerization initiator, specifically, for example, benzoin, and the like can be exemplified.

[0180] As the benzil-based photopolymerization initiator, specifically, for example, benzil, and the like can be exemplified.

[0181] As the benzophenone-based photopolymerization initiator, specifically, for example, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like can be exemplified.

[0182] As the ketal-based photopolymerization initiator, specifically, for example, benzil dimethyl ketal, and the like can be exemplified.

[0183] As the thioxanthone-based photopolymerization initiator, specifically, for example, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like can be exemplified.

[0184] As the acylphosphine-based photopolymerization initiator, specifically, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and the like can be exemplified.

[0185] As the content of the photopolymerization initiator, for example, 0.001 parts by weight to 0.5 parts by weight is preferable with respect to 100 parts by weight of the total monomers (monomer composition) that can be used to constitute the acrylic oligomer.

[0186] At the time of polymerization of the acrylic oligomer, in order to adjust the molecular weight (preferably in order to adjust the weight average molecular weight to 1000 to 30000), a chain transfer agent can be used. As the chain transfer agent, for example, 2-mercaptoethanol, α-thioglycerol, 2,3-dimercapto-l-propanol, octyl mercaptan, t-nonyl mercaptan, dodecyl mercaptan (lauryl mercaptan), t-dodecyl mercaptan, glycidyl mercaptan, thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, ethylene glycol thioglycolate, neopentyl glycol thioglycolate, pentaerythritol thioglycolate, α-methylstyrene dimer, and the like can be exemplified. Among them, from the viewpoint of suppressing whitening and the like of the adhesive film of the present application, α-thioglycerol, methyl thioglycolate are preferable, and α-thioglycerol is particularly preferable. The chain transfer agent can be only one kind, or two or more kinds.

[0187] The content of the chain transfer agent is, for example, preferably 0.1 parts by weight to 20 parts by weight, more preferably 0.2 parts by weight to 15 parts by weight, and further preferably 0.3 parts by weight to 10 parts by weight, with respect to 100 parts by weight of the total monomers (monomer composition) that can be used to constitute the acrylic oligomer.

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

[0189] The thermosetting acrylic adhesive composition can contain any appropriate other component within a range not impairing the effects of the present application. As such other components, for example, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, foils, softening agents, anti-aging agents, electrically conductive agents, ultraviolet absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, anticorrosive agents, heat-resistant stabilizers, polymerization inhibitors, lubricants, other crosslinking agents, solvents, catalysts, crosslinking catalysts, retardation crosslinking agents, and the like can be exemplified.

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

[0191] Another embodiment of the acrylic polymer is an acrylic polymer (P2) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator. As the method of polymerization using a photopolymerization initiator, for example, any appropriate method known in the art or the like can be employed within a range not impairing the effects of the present application. In the polymerization using a photopolymerization initiator, typically, light such as UV is irradiated.

[0192] The acrylic polymer (P2) is a substance obtained by polymerizing the monomer component (M2). The monomer component (M2) does not include the crosslinking agent described later that can be included in the acrylic adhesive composition. When the acrylic polymer (P2) is obtained by polymerization, in addition to the monomer component (M2) and the photopolymerization initiator, any appropriate additive can be used within a range not impairing the effects of the present application.

[0193] The acrylic polymer (P2) can be defined as a substance obtained by polymerizing the monomer component (M2). The reason for this is that, in the case of the acrylic polymer (P2), the monomer component (M2) undergoes a polymerization reaction, thereby becoming the acrylic polymer (P2), and the acrylic polymer (P1) cannot be directly determined from the structure thereof, and furthermore, there are cases where it is substantially impractical ("impossible / impractical cases"), and thus the acrylic polymer (P2) is appropriately determined as a "substance" according to the definition of "a substance obtained by polymerizing the monomer component (M2)".

[0194] The monomer component (M2) preferably contains an alkyl (meth)acrylate (a2) and a polar group-containing monomer (b2). The alkyl (meth)acrylate (a2) can be only one kind, or two or more kinds. The polar group-containing monomer (b2) can be only one kind, or two or more kinds.

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

[0196] The alkyl group of the ester moiety of the (meth)acrylic acid alkyl ester (a2) (hereinafter, sometimes referred to as "alkyl group of the ester moiety") does not include an alkyl group containing a hydroxyl group and an alkyl group containing a polar group other than a hydroxyl group. Thus, the (meth)acrylic acid alkyl ester (a2) can be clearly distinguished from the polar group-containing monomer (b2).

[0197] The content ratio of the (meth)acrylic acid alkyl ester (a2) in the monomer component (M2) is preferably from 50% by weight 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, the chain refers to both a straight chain and a branched chain. The alkyl group of the ester moiety is preferably a chain alkyl group having 1 to 20 carbon atoms.

