Pressure-sensitive adhesive agent composition and pressure-sensitive adhesive film

Abstract

The present invention provides: a pressure-sensitive adhesive film capable of exhibiting both excellent antistatic properties and corrosion resistance; a pressure-sensitive adhesive agent composition that forms a pressure-sensitive adhesive agent constituting a pressure-sensitive adhesive agent layer included in the pressure-sensitive adhesive film; and an optical device and an electronic device including the pressure-sensitive adhesive film.　A pressure-sensitive adhesive agent composition according to an embodiment of the present invention contains a base polymer and an ionic compound. The ionic compound is formed of a cationic species and an anionic species. The anionic species is at least one selected from the group consisting of borate anions and dicyanamide anions.

Description

Pressure-sensitive adhesive composition and pressure-sensitive adhesive film

[0001] The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive film, and also to an optical device and an electronic device that include such a pressure-sensitive adhesive film.

[0002] In the manufacturing process of optical devices and electronic devices, pressure-sensitive adhesive films are sometimes used as surface protection films or reinforcing films to prevent scratches on the surfaces of optical or electronic components and to impart impact resistance during processing, assembly, inspection, transportation, etc. Pressure-sensitive adhesive films are also sometimes used as joining members for constituting optical or electronic components.

[0003] Optical components, electronic components, and adhesive films such as those mentioned above have high electrical insulation properties and generate static electricity due to friction or peeling. For example, if a voltage is applied to a liquid crystal panel while such static electricity remains, there is a risk that the orientation of the liquid crystal molecules may be lost or the liquid crystal panel may be damaged. Furthermore, the presence of static electricity can attract dust and reduce workability.

[0004] A technique has been reported in which an ionic compound is incorporated as an antistatic agent into a pressure-sensitive adhesive layer contained in the pressure-sensitive adhesive film to impart antistatic properties to the pressure-sensitive adhesive film (for example, Patent Document 1).

[0005] However, when a conventional pressure-sensitive adhesive film containing an antistatic agent-containing pressure-sensitive adhesive layer is used in the manufacturing process of an optical device or electronic device, or when used as a joining material for constructing an optical component or an electronic component, there is a problem that corrosion occurs in the electrode portion of the adherend.

[0006] Japanese Patent Application Laid-Open No. 2023-164531

[0007] The object of the present invention is to provide an adhesive film that can exhibit both excellent antistatic properties and corrosion resistance, an adhesive composition that forms an adhesive constituting an adhesive layer contained in the adhesive film, and an optical device and an electronic device that include the adhesive film.

[0008] [1] A pressure-sensitive adhesive composition according to an embodiment of the present invention comprises a base polymer and an ionic compound, wherein the ionic compound comprises a cationic species and an anionic species, and the anionic species is at least one selected from the group consisting of a borate anion and a dicyanamide anion. [2] In the pressure-sensitive adhesive composition according to the above [1], the cationic species may be at least one selected from the group consisting of an onium cation and a metal cation. [3] In the pressure-sensitive adhesive composition according to the above [1] or [2], the borate anion may not contain both elemental fluorine and elemental sulfur. [4] In the pressure-sensitive adhesive composition according to any one of the above [1] to [3], the base polymer may be at least one selected from an acrylic resin, a polyol, and a urethane prepolymer. [5] In the pressure-sensitive adhesive composition according to any one of the above [1] to [4], the amount of the ionic compound per 100 parts by weight of the base polymer may be 0.001 to 30 parts by weight. [6] An adhesive film according to an embodiment of the present invention comprises a pressure-sensitive adhesive layer composed of an adhesive formed from the pressure-sensitive adhesive composition described in any one of [1] to [5] above. [7] The pressure-sensitive adhesive film described in [6] above may be used for at least one selected from the group consisting of a surface protective film and a reinforcing film. [8] An optical device according to an embodiment of the present invention comprises the pressure-sensitive adhesive film described in [6] or [7] above. [9] An electronic device according to an embodiment of the present invention comprises the pressure-sensitive adhesive film described in [6] or [7] above.

[0009] According to the present invention, it is possible to provide an adhesive film that can exhibit both excellent antistatic properties and corrosion resistance, an adhesive composition that forms an adhesive that constitutes an adhesive layer contained in the adhesive film, and an optical device and an electronic device that include the adhesive film.

[0010] 1 is a schematic cross-sectional view of an adhesive film according to one embodiment of the present invention.

[0011] In this specification, the expression "(meth)acrylic" means "acrylic and / or methacrylic", the expression "(meth)acrylate" means "acrylate and / or methacrylate", the expression "(meth)allyl" means "allyl and / or methallyl", and the expression "(meth)acrolein" means "acrolein and / or methacrolein". Furthermore, in this specification, the expression "acid (salt)" means "acid and / or its salt". Examples of salts include alkali metal salts and alkaline earth metal salts, and specific examples include sodium salts and potassium salts.

[0012] <<1. Overall Configuration>> The pressure-sensitive adhesive composition according to an embodiment of the present invention includes a base polymer and an ionic compound. The base polymer may be of only one type, or may contain two or more types. The ionic compound may be of only one type, or may contain two or more types.

