Adhesive film and flexible device

Abstract

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 visibility of a member such as an optical sensor from a display surface and reduction in visibility of an uneven part of the antistatic layer when disposed between an image display panel and a member such as an optical sensor disposed on the back surface of the image display panel and to provide a flexible device having such an adhesive film.SOLUTION: There is provided an adhesive film having an antistatic layer, a substrate layer and an adhesive layer in this order, wherein the antistatic layer is a coating layer formed by coating an antistatic treatment solution, the haze of the adhesive film is 3.0% to 7.5%, the Marangoni number of the antistatic treatment solution is 10 or less and the capillary number of the antistatic treatment liquid is 5 or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an adhesive film. The present invention also relates to a flexible device provided with such an adhesive film. [Background technology]

[0002] Adhesive films are sometimes attached to the surfaces of optical and electronic components such as organic EL panels, LCD panels, touch panels, etc., for the purpose of imparting rigidity and impact resistance, protecting the surface, etc. Such adhesive films usually have an adhesive layer laminated on a substrate layer.

[0003] In order to prevent the surfaces of optical or electronic devices from being scratched during processing, assembly, inspection, transportation, etc., scratching or damage to the adherend can be suppressed by attaching an adhesive film to the surface of the optical or electronic device, or the optical or electronic components that make up these devices (Patent Document 1).

[0004] In recent years, displays have become increasingly bezel-less, and a configuration has been proposed in which an optical sensor such as a fingerprint sensor is disposed in the display area of ​​the display. For example, by disposing an optical sensor on the back surface of an organic EL panel as a display element, a configuration having an optical sensor within the display area can be realized.

[0005] However, such a configuration has a problem in that, when the screen is viewed in a bright place, members such as an optical sensor disposed on the rear surface of the image display panel are visible.

[0006] One way to solve this problem is to place a high-haze adhesive film on the back of the image display panel (between the image display panel and the optical sensor), which can reduce the visibility of components such as the optical sensor from the display surface.

[0007] On the other hand, adhesive films, optical components, and electronic components have high electrical insulation properties and generate static electricity due to friction or peeling. In such cases, if a voltage is applied to liquid crystal while static electricity remains, there is a concern that the orientation of the liquid crystal molecules may be lost or the liquid crystal panel may be damaged. In addition, the presence of static electricity may attract dust or reduce workability.

[0008] In order to prevent the generation of such static electricity, it has been proposed to provide an antistatic layer on the adhesive film. For example, it has been reported that the generation of static electricity occurs when an antistatic layer is provided on the back side (the side opposite to the adhesive layer) of the base layer of the adhesive film. As such an antistatic layer, a coating layer formed by applying an antistatic treatment liquid is known (Patent Document 2).

[0009] However, as mentioned above, if a high haze adhesive film is placed on the back of the image display panel (between the image display panel and the optical sensor) in order to solve the problem of components such as the optical sensor being visible, then uneven parts of the coating layer formed by applying the antistatic treatment liquid (such as uneven processing or coating streaks) will become visible, resulting in a problem of reduced yield. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2020-41113 A [Patent Document 2] JP 2020-204010 A Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention aims to provide an adhesive film having an antistatic layer, a base layer, and an adhesive layer in this order, which, when placed between an image display panel and a member such as an optical sensor arranged on the back surface of the image display panel, can simultaneously reduce the visibility of the member such as an optical sensor from the display surface and reduce the visibility of an uneven portion of the antistatic layer. Also, the present invention aims to provide a flexible device including such an adhesive film. [Means for solving the problem]

[0012] [1] An adhesive film according to an embodiment of the present invention is an adhesive film having an antistatic layer, a base layer, and an adhesive layer in that order, the antistatic layer being a coating layer formed by applying an antistatic treatment liquid, the haze of the adhesive film being 3.0% to 7.5%, the Marangoni number of the antistatic treatment liquid being 10 or less, and the capillary number of the antistatic treatment liquid being 5 or less. [2] In the pressure-sensitive adhesive film described in [1] above, the antistatic treatment liquid may contain a conductive polymer. [3] In the pressure-sensitive adhesive film according to the above [1] or [2], the pressure-sensitive adhesive layer may be made of an acrylic pressure-sensitive adhesive. [4] A flexible device according to an embodiment of the present invention includes the adhesive film described in any one of [1] to [3] above. Effect of the Invention

[0013] According to the present invention, it is possible to provide an adhesive film having an antistatic layer, a base layer, and an adhesive layer in this order, which, when placed between an image display panel and a member such as an optical sensor placed on the back surface of the image display panel, can simultaneously reduce the visibility of the member such as an optical sensor from the display surface and reduce the visibility of the non-uniform portion of the antistatic layer. Also, it is possible to provide a flexible device including such an adhesive film. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view showing one embodiment of the pressure-sensitive adhesive film of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <<A. Adhesive film>> The pressure-sensitive adhesive film according to the embodiment of the present invention has an antistatic layer, a base layer, and a pressure-sensitive adhesive layer in this order. The pressure-sensitive adhesive film of the present invention may have any appropriate other layer as long as the effect of the present invention is not impaired, as long as the pressure-sensitive adhesive film has an antistatic layer, a base layer, and a pressure-sensitive adhesive layer in this order.

[0016] The substrate layer may be one layer or two or more layers.

[0017] The pressure-sensitive adhesive layer may be one layer, or two or more layers.

[0018] The antistatic layer may be a single layer or may be two or more layers.

[0019] 1 is a schematic cross-sectional view showing one embodiment of the pressure-sensitive adhesive film of the present invention. In FIG. 1, the pressure-sensitive adhesive film 100 of the present invention has an antistatic layer 30, a base layer 10, and a pressure-sensitive adhesive layer 20.

[0020] The pressure-sensitive adhesive film according to the embodiment of the present invention may be provided with any appropriate release liner on the surface of the pressure-sensitive adhesive layer opposite the base layer for protection until use, etc.

[0021] Examples of the release liner include a release liner in which the surface of a substrate (liner substrate) such as paper or plastic film is silicone-treated, a release liner in which the surface of a substrate (liner substrate) such as paper or plastic film is laminated with a polyolefin resin, etc. Examples of the plastic film as the liner substrate include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, etc.

[0022] The thickness of the release liner is preferably from 1 μm to 500 μm, more preferably from 3 μm to 450 μm, still more preferably from 5 μm to 400 μm, and particularly preferably from 10 μm to 300 μm.

[0023] The pressure-sensitive adhesive film according to the embodiment of the present invention has a total thickness excluding the release liner of preferably 1 μm to 500 μm, more preferably 5 μm to 200 μm, even more preferably 10 μm to 150 μm, and particularly preferably 20 μm to 100 μm. When the total thickness excluding the release liner of the pressure-sensitive adhesive film according to the embodiment of the present invention is within the above range, the effects of the present invention can be more effectively exhibited.

[0024] In the pressure-sensitive adhesive film according to the embodiment of the present invention, the antistatic layer is a coating layer formed by applying an antistatic treatment liquid. The antistatic layer will be described later.

[0025] The adhesive film according to the embodiment of the present invention has a haze of 3.0% to 7.5%, a Marangoni number of the antistatic treatment liquid of 10 or less, and a capillary number of the antistatic treatment liquid of 5 or less. The adhesive film according to the embodiment of the present invention can exhibit the effects of the present invention by having (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 each fall within the above-mentioned specific ranges. Typically, when the adhesive film according to the embodiment of the present invention is disposed between an image display panel and a member such as an optical sensor disposed on the back of the image display panel, it can simultaneously reduce the visibility of the member such as the optical sensor from the display surface and reduce the visibility of the non-uniform part of the antistatic layer. If at least one of (1) the haze of the adhesive film, (2) the Marangoni number of the antistatic treatment liquid, and (3) the capillary number of the antistatic treatment liquid falls outside the above-mentioned specific ranges, the effects of the present invention may not be exhibited.

[0026] The adhesive film according to the embodiment of the present invention has a haze of 3.0% to 7.5%, preferably 3.5% to 7.5%, more preferably 4.0% to 7.5%, and even more preferably 4.5% to 7.5%, as described above. If the haze of the adhesive film is too small outside the above range, when the adhesive film is placed between an image display panel and a member such as an optical sensor placed on the back of the image display panel, the member such as an optical sensor may be visible from the display surface. If the haze of the adhesive film is too large outside the above range, non-uniform parts of the antistatic layer (such as uneven processing or coating streaks) may be visible, and the yield may decrease.

[0027] In the pressure-sensitive adhesive film according to the embodiment of the present invention, the Marangoni number of the antistatic treatment liquid is 10 or less, preferably 8 or less, more preferably 7 or less, and particularly preferably 6 or less, as described above. If the Marangoni number of the antistatic treatment liquid is too large outside the above range, there is a risk that uneven treatment may easily occur in the antistatic layer. In reality, the lower limit of the Marangoni number of the antistatic treatment liquid is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 1.0 or more. A method for calculating the Marangoni number of the antistatic treatment liquid will be described later.

[0028] In the pressure-sensitive adhesive film according to the embodiment of the present invention, the capillary number of the antistatic treatment liquid is 5 or less as described above. If the capillary number of the antistatic treatment liquid is too large outside the above range, coating streaks may easily occur in the antistatic layer. In reality, the lower limit of the capillary number of the antistatic treatment liquid is preferably 0 or more. A method for calculating the capillary number of the antistatic treatment liquid will be described later.

[0029] The base layer of the pressure-sensitive adhesive film according to the embodiment of the present invention may contain particles (filler) to prevent blocking, etc. In order to further exert the effects of the present invention, the pressure-sensitive adhesive film according to the embodiment of the present invention may further include particles or particle aggregates having a Feret diameter of 0.5 μm or more per unit area (0.01 mm 2 The number of particles observed per 100 particles is preferably 10 to 110 particles, more preferably 20 to 100 particles, even more preferably 30 to 90 particles, and particularly preferably 40 to 80 particles. If the number is too small outside the above range, for example, when the device is disposed between an image display panel and a member such as an optical sensor disposed on the rear surface of the image display panel, the member such as an optical sensor may be easily visible from the display surface. If the number is too large outside the above range, particles or particle aggregates may be easily recognized as foreign matter in foreign matter inspection, which may reduce productivity.

[0030] The Feret diameter is an index of the size of the target particle or particle aggregate, and is also called the unidirectional diameter. The Feret diameter is the distance between parallel lines that sandwich the projected image of the particle in a fixed direction, and refers to the length of the longest point in the linear distance. The Feret diameter can be observed and measured using a digital microscope, etc. The shape of the particle or particle aggregate can be a wide variety of shapes, such as spherical, spheroidal, acicular, various geometric shapes, and various irregular shapes.