[0199] As an example compound of the (meth)acrylic acid alkyl ester (a2) in which the alkyl group of the ester moiety is a chain alkyl group having 1 to 20 carbon atoms, the example compounds of the (meth)acrylic acid alkyl ester (a1) of the item of [A-2-1-1. (Meth)acrylic acid alkyl ester (a1)] can be cited.

[0200] [A-2-3-2. Polar group-containing monomer (b2)]

[0201] The content ratio of the polar group-containing monomer (b2) in the monomer component (M2) is preferably from 1% by weight to 50% by weight.

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

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

[0204] As an example compound of the hydroxyl group-containing monomer (b2-1), the example compounds of the hydroxyl group-containing monomer (b1-1) of the item of [A-2-1-2. Polar group-containing monomer (b1)] can be cited.

[0205] As the monomer (b2-1) having a hydroxyl group, (meth)acrylic acid hydroxyalkyl ester can be preferably exemplified, and more preferably, (meth)acrylic acid hydroxyalkyl ester in which the alkyl moiety of the hydroxyalkyl group is a linear alkyl group having 2 to 4 carbon atoms can be exemplified, and further preferably, 2-hydroxyethyl acrylate (HEA) (homopolymer thereof has a glass transition temperature Tg = -15°C), 4-hydroxybutyl acrylate (4HBA) (homopolymer thereof has a glass transition temperature Tg = -40°C), and particularly preferably, 4-hydroxybutyl acrylate (4HBA) (homopolymer thereof has a glass transition temperature Tg = -40°C) can be exemplified.

[0206] The monomer (b2-2) having a polar group other than a hydroxyl group can be only one or two or more.

[0207] As an example of the monomer (b2-2) having a polar group other than a hydroxyl group, the example of the monomer (b1-2) having a polar group other than a hydroxyl group of the item of [A-2-1-2. Monomer (b1) having a polar group] can be cited.

[0208] As the monomer (b2-2) having a polar group other than a hydroxyl group, N-vinyl-2-pyrrolidone (homopolymer thereof has a glass transition temperature Tg = 80°C) can be preferably exemplified.

[0209] The monomer component (M2) preferably contains (meth)acrylic acid alkyl ester (a2) and at least one selected from the group consisting of the monomer (b2-1) having a hydroxyl group and the monomer (b2-2) having a polar group other than a hydroxyl group, and more preferably, (meth)acrylic acid alkyl ester (a2), the monomer (b2-1) having a hydroxyl group, and the monomer (b2-2) having a polar group other than a hydroxyl group, and further preferably, (meth)acrylic acid alkyl ester (a2-1) of which the homopolymer has a glass transition temperature Tg in the range of -40°C to -10°C (preferably, -35°C to -15°C, and more preferably, -30°C to -20°C), (meth)acrylic acid alkyl ester (a2-2) of which the homopolymer has a glass transition temperature Tg in the range of -80°C to -60°C (preferably, -75°C to -60°C, and more preferably, -75°C to -65°C), the monomer (b2-1) having a hydroxyl group, and the monomer (b2-2) having a polar group other than a hydroxyl group.

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

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

[0212] The monomer component (M2) can contain other monomer (c2) that does not correspond to any of the alkyl (meth) acrylate (a2) and the monomer containing a polar group (b2). The other monomer (c2) can be used for the purpose of adjusting the glass transition temperature (Tg) of the acrylic polymer (P2), adjusting the adhesion properties, and the like, for example. The other monomer can be only one, or two or more.

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

[0214] As the photopolymerization initiator, any appropriate photopolymerization initiator can be appropriately selected depending on the type of the polymerization method. The photopolymerization initiator can be only one, or two or more.

[0215] As an example compound of the photopolymerization initiator, the example compounds of the photopolymerization initiator of the item of [A-2-2-2. Acrylic oligomer] can be cited.

[0216] The amount of use of the photopolymerization initiator can be set to any appropriate amount of use within a range not impairing the effects of the present application. The amount of use of the photopolymerization initiator 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, with respect to 100 parts by weight of the monomer component (M2).

[0217] <A-2-4. Photocuring acrylic adhesive composition and photocuring acrylic adhesive>

[0218] Another embodiment of the acrylic adhesive is a photocuring acrylic adhesive, which is formed by a photocuring reaction of a photocuring acrylic adhesive composition containing the acrylic polymer (P2), for example.