[0013] Any appropriate base polymer may be used as the base polymer as long as it does not impair the effects of the present invention. Preferably, the base polymer is at least one selected from the group consisting of an acrylic resin, a polyol, and a urethane prepolymer.

[0014] Representative embodiments in which the base polymer is an acrylic resin include an embodiment in which the base polymer is an acrylic resin (A) and an embodiment in which the base polymer is an acrylic resin (B). The acrylic resins (A) and (B) will be described in detail later.

[0015] In an embodiment in which the base polymer is an acrylic resin (A), the adhesive composition according to an embodiment of the present invention will be expressed as an acrylic adhesive composition (A), the adhesive formed from the adhesive composition according to an embodiment of the present invention will be expressed as an acrylic adhesive (A), the adhesive layer composed of the adhesive formed from the adhesive composition according to an embodiment of the present invention will be expressed as an acrylic adhesive layer (A), and the adhesive film according to an embodiment of the present invention will be expressed as an acrylic adhesive film (A).

[0016] In an embodiment in which the base polymer is an acrylic resin (B), the adhesive composition according to an embodiment of the present invention will be expressed as an acrylic adhesive composition (B), the adhesive formed from the adhesive composition according to an embodiment of the present invention will be expressed as an acrylic adhesive (B), the adhesive layer composed of the adhesive formed from the adhesive composition according to an embodiment of the present invention will be expressed as an acrylic adhesive layer (B), and the adhesive film according to an embodiment of the present invention will be expressed as an acrylic adhesive film (B).

[0017] In an embodiment in which the base polymer is a polyol, the adhesive composition according to an embodiment of the present invention will be expressed as a urethane-based adhesive composition (C), the adhesive formed from the adhesive composition according to an embodiment of the present invention will be expressed as a urethane-based adhesive (C), the adhesive layer composed of the adhesive formed from the adhesive composition according to an embodiment of the present invention will be expressed as a urethane-based adhesive layer (C), and the adhesive film according to an embodiment of the present invention will be expressed as a urethane-based adhesive film (C).

[0018] In the case where the base polymer is a urethane prepolymer, the pressure-sensitive adhesive composition according to an embodiment of the present invention is expressed as a urethane-based pressure-sensitive adhesive composition (D), the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition according to an embodiment of the present invention is expressed as a urethane-based pressure-sensitive adhesive (D), the pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition according to an embodiment of the present invention is expressed as a urethane-based pressure-sensitive adhesive layer (D), and the pressure-sensitive adhesive film according to an embodiment of the present invention is expressed as a urethane-based pressure-sensitive adhesive film (D).

[0019] Generally, known urethane polymers include "prepolymer-type urethane polymers" produced by reacting a urethane prepolymer with a polyfunctional isocyanate compound, and "one-shot-type urethane polymers" produced by directly reacting a polyol with a polyfunctional isocyanate compound without using a urethane prepolymer. Urethane prepolymers are typically obtained by reacting a polyol with a polyfunctional isocyanate compound, and have hydroxyl groups at the molecular terminals.

[0020] The urethane polymer contained in the urethane-based pressure-sensitive adhesive (C) is typically a one-shot urethane polymer. The one-shot urethane polymer may be of only one type, or may be of two or more types. The one-shot urethane polymer is obtained by reacting a polyol (not a urethane prepolymer) as a base polymer with a polyfunctional isocyanate compound. Therefore, when the urethane polymer is a one-shot urethane polymer, the urethane-based pressure-sensitive adhesive composition that forms the urethane-based pressure-sensitive adhesive typically contains a polyol (not a urethane prepolymer) as a base polymer.

[0021] The urethane polymer contained in the urethane-based pressure-sensitive adhesive (D) is typically a prepolymer-type urethane polymer. The prepolymer-type urethane polymer may be of only one type, or may be of two or more types. The prepolymer-type urethane polymer is obtained by reacting a urethane prepolymer as a base polymer with a polyfunctional isocyanate compound. Therefore, when the urethane polymer is a prepolymer-type urethane polymer, the urethane-based pressure-sensitive adhesive composition that forms the urethane-based pressure-sensitive adhesive typically contains a urethane prepolymer as a base polymer.

[0022] The content of the base polymer in the PSA composition can be any appropriate content ratio within a range that does not impair the effects of the present invention, depending on the type of base polymer used, the type of ionic compound, etc. The content of the base polymer in the PSA composition is typically, in terms of solid content, preferably 60 wt % to 99.9 wt %, more preferably 65 wt % to 99.9 wt %, even more preferably 70 wt % to 99.9 wt %, and particularly preferably 75 wt % to 99.9 wt %.

[0023] The content of the ionic compound in the PSA composition may be any appropriate content within a range that does not impair the effects of the present invention, depending on the type of base polymer used, the type of ionic compound, etc. In order to further exhibit the effects of the present invention, the content of the ionic compound in the PSA composition is preferably 0.001 wt % to 30 wt % in terms of solid content.

[0024] In one embodiment, the content of the ionic compound in the PSA composition is more preferably 0.001 wt % to 10 wt %, even more preferably 0.005 wt % to 7 wt %, particularly preferably 0.01 wt % to 5 wt %, and most preferably 0.05 wt % to 3 wt %.