[0031] ≪A-1. Base material layer≫ As the substrate layer, a substrate formed from any suitable material may be used depending on the purpose, as long as the effect of the present invention is not impaired. Examples of such materials include resin sheets, nonwoven fabrics, paper, metal foils, woven fabrics, rubber sheets, foam sheets, and laminates thereof (particularly laminates containing resin sheets).

[0032] Examples of resins that may be used to form the resin sheet include acrylic resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyvinyl acetate, polyphenylene sulfide (PPS), fluorine-based resins, polyether ether ketone (PEEK), and cyclic olefin polymers.

[0033] Examples of nonwoven fabrics include nonwoven fabrics made of heat-resistant natural fibers such as nonwoven fabrics containing Manila hemp; and synthetic resin nonwoven fabrics such as polypropylene resin nonwoven fabrics, polyethylene resin nonwoven fabrics, and ester resin nonwoven fabrics.

[0034] The thickness of the base layer may be any appropriate thickness depending on the purpose, as long as the effect of the present invention is not impaired. Such a thickness is preferably 4 μm to 500 μm, more preferably 10 μm to 300 μm, even more preferably 20 μm to 200 μm, particularly preferably 30 μm to 150 μm, and most preferably 40 μm to 100 μm. When the thickness of the base layer is within the above range, the effect of the present invention can be more effectively exhibited.

[0035] 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.

[0036] The base layer may contain an antistatic agent. For example, a resin sheet in which an antistatic agent is kneaded can be used as the base layer containing an antistatic agent. Such a resin sheet can be formed from a base layer forming composition containing a resin and an antistatic agent.

[0037] The substrate layer may be subjected to a surface treatment, such as a corona treatment, a plasma treatment, a chromate treatment, an ozone exposure, a flame exposure, a high-voltage shock exposure, an ionizing radiation treatment, or a coating treatment with a primer.

[0038] Examples of organic coating materials include materials described in Plastic Hard Coat Materials II (CMC Publishing, (2004)). As such organic coating materials, preferably, urethane-based polymers are used, and more preferably, polyacrylic urethane, polyester urethane, or precursors thereof are used. This is because they are easy to apply to the substrate layer A1, and a wide variety of them can be selected industrially and are inexpensively available. Examples of such urethane-based polymers include polymers made of a reaction mixture of an isocyanate monomer and an alcoholic hydroxyl group-containing monomer (e.g., a hydroxyl group-containing acrylic compound or a hydroxyl group-containing ester compound). The organic coating material may contain, as an optional additive, a chain extender such as polyamine, an antiaging agent, an oxidation stabilizer, and the like.

[0039] The base layer may contain any other appropriate additives depending on the purpose, as long as the effects of the present invention are not impaired.

[0040] <A-2. Adhesive layer> The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 250 μm, more preferably 2 μm to 150 μm, even more preferably 3 μm to 100 μm, particularly preferably 5 μm to 50 μm, and most preferably 10 μm to 35 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, the effects of the present invention can be more effectively exhibited.

[0041] The adhesive layer is composed of any suitable adhesive as long as it does not impair the effects of the present invention. Examples of such adhesives include acrylic adhesives, rubber adhesives, silicone adhesives, and urethane adhesives. In terms of being able to further exert the effects of the present invention, the adhesive layer is preferably composed of an acrylic adhesive.

[0042] The acrylic adhesive is formed from an acrylic adhesive composition. In this way, the acrylic adhesive can be defined as being formed from an acrylic adhesive composition. This is because the adhesive becomes an adhesive by crosslinking reaction of the adhesive composition, typically by heating or irradiating with active energy rays, and therefore it is impossible and practical to directly identify the adhesive by its structure ("impossible / impractical circumstances"). Therefore, the adhesive is appropriately defined as a "thing" by the definition of "something formed from an adhesive composition."

[0043] The pressure-sensitive adhesive layer can be formed from an acrylic pressure-sensitive adhesive composition by any suitable method. For example, the pressure-sensitive adhesive layer can be formed by applying an acrylic pressure-sensitive adhesive composition to any suitable substrate, and optionally heating, irradiating with active energy rays (such as ultraviolet rays), drying, and optionally curing the composition to form a pressure-sensitive adhesive layer on the substrate.

[0044] As a means for applying the acrylic pressure-sensitive adhesive composition, any appropriate means may be adopted as long as the effects of the present invention are not impaired. Examples of such application means include roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, and die coating.

[0045] The acrylic pressure-sensitive adhesive composition may be heated or dried by any appropriate means as long as the effects of the present invention are not impaired. Examples of such heating and drying means include heating to 60° C. to 180° C., and aging at about room temperature.

[0046] The acrylic pressure-sensitive adhesive composition may be cured by any suitable means as long as the effects of the present invention are not impaired. Examples of such curing means include ultraviolet irradiation, laser irradiation, α-ray irradiation, β-ray irradiation, γ-ray irradiation, X-ray irradiation, and electron beam irradiation.

[0047] As typical methods for forming an acrylic pressure-sensitive adhesive from an acrylic pressure-sensitive adhesive composition, there are: (1) a method of forming a thermosetting acrylic pressure-sensitive adhesive by a crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition containing an acrylic polymer prepared by solution polymerization using a thermal polymerization initiator; and (2) a method of forming a photocurable acrylic pressure-sensitive adhesive by a photocuring reaction of a photocurable acrylic pressure-sensitive 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 pressure-sensitive adhesive, typically, (1) a thermosetting acrylic pressure-sensitive adhesive formed by a crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition containing an acrylic polymer (P1) prepared by solution polymerization using a thermal polymerization initiator; and (2) a photocurable acrylic pressure-sensitive adhesive formed by a photocuring reaction of a photocurable acrylic pressure-sensitive adhesive composition containing an acrylic polymer (typically, an acrylic partial polymer) (P2) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator.

[0048] <A-2-1. Acrylic polymer (P1)> 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 can be adopted within the range not impairing the effects of the present invention, such as a conventionally known method.

[0049] The acrylic polymer (P1) is obtained by polymerizing a monomer component (M1). The monomer component (M1) here does not include a crosslinking agent described later that may be contained in the acrylic pressure-sensitive adhesive composition. When obtaining the acrylic polymer (P1) by polymerization, in addition to the monomer component (M1) and the thermal polymerization initiator, any appropriate additive can be used within the range not impairing the effects of the present invention.

[0050] The acrylic polymer (P1) can be defined as something obtained by polymerizing the monomer component (M1) in this way. This is because the acrylic polymer (P1) becomes the acrylic polymer (P1) through the polymerization reaction of the monomer component (M1), and it is impossible to directly identify the acrylic polymer (P1) by its structure, and there are circumstances that make it almost impractical ("impossible / impractical circumstances"). Therefore, the acrylic polymer (P1) is appropriately defined as a "product" by the definition of "something obtained by polymerizing the monomer component (M1)."

[0051] The acrylic polymer (P1) has a Tg of preferably -85°C to -30°C, more preferably -80°C to -40°C, further preferably -75°C to -50°C, and particularly preferably -70°C to -60°C.

[0052] The Tg of the acrylic polymer (P1) refers to a value calculated from the Fox formula based on the Tg of a homopolymer of each monomer constituting the acrylic polymer (P1) and the weight fraction of the monomer (copolymerization ratio on a weight basis).

[0053] The Fox equation, as shown below, is a relational expression between the Tg of a copolymer and the glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer. 1 / Tg=Σ(Wi / Tgi)

[0054] In the above Fox formula, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction (copolymerization ratio by weight) of monomer i in the copolymer, and Tgi is the glass transition temperature (unit: K) of a homopolymer of monomer i. As the Tg of the homopolymer, a value described in a publicly known document is adopted.

[0055] As the Tg of the homopolymer, for example, the following values ​​can be specifically used: n-Butyl acrylate (BA): -55℃ Lauryl acrylate (LA): -23℃ 2-Ethylhexyl acrylate (2EHA): -70℃ 2-Hydroxyethyl acrylate (2HEA): -15℃ 4-Hydroxybutyl acrylate (2HBA): -40℃ N-vinyl-2-pyrrolidone (NVP): 80℃

[0056] For the Tg of homopolymers other than those exemplified above, the values ​​listed in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. When multiple values ​​are listed in the "Polymer Handbook," the conventional value is used. For monomers not listed in the "Polymer Handbook," the catalog value of the monomer manufacturer is used. For the Tg of homopolymers of monomers not listed in the "Polymer Handbook" and for which no catalog value is provided by the monomer manufacturer, the value obtained by the measurement method described in JP 2007-51271 A is used.

[0057] The monomer component (M1) preferably contains an alkyl (meth)acrylate (a1) and a polar group-containing monomer (b1). The alkyl (meth)acrylate (a1) may be of only one type or of two or more types. The polar group-containing monomer (b1) may be of only one type or of two or more types.

[0058] [A-2-1-1. Alkyl (meth)acrylate (a1)] The alkyl group of the ester moiety of the alkyl (meth)acrylate (a1) (hereinafter sometimes referred to as the "alkyl group of the ester moiety") does not include an alkyl group containing a hydroxyl group or an alkyl group containing a polar group other than a hydroxyl group. Therefore, the alkyl (meth)acrylate (a1) is clearly distinguished from the polar group-containing monomer (b1).

[0059] The content of the alkyl (meth)acrylate (a1) in the monomer component (M1) is preferably 70% by weight to 99.9% by weight, more preferably 80% by weight to 99.5% by weight, even more preferably 90% by weight to 99.2% by weight, still more preferably 93% by weight to 99.2% by weight, particularly preferably 95% by weight to 99% by weight, and most preferably 97% by weight to 99% by weight.

[0060] The alkyl group in 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, even more 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.

[0061] The alkyl group of the ester moiety is preferably a chain alkyl group, where chain includes both linear and branched chains.

[0062] Examples of the alkyl(meth)acrylate (a1) in which the alkyl group of the ester moiety is a chain alkyl group having 1 to 20 carbon atoms include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, isopropyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, s-butyl(meth)acrylate, pentyl(meth)acrylate, isopentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, isopropyl(meth)acrylate, butyl ... Examples of such acrylates include isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

[0063] The alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) has a glass transition temperature Tg of its homopolymer of preferably −10° C. or lower, more preferably −12° C. or lower, even more 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.