[0219] The photocurable acrylic adhesive is formed from the photocurable acrylic adhesive composition by any appropriate method. As such a forming method, representative examples include a method in which the photocurable acrylic adhesive composition is applied to any appropriate substrate, and then another any appropriate substrate is placed on the surface of the adhesive layer formed by the application, and cured by ultraviolet irradiation to form. As the substrate, for example, the aforementioned release liner can be cited. As the method of application of the photocurable acrylic adhesive composition, any appropriate method of application can be cited within a range not impairing the effects of the present application. As such a method of application, for example, roll coating, gravure roll coating, reverse roll coating, roll kiss coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, and die coating can be cited.

[0220] In the formation of the photocurable acrylic adhesive, heating can be performed as needed. Furthermore, aging can be performed for the purpose of adjustment of the transfer of the components within the formed photocurable acrylic adhesive, progress of the crosslinking reaction, relaxation of the strain possibly present within the photocurable acrylic adhesive, and the like.

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

[0222] The photocurable acrylic adhesive composition preferably contains the crosslinking agent (L2). The crosslinking agent (L2) can be only one or two or more.

[0223] The content of the crosslinking agent (L2) in the photocurable acrylic adhesive composition can be set to any appropriate content within a range not impairing the effects of the present application. The content of the crosslinking agent (L2) in the photocurable acrylic adhesive composition is preferably 0.001 parts by weight to 0.5 parts by weight, more preferably 0.005 parts by weight to 0.3 parts by weight, further preferably 0.01 parts by weight to 0.2 parts by weight, and particularly preferably 0.05 parts by weight to 0.1 parts by weight, relative to 100 parts by weight of the acrylic polymer (P2).

[0224] As the crosslinking agent (L2), any appropriate crosslinking agent can be used within a range not impairing the effects of the present application. As such a crosslinking agent (L2), a polyfunctional (meth)acrylate is preferably cited.

[0225] As the multifunctional (meth)acrylate, any appropriate multifunctional (meth)acrylate can be used within a range not impairing the effects of the present application. The multifunctional (meth)acrylate can be only one or two or more. As such multifunctional (meth)acrylates, specifically, for example, the following can be listed: ester compounds of (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, and the like of polyhydric alcohols and (meth)acrylic acid; allyl (meth)acrylate; vinyl (meth)acrylate; divinylbenzene; epoxy acrylate; polyester acrylate; urethane acrylate; butyl di(meth)acrylate; hexyl di(meth)acrylate.

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

[0227] The photocuring-type acrylic adhesive composition can contain an acrylic oligomer. The acrylic oligomer can be only one or two or more.

[0228] The content of the acrylic oligomer in the photocuring-type acrylic adhesive composition can be set to any appropriate content within a range not impairing the effects of the present application. The content of the acrylic oligomer in the photocuring-type acrylic adhesive composition is preferably 0.1 parts by weight to 20 parts by weight, more preferably 1 part by weight to 15 parts by weight, further preferably 2 parts by weight to 10 parts by weight, and particularly preferably 3 parts by weight to 8 parts by weight, relative to 100 parts by weight of the acrylic polymer (P2).

[0229] Details of the acrylic oligomer can be explained by referring to the description of the item of [A-2-2-2. Acrylic Oligomer].

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

[0231] The photocurable acrylic adhesive composition can contain any other appropriate component within a range not impairing the effects of the present application. As such other components, for example, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, foils, softening agents, anti-aging agents, electrically conductive agents, ultraviolet absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, anticorrosive agents, heat-resistant stabilizers, polymerization inhibitors, lubricants, other crosslinking agents, solvents, catalysts, crosslinking catalysts, retardation crosslinking agents, and the like can be exemplified.

[0232] A-3. Antistatic Layer

[0233] As the thickness of the antistatic layer, any appropriate thickness can be employed within a range not impairing the effects of the present application. In terms of further embodying the effects of the present application, the thickness of the antistatic layer is preferably from 3 nm to 500 nm, more preferably from 3 nm to 100 nm, further preferably from 3 nm to 60 nm, and particularly preferably from 8 nm to 55 nm.

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

[0235] As the method of forming the antistatic layer, any appropriate method can be employed within a range not impairing the effects of the present application. As such a method, for example, a method of applying an antistatic treatment liquid to a substrate (substrate layer) and drying or curing the same can be exemplified.

[0236] Representatively, the antistatic treatment liquid contains an electrically conductive polymer. The electrically conductive polymer can be only one or two or more.

[0237] As the electrically conductive polymer, any appropriate antistatic layer can be employed within a range not impairing the effects of the present application. As such an electrically conductive polymer, for example, water-soluble electrically conductive polymers, water-dispersible electrically conductive polymers can be exemplified.

[0238] As the water-soluble electrically conductive polymer, for example, polyaniline sulfonic acid, poly(isothiophenediyl-sulfonate) compounds, (meth)acrylate-based polymers containing quaternary ammonium salts can be exemplified, and polyaniline sulfonic acid is preferred.