[0025] In another embodiment, the content of the ionic compound in the pressure-sensitive adhesive composition is more preferably 0.001 wt % to 20 wt %, and even more preferably 0.001 wt % to 10 wt %. This embodiment may be a content suitable for a pressure-sensitive adhesive composition that forms a pressure-sensitive adhesive constituting a pressure-sensitive adhesive layer in an optical laminate including a polarizing film and a pressure-sensitive adhesive layer, for example.

[0026] The pressure-sensitive adhesive film according to an embodiment of the present invention includes a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition according to an embodiment of the present invention. The pressure-sensitive adhesive film according to an embodiment of the present invention may include any appropriate other layer, as long as it includes a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition according to an embodiment of the present invention. Such other layer may be a single layer or two or more layers. Examples of such other layers include a substrate layer, a release liner (sometimes referred to as a release sheet or separator), an antistatic layer, an easy-adhesion layer, an easy-slip layer, a release layer, a hard coat layer, and an anti-reflective layer. The pressure-sensitive adhesive film according to one embodiment of the present invention has a laminate structure in which a substrate layer, a pressure-sensitive adhesive layer, and a release liner are laminated in this order, with the release liner being the outermost layer. The pressure-sensitive adhesive film according to another embodiment of the present invention has a laminate structure in which a substrate layer and a pressure-sensitive adhesive layer are laminated in this order, with the pressure-sensitive adhesive layer being the outermost layer. An embodiment in which an antistatic layer is provided on the opposite side of the substrate layer from the pressure-sensitive adhesive layer is also a pressure-sensitive adhesive film according to an embodiment of the present invention. An easy-adhesion layer may also be provided between the substrate layer and the pressure-sensitive adhesive layer.

[0027] The thickness of the pressure-sensitive adhesive film according to the embodiment of the present invention is preferably 5.5 μm to 500 μm, more preferably 10 μm to 400 μm, even more preferably 20 μm to 300 μm, even more preferably 30 μm to 200 μm, even more preferably 40 μm to 190 μm, particularly preferably 50 μm to 180 μm, and most preferably 60 μm to 170 μm.

[0028] Figure 1 is a schematic cross-sectional view of a PSA film according to one embodiment of the present invention. In Figure 1, PSA film 100 comprises a release liner 10, a PSA layer 20, and a substrate layer 30. In the embodiment shown in Figure 1, release liner 10 and PSA layer 20 are directly laminated together, and PSA layer 20 and substrate layer 30 are directly laminated together. Release liner 10 can be peeled off at the time of use. Unlike Figure 1, there may be an easy-adhesion layer or an antistatic layer between PSA layer 20 and substrate layer 30, or an antistatic layer may be present on the side of substrate layer 30 opposite PSA layer 20.

[0029] The pressure-sensitive adhesive layer may be a single layer or may be two or more layers, and is typically a single layer.

[0030] In one embodiment, the thickness of the pressure-sensitive adhesive layer is preferably 0.5 μm to 200 μm, more preferably 1 μm to 150 μm, even more preferably 5 μm to 100 μm, and particularly preferably 10 μm to 80 μm, from the viewpoint of further exhibiting the effects of the present invention. In another embodiment, the thickness of the pressure-sensitive adhesive layer is preferably 0.5 μm to 100 μm, more preferably 1 μm to 50 μm, even more preferably 2 μm to 40 μm, and particularly preferably 3 μm to 30 μm, from the viewpoint of further exhibiting the effects of the present invention.

[0031] The substrate layer may be a single layer or two or more layers. The substrate layer may be stretched.

[0032] The thickness of the substrate layer is preferably 4 μm to 450 μm, more preferably 8 μm to 400 μm, still more preferably 12 μm to 350 μm, and particularly preferably 16 μm to 250 μm.

[0033] An antistatic layer containing any suitable antistatic agent such as a conductive polymer, carbon nanotube, ion-conductive polymer, etc. may be provided on the surface of the substrate layer on which the pressure-sensitive adhesive layer is not applied, for the purpose of suppressing the generation of static electricity, etc. Furthermore, for the purpose of forming a roll that is easy to unwind, for example, the substrate layer may be subjected to a release treatment by adding a fatty acid amide, polyethyleneimine, long-chain alkyl additive, etc., or a coating layer made of any suitable release agent such as a silicone-based, long-chain alkyl-based, or fluorine-based release agent may be provided.

[0034] Any appropriate material may be used as the material for the substrate layer depending on the application. Examples include plastic, paper, metal film, nonwoven fabric, etc. Plastic is preferred. That is, the substrate layer is preferably a plastic film. The substrate layer may be made of one material or two or more materials. For example, it may be made of two or more plastics.

[0035] Examples of the plastics include polyester resins, polyolefin resins, cyclic polyolefin resins, polyamide resins, polyimide resins, polyether ether ketone, polyethersulfone, polyarylate resins, and aramid resins. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include homopolymers of olefin monomers and copolymers of olefin monomers. Specific examples include homopolypropylene; propylene copolymers such as block copolymers, random copolymers, and graft copolymers containing ethylene as a copolymerization component; reactor TPO; ethylene copolymers such as low-density, high-density, linear low-density, and ultra-low-density copolymers; ethylene copolymers such as ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-methacrylic acid copolymers, and ethylene-methyl methacrylate copolymers. Examples of cyclic polyolefin resins include norbornene resins.