[0064] Here, as the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1), a value described in a publicly known document may be used, for example, the value described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989). When multiple values ​​are described in the "Polymer Handbook," the conventional value is used. For alkyl (meth)acrylates not described in the "Polymer Handbook," the catalog value of the monomer manufacturer is used. For the Tg of the homopolymer of alkyl (meth)acrylates not described in the "Polymer Handbook" and for which no catalog value is provided by the monomer manufacturer, the value obtained by the measurement method described in JP-A-2007-51271 is used.

[0065] The alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) preferably includes an alkyl (meth)acrylate (a1-1) having a glass transition temperature Tg of its homopolymer within the range of -40°C to -10°C (preferably -35°C to -15°C, and more preferably -30°C to -20°C).

[0066] An example of the alkyl (meth)acrylate (a1-1) is lauryl acrylate (LA) (the glass transition temperature Tg of its homopolymer is −23° C.).

[0067] The content of the alkyl (meth)acrylate (a1-1) in the total amount of alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) is preferably 1 to 30% by weight, more preferably 2 to 20% by weight, even more preferably 4 to 15% by weight, particularly preferably 5 to 12% by weight, and most preferably 6 to 10% by weight.

[0068] The content of the alkyl (meth)acrylate (a1-1) in the total amount of the monomer component (M1) is preferably 1 wt % to 30 wt %, more preferably 2 wt % to 20 wt %, even more preferably 4 wt % to 15 wt %, particularly preferably 5 wt % to 12 wt %, and most preferably 6 wt % to 10 wt %.

[0069] The alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) preferably contains an alkyl (meth)acrylate (a1-2) having a glass transition temperature Tg of its homopolymer within the range of -80°C to -60°C (preferably -75°C to -60°C, and more preferably -75°C to -65°C).

[0070] An example of the alkyl (meth)acrylate (a1-2) is 2-ethylhexyl acrylate (2EHA) (the glass transition temperature Tg of its homopolymer is −70° C.).

[0071] The content of the alkyl (meth)acrylate (a1-2) in the total amount of the alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) is preferably 40% by weight to 95% by weight, more preferably 50% by weight to 90% by weight, even more preferably 55% by weight to 85% by weight, particularly preferably 60% by weight to 80% by weight, and most preferably 65% ​​by weight to 75% by weight.

[0072] The content of the alkyl (meth)acrylate (a1-2) in the total amount of the monomer component (M1) is preferably 40% by weight to 95% by weight, more preferably 50% by weight to 90% by weight, even more preferably 55% by weight to 85% by weight, particularly preferably 60% by weight to 80% by weight, and most preferably 65% ​​by weight to 75% by weight.

[0073] The alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) preferably includes an alkyl (meth)acrylate (a1-3) whose homopolymer has a glass transition temperature Tg in the range of more than -60°C and less than -40°C.

[0074] An example of the alkyl (meth)acrylate (a1-3) is n-butyl acrylate (BA) (the glass transition temperature Tg of its homopolymer is −55° C.).

[0075] The content of the alkyl (meth)acrylate (a1-3) in the total amount of the alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) is preferably 1 to 50% by weight, more preferably 5 to 35% by weight, even more preferably 10 to 30% by weight, particularly preferably 13 to 28% by weight, and most preferably 15 to 25% by weight.

[0076] The content of the alkyl (meth)acrylate (a1-3) in the total amount of the monomer component (M1) is preferably 1 weight % to 50 weight %, more preferably 5 weight % to 35 weight %, even more preferably 10 weight % to 30 weight %, particularly preferably 13 weight % to 28 weight %, and most preferably 15 weight % to 25 weight %.

[0077] [A-2-1-2. Polar group-containing monomer (b1)] The content of the polar group-containing monomer (b1) in the monomer component (M1) is preferably 0.1 to 30% by weight, more preferably 0.5 to 20% by weight, even more preferably 0.8 to 10% by weight, still more preferably 0.8 to 7% by weight, particularly preferably 1 to 5% by weight, and most preferably 1 to 3% by weight.

[0078] The polar group-containing monomer (b1) preferably contains at least one selected from the group consisting of a hydroxyl group-containing monomer (b1-1) and a monomer (b1-2) having a polar group other than a hydroxyl group, and more preferably contains both the hydroxyl group-containing monomer (b1-1) and the monomer (b1-2) having a polar group other than a hydroxyl group.

[0079] The hydroxyl group-containing monomer (b1-1) may be of one type only, or of two or more types.

[0080] Examples of the hydroxyl group-containing monomer (b1-1) include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; polypropylene glycol mono(meth)acrylate; and N-hydroxyethyl (meth)acrylamide.

[0081] The hydroxyl-containing monomer (b1-1) has a glass transition temperature Tg of its homopolymer of preferably -60°C to -10°C, more preferably -55°C to -10°C, and further preferably -45°C to -10°C.

[0082] With regard to the glass transition temperature Tg of the homopolymer of the hydroxyl group-containing monomer (b1-1), the explanation of the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [1-2-1-1. Alkyl (meth)acrylate (a1)] may be cited.

[0083] The hydroxyl group-containing monomer (b1-1) is preferably a hydroxyalkyl(meth)acrylate, more preferably a hydroxyalkyl(meth)acrylate in which the alkyl group moiety of the hydroxyalkyl group is a linear alkyl group having 2 to 4 carbon atoms, still more preferably 2-hydroxyethyl acrylate (HEA) (glass transition temperature of its homopolymer Tg = -15°C) or 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C), particularly preferably 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C).

[0084] The content of the hydroxyl group-containing monomer (b1-1) in the polar group-containing monomer (b1) is preferably 1 wt % to 99 wt %, more preferably 20 wt % to 90 wt %, even more preferably 40 wt % to 80 wt %, particularly preferably 45 wt % to 75 wt %, and most preferably 50 wt % to 70 wt %.

[0085] The content of the hydroxyl group-containing monomer (b1-1) in the monomer component (M1) is preferably 0.001 to 10% by weight, more preferably 0.01 to 5% by weight, even more preferably 0.05 to 3% by weight, particularly preferably 0.1 to 2% by weight, and most preferably 0.5 to 1.5% by weight.

[0086] The monomer (b1-2) having a polar group other than a hydroxyl group may be of one type only, or of two or more types.

[0087] Examples of the monomer (b1-2) having a polar group other than a hydroxyl group include N-vinyl-2-pyrrolidone, nitrogen-containing monomers other than N-vinyl-2-pyrrolidone, carboxyl group-containing monomers, sulfonic acid group-containing monomers, phosphate group-containing monomers, cyano group-containing monomers, acid anhydride group-containing monomers, vinyl esters (e.g., vinyl acetate (VAc), vinyl propionate, vinyl laurate), aromatic vinyl compounds, amide group-containing monomers, epoxy group-containing monomers, (meth)acryloylmorpholine, and vinyl ethers.

[0088] Examples of carboxy group-containing monomers include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

[0089] Examples of nitrogen-containing monomers other than N-vinyl-2-pyrrolidone include nitrogen-containing vinyl monomers such as methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinylcarboxylic acid amides, and N-vinylcaprolactam; and cyano group-containing acrylic monomers such as acrylonitrile and methacrylonitrile.

[0090] In order to further exert the effects of the present invention, the monomer (b1-2) having a polar group other than a hydroxyl group has a glass transition temperature Tg of its homopolymer of preferably -30°C to 100°C, more preferably -20°C to 95°C, and even more preferably -10°C to 90°C.

[0091] The monomer (b1-2) having a polar group other than a hydroxyl group is preferably a monomer having a polar group other than a hydroxyl group, the glass transition temperature Tg of which homopolymer is 50° C. to 100° C. The glass transition temperature Tg of the homopolymer of this monomer is preferably 60° C. to 95° C., and more preferably 70° C. to 90° C.

[0092] With regard to the glass transition temperature Tg of the homopolymer of the monomer (b1-2) having a polar group other than a hydroxyl group, the explanation of the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [1-2-1-1. Alkyl (meth)acrylate (a1)] may be cited.

[0093] A preferred example of the monomer (b1-2) having a polar group other than a hydroxyl group is N-vinyl-2-pyrrolidone (the glass transition temperature Tg of its homopolymer is 80° C.).

[0094] The content of the monomer (b1-2) having a polar group other than a hydroxyl group in the polar group-containing monomer (b1) is preferably 1 wt % to 99 wt %, more preferably 10 wt % to 80 wt %, even more preferably 20 wt % to 60 wt %, particularly preferably 25 wt % to 55 wt %, and most preferably 30 wt % to 50 wt %.

[0095] The content of the monomer (b1-2) having a polar group other than a hydroxyl group in the monomer component (M1) is preferably 0.0001 to 10% by weight, more preferably 0.005 to 5% by weight, even more preferably 0.01 to 3% by weight, particularly preferably 0.05 to 2% by weight, and most preferably 0.1 to 1% by weight.

[0096] The monomer component (M1) preferably contains an alkyl(meth)acrylate (a1) and at least one selected from the group consisting of a hydroxyl-containing monomer (b1-1) and a monomer (b1-2) having a polar group other than a hydroxyl group, more preferably contains an alkyl(meth)acrylate (a1), a hydroxyl-containing monomer (b1-1), and a monomer (b1-2) having a polar group other than a hydroxyl group, and further ... the glass transition temperature Tg of the homopolymer being within a range of -80°C to -60°C (preferably -75°C to -60°C, and more preferably -75°C to -65°C); the alkyl (meth)acrylate (a1-3) the glass transition temperature Tg of the homopolymer being within a range of more than -60°C to less than -40°C; a hydroxyl group-containing monomer (b1-1); and a monomer (b1-2) having a polar group other than a hydroxyl group.

[0097] In the monomer component (M1), an alkyl (meth)acrylate (a1-1) whose 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), an alkyl (meth)acrylate (a1-2) whose 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), and a homopolymer thereof. The total content of the alkyl (meth)acrylate (a1-3), the hydroxyl group-containing monomer (b1-1), and the monomer (b1-2) having a polar group other than a hydroxyl group, each of which has a glass transition temperature Tg in the range of more than -60°C and less than -40°C, is preferably 60% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, even more preferably 80% by weight to 100% by weight, particularly preferably 90% by weight to 100% by weight, and most preferably 95% by weight to 100% by weight.

[0098] Specifically, the monomer component (M1) preferably includes lauryl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, n-butyl acrylate, and N-vinyl-2-pyrrolidone.

[0099] [A-2-1-3. Other monomers (c1)] The monomer component (M1) may contain other monomers (c1) that do not fall under either the alkyl (meth)acrylate (a1) or the polar group-containing monomer (b1). The other monomers (c1) can be used for the purpose of, for example, adjusting the glass transition temperature (Tg) of the acrylic polymer (P1) or adjusting the adhesive performance. The other monomers may be one type or two or more types.