[0239] As the water-dispersible electrically conductive polymer, for example, polyanion-doped polythiophenes, polyaniline can be exemplified, and polyanion-doped polythiophenes are preferred.

[0240] As the polythiophenes which can be used as the water-dispersible conductive polymer, for example, 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), poly(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-heptyloxythiophene), poly(3-octyloxythiophene), poly(3-decyloxythiophene), 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-didodecyloxythiophene), poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), poly(3,4-butylenedioxythiophene), 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) can be listed. The polymerization degree of the polythiophenes is preferably 2 to 1000, more preferably 5 to 100, in view of the aspect in which the effect of the present application can be further exhibited.

[0241] As the water-dispersible conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) is preferred in view of the aspect in which the effect of the present application can be further exhibited.

[0242] The polyanion is a polymer having a structural unit of an anionic group, and functions as a dopant for the polythiophene. As the polyanion, for example, polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polyacrylic acid sulfonic acid, polymethacrylic acid sulfonic acid, poly(2-acrylamido-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, poly(methacrylate sulfide ethyl), poly(4-sulfobutyl methacrylate), polymethallyloxybenzenesulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacrylic acid carboxylic acid, polymethacrylic acid carboxylic acid, poly(2-acrylamido-2-methylpropane carboxylic acid), polyisoprene carboxylic acid, polyacrylic acid, and polysulfonated phenylacetylene can be listed. The polyanion can be a homopolymer of these, or a copolymer of two or more. In terms of excellent doping and dispersibility to the polythiophene, the weight average molecular weight (Mw) of the polyanion is preferably 1,000 to 10 million, more preferably 2,000 to 5 million.

[0243] As the polyanion, in terms of further exhibiting the effects of the present application, polystyrene sulfonic acid (PSS) is preferred.

[0244] As the antistatic layer, for example, in the case where poly(3,4-ethylenedioxythiophene) (PEDOT) is used as the polythiophene, and polystyrene sulfonic acid (PSS) is used as the polyanion capable of doping the polythiophene, PEDOT and PSS interact, and exist in close proximity, whereby the electrons of PEDOT are taken away by PSS, and the antistatic layer can exhibit excellent conductivity.

[0245] As a commercially available product of the polythiophene doped with the polyanion, for example, "Bytron P" manufactured by H. C. Stark Co., "SEPLEGYDA" manufactured by Shin Etsu Polymer Co., "VERAZOL" manufactured by Sanko Chemical Co., and the like can be listed.

[0246] In terms of further exhibiting the effects of the present application, the weight average molecular weight (Mw) of polystyrene of polyaniline sulfonic acid, which can be used as the water-soluble conductive polymer component, is preferably 1 x 10 3 ~ 5 x 10 5 , more preferably 5 x 10 3 ~ 3 x 10 5 .

[0247] As a commercially available product of polyaniline sulfonic acid, for example, "aqua PASS" manufactured by MITSUBISHI RAYON Co., and the like can be listed.

[0248] The antistatic treatment liquid preferably contains a binder. The binder can be only one or two or more. The content ratio of the binder in the antistatic layer as a whole is preferably 50 to 95% by weight, more preferably 60 to 90% by weight, in view of further embodying the effects of the present application.

[0249] As the binder, any appropriate resin can be used without impairing the effects of the present application. As such a binder, for example, polyester-based resins, acrylic-based resins, polyvinyl-based resins, urethane-based resins, melamine-based resins, and epoxy-based resins can be listed.

[0250] The binder preferably contains a polyester-based resin in view of further embodying the effects of the present application. The polyester-based resin contains polyester as a main component, and the content ratio thereof is preferably 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 that no component intended to be added is contained, and means that incidental mixing, impurities produced as by-products, and the like are excluded.

[0251] If a polyester-based resin is used as the binder, the surface free energy of the polyester-based resin is small, and therefore, even if no additive such as a lubricant is incorporated, the occurrence of edge crimping and the like can be suppressed when the antistatic agent composition is applied to a substrate to form a film.

[0252] The polyester preferably has a structure in which at least one compound (polybasic acid component) selected from among polybasic acids (typically, dicarboxylic acids) having two or more carboxyl groups in one molecule and derivatives thereof (anhydrides, esters, halides, and the like of polybasic acids) and at least one compound (polyhydric alcohol component) selected from among polyhydric alcohols (typically, diols) having two or more hydroxyl groups in one molecule are condensed.