[0036] The substrate layer may contain any appropriate additives as needed. Examples of additives that may be contained in the substrate layer include antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, fillers, and pigments. The type, number, and amount of additives that may be contained in the substrate layer may be appropriately set depending on the purpose.

[0037] Examples of release liners include release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is treated with silicone, and release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is laminated with a polyolefin resin.

[0038] Examples of plastic films usable as liner substrates include polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, and ethylene-vinyl acetate copolymer films.

[0039] The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, even more preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

[0040] The pressure-sensitive adhesive film according to the embodiment of the present invention can exhibit excellent antistatic properties, and the surface resistance value of the pressure-sensitive adhesive layer surface (applied voltage = 100 V, application time 15 seconds) in an environment of a temperature of 25°C and a relative humidity of 50% is preferably 1.0 × 10 12 Ω or less, and more preferably 5.0 × 10 11 Ω or less, and more preferably 1.0 × 10 11 Ω or less, and particularly preferably 5.0 × 10 10 Ω or less, and most preferably 1.0×10 10 The lower limit of the surface resistivity is preferably as low as possible from the viewpoint of antistatic properties. 6 Ω or more, and 1.0 × 10 7 It can be Ω or more.

[0041] <<2. Pressure-sensitive adhesive composition>> As described above, typical pressure-sensitive adhesive compositions according to embodiments of the present invention include the acrylic pressure-sensitive adhesive composition (A), the acrylic pressure-sensitive adhesive composition (B), the urethane pressure-sensitive adhesive composition (C), and the urethane pressure-sensitive adhesive composition (D).

[0042] The acrylic pressure-sensitive adhesive composition (A) contains an acrylic resin (A) as a base polymer and an ionic compound. The acrylic pressure-sensitive adhesive composition (A) will be described in detail later.

[0043] The acrylic pressure-sensitive adhesive composition (B) contains an acrylic resin (B) as a base polymer and an ionic compound. The acrylic pressure-sensitive adhesive composition (B) will be described in detail later.

[0044] The urethane-based pressure-sensitive adhesive composition (C) contains a polyol as a base polymer and an ionic compound. The urethane-based pressure-sensitive adhesive composition (C) will be described in detail later.

[0045] The urethane-based pressure-sensitive adhesive composition (D) contains a urethane prepolymer as a base polymer and an ionic compound. The urethane-based pressure-sensitive adhesive composition (D) will be described in detail later.

[0046] 2-1. Ionic Compound The pressure-sensitive adhesive composition according to an embodiment of the present invention contains an ionic compound. The ionic compound comprises a cationic species and an anionic species. Any appropriate ionic compound can be adopted as such an ionic compound as long as it does not impair the effects of the present invention.

[0047] The ionic compound may be an ionic liquid, which means a molten salt (ionic compound) that is liquid at 25°C.

[0048] In terms of being able to exhibit the effects of the present invention, the anion species is preferably at least one selected from the group consisting of borate anion and dicyanamide anion. By employing at least one selected from the group consisting of borate anion and dicyanamide anion as the anion species, the effects of the present invention can be exhibited.

[0049] Examples of borate anions include bis(oxalate)borate, bis(mandelato)borate, bis(salicylato)borate, bis(malonato)borate, bis(succinato)borate, bis(glutolato)borate, and bis(adipato)borate. Of these, bis(oxalate)borate represented by the following chemical formula (A) is preferred in that it can further exhibit the effects of the present invention.

[0050]

[0051] The borate anion preferably does not contain at least one selected from the group consisting of fluorine and sulfur, and more preferably does not contain both fluorine and sulfur. By employing a borate anion that does not contain at least one selected from the group consisting of fluorine and sulfur (preferably does not contain both fluorine and sulfur) as the anion species, the effects of the present invention can be more effectively exhibited.

[0052] In the borate anion, an oxygen atom is preferably directly bonded to a boron atom, which can exert the effect of further increasing the electrical conductivity.

[0053] Dicyanamide anion is (CN)N - It is an anion represented by the formula:

[0054] As the cation species, any appropriate cation can be used as long as it does not impair the effects of the present invention. In terms of being able to further exhibit the effects of the present invention, such a cation is preferably at least one selected from the group consisting of onium cations and metal cations.

[0055] As the onium cation, any appropriate onium cation can be adopted as long as it does not impair the effects of the present invention. In terms of being able to further exhibit the effects of the present invention, such onium cation is preferably at least one selected from ammonium cations (nitrogen-containing onium cations), sulfonium cations (sulfur-containing onium cations), and phosphorus-containing onium cations (phosphonium cations), and more preferably ammonium cations (nitrogen-containing onium cations).

[0056] The onium cation has, for example, at least one type selected from the group consisting of cation structures represented by the following general formulas (1) to (4). The cation structures represented by general formulas (1) to (3) are cation structures that can be contained in the above-mentioned ammonium cation (nitrogen-containing onium cation). The cation structure represented by general formula (4) is a cation structure that can be contained in the above-mentioned sulfonium cation (sulfur-containing onium cation) and phosphorus-containing onium cation (phosphonium cation).

[0057] In general formula (1), R a represents a hydrocarbon group having 4 to 20 carbon atoms, which may contain a heteroatom; R b and R c are the same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and may contain a heteroatom. However, when the nitrogen atom contains a double bond, R c There is no.