[0100] The content of other monomers (c1) in the monomer component (M1) is preferably 20% by weight or less, more preferably 10% by weight or less, even more preferably 5% by weight or less, particularly preferably 3% by weight or less, and most preferably 1% by weight or less.

[0101] [A-2-1-4. Thermal polymerization initiator] The thermal polymerization initiator can be appropriately selected from any suitable thermal polymerization initiator depending on the type of polymerization method. The thermal polymerization initiator may be one type only, or two or more types may be used.

[0102] Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, and the like. hydrochloride, azo initiators such as 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate (VA-057, Wako Pure Chemical Industries, Ltd.); persulfates such as potassium persulfate and ammonium persulfate, di(2-ethylhexyl)peroxydicarbonate, di Examples of the initiator include peroxide initiators such as (4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoyl peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butyl hydroperoxide, and hydrogen peroxide; redox initiators that combine a peroxide and a reducing agent, such as a combination of a persulfate and sodium hydrogen sulfite, or a combination of a peroxide and sodium ascorbate; substituted ethane initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds.

[0103] The amount of the thermal polymerization initiator used may be set to any appropriate amount within the range that does not impair the effects of the present invention. The amount of the thermal polymerization initiator used is preferably 0.001 to 10 parts by weight, more preferably 0.005 to 5 parts by weight, still more preferably 0.007 to 3 parts by weight, and particularly preferably 0.01 to 1 part by weight, relative to 100 parts by weight of the monomer component (M1).

[0104] <A-2-2. Thermosetting Acrylic Pressure-Sensitive Adhesive Composition and Thermosetting Acrylic Pressure-Sensitive Adhesive> One embodiment of the acrylic pressure-sensitive adhesive is a thermosetting acrylic pressure-sensitive adhesive, which is typically formed by a crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition containing an acrylic polymer (P1).

[0105] The thermosetting acrylic pressure-sensitive adhesive is formed from the thermosetting acrylic pressure-sensitive adhesive composition by any suitable method. Such a forming method typically includes applying the thermosetting acrylic pressure-sensitive adhesive composition onto any suitable substrate, heating and drying as necessary, and curing as necessary to form the thermosetting acrylic pressure-sensitive adhesive in a sheet form on the substrate. As such a coating method, any coating method can be adopted as long as the effects of the present invention are not impaired. Examples of such coating methods include roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, and die coating.

[0106] For the heating and drying of the thermosetting acrylic pressure-sensitive adhesive composition, any suitable means can be adopted as long as the effects of the present invention are not impaired. Examples of such heating and drying means include heating to about 60°C to 180°C. For the curing of the acrylic pressure-sensitive adhesive composition, any suitable means can be adopted as long as the effects of the present invention are not impaired. Examples of such curing means include ultraviolet irradiation, laser beam irradiation, alpha-ray irradiation, beta-ray irradiation, gamma-ray irradiation, X-ray irradiation, and electron beam irradiation.

[0107] When forming the thermosetting acrylic pressure-sensitive adhesive, aging may be performed as necessary for the purpose of adjusting component migration in the formed thermosetting acrylic pressure-sensitive adhesive, promoting the crosslinking reaction, and relaxing the strain that may exist in the photocurable acrylic pressure-sensitive adhesive.

[0108] [A-2-2-1. Crosslinking agent (L1)] The thermosetting acrylic pressure-sensitive adhesive composition preferably contains a crosslinking agent (L1). The crosslinking agent (L1) may be of one type only, or of two or more types.

[0109] The use of the crosslinking agent (L1) can impart an appropriate cohesive strength to the thermosetting acrylic pressure-sensitive adhesive. The crosslinking agent (L1) can be contained in the thermosetting acrylic pressure-sensitive adhesive in a form after crosslinking reaction, a form before crosslinking reaction, a form after partial crosslinking reaction, an intermediate or composite form thereof, or the like. The crosslinking agent (L1) is typically contained in the thermosetting acrylic pressure-sensitive adhesive in a form after crosslinking reaction.

[0110] The content of the crosslinking agent (L1) in the thermosetting acrylic pressure-sensitive adhesive composition is preferably 0.005 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, even more preferably 0.01 to 3 parts by weight, still more preferably 0.01 to 1 part by weight, even more preferably 0.01 to 0.7 parts by weight, still more 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).

[0111] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a silicone-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a silane-based crosslinking agent, an alkyl etherified melamine-based crosslinking agent, a metal chelate-based crosslinking agent, a peroxide, and the like. In terms of being able to further exert the effects of the present invention, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, or a peroxide is preferable, and an isocyanate-based crosslinking agent or a peroxide is more preferable.

[0112] The isocyanate crosslinking agent may be a compound having two or more isocyanate groups (including isocyanate regenerating polar groups in which the isocyanate group is temporarily protected by a blocking agent or oligomerization) in one molecule. Examples of the isocyanate crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate.

[0113] Examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and polymethylene polyphenyl isocyanate; trimethylolpropane / tolylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate HL), and isocyanurate of hexamethylene diisocyanate (e.g., manufactured by Tosoh Corporation, isocyanate adducts such as CORONATE HX; trimethylolpropane adduct of xylylene diisocyanate (e.g., Mitsui Chemicals, Inc., trade name: TAKENATE D110N), trimethylolpropane adduct of xylylene diisocyanate (e.g., Mitsui Chemicals, Inc., trade name: TAKENATE D120N), trimethylolpropane adduct of isophorone diisocyanate (e.g., Mitsui Chemicals, Inc., trade name: TAKENATE D140N), trimethylolpropane adduct of hexamethylene diisocyanate (e.g., Mitsui Chemicals, Inc., trade name: TAKENATE D160N); polyether polyisocyanate, polyester polyisocyanate, and adducts of these with various polyols; and polyisocyanates multifunctionalized with isocyanurate bonds, biuret bonds, allophanate bonds, etc. Among these, aromatic isocyanates and alicyclic isocyanates are preferred because they can achieve a good balance between deformability and cohesive strength.

[0114] As the epoxy crosslinking agent, a multifunctional epoxy compound having two or more epoxy groups in one molecule can be used. Examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 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, and the like. Examples of epoxy crosslinking agents include glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. Examples of commercially available epoxy crosslinking agents include "Tetrad C" and "Tetrad X" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0115] Examples of peroxides include dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butyl hydroperoxide, t-butylcumyl 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-butylperoxy Neodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl 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-butylperoxy-2-ethylhexyl carbonate, t-amyl peroxyisopropyl carbonate, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-hexanoate, t-butyl peroxypivalate, and t-hexyl peroxypivalate can be mentioned. Commercially available peroxides include, for example, the trade names "Niper BMT" series and "Niper BW" series manufactured by Nippon Oil & Fats Corporation.

[0116] [A-2-2-2. Acrylic oligomer] The thermosetting acrylic pressure-sensitive adhesive composition may contain an acrylic oligomer. The acrylic oligomer may be of only one type, or of two or more types.

[0117] The content of the acrylic oligomer in the thermosetting acrylic pressure-sensitive adhesive composition can be set to any appropriate content within the range that does not impair the effects of the present invention. The content of the acrylic oligomer in the thermosetting acrylic pressure-sensitive adhesive composition is preferably 0.1 part by weight to 20 parts by weight, more preferably 1 part by weight to 15 parts by weight, still more preferably 2 parts by weight to 10 parts by weight, and particularly preferably 3 parts by weight to 8 parts by weight with respect to 100 parts by weight of the acrylic polymer (P1).

[0118] The weight average molecular weight of the acrylic oligomer is preferably 1000 to 30000, more preferably 1000 to 20000, still more preferably 1500 to 10000, and particularly preferably 2000 to 8000.

[0119] The weight average molecular weight (Mw) can be determined by conversion to polystyrene by the GPC method. For example, it can be measured under the following conditions using a high-speed GPC device "HPLC-8120GPC" manufactured by Tosoh Corporation. Column: TSKgel SuperHZM-H / HZ4000 / HZ3000 / HZ2000 Solvent: Tetrahydrofuran Flow rate: 0.6 ml / min

[0120] The glass transition temperature (Tg) of the acrylic oligomer is preferably 20°C to 300°C, more preferably 30°C to 300°C, and still more preferably 40°C to 300°C.

[0121] The Tg of the acrylic oligomer refers to a value obtained from Fox's equation based on the Tg of the homopolymer of each monomer constituting the acrylic oligomer and the weight fraction (copolymerization ratio based on weight) of the monomer. For Fox's equation and the Tg of various homopolymers, the description in the section <A-2-1. Acrylic Polymer (P1)> can be incorporated by reference.

[0122] The acrylic oligomer is preferably an acrylic oligomer obtained from a monomer composition containing, as an essential component, a (meth)acrylic acid ester having a cyclic structure in the molecule, and more preferably an acrylic oligomer obtained from a monomer composition containing, as essential components, a (meth)acrylic acid ester having a cyclic structure in the molecule and a (meth)acrylic acid alkyl ester having a linear or branched alkyl group.

[0123] The (meth)acrylic acid ester having a cyclic structure in the molecule may be of only one type, or of two or more types.

[0124] The (meth)acrylic acid alkyl ester having a linear or branched alkyl group may be of only one type, or of two or more types.

[0125] The cyclic structure in the (meth)acrylic acid ester having a cyclic structure in the molecule may be either an aromatic ring or a non-aromatic ring.

[0126] Examples of the aromatic ring include aromatic carbocycles (for example, monocyclic carbocycles such as a benzene ring, and condensed carbocycles such as a naphthalene ring), and various aromatic heterocycles.

[0127] Examples of non-aromatic rings include non-aromatic aliphatic rings (non-aromatic alicyclic rings) (e.g., cycloalkane rings such as cyclopentane ring, cyclohexane ring, cycloheptane ring, and cyclooctane ring; cycloalkene rings such as cyclohexene ring), non-aromatic bridged rings (e.g., bicyclic hydrocarbon rings such as pinane, pinene, bornane, norbornane, and norbornene; tricyclic or higher aliphatic hydrocarbon rings (bridged hydrocarbon rings) such as adamantane), and non-aromatic heterocycles (e.g., epoxy ring, oxolane ring, oxetane ring, etc.). Examples of tricyclic or higher aliphatic hydrocarbon rings (tricyclic or higher bridged hydrocarbon rings) include, for example, dicyclopentanyl group, dicyclopentenyl group, adamantyl group, tricyclopentanyl group, and tricyclopentenyl group.