[0253] As the compound which can be used as the polycarboxylic acid component, for example, the following can be listed: oxalic acid, malonic acid, difluoromalic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±) -malic acid, mesotartaric acid, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, dithioadipic acid, methyladipic acid, dimethyladipic acid, tetramethyladipic acid, methyleneadipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3, 3, 6, 6-tetramethyloctanedioic acid, azelaic acid, sebacic acid, perfluorosebacic acid, tridecanedioic acid, dodecanedioic acid, tridecyl dicarboxylic acid, tetradecyl dicarboxylic acid and the like aliphatic dicarboxylic acids; cycloalkyl dicarboxylic acids (for example, 1, 4-cyclohexanedicarboxylic acid, 1, 2-cyclohexanedicarboxylic acid), 1, 4- (2-norbornene) dicarboxylic acid, 5-norbornene-2, 3-dicarboxylic acid (nadic acid), adamantanedioic acid, spiroheptanedicarboxylic acid and the like alicyclic dicarboxylic acids; phthalic acid, isophthalic acid, dithioisophthalic acid, methylisophthalic acid, dimethylisophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalene dicarboxylic acid, fluorenone dicarboxylic acid, anthracene dicarboxylic acid, biphenyl dicarboxylic acid, biphenylene dicarboxylic acid, dimethylbiphenylene dicarboxylic acid, 4, 4" -p- biphenylylene dicarboxylic acid, 4, 4" -p-quaterphenyl dicarboxylic acid, bibenzyl dicarboxylic acid, azobenzene dicarboxylic acid, homophthalic acid, benzene diacetic acid, benzene dipropionic acid, naphthalene dicarboxylic acid, naphthalene dipropionic acid, biphenyl diacetic acid, biphenyl dipropionic acid, 3, 3' -[4, 4' - (methylenebis-p- biphenylylene) ] dipropionic acid, 4, 4' -bibenzyl diacetic acid, 3, 3' (4, 4' -bibenzyl) dipropionic acid, oxodiphenylacetic acid and the like aromatic dicarboxylic acids; anhydrides of any of the above polycarboxylic acids; esters of any of the above polycarboxylic acids (for example, alkyl esters. These can be monoesters, diesters and the like); acid halides (for example, dicarboxylic acid chlorides) corresponding to any of the above polycarboxylic acids.

[0254] As the compound which can be used as the polycarboxylic acid component, in terms of further embodying the effects of the present application, the following are preferably listed: terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid and the like aromatic dicarboxylic acids and anhydrides thereof; adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, nadic acid, 1, 4-cyclohexanedicarboxylic acid and the like aliphatic dicarboxylic acids and anhydrides thereof; and lower alkyl esters of the above dicarboxylic acids (for example, esters with monohydric alcohols having 1 to 3 carbon atoms).

[0255] As the compounds which can be used as the polyol component, for example, glycols such as 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-cyclohexanedimethanol, 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 the like. As other examples, alkylene oxide adducts (e.g., an ethylene oxide adduct, a propylene oxide adduct, and the like) of these compounds can be mentioned.

[0256] In aspects in which the effects of the present application can be further exhibited, the weight average molecular weight (Mw) of the polyester-based resin, as measured by gel permeation chromatography (GPC) in terms of a standard polystyrene, is preferably 5 x 10 3 ~ 1.5 x 10 5 , more preferably 1 x 10 4 ~ 6 x 10 4 .

[0257] In aspects in which the effects of the present application can be further exhibited, the glass transition temperature (Tg) of the polyester-based resin is preferably 0°C to 120°C, more preferably 10°C to 80°C.

[0258] As the polyester-based resin, commercially available products such as "VYLONAL" manufactured by Toyobo Co., Ltd. and the like can be used.

[0259] As the binder, a resin other than the polyester-based resin (e.g., an acrylic resin, an acryl urethane resin, an acryl styrene resin, an acryl silicone resin, a silicone resin, a polysilazane resin, a polyurethane resin, a fluorine resin, a polyvinyl alcohol resin, a polyolefin resin, and the like) can be further contained.

[0260] In the case where the antistatic treatment liquid contains the binder, the content ratio of the conductive polymer with respect to 100 parts by weight of the binder is preferably 10 parts by weight to 200 parts by weight, more preferably 25 parts by weight to 150 parts by weight, and further preferably 40 parts by weight to 120 parts by weight. If the content ratio of the conductive polymer with respect to 100 parts by weight of the binder is too small outside the above range, the antistatic property can be reduced. If the content ratio of the conductive polymer with respect to 100 parts by weight of the binder is too large outside the above range, the adhesion of the antistatic layer to an adjacent layer can be reduced, and the transparency can be reduced.