[0058] In general formula (2), R d represents a hydrocarbon group having 2 to 20 carbon atoms, which may contain a heteroatom; R e , R f , and R g are the same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may contain a heteroatom.

[0059] In general formula (3), R h represents a hydrocarbon group having 2 to 20 carbon atoms, which may contain a heteroatom; R i , R j , and R k are the same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may contain a heteroatom.

[0060] In general formula (4), Z represents a nitrogen atom, a sulfur atom, or a phosphorus atom, and R l , R m , R n , and R o are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms, which may contain a heteroatom. However, when Z is a sulfur atom, R oThere is no.

[0061] Examples of the cation structure represented by general formula (1) include a pyridinium cation structure, a pyrrolidinium cation structure, a piperidinium cation structure, a cation structure having a pyrroline skeleton, and a cation structure having a pyrrole skeleton.

[0062] Specific examples of cationic species having a cationic structure represented by general formula (1) include cations such as 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-ethyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-hexyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-octyl-4-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, and 1,1-dimethylpyrrolidinium cation. pyrrolidinium cation; 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidinium cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium cation, 1-ethyl-1-propylpyrrolidinium cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, 1 pyrrolidinium cations such as 1-ethyl-1-heptylpyrrolidinium cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, and 1,1-dibutylpyrrolidinium cation; 1-propylpiperidinium cation, 1-pentylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, and the like; piperidinium cations such as 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, 1-propyl-1-butylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1,1-dipropylpiperidinium cation, and 1,1-dibutylpiperidinium cation;Examples include 2-methyl-1-pyrroline cation; 1-ethyl-2-phenylindole cation; 1,2-dimethylindole cation; 1-ethylcarbazole cation; and cations such as these further having at least one group selected from the group consisting of a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group).

[0063] Among these, in terms of further exhibiting the effects of the present invention, preferred are pyridinium cations such as 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-ethyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-hexyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, and 1-octyl-4-methylpyridinium cation; 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidinium cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium cation, 1-ethyl-1-propylpyrrolidinium cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl ... and 1-ethyl-1 pyrrolidinium cations such as 1-hexylpyrrolidinium cation and 1-ethyl-1-heptylpyrrolidinium cation; piperidinium cations such as 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, and 1-propyl-1-butylpiperidinium cation; cations such as these cations further having at least one selected from the group consisting of a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group);and more preferably, a 1-hexylpyridinium cation, a 1-ethyl-3-methylpyridinium cation, a 1-butyl-3-methylpyridinium cation, a 1-octyl-4-methylpyridinium cation, a 1-methyl-1-propylpyrrolidinium cation, a 1-methyl-1-propylpiperidinium cation, or a cation further having at least one selected from the group consisting of a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group);

[0064] Examples of the cation structure represented by general formula (2) include an imidazolium cation structure, a tetrahydropyrimidinium cation structure, and a dihydropyrimidinium cation structure.

[0065] Specific examples of cationic species having a cationic structure represented by general formula (2) include, for example, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, and imidazolium cations such as imidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, and 1-hexyl-2,3-dimethylimidazolium cation; 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4 tetrahydropyrimidinium cations such as 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, dihydropyrimidinium cations such as 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, and 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation; and cations which further have at least one selected from the group consisting of a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group).

[0066] Among these, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, and 1-tetradecyl-3-methylimidazolium cation are preferred, as they can more effectively exhibit the effects of the present invention. imidazolium cations such as 1-ethyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, and cations which further contain at least one selected from the group consisting of a vinyl group (CH2=CH- group) and an allyl group (CH2=CH-CH2- group). More preferred are 1-ethyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, and cations which further contain at least one selected from the group consisting of a vinyl group (CH2=CH- group) and an allyl group (CH2=CH-CH2- group).

[0067] Examples of the cation structure represented by general formula (3) include a pyrazolium cation structure and a pyrazolinium cation structure.

[0068] Specific examples of the cationic species having the cationic structure represented by general formula (3) include pyrazolium cations such as a 1-methylpyrazolium cation, a 3-methylpyrazolium cation, a 1-ethyl-2-methylpyrazolinium cation, a 1-ethyl-2,3,5-trimethylpyrazolium cation, a 1-propyl-2,3,5-trimethylpyrazolium cation, and a 1-butyl-2,3,5-trimethylpyrazolium cation; pyrazolinium cations such as a 1-ethyl-2,3,5-trimethylpyrazolinium cation, a 1-propyl-2,3,5-trimethylpyrazolinium cation, and a 1-butyl-2,3,5-trimethylpyrazolinium cation; and cations in which these cations further have at least one selected from the group consisting of a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group).

[0069] Examples of the cation structure represented by general formula (4) include a tetraalkylammonium cation structure, a trialkylsulfonium cation structure, a tetraalkylphosphonium cation structure, and structures in which a part of the alkyl groups is substituted with an alkenyl group, an alkoxyl group, or an epoxy group.