[0128] Specific examples of the (meth)acrylic acid ester having a cyclic structure in the molecule include (meth)acrylic acid cycloalkyl esters such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate; (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1- Examples of (meth)acrylic acid esters include those having an aliphatic hydrocarbon ring having three or more rings, such as adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate; and (meth)acrylic acid esters having an aromatic ring, such as (meth)acrylic acid aryl esters, such as phenyl (meth)acrylate, (meth)acrylic acid aryloxyalkyl esters, such as phenoxyethyl (meth)acrylate, and (meth)acrylic acid arylalkyl esters, such as benzyl (meth)acrylate.

[0129] As the (meth)acrylic acid ester having a cyclic structure in the molecule, from the viewpoint of being able to more effectively exert the effects of the present invention, preferably, a non-aromatic ring-containing (meth)acrylic acid ester is used, more preferably, cyclohexyl acrylate (CHA), cyclohexyl methacrylate (CHMA), dicyclopentanyl acrylate (DCPA), dicyclopentanyl methacrylate (DCPMA), and even more preferably, dicyclopentanyl acrylate (DCPA) and dicyclopentanyl methacrylate (DCPMA).

[0130] The content of the (meth)acrylic acid ester having a cyclic structure in the molecule in all monomers that can be used to constitute the acrylic oligomer is preferably 10 parts by weight to 90 parts by weight, and more preferably 20 parts by weight to 80 parts by weight, relative to 100 parts by weight of all monomers, in order to further exert the effects of the present invention.

[0131] Examples of (meth)acrylic acid alkyl esters having a linear or branched alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and (meth)acrylic acid. Examples of the (meth)acrylic acid alkyl ester include isooctyl, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Among these, methyl methacrylate (MMA) is preferred in that it can further exert the effects of the present invention.

[0132] The content of the (meth)acrylic acid alkyl ester having a linear or branched alkyl group in all monomers that can be used to constitute the acrylic oligomer is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, and even more preferably 20 to 60 parts by weight, relative to 100 parts by weight of all monomers.

[0133] The total monomers (monomer composition) that can be used to form the acrylic oligomer may contain other monomers (copolymerizable monomers) that can be copolymerized with the (meth)acrylic acid esters having a cyclic structure in the molecule and the (meth)acrylic acid alkyl esters having a linear or branched alkyl group. The content of the other monomers (copolymerizable monomers) in the total monomers (monomer composition) that can be used to form the acrylic oligomer is preferably less than 50 parts by weight, more preferably 40 parts by weight or less, even more preferably 30 parts by weight or less, and particularly preferably 20 parts by weight or less, based on 100 parts by weight of the total monomers.

[0134] Examples of such other monomers (copolymerizable monomers) include alkoxyalkyl (meth)acrylates (e.g., 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, 4-ethoxybutyl (meth)acrylate, etc.), carboxyl group-containing monomers (e.g., acid anhydride group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, maleic anhydride, etc.), hydroxyl group-containing monomers (e.g., hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, etc.); vinyl alcohol; allyl alcohol; etc. etc.), amide group-containing monomers (e.g., (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, etc.), amino group-containing monomers (e.g., aminoethyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, t-butylaminoethyl(meth)acrylate, 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., cyclohexylmaleimide, isopropylmaleimide, etc.), etc.

[0135] The total monomers (monomer composition) usable for constituting the acrylic oligomer particularly preferably contain (1) at least one monomer selected from dicyclopentanyl acrylate, dicyclopentanyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate, and (2) methyl methacrylate. In this case, the content of the monomer (1) is preferably 30 to 70 parts by weight, and the content of the monomer (2) is preferably 30 to 70 parts by weight, relative to 100 parts by weight of the total monomers (monomer composition) usable for constituting the acrylic oligomer.

[0136] The acrylic oligomer can be produced by any suitable polymerization within the scope of not impairing the effects of the present invention. Examples of such polymerization methods include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method by irradiation with active energy rays (active energy ray polymerization method). Among these, the bulk polymerization method and the solution polymerization method are preferred, and the solution polymerization method is more preferred.

[0137] Examples of the solvent that can be used in the polymerization include organic solvents such as esters such as ethyl acetate and n-butyl acetate, aromatic hydrocarbons such as toluene and benzene, aliphatic hydrocarbons such as n-hexane and n-heptane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, ketones such as methyl ethyl ketone and methyl isobutyl ketone, etc. The solvent may be one type only, or two or more types may be used.

[0138] In the polymerization, any appropriate polymerization initiator (for example, a thermal polymerization initiator or a photopolymerization initiator) may be used within a range that does not impair the effects of the present invention. The polymerization initiator may be one type or two or more types. In addition, when solution polymerization is performed, it is preferable to use an oil-soluble polymerization initiator.

[0139] As the thermal polymerization initiator, any suitable thermal polymerization initiator may be adopted within a range that does not impair the effects of the present invention. The thermal polymerization initiator may be one type or two or more types. For specific examples of such thermal polymerization initiators, the explanation in the section [A-2-1-4. Thermal polymerization initiator] may be used.

[0140] The content of the thermal polymerization initiator is, for example, preferably 0.1 to 15 parts by weight based on 100 parts by weight of all monomers (monomer composition) that can be used to constitute the acrylic oligomer.

[0141] As the photopolymerization initiator, any appropriate photopolymerization initiator may be used as long as it does not impair the effects of the present invention. The photopolymerization initiator may be one type or two or more types.

[0142] Examples of the photopolymerization initiator include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators.

[0143] Specific examples of benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one (a commercially available product is, for example, the trade name "OMNIRAD651", manufactured by IGM Resins BV), and anisole methyl ether.

[0144] Specific examples of acetophenone-based photopolymerization initiators include 1-hydroxycyclohexyl phenyl ketone (a commercially available product is, for example, the trade name "OMNIRAD184", manufactured by IGM Resins BV), 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (a commercially available product is, for example, the trade name "OMNIRAD2959", manufactured by IGM Resins BV), 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and methoxyacetophenone.

[0145] Specific examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)-phenyl]-2-hydroxy-2-methylpropan-1-one, and the like.

[0146] Specific examples of aromatic sulfonyl chloride photopolymerization initiators include 2-naphthalenesulfonyl chloride.

[0147] Specific examples of photoactive oxime-based photopolymerization initiators include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime.

[0148] Specific examples of benzoin-based photopolymerization initiators include benzoin.

[0149] Specific examples of benzyl-based photopolymerization initiators include benzyl.

[0150] Specific examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexyl phenyl ketone.

[0151] Specific examples of the ketal-based photopolymerization initiator include benzyl dimethyl ketal.

[0152] Specific examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0153] Specific examples of the acylphosphine photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and the like.

[0154] The content of the photopolymerization initiator is, for example, preferably 0.001 to 0.5 parts by weight based on 100 parts by weight of all monomers (monomer composition) that can be used to constitute the acrylic oligomer.

[0155] In the polymerization of the acrylic oligomer, a chain transfer agent may be used to adjust the molecular weight (preferably to adjust the weight average molecular weight to 1000 to 30000). Examples of the chain transfer agent include 2-mercaptoethanol, α-thioglycerol, 2,3-dimercapto-1-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, thioglycolic acid ester of ethylene glycol, thioglycolic acid ester of neopentyl glycol, thioglycolic acid ester of pentaerythritol, and α-methylstyrene dimer. Among these, from the viewpoint of suppressing whitening of the pressure-sensitive adhesive film of the present invention, α-thioglycerol and methyl thioglycolate are preferred, and α-thioglycerol is particularly preferred. The chain transfer agent may be one type or two or more types.

[0156] The content of the chain transfer agent is, for example, preferably 0.1 to 20 parts by weight, more preferably 0.2 to 15 parts by weight, and even more preferably 0.3 to 10 parts by weight, relative to 100 parts by weight of all monomers (monomer composition) that can be used to constitute the acrylic oligomer.

[0157] [A-2-2-3. Other ingredients] The thermosetting acrylic adhesive composition may contain any other appropriate components within the scope of not impairing the effects of the present invention. Examples of such other components include tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, foil-like materials, softeners, anti-aging agents, conductive agents, UV absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, other crosslinking agents, solvents, catalysts, crosslinking catalysts, crosslinking retarders, etc.

[0158] <A-2-3. Acrylic polymer (P2)> Another embodiment of the acrylic polymer is an acrylic polymer (P2) adjusted by polymerization (typically, partial polymerization) using a photopolymerization initiator. As the method of polymerization using a photopolymerization initiator, for example, any appropriate method can be adopted as long as the effects of the present invention are not impaired, such as a conventionally known method. In the polymerization using a photopolymerization initiator, typically, it is carried out by irradiating light such as UV.

[0159] The acrylic polymer (P2) is obtained by polymerizing a monomer component (M2). The monomer component (M2) here does not include a crosslinking agent described later that may be contained in the acrylic pressure-sensitive adhesive composition. When obtaining the acrylic polymer (P2) by polymerization, in addition to the monomer component (M2) and the photopolymerization initiator, any appropriate additive may be used as long as the effects of the present invention are not impaired.

[0160] Thus, the acrylic polymer (P2) can be defined as being obtained by polymerizing the monomer component (M2). This is because the acrylic polymer (P2) is formed when the monomer component (M2) undergoes a polymerization reaction to become the acrylic polymer (P2), and it is impossible to directly specify the acrylic polymer (P1) based on its structure, and there are circumstances ( "impossible and impractical circumstances") that are approximately not practical. Therefore, by the definition of "being obtained by polymerizing the monomer component (M2)", the acrylic polymer (P2) is properly specified as a "substance".

[0161] The monomer component (M2) preferably includes an alkyl (meth) acrylate (a2) and a polar group-containing monomer (b2). The alkyl (meth) acrylate (a2) may be only one kind or two or more kinds. The polar group-containing monomer (b2) may be only one kind or two or more kinds.

[0162] [A-2-3-1. Alkyl (meth) acrylate (a2)] The alkyl group of the ester moiety of the alkyl (meth)acrylate (a2) (hereinafter sometimes referred to as the "alkyl group of the ester moiety") does not include an alkyl group containing a hydroxyl group or an alkyl group containing a polar group other than a hydroxyl group. Therefore, the alkyl (meth)acrylate (a2) is clearly distinguished from the polar group-containing monomer (b2).

[0163] The content of the alkyl (meth)acrylate (a2) in the monomer component (M2) is preferably 50% by weight to 99% by weight.