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

[0262] As the crosslinking agent, a crosslinking agent used for crosslinking of a general resin can be used. As such a crosslinking agent, for example, a melamine-based crosslinking agent, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent can be listed. The amount of use of the crosslinking agent can be appropriately adjusted according to the purpose.

[0263] The antistatic treatment liquid can contain any other appropriate component within a range not impairing the effects of the present application. As such other components, for example, solvents, other antistatic components (organic conductive substances other than conductive polymers, inorganic conductive substances, other antistatic agents, etc.), surfactants, leveling agents, lubricants, antioxidants, colorants (pigments, dyes, etc.), flowability adjusting agents (thixotropic agents, tackifiers, etc.), film-forming aids, defoaming agents, preservatives, PET oligomer sealants can be listed.

[0264] As the solvent, an organic solvent, water, or a mixed solvent thereof can be listed. The solvent can be only one kind, or two or more kinds. As the organic solvent, for example, 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; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and dialkylene glycol monoalkyl ethers can be listed.

[0265] In terms of further embodying the effects of the present application, as the solvent, a mixed solvent of an organic solvent and water is preferred, a mixed solvent of an aliphatic or alicyclic alcohol and water is more preferred, and a mixed solvent of an aliphatic alcohol and water is further preferred.

[0266] In the case where the solvent is a mixed solvent of an organic solvent and water, as one of the technical solutions capable of further embodying the effects of the present application, adjustment of the mixing ratio of the organic solvent and water can be listed. By such adjustment of the mixing ratio of the organic solvent and water, the Marangoni number of the antistatic treatment liquid can be adjusted. For example, in the case where the organic solvent is ethanol, the concentration of ethanol in the mixed solvent of the organic solvent and water is preferably 30% by weight to 70% by weight, and more preferably 40% by weight to 60% by weight.

[0267] B. Flexible devices

[0268] The adhesive film of the embodiment of the present application can be applied to various devices. Representatively, it can be applied to flexible devices such as bendable devices (devices capable of being bent), foldable devices (devices capable of being folded), and rollable devices (devices capable of being rolled) having movable bending portions.

[0269] That is, the flexible device of the embodiment of the present application has the adhesive film of the embodiment of the present application. The flexible device of the embodiment of the present application can include any other appropriate members as long as it has the adhesive film of the present application.

[0270] Example

[0271] Hereinafter, the present application will be described more specifically by citing examples and comparative examples. However, the present application is not limited to any of them. Note that in the following description, "parts" and "%" are based on weight unless otherwise specified.

[0272] Measurement of haze of adhesive film

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

[0274] The haze was calculated using the following formula.

[0275] Haze (%) = (Td / Tt) x 100

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

[0277] Observation of particles or agglomerates of particles in adhesive film

[0278] The adhesive film was observed using a digital microscope (OLYMPUS, BX51, objective lens: UMPlanFI 50x / 0.75BD P) to measure the Feret diameter of the particles or agglomerates of particles in the adhesive film. Then, the number of particles or agglomerates of particles having a Feret diameter of 0.5 μm or more observed per unit area (0.01 mm 2 ) was counted.

[0279] Calculation of Marangoni number

[0280] The viscosity η of the antistatic treatment liquid at 20°C, the surface tension σ at 20°C and 40°C were measured, and the Marangoni number Mg was calculated according to (Formula 1). The viscosity η was measured using a viscometer (manufactured by Tokimec, Inc., RE-85U) using a cone rotor (1° 34' x R24) at a rotation speed of 100 rpm. The surface tension σ was measured using a static surface tension meter (manufactured by Kyowa Interface Science Co., Ltd., DY-500). Note that the thermal diffusivity a was calculated to be 9.52 x 10 －8 m / s using (Formula 2) from the density p, specific heat Cp, thermal conductivity k of 50% ethanol aqueous solution at 20°C. 2 The film thickness L was set to 3.0 x 10 －8 m.

[0281] [Formula 1]

[0282]

[0283] <Calculation of Capillary Number>

[0284] The viscosity at 20°C, the surface tension σ at 20°C of the antistatic treatment liquid were measured, and the capillary number Ca was calculated from (Formula 3). The viscosity μ was measured using a viscometer (manufactured by Tokimec, Inc., RE-85U) using a conical rotor (1° 34' x R24) at a rotation speed of 100 rpm. The surface tension σ was measured using a static surface tension meter (manufactured by Kyowa Interface Science Co., Ltd., DY-500). Note that the speed U was set to 20 m / min.

[0285] [Formula 2]

[0286] (Formula 3)

[0287]

[0288] <Counting of Number of Treatment Unevennesses>

[0289] The adhesive film was cut to a width of 60 mm x length of 120 mm, and the adhesive film was set on a black plate with the antistatic treatment layer facing upward. A three-wavelength lamp (manufactured by Yamada Light Co., Ltd., Z-208) was made to irradiate the set adhesive film, and the number of treatment unevennesses visually recognized when visually observing from the upper portion of the adhesive film was counted. Note that the treatment unevennesses were unevennesses such as streaks, circles, ellipses, and waves.