[0070] Specific examples of the cation species having the cation structure represented by general formula (4) include, for example, tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethylpropylammonium cation, trimethyldecylammonium cation, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N,N-dimethyl-N-ethyl-N-propylammonium cation, N,N-dimethyl-N-ethyl-N-butylammonium cation, N,N-dimethyl-N-ethyl-N-pentylammonium cation, N,N-dimethyl-N-ethyl-N-hexylammonium cation, N,N-dimethyl-N-ethyl-N-heptylammonium cation, N,N-dimethyl-N-ethyl-N-nonylammonium cation, N,N -dimethyl-N,N-dipropylammonium cation, N,N-diethyl-N-propyl-N-butylammonium cation, N,N-dimethyl-N-propyl-N-pentylammonium cation, N,N-dimethyl-N-propyl-N-hexylammonium cation, N,N-dimethyl-N-propyl-N-heptylammonium cation, N,N-dimethyl-N-butyl-N-hexylammonium cation, N,N-diethyl-N-butyl-N-heptylammonium cation, N,N-dimethyl-N-pentyl-N-hexylammonium ammonium cation, N,N-dimethyl-N,N-dihexylammonium cation, trimethylheptylammonium cation, N,N-diethyl-N-methyl-N-propylammonium cation, N,N-diethyl-N-methyl-N-pentylammonium cation, N,N-diethyl-N-methyl-N-heptylammonium cation, N,N-diethyl-N-propyl-N-pentylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, triethylheptylammonium cation, N,Tetraalkylammonium cations such as N-dipropyl-N-methyl-N-ethylammonium cation, N,N-dipropyl-N-methyl-N-pentylammonium cation, N,N-dipropyl-N-butyl-N-hexylammonium cation, N,N-dipropyl-N,N-dihexylammonium cation, N,N-dibutyl-N-methyl-N-pentylammonium cation, N,N-dibutyl-N-methyl-N-hexylammonium cation, trioctylmethylammonium cation, and N-methyl-N-ethyl-N-propyl-N-pentylammonium cation; trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, and the like. trialkylsulfonium cations such as tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation; and cations in which these cations further have at least one selected from the group consisting of a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group).

[0071] As the metal cation, any appropriate metal cation can be used as long as it does not impair the effects of the present invention. In terms of being able to further exhibit the effects of the present invention, such metal cation is preferably an alkali metal cation such as a Li cation, a Na cation, or a K cation.

[0072] The ionic compound may be a compound consisting of the above-described cation species and at least one anion species selected from the group consisting of borate anion and dicyanamide anion.In terms of being able to further exhibit the effects of the present invention, the ionic compound may preferably be a compound consisting of a combination of pyridinium cation and borate anion, a compound consisting of a combination of pyridinium cation and dicyanamide anion, a compound consisting of a combination of imidazolium cation and borate anion, a compound consisting of a combination of imidazolium cation and dicyanamide anion, a compound consisting of a combination of metal cation and borate anion, or a compound consisting of a combination of metal cation and dicyanamide anion, and more preferably Examples of suitable cation exchangers include 1-butyl-3-methylpyridinium bis(oxalate)borate, 1-butyl-3-methylpyridinium dicyanamide, 1-ethyl-3-methylimidazolium bis(oxalate)borate, 1-ethyl-3-methylimidazolium dicyanamide, 1-hexyl-3-methylimidazolium bis(oxalate)borate, 1-hexyl-3-methylimidazolium dicyanamide, 1-octyl-3-methylimidazolium bis(oxalate)borate, 1-octyl-3-methylimidazolium dicyanamide, lithium bis(oxalate)borate, and lithium dicyanamide.

[0073] The ionic compound may be commercially available or synthesized by any suitable method. For example, the ionic liquid may be synthesized by the halide method, hydroxide method, acid ester method, complex formation method, neutralization method, or the like, as described in "Ionic Liquids - The Frontline and Future of Development" (published by CMC Publishing).

[0074] <<2-2. Acrylic Pressure-Sensitive Adhesive Composition (A)>> One embodiment of the pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive composition (A). The acrylic pressure-sensitive adhesive composition (A) contains an acrylic resin (A) as a base polymer and an ionic compound. As the ionic compound, the ionic compounds described in the section <<2-1. Ionic Compounds>> can be used.

[0075] <2-2-a. Acrylic Resin (A)> The content of the acrylic resin (A) in the acrylic pressure-sensitive adhesive composition (A), calculated as solid content, is preferably 60 wt % to 99.999 wt %, more preferably 65 wt % to 99.99 wt %, even more preferably 70 wt % to 99.9 wt %, particularly preferably 75 wt % to 99.9 wt %, and most preferably 78 wt % to 99.9 wt %.

[0076] As the acrylic resin (A), any appropriate acrylic resin can be used as long as it does not impair the effects of the present invention.

[0077] The weight average molecular weight of the acrylic resin (A) is preferably 300,000 to 2,500,000, more preferably 350,000 to 2,000,000, even more preferably 400,000 to 1,800,000, and particularly preferably 500,000 to 1,500,000, in terms of being able to further exhibit the effects of the present invention.

[0078] The acrylic resin (A) is preferably an acrylic resin formed by polymerization from a composition (A) containing: (component a) a (meth)acrylic acid alkyl ester in which the alkyl group in the alkyl ester moiety has 4 to 12 carbon atoms; and (component b) at least one selected from the group consisting of a (meth)acrylic acid ester having an OH group and (meth)acrylic acid, in order to further exhibit the effects of the present invention.