[0164] The alkyl group of the ester moiety is preferably an alkyl group having 1 to 20 carbon atoms. The alkyl group of the ester moiety is preferably a chain alkyl group. Here, chain means linear and branched. The alkyl group of the ester moiety is preferably a chain alkyl group having 1 to 20 carbon atoms.

[0165] As exemplary compounds of alkyl (meth)acrylate (a2) in which the alkyl group of the ester moiety is a chain alkyl group having 1 to 20 carbon atoms, the exemplary compounds of alkyl (meth)acrylate (a1) in the section [A-2-1-1. Alkyl (meth)acrylate (a1)] can be cited.

[0166] [A-2-3-2. Polar group-containing monomer (b2)] The content of the polar group-containing monomer (b2) in the monomer component (M2) is preferably 1% by weight to 50% by weight.

[0167] The polar group-containing monomer (b2) preferably includes 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 includes both the hydroxyl group-containing monomer (b2-1) and the monomer (b2-2) having a polar group other than a hydroxyl group.

[0168] The hydroxyl group-containing monomer (b2-1) may be of one type only, or of two or more types.

[0169] As the exemplary compounds of the hydroxyl group-containing monomer (b2-1), the exemplary compounds of the hydroxyl group-containing monomer (b1-1) in the section [A-2-1-2. Polar group-containing monomer (b1)] can be cited.

[0170] The hydroxyl group-containing monomer (b2-1) is preferably a hydroxyalkyl(meth)acrylate, more preferably a hydroxyalkyl(meth)acrylate in which the alkyl group moiety of the hydroxyalkyl group is a linear alkyl group having 2 to 4 carbon atoms, still more preferably 2-hydroxyethyl acrylate (HEA) (glass transition temperature of its homopolymer Tg = -15°C) or 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C), particularly preferably 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C).

[0171] The monomer (b2-2) having a polar group other than a hydroxyl group may be of one type only, or of two or more types.

[0172] As the exemplary compounds of the monomer (b2-2) having a polar group other than a hydroxyl group, the exemplary compounds of the monomer (b1-2) having a polar group other than a hydroxyl group in the section [A-2-1-2. Polar group-containing monomer (b1)] can be cited.

[0173] A preferred example of the monomer (b2-2) having a polar group other than a hydroxyl group is N-vinyl-2-pyrrolidone (the glass transition temperature Tg of its homopolymer is 80° C.).

[0174] The monomer component (M2) preferably contains an alkyl(meth)acrylate (a2) and at least one selected from the group consisting of a hydroxyl-containing monomer (b2-1) and a monomer (b2-2) having a polar group other than a hydroxyl group, more preferably contains an alkyl(meth)acrylate (a2), a hydroxyl-containing monomer (b2-1), and a monomer (b2-2) having a polar group other than a hydroxyl group, and further preferably contains an alkyl(meth)acrylate (a2), a hydroxyl-containing monomer (b2-1), and a monomer (b2-2) having a polar group other than a hydroxyl group, and further preferably contains a monomer having a glass transition temperature Tg of - The composition comprises an alkyl (meth)acrylate (a2-1) having 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), an alkyl (meth)acrylate (a2-2) having a glass transition temperature Tg of its homopolymer in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), a hydroxyl group-containing monomer (b2-1), and a monomer (b2-2) having a polar group other than a hydroxyl group.

[0175] Specifically, the monomer component (M2) preferably includes lauryl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, and N-vinyl-2-pyrrolidone.

[0176] [A-2-3-3. Other monomers (c2)] The monomer component (M2) may contain other monomers (c2) that do not fall under either the alkyl (meth)acrylate (a2) or the polar group-containing monomer (b2). The other monomers (c2) can be used for the purpose of, for example, adjusting the glass transition temperature (Tg) of the acrylic polymer (P2) or adjusting the adhesive performance. The other monomers may be one type or two or more types.

[0177] [A-2-3-4. Photopolymerization initiator] The photopolymerization initiator can be appropriately selected from any suitable photopolymerization initiator depending on the type of polymerization method. The photopolymerization initiator may be one type only, or two or more types may be used.

[0178] As exemplary compounds of the photopolymerization initiator, the exemplary compounds of the photopolymerization initiator in the section of [A-2-2-2. Acrylic oligomer] can be cited.

[0179] The amount of the photopolymerization initiator used can be set to any appropriate amount as long as the effects of the present invention are not impaired. The amount of the photopolymerization 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, still more 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).

[0180] <A-2-4. Photocurable acrylic pressure-sensitive adhesive composition and photocurable acrylic pressure-sensitive adhesive> Another embodiment of the acrylic pressure-sensitive adhesive is a photocurable acrylic pressure-sensitive adhesive, which is typically formed by the photocuring reaction of a photocurable acrylic pressure-sensitive adhesive composition containing an acrylic polymer (P2).

[0181] The photocurable acrylic pressure-sensitive adhesive is formed from the photocurable acrylic pressure-sensitive adhesive composition by any appropriate method. As such a forming method, typically, a method of applying the photocurable acrylic pressure-sensitive adhesive composition onto any appropriate substrate, then placing another arbitrary appropriate substrate on the surface of the adhesive layer formed by the application, and curing by ultraviolet irradiation can be mentioned. Examples of the substrate include the above-mentioned release liner. As the method of applying the photocurable acrylic pressure-sensitive adhesive composition, any appropriate application method can be mentioned as long as the effects of the present invention are not impaired. Examples of such application methods include roll coating method, gravure roll coating method, reverse roll coating method, kiss roll coating method, dip roll coating method, bar coating method, roll brush coating method, spray coating method, knife coating method, air knife coating method, comma coating method, direct coating method, die coating method.

[0182] When forming the photocurable acrylic pressure-sensitive adhesive, heating may be performed as necessary. In addition, aging may be performed for the purpose of adjusting the component migration in the formed photocurable acrylic pressure-sensitive adhesive, promoting the crosslinking reaction, and relaxing distortion that may exist in the photocurable acrylic pressure-sensitive adhesive.

[0183] [A-2-4-1. Crosslinking agent (L2)] The photocurable acrylic pressure-sensitive adhesive composition preferably contains a crosslinking agent (L2). The crosslinking agent (L2) may be of one type only, or of two or more types.

[0184] The content of the crosslinking agent (L2) in the photocurable acrylic pressure-sensitive adhesive composition may be set to any appropriate content within the range that does not impair the effects of the present invention. The content of the crosslinking agent (L2) in the photocurable acrylic pressure-sensitive adhesive composition is preferably 0.001 to 0.5 parts by weight, more preferably 0.005 to 0.3 parts by weight, still more preferably 0.01 to 0.2 parts by weight, and particularly preferably 0.05 to 0.1 parts by weight, based on 100 parts by weight of the acrylic polymer (P2).

[0185] As the crosslinking agent (L2), any appropriate crosslinking agent can be used as long as it does not impair the effects of the present invention. As such a crosslinking agent (L2), preferably, a multifunctional (meth)acrylate is used.

[0186] As the polyfunctional (meth)acrylate, any appropriate polyfunctional (meth)acrylate may be adopted as long as the effects of the present invention are not impaired. The polyfunctional (meth)acrylate may be one type only, or two or more types. Specific examples of such polyfunctional (meth)acrylates include (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-ethylene glycol di(meth)acrylate, 1,6- Examples of the polyhydric alcohol include ester compounds of polyhydric alcohols and (meth)acrylic acid, such as hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethane tri(meth)acrylate; allyl (meth)acrylate; vinyl (meth)acrylate; divinylbenzene; epoxy acrylate; polyester acrylate; urethane acrylate; butyl di(meth)acrylate; and hexyl di(meth)acrylate.

[0187] [A-2-4-2. Acrylic oligomer] The photocurable acrylic pressure-sensitive adhesive composition may contain an acrylic oligomer. The acrylic oligomer may be of only one type, or of two or more types.

[0188] The content of the acrylic oligomer in the photocurable acrylic pressure-sensitive adhesive composition may be set to any appropriate content within the range that does not impair the effects of the present invention. The content of the acrylic oligomer in the photocurable acrylic pressure-sensitive adhesive composition is preferably 0.1 to 20 parts by weight, more preferably 1 to 15 parts by weight, still more preferably 2 to 10 parts by weight, and particularly preferably 3 to 8 parts by weight, based on 100 parts by weight of the acrylic polymer (P2).

[0189] For details of the acrylic oligomer, the explanation in the section [A-2-2-2. Acrylic Oligomer] may be used.

[0190] [A-2-4-3. Other ingredients] The photocurable acrylic adhesive composition may contain any other appropriate components within the scope of not impairing the effects of the present invention. Examples of such other components include tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, foil-like materials, softeners, anti-aging agents, conductive agents, UV absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, other crosslinking agents, solvents, catalysts, crosslinking catalysts, crosslinking retarders, etc.

[0191] <A-3. Antistatic layer> The thickness of the antistatic layer may be any appropriate thickness within a range that does not impair the effects of the present invention. In terms of being able to more effectively exhibit the effects of the present invention, the thickness of the antistatic layer is preferably 3 nm to 500 nm, more preferably 3 nm to 100 nm, even more preferably 3 nm to 60 nm, and particularly preferably 8 nm to 55 nm.

[0192] The antistatic layer is a coating layer formed by applying an antistatic treatment liquid.

[0193] As a method for forming the antistatic layer, any appropriate method can be adopted as long as it does not impair the effects of the present invention. A representative example of such a method is a method in which an antistatic treatment liquid is applied onto a substrate (substrate layer) and then dried or cured.

[0194] The antistatic treatment liquid typically contains a conductive polymer. The conductive polymer may be of only one type or of two or more types.

[0195] As the conductive polymer, any appropriate antistatic layer can be used as long as it does not impair the effects of the present invention. Examples of such conductive polymers include water-soluble conductive polymers and water-dispersible conductive polymers.

[0196] Examples of the water-soluble conductive polymer include polyaniline sulfonic acid, poly(isothianaphthene diyl-sulfonate) compounds, and quaternary ammonium salt-containing (meth)acrylic acid ester polymers, and polyaniline sulfonic acid is preferred.

[0197] Examples of the water-dispersible conductive polymer include polythiophenes and polyaniline doped with polyanions, and preferably polythiophenes doped with polyanions.