[0290] <Counting of Number of Streaks>

[0291] The adhesive film was cut to a width of 60 mm x length of 120 mm, and the adhesive film was set on a black plate with the antistatic treatment layer facing upward. A three-wavelength lamp (manufactured by Yamada Light Co., Ltd., Z-208) was made to irradiate the set adhesive film, and the number of streak-like appearance defects of 30 mm or more in length visually recognized when visually observing from the upper portion of the adhesive film was counted.

[0292] <Method for Confirming Visual Recognition>

[0293] The adhesive film was cut to a width of 50 mm and a length of 50 mm, and the release liner was peeled off and attached to the antistatic treatment layer surface of another adhesive film, thereby obtaining a laminate of two adhesive films. The obtained laminated adhesive film was stacked in such a manner that the adhesive film became 50 sheets, and the release liner was peeled off, thereby producing a test sample. A paper on which the brand mark of Denki Kagaku Kogyo Kabushiki Kaisha was printed in a length of 30 mm and a width of 90 mm was prepared, and the test sample was set at a height of 30 cm from the paper, and the brand mark of Denki Kagaku Kogyo Kabushiki Kaisha was visually observed through the test sample from a position at a height of 30 cm from the test sample. The cases were classified into three stages: a case in which the brand mark could be clearly read was x, a case in which the brand mark could be read but was difficult to read was Δ, and a case in which the brand mark could not be read was o. Note that the brand mark of Denki Kagaku Kogyo Kabushiki Kaisha was obtained from the home page of Denki Kagaku Kogyo Kabushiki Kaisha.

[0294] [Production Example 1] Production of Antistatic Treatment Liquid

[0295] An aqueous solution (H. C. Stark Co., product name "Baytron P") containing 0.5% by weight of poly(3,4-dioxythiophene) (PEDOT) and 0.8% by weight of polystyrene sulfonate (number average molecular weight 150,000) (PSS) (hereinafter also referred to as "conductive polymer aqueous solution") was prepared as a conductive polymer.

[0296] A dispersion liquid containing 25% by weight of polyester resin as an adhesive (Toyo Spinning Co., product name "VYLONAL MD-1480" (aqueous dispersion of saturated copolymer polyester resin)) (hereinafter also referred to as "adhesive dispersion liquid") was prepared.

[0297] An aqueous dispersion of camauba wax (Nippon Wax Co., product name "Refined Camauba Wax No. 2 Powder") (hereinafter also referred to as "lubricant dispersion liquid") was prepared as a lubricant.

[0298] The above-mentioned conductive polymer aqueous solution (50 parts by weight in terms of solid content), the above-mentioned adhesive dispersion liquid (100 parts by weight in terms of solid content), and the above-mentioned lubricant dispersion liquid (30 parts by weight in terms of solid content) were mixed, and a conductive material aqueous solution was produced. To 100 parts by weight of the produced conductive material aqueous solution, 20 parts by weight of a melamine-based crosslinking agent was added, and the concentration of the solid content was diluted with a 1:1 mixture of water and EKINEN F-6 (manufactured by Japan Alcohol Trading Co.) so that the concentration became a predetermined concentration. As the predetermined concentration, concentrations of 0.4% by weight, 0.6% by weight, 1.0% by weight, and 1.5% by weight were used.

[0299] [Production Example 2] Production of Acrylic Polymer

[0300] To a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introducing tube, a cooler, 2EHA (2-ethylhexyl acrylate): 70.3 parts by weight, LA (lauryl acrylate): 8.0 parts by weight, BA (n-butyl acrylate): 20.1 parts by weight, 4HBA (4-hydroxybutyl acrylate): 1.0 part by weight, NVP (N-vinyl-2-pyrrolidone): 0.6 part by weight, AIBN (2,2'-azobisisobutyronitrile) as a polymerization initiator: 0.1 part by weight were charged in such a manner that the concentration of the total of them became 47% by weight, and ethyl acetate was charged. Nitrogen was replaced in the system while slowly stirring for 1 hour, and a polymerization reaction was carried out at a liquid temperature of about 56°C for 6 hours. After the reaction was completed, ethyl acetate was added, and the concentration of the polymer was adjusted to 24% by weight, whereby an acrylic polymer solution was obtained.