[0079] The component a and the component b may each independently be one type or two or more types.

[0080] Examples of (meth)acrylic acid alkyl esters (component a) in which the alkyl group in the alkyl ester moiety has 4 to 12 carbon atoms include n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. Among these, n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferred, and n-butyl acrylate and 2-ethylhexyl acrylate are more preferred, in terms of the ability to further exhibit the effects of the present invention.

[0081] Examples of the at least one (component b) selected from the group consisting of (meth)acrylic acid esters having an OH group and (meth)acrylic acid include (meth)acrylic acid esters having an OH group such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate. Among these, hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, and (meth)acrylic acid are preferred, and hydroxyethyl acrylate, hydroxybutyl acrylate, and acrylic acid are more preferred, in terms of being able to further exhibit the effects of the present invention.

[0082] The composition (A) may contain a copolymerizable monomer (component c) other than the components a and b. The copolymerizable monomer (component c) may be of one type only, or may be of two or more types. Examples of such copolymerizable monomers (component c) include (meth)acrylic acid alkyl esters in which the alkyl group in the alkyl ester moiety has 1 to 3 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate; carboxyl group-containing monomers (excluding (meth)acrylic acid) such as itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and acid anhydrides thereof (for example, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride); amide group-containing monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide; and amino group-containing monomers such as aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate. mers; epoxy group-containing monomers such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; heterocycle-containing monomers such as N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, and vinyloxazole; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; phosphate group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate; (meth)acrylic acid esters having an alicyclic hydrocarbon group such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate;Aromatic ring-containing (meth)acrylates such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenoxybenzyl (meth)acrylate (for example, m-phenoxybenzyl (meth)acrylate), thiophenoxybenzyl (meth)acrylate, and benzyl benzyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypoly (meth)acrylic acid alkoxyalkyl esters such as polyethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyl toluene; olefins and dienes such as ethylene, butadiene, isoprene, and isobutylene; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

[0083] A polyfunctional monomer may also be used as the copolymerizable monomer (component c). A polyfunctional monomer refers to a monomer having two or more ethylenically unsaturated groups in one molecule. Any appropriate ethylenically unsaturated group may be used as the ethylenically unsaturated group as long as the effects of the present invention are not impaired. Examples of such ethylenically unsaturated groups include radically polymerizable functional groups such as vinyl groups, propenyl groups, isopropenyl groups, vinyl ether groups (vinyloxy groups), and allyl ether groups (allyloxy groups). Examples of polyfunctional monomers include hexanediol di(meth)acrylate, butanediol di(meth)acrylate, (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 hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate.

[0084] The copolymerizable monomer (component c) is preferably a (meth)acrylic acid alkyl ester in which the alkyl group in the alkyl ester moiety has 1 to 3 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, or propyl (meth)acrylate; a heterocycle-containing monomer such as N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, or vinyloxazole; or a phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenoxybenzyl (meth)acrylate (for example, m-phenoxybenzyl (meth)acrylate), thiophenoxybenzyl (meth)acrylate, or benzyl benzyl (meth)acrylate. Examples of aromatic ring-containing (meth)acrylates include (meth)acrylic acid alkoxyalkyl esters such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate; and more preferred examples include methyl (meth)acrylate, N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, benzyl (meth)acrylate, phenoxybenzyl (meth)acrylate, and 2-methoxyethyl (meth)acrylate.

[0085] The content of the (meth)acrylic acid alkyl ester (component a) having 4 to 12 carbon atoms in the alkyl group of the alkyl ester moiety in the total amount of monomer components constituting the acrylic resin (A) is, in order to further exhibit the effects of the present invention, for example, 10% by weight or more, preferably 20% by weight or more, more preferably 30% by weight or more, even more preferably 50 to 99% by weight, and particularly preferably 60 to 98% by weight, relative to the total amount of monomer components constituting the acrylic resin (A). In one embodiment, the content of the (meth)acrylic acid alkyl ester (component a) having 4 to 12 carbon atoms in the alkyl group of the alkyl ester moiety is more preferably 70 to 97% by weight, particularly preferably 80 to 97% by weight, and most preferably 88 to 96% by weight.

[0086] The content of at least one selected from the group consisting of (meth)acrylic acid esters having an OH group and (meth)acrylic acid (component b) in the total amount of monomer components constituting the acrylic resin (A) is, for example, 0.1% by weight or more, preferably 0.2 to 30% by weight, more preferably 0.3 to 20% by weight, even more preferably 0.4 to 15% by weight, and particularly preferably 0.5 to 12% by weight, relative to the total amount of monomer components constituting the acrylic resin (A), in order to further exhibit the effects of the present invention.

[0087] The content of the copolymerizable monomer (component c) in the total amount of the monomer components constituting the acrylic resin (A) is, for example, 0 to 80% by weight, preferably 0 to 70% by weight, more preferably 0 to 60% by weight, even more preferably 0 to 50% by weight, particularly preferably 0 to 40% by weight, and most preferably 0 to 30% by weight, relative to the total amount of the monomer components constituting the acrylic resin (A), in terms of being able to further exhibit the effects of the present invention.