[0198] Examples of polythiophenes that can be used as the water-dispersible conductive polymer include polythiophene, poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), poly(3-butylthiophene), poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3-octadecylthiophene), poly(3-bromothiophene), and poly(3-chlorothiophene). thiophene), 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-butenedioxythiophene), poly(3-methyl-4-methoxythiophene), poly(3-methyl-4-ethoxythiophene), poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), and poly(3-methyl-4-carboxybutylthiophene). The degree of polymerization of polythiophenes is preferably 2 to 1000, more preferably 5 to 100, in order to more effectively exhibit the effects of the present invention.

[0199] As the water-dispersible conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) is preferable in that the effects of the present invention can be more effectively exhibited.

[0200] Polyanions are polymers of structural units having an anionic group, and act as dopants for polythiophenes. Examples of polyanions include polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly(2-acrylamido-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, polysulfoethyl methacrylate, poly(4-sulfobutyl methacrylate), polymethallyloxybenzene sulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly(2-acrylamido-2-methylpropane carboxylic acid), polyisoprene carboxylic acid, polyacrylic acid, and polysulfonated phenylacetylene. Polyanions may be homopolymers of these, or copolymers of two or more of them. The weight average molecular weight (Mw) of the polyanions is preferably from 1,000 to 1,000,000, and more preferably from 2,000 to 500,000, in view of excellent doping and dispersibility in polythiophenes.

[0201] As the polyanion, polystyrene sulfonic acid (PSS) is preferable since it can further exert the effects of the present invention.

[0202] For example, when poly(3,4-ethylenedioxythiophene) (PEDOT) is used as a polythiophene in an antistatic layer, and polystyrene sulfonate (PSS) is used as a polyanion with which the polythiophene can be doped, PEDOT and PSS interact with each other and exist in close proximity to each other, so that the PSS can steal electrons from PEDOT, thereby enabling the antistatic layer to exhibit excellent conductivity.

[0203] Commercially available polythiophenes doped with polyanions include, for example, poly(3,4-ethylenedioxythiophene) / polystyrenesulfonic acid (PEDOT / PSS) available under the trade name "Bytron P" manufactured by H.C. Stark Corporation, "Sepulgida" manufactured by Shin-Etsu Polymer Co., Ltd., and "Verasol" manufactured by Soken Chemical & Engineering Co., Ltd.

[0204] The polystyrene-equivalent weight average molecular weight (Mw) of the polyaniline sulfonic acid that can be used as the water-soluble conductive polymer component is preferably 1×10 3 ~5×10 5 and more preferably 5×10 3 ~3×10 5 It is.

[0205] An example of a commercially available polyaniline sulfonic acid product is "aquaPASS" manufactured by Mitsubishi Rayon Co., Ltd.

[0206] The antistatic treatment liquid preferably contains a binder. The binder may be of only one type, or may be of two or more types. The content of the binder in the entire antistatic layer is preferably 50% by weight to 95% by weight, more preferably 60% by weight to 90% by weight, in order to further exert the effects of the present invention.

[0207] As the binder, any appropriate resin may be used as long as it does not impair the effects of the present invention. Examples of such binders include polyester resins, acrylic resins, polyvinyl resins, urethane resins, melamine resins, and epoxy resins.

[0208] In order to more effectively exert the effects of the present invention, the binder preferably contains a polyester-based resin. The polyester-based resin contains polyester as a main component, and the content ratio is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, even more preferably 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably substantially 100% by weight. Here, "substantially" means that it does not contain any intentionally added components, and means that impurities that happen to be mixed in or by-produced are excluded.

[0209] When a polyester-based resin is used as a binder, since the polyester-based resin has a small surface free energy, it is possible to suppress repelling and the like when the antistatic agent composition is applied to a substrate to form a film without blending an additive such as a lubricant.

[0210] The polyester preferably has a structure obtained by condensing at least one compound (polycarboxylic acid component) selected from polycarboxylic acids (typically dicarboxylic acids) having two or more carboxyl groups in one molecule and their derivatives (anhydrides, esters, halides, etc. of polycarboxylic acids) with at least one compound (polyhydric alcohol component) selected from polyhydric alcohols (typically diols) having two or more hydroxyl groups in one molecule.

[0211] Examples of compounds that can be used as the polyvalent carboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±)-malic acid, meso-tartaric acid, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, dithioadipic acid, methyladipic acid, dimethyladipic acid, tetramethyladipic acid, methyleneadipic acid, muconic acid, galactosamine ... Aliphatic dicarboxylic acids such as lactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6-tetramethylsuberic acid, azelaic acid, sebacic acid, perfluorosebacic acid, brassylic acid, dodecyldicarboxylic acid, tridecyldicarboxylic acid, and tetradecyldicarboxylic acid; cycloalkyldicarboxylic acids (e.g., 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), 1,4-(2-norbornene)dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid (himic acid), and adamantanedicarboxylic acid. , spiroheptanedicarboxylic acid and other 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, naphthalenedicarboxylic acid, oxofluorenedicarboxylic acid, anthracenedicarboxylic acid, biphenyldicarboxylic acid, biphenylenedicarboxylic acid, dimethylbiphenylenedicarboxylic acid, 4,4”-p-terephenylenedicarboxylic acid, 4, Aromatic dicarboxylic acids such as 4"-p-quartylphenyldicarboxylic acid, bibenzyldicarboxylic acid, azobenzenedicarboxylic acid, homophthalic acid, phenylenediacetic acid, phenylenedipropionic acid, naphthalenedicarboxylic acid, naphthalenedipropionic acid, biphenyldiacetic acid, biphenyldipropionic acid, 3,3'-[4,4'-(methylenedi-p-biphenylene)]dipropionic acid, 4,4'-bibenzyldiacetic acid, 3,3'(4,4'-bibenzyl)dipropionic acid, and oxydi-p-phenylenediacetic acid; acid anhydrides of any of the above-mentioned polyvalent carboxylic acids;Examples of the polycarboxylic acid include esters of any of the polycarboxylic acids described above (e.g., alkyl esters, which may be monoesters, diesters, etc.); and acid halides corresponding to any of the polycarboxylic acids described above (e.g., dicarboxylic acid chlorides).

[0212] Compounds that can be used as the polyvalent carboxylic acid component, from the viewpoint of further exerting the effects of the present invention, preferably include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and acid anhydrides thereof; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, himic acid, and 1,4-cyclohexanedicarboxylic acid, and acid anhydrides thereof; and lower alkyl esters of the above dicarboxylic acids (for example, esters with monoalcohols having 1 to 3 carbon atoms).

[0213] Examples of compounds that can be used as the polyhydric alcohol component include diols 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, xylylene glycol, hydrogenated bisphenol A, and bisphenol A. Other examples include alkylene oxide adducts of these compounds (e.g., ethylene oxide adducts, propylene oxide adducts, etc.).

[0214] The molecular weight of the polyester resin is preferably 5×10 in terms of the weight average molecular weight (Mw) calculated as standard polystyrene as measured by gel permeation chromatography (GPC), in order to more effectively exhibit the effects of the present invention. 3 ~1.5×10 5 and more preferably 1×10 4~6×10 4 It is.

[0215] The glass transition temperature (Tg) of the polyester resin is preferably from 0° C. to 120° C., and more preferably from 10° C. to 80° C., in order to more effectively exert the effects of the present invention.

[0216] As the polyester resin, a commercially available product available from Toyobo Co., Ltd. under the trade name "Vylonal" can be used.

[0217] The binder may further contain a resin other than polyester-based resin (e.g., acrylic-based resin, acrylic urethane-based resin, acrylic styrene-based resin, acrylic silicone-based resin, silicone-based resin, polysilazane-based resin, polyurethane-based resin, fluorine-based resin, polyvinyl alcohol-based resin, polyolefin-based resin, etc.).

[0218] When the antistatic treatment liquid contains a binder, the content ratio of the conductive polymer relative 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 even more preferably 40 parts by weight to 120 parts by weight. If the content ratio of the conductive polymer relative to 100 parts by weight of the binder is too small outside the above range, the antistatic properties may be reduced. If the content ratio of the conductive polymer relative to 100 parts by weight of the binder is too large outside the above range, the adhesion of the antistatic layer to adjacent layers may be reduced, or the transparency may be reduced.

[0219] The antistatic treatment liquid preferably contains a crosslinking agent. The crosslinking agent may be of only one type, or of two or more types.

[0220] As the crosslinking agent, a crosslinking agent used for crosslinking of general resins can be adopted. Examples of such crosslinking agents include melamine-based crosslinking agents, isocyanate-based crosslinking agents, and epoxy-based crosslinking agents. The amount of the crosslinking agent used can be appropriately adjusted depending on the purpose.

[0221] The antistatic treatment liquid may contain any other appropriate components within the scope of not impairing the effects of the present invention. Examples of such other components include 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.), flow regulators (thixotropic agents, thickeners, etc.), film-forming assistants, antifoaming agents, preservatives, and PET oligomer sealants.

[0222] Examples of the solvent include organic solvents, water, and mixed solvents thereof. The solvent may be one type or two or more types. Examples of the organic solvent include esters such as ethyl acetate; ketones such as methyl ethyl ketone, acetone, and cyclohexanone; cyclic ethers such as tetrahydrofuran (THF) and dioxane; aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol, and cyclohexanol; glycol ethers such as alkylene glycol monoalkyl ethers (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether), and dialkylene glycol monoalkyl ethers.

[0223] In terms of being able to more effectively exhibit the effects of the present invention, the solvent is preferably a mixed solvent of an organic solvent and water, more preferably a mixed solvent of an aliphatic or alicyclic alcohol and water, and even more preferably a mixed solvent of an aliphatic alcohol and water.

[0224] When the solvent is a mixed solvent of an organic solvent and water, one of the technical means for enhancing the effect of the present invention is to adjust the mixing ratio of the organic solvent and water. By adjusting the mixing ratio of the organic solvent and water in this way, the Marangoni number of the antistatic treatment liquid can be adjusted. For example, when 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, more preferably 40% by weight to 60% by weight.

[0225] <<B. Flexible Devices>> The adhesive film according to the embodiment of the present invention can be applied to various devices, typically flexible devices such as bendable devices having movable bending parts, foldable devices, and rollable devices.

[0226] That is, the flexible device according to the embodiment of the present invention includes the adhesive film according to the embodiment of the present invention. The flexible device according to the embodiment of the present invention may include any appropriate other member as long as it includes the adhesive film of the present invention. EXAMPLES

[0227] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited thereto. In the following description, "parts" and "%" are by weight unless otherwise specified.