[0301] [Production Example 3] Production of Acrylic Oligomer

[0302] DCPMA (dicyclopentyl methacrylate) as a monomer component: 60 parts by weight and MMA (methyl methacrylate): 40 parts by weight, α-thioglycerol as a chain transfer agent: 3.5 parts by weight, and toluene as a polymerization solvent: 100 parts by weight were mixed, and stirred at 70°C for 1 hour under a nitrogen atmosphere. Next, AIBN as a thermal polymerization initiator: 0.2 parts by weight was charged, and after the reaction was carried out at 70°C for 2 hours, the temperature was raised to 80°C, and the reaction was carried out for 2 hours, whereby an acrylic oligomer was obtained. The weight average molecular weight Mw of the acrylic oligomer was 5100, and the glass transition temperature (Tg) was 130°C.

[0303] [Production Example 4] Production of Coating Solution of Acrylic Adhesive Composition

[0304] The acrylic polymer obtained in Production Example 2: 100 parts by weight, NYPER BMT-40SV (manufactured by NOF Corporation) as a crosslinking agent: 0.28 parts by weight, the acrylic oligomer obtained in Production Example 3: 3 parts by weight, and IRGANOX 1010 (manufactured by BASF) as an antioxidant: 0.3 parts by weight were mixed, and sufficiently stirred, and diluted with ethyl acetate in such a manner that the total solid content became 17% by weight, whereby a coating solution of an acrylic adhesive composition was obtained.

[0305] [Example 1]

[0306] The antistatic treatment solution obtained in Production Example 1 having a concentration of 1.0% was applied to the surface of a PET substrate (Lumirror S10#50, manufactured by Toray Corporation) opposite to the easily-adhering treated surface using a Meyer bar, and dried at 130°C for 1 minute to remove the solvent, thereby forming an antistatic layer (thickness: 0.03 μm), and a PET film with an antistatic layer was produced.

[0307] The coating solution of the acrylic adhesive composition obtained in Production Example 4 was applied to the easily-adhering treated surface of the PET film with an antistatic layer obtained above so as to have a dry thickness of 13 μm, and dried at a drying temperature of 155°C for 2 minutes. Subsequently, a release sheet (product name: MRQ50T100J, manufactured by Mitsubishi Chemical Corporation) formed of a polyester resin having a thickness of 50 μm and having a silicone-treated surface was attached to the surface of the adhesive layer obtained above so as to contact the silicone-treated surface, and an adhesive film (1) was obtained.

[0308] The results are shown in Table 1.

[0309] [Example 2]

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

[0311] The results are shown in Table 1.

[0312] [Example 3]

[0313] The same procedure as in Example 1 was carried out, except that the antistatic treatment solution obtained in Production Example 1 having a concentration of 0.6% was used as the antistatic treatment solution, and an adhesive film (3) was obtained.

[0314] The results are shown in Table 1.

[0315] [Example 4]

[0316] The same procedure as in Example 2 was carried out, except that the antistatic treatment solution obtained in Production Example 1 having a concentration of 0.6% was used as the antistatic treatment solution, and an adhesive film (4) was obtained.

[0317] The results are shown in Table 1.

[0318] [Comparative Example 1]

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

[0320] The results are shown in Table 1.

[0321] [Comparative Example 2]

[0322] Using the antistatic treatment liquid obtained in Production Example 1 having a concentration of 0.4% as the antistatic treatment liquid, other than this, the same as in Example 1 was performed, and an adhesive film (C2) was obtained.

[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, other than this, the same as in Comparative Example 2 was performed, and an adhesive film (C3) was obtained.

[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, other than this, the same as in Comparative Example 2 was performed, and an adhesive film (C4) was obtained.

[0329] The results are shown in Table 1.

[0330] [Comparative Example 5]

[0331] Using the antistatic treatment liquid obtained in Production Example 1 having a concentration of 1.5% as the antistatic treatment liquid, other than this, the same as in Example 1 was performed, and an adhesive film (C5) was obtained.

[0332] The results are shown in Table 1.

[0333] [Table 1]

[0334]

[0335] Industrial Applicability

[0336] The adhesive film of the present application can be applied to various devices. Representatively, it can be applied to flexible devices such as bendable devices (devices that can be bent), foldable devices (devices that can be folded), rollable devices (devices that can be rolled), and the like, having movable bending portions.

Claims

1. An adhesive film comprising an antistatic layer, a substrate layer and an adhesive layer in this order, 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. The capillary number of the antistatic treatment liquid is 5 or less.

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. The adhesive film according to claim 1 , wherein The Feret diameter of the particles or the aggregates of the particles in the adhesive film is 0.5 μm or more per unit area, i.e., 0.01 mm 2 The number of observed cells ranges from 10 to 110. 5 . A flexible device comprising the adhesive film according to claim 1 .

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