[0228] <Measurement of Haze of Adhesive Film> 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. The haze was calculated according to the following formula. Haze(%)=(Td / Tt)×100 (Td: diffuse transmittance, Tt: total light transmittance)

[0229] <Observation of particles or particle aggregates in adhesive film> The adhesive film was observed using a digital microscope (OLYMPUS, BX51, objective lens: UMPlanFI 50x / 0.75 BD P) to measure the Feret diameter of particles or particle aggregates in the adhesive film. The unit area (0.01 mm2) of particles or particle aggregates with a Feret diameter of 0.5 μm or more was then calculated. 2 The number of particles observed per 100 μm was counted.

[0230] <Calculation of Marangoni number> The viscosity of the antistatic treatment liquid at 20°C and the surface tension at 20°C and 40°C were measured, and the Marangoni number was calculated from (Equation 1). The viscosity was measured using a viscometer (Toki Sangyo Co., Ltd., RE-85U) with a cone rotor (1°34' x R24) at a rotation speed of 100 rpm. The surface tension was measured with a static surface tensiometer (Kyowa Interface Science Co., Ltd., DY-500). The thermal diffusivity was calculated as 9.52 x 10 using (Equation 2) from the density, specific heat, and thermal conductivity of a 50% ethanol aqueous solution at 20°C. -8 m 2 / s. The film thickness L was calculated to be 3.0×10 -8 The value was m.

number

[0231] <Calculation of the number of capillaries> The viscosity and surface tension of the antistatic treatment liquid at 20°C were measured, and the capillary number was calculated from (Equation 3). The viscosity was measured using a viscometer (Toki Sangyo Co., Ltd., RE-85U) with a cone rotor (1°34' x R24) at a rotation speed of 100 rpm. The surface tension was measured with a static surface tensiometer (Kyowa Interface Science Co., Ltd., DY-500). The speed was 20 m / min.

number

[0232] <Counting the number of uneven processing> The adhesive film was cut to a width of 60 mm and a length of 120 mm, and placed on a black board with the antistatic treatment layer facing up. The adhesive film was irradiated with a three-wavelength light (Yamada Lighting Co., Ltd., Z-208), and the number of processing irregularities that were visible when visually observed from above the adhesive film was counted. The processing irregularities can be streaky, round, oval, wavy, or other irregularities.

[0233] <Counting the number of coating streaks> The adhesive film was cut to a width of 60 mm and a length of 120 mm, and placed on a black board with the antistatic treatment layer facing up. The adhesive film was irradiated with a three-wavelength light (Yamada Lighting Co., Ltd., Z-208), and the number of streak-like appearance defects 30 mm or longer that were visually observed when visually observing the adhesive film from above was counted.

[0234] <How to check visibility> The adhesive film was cut to a width of 50 mm and a length of 50 mm, the release liner was peeled off, and the film was attached to the antistatic layer of another adhesive film to obtain a laminate of two adhesive films. 50 adhesive films were laminated, and the release liner of the laminated adhesive film obtained was peeled off to prepare a test sample. Paper was prepared on which the Nitto Denko brand mark was printed to a length of 30 mm and a width of 90 mm, and the test sample was set at a height of 30 cm from the paper. The Nitto Denko brand mark was visually observed through the test sample from a height of 30 cm from the test sample. The brand mark was divided into three grades: × if it was clearly decipherable, △ if it was decipherable but difficult to read, and ○ if it was not decipherable. The Nitto Denko brand mark is available from the Nitto Denko website.

[0235] [Production Example 1]: Production of antistatic treatment solution As a conductive polymer, an aqueous solution containing 0.5 wt % poly(3,4-dioxythiophene) (PEDOT) and 0.8 wt % polystyrene sulfonate (number average molecular weight 150,000) (PSS) (HC Stark product, product name "Baytron P") (hereinafter also referred to as "conductive polymer aqueous solution") was prepared. A dispersion containing 25% by weight of a polyester resin as a binder (manufactured by Toyobo Co., Ltd., product name "Binalol MD-1480" (aqueous dispersion of saturated copolymerized polyester resin) (hereinafter also referred to as "binder dispersion") was prepared. As a slip agent, an aqueous dispersion of carnauba wax (manufactured by Nippon Wax Co., Ltd., product name "Refined Carnauba Wax No. 2 Powder") (hereinafter also referred to as "slip agent dispersion") was prepared. The conductive polymer aqueous solution was mixed with 50 parts by weight of the conductive polymer aqueous solution in terms of solid content, 100 parts by weight of the binder dispersion in terms of solid content, and 30 parts by weight of the slip agent dispersion in terms of solid content to prepare a conductive aqueous solution. 20 parts by weight of a melamine-based crosslinking agent was added to 100 parts by weight of the conductive aqueous solution prepared, and the solution was diluted with a 1:1 mixture of water and Equinene F-6 (manufactured by Japan Alcohol Sales Co., Ltd.) so that the solid concentration became a predetermined concentration, thereby preparing an antistatic treatment solution. The predetermined concentrations were 0.4% by weight, 0.6% by weight, 1.0% by weight, and 1.5% by weight.

[0236] [Production Example 2]: Production of acrylic polymer In a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 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 parts by weight, NVP (N-vinyl-2-pyrrolidone): 0.6 parts by weight, and AIBN (2,2'-azobisisobutyronitrile): 0.1 parts by weight as a polymerization initiator were added, and ethyl acetate was added so that the total concentration of these was 47% by weight. The system was replaced with nitrogen over 1 hour while gently stirring, and the liquid temperature in the flask was kept at around 56 ° C. to carry out a polymerization reaction for 6 hours. After the reaction was completed, ethyl acetate was added to adjust the polymer concentration to 24% by weight, and an acrylic polymer solution was obtained.

[0237] [Production Example 3]: Production of acrylic oligomer As monomer components, 60 parts by weight of DCPMA (dicyclopentanyl methacrylate) and 40 parts by weight of MMA (methyl methacrylate), 3.5 parts by weight of α-thioglycerol as a chain transfer agent, and 100 parts by weight of toluene as a polymerization solvent were mixed and stirred at 70°C for 1 hour under a nitrogen atmosphere. Next, 0.2 parts by weight of AIBN was added as a thermal polymerization initiator and reacted at 70°C for 2 hours, and then the temperature was raised to 80°C and reacted for 2 hours to obtain an acrylic oligomer. The weight average molecular weight Mw of the acrylic oligomer was 5100 and the glass transition temperature (Tg) was 130°C.

[0238] [Production Example 4]: Production of coating solution of acrylic adhesive composition 100 parts by weight of the acrylic polymer obtained in Production Example 2, 0.28 parts by weight of Niper BMT-40SV (manufactured by NOF Corporation) as a crosslinking agent, 3 parts by weight of the acrylic oligomer obtained in Production Example 3, and 0.3 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant were mixed, thoroughly stirred, and diluted with ethyl acetate to a total solids content of 17% by weight, thereby obtaining a coating solution of an acrylic pressure-sensitive adhesive composition.

[0239] [Example 1] The antistatic treatment solution having a concentration of 1.0% obtained in Production Example 1 was applied using a Mayer bar to the side opposite the easy-adhesion treated side of a PET substrate (Lumirror S10#50, manufactured by Toray Industries, Inc.), and the solvent was removed by drying at 130°C for 1 minute to form an antistatic layer (thickness: 0.03 μm), thereby producing a PET film with an antistatic layer. The coating solution of the acrylic adhesive composition obtained in Production Example 4 was applied to the adhesion-facilitating surface of the obtained PET film with an antistatic layer so that the thickness after drying would be 13 μm, and dried under conditions of a drying temperature of 155° C. and a drying time of 2 minutes. Next, a release sheet (product name: MRQ50T100J, manufactured by Mitsubishi Chemical Corporation) made of polyester resin and having a thickness of 50 μm and one side of which had been silicone-treated was attached to the surface of the obtained adhesive layer so that the silicone-treated surface was in contact with the surface, thereby obtaining an adhesive film (1). The results are shown in Table 1.

[0240] [Example 2] An adhesive film (2) was obtained in the same manner as in Example 1, except that the PET substrate was changed to T100C50 manufactured by Mitsubishi Chemical Corporation. The results are shown in Table 1.

[0241] [Example 3] An adhesive film (3) was obtained in the same manner as in Example 1, except that the antistatic treatment liquid having a concentration of 0.6% obtained in Production Example 1 was used as the antistatic treatment liquid. The results are shown in Table 1.

[0242] [Example 4] An adhesive film (4) was obtained in the same manner as in Example 2, except that the antistatic treatment liquid having a concentration of 0.6% obtained in Production Example 1 was used as the antistatic treatment liquid. The results are shown in Table 1.

[0243] [Comparative Example 1] An adhesive film (C1) was obtained in the same manner as in Example 1, except that the PET substrate was changed to Lumirror T60#50 manufactured by Toray Industries, Inc. The results are shown in Table 1.

[0244] [Comparative Example 2] An adhesive film (C2) was obtained in the same manner as in Example 1, except that the antistatic treatment liquid having a concentration of 0.4% obtained in Production Example 1 was used as the antistatic treatment liquid. The results are shown in Table 1.

[0245] [Comparative Example 3] A pressure-sensitive adhesive film (C3) was obtained in the same manner as in Comparative Example 2, except that the PET substrate was changed to T100C50 manufactured by Mitsubishi Chemical Corporation. The results are shown in Table 1.

[0246] [Comparative Example 4] A pressure-sensitive adhesive film (C3) was obtained in the same manner as in Comparative Example 2, except that the PET substrate was changed to Lumirror T60#50 manufactured by Toray Industries, Inc. The results are shown in Table 1.

[0247] [Comparative Example 5] An adhesive film (C5) was obtained in the same manner as in Example 1, except that the antistatic treatment liquid having a concentration of 1.5% obtained in Production Example 1 was used as the antistatic treatment liquid. The results are shown in Table 1.

[0248] [Table 1] [Industrial Applicability]

[0249] The pressure-sensitive adhesive film of the present invention can be applied to various devices. Typically, it can be applied to flexible devices such as bendable devices (devices that can be bent) having movable bending parts, foldable devices (devices that can be folded), and rollable devices (devices that can be rolled up). [Explanation of symbols]

[0250] 100 Adhesive Film 10 Base material layer 20 Adhesive layer 30 Antistatic layer

Claims

1. An adhesive film having an antistatic layer, a base material layer, and an adhesive layer in this order, wherein the antistatic layer is a coating layer formed by coating 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, an adhesive film.

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

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

4. The adhesive film according to claim 1, wherein the number of particles or aggregates of particles having a Feret diameter of 0.5 μm or more observed per unit area (0.01 mm2) in the adhesive film is 10 to 110.

5. A flexible device comprising the adhesive film according to any one of claims 1 to 4.

Images