[0088] In one embodiment, the monomer components constituting the acrylic resin (A) may contain, as the copolymerizable monomer (component c), the aforementioned (meth)acrylic acid alkyl ester in which the alkyl group in the alkyl ester moiety has 1 to 3 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, or propyl (meth)acrylate. When the monomer components constituting the acrylic resin (A) contain such a (meth)acrylic acid alkyl ester in which the alkyl group in the alkyl ester moiety has 1 to 3 carbon atoms, the content of such a (meth)acrylic acid alkyl ester in which the alkyl group in the alkyl ester moiety has 1 to 3 carbon atoms in the total amount of the monomer components constituting the acrylic resin (A) is preferably 0.1 wt % or more, more preferably 0.1 wt % to 40 wt %, even more preferably 0.5 wt % to 30 wt %, and particularly preferably 1 wt % to 20 wt %, relative to the total amount of the monomer components constituting the acrylic resin (A).

[0089] In one embodiment, the monomer components constituting the acrylic resin (A) may contain, as a copolymerizable monomer (component c), the aforementioned heterocycle-containing monomers such as N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, and vinyloxazole. When the monomer components constituting the acrylic resin (A) contain such heterocycle-containing monomers, the content of such heterocycle-containing monomers in the total amount of the monomer components constituting the acrylic resin (A) is preferably 0.1 wt % or more, more preferably 0.1 wt % to 30 wt %, even more preferably 0.5 wt % to 25 wt %, and particularly preferably 1 wt % to 20 wt %, based on the total amount of the monomer components constituting the acrylic resin (A).

[0090] The composition (A) may contain any appropriate other components as long as the effects of the present invention are not impaired. Examples of such other components include a polymerization initiator, a chain transfer agent, and a solvent. The content of these other components may be any appropriate content as long as the effects of the present invention are not impaired.

[0091] The polymerization initiator may be a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), or the like, depending on the type of polymerization reaction. Only one type of polymerization initiator may be used, or two or more types may be used.

[0092] A thermal polymerization initiator is preferably employed when obtaining the acrylic resin (A) by solution polymerization. Examples of such thermal polymerization initiators include azo polymerization initiators, peroxide polymerization initiators (e.g., dibenzoyl peroxide, tert-butyl permaleate), and redox polymerization initiators. Among these thermal polymerization initiators, the azo polymerization initiators disclosed in JP-A-2002-69411 are particularly preferred. Such azo polymerization initiators are preferred because decomposition products of the polymerization initiator are less likely to remain in the acrylic polymer as moieties that cause the generation of gases (outgassing) upon heating. Examples of azo polymerization initiators include 2,2'-azobisisobutyronitrile (hereinafter sometimes referred to as AIBN), 2,2'-azobis-2-methylbutyronitrile (hereinafter sometimes referred to as AMBN), 2,2'-azobis(2-methylpropionate)dimethyl, and 4,4'-azobis-4-cyanovaleric acid.

[0093] The photopolymerization initiator can be preferably used when obtaining the acrylic resin (A) by active energy ray polymerization. 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, and thioxanthone-based photopolymerization initiators. Specific examples of these photopolymerization initiators that can be used include known photopolymerization initiators.

[0094] As the chain transfer agent, known chain transfer agents can be used. The chain transfer agent may be one kind or two or more kinds.

[0095] Any appropriate solvent can be used as the solvent as long as it does not impair the effects of the present invention. Examples of such solvents 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; and ketones such as methyl ethyl ketone and methyl isobutyl ketone. Only one type of solvent may be used, or two or more types may be used.

[0096] The acrylic resin (A) can be produced by any appropriate polymerization method as long as the effects of the present invention are not impaired. Polymerization methods that can be used to polymerize the acrylic resin (A) include, for example, solution polymerization, emulsion polymerization, bulk polymerization, and active energy ray polymerization using ultraviolet or other radiation. Representative examples include solution polymerization and active energy ray polymerization, with solution polymerization being preferred. The monomer supply method used in solution polymerization can be appropriately selected from a batch feed method in which the entire amount of the monomer components is supplied at once, a continuous feed (dropping) method, a divided feed (dropping) method, and the like. The polymerization temperature can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, and the like, and is preferably 20°C to 160°C, more preferably 30°C to 140°C, even more preferably 40°C to 120°C, and particularly preferably 50°C to 100°C. The polymerization time can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, and the like, and is preferably 1 hour to 24 hours, more preferably 1 hour to 12 hours.

[0097] The amount of the polymerization initiator used may be any appropriate amount as long as the effects of the present invention are not impaired. The amount of the polymerization initiator used is, for example, preferably 0.01 to 15% by weight based on the total amount of the monomer components constituting the acrylic resin (A).

[0098] The amount of the chain transfer agent used may be any appropriate amount as long as the effects of the present invention are not impaired, and is, for example, preferably 0.01 to 15% by weight based on the total amount of the monomer components constituting the acrylic resin (A).

[0099] <2-2-b. Crosslinking agent> The acrylic pressure-sensitive adhesive composition (A) may contain a crosslinking agent. Use of a crosslinking agent can further enhance the effects of the present invention. The crosslinking agent may be of only one type, or may be of two or more types.

[0100] Examples of crosslinking agents include polyfunctional isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, as well as urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. Among these, at least one selected from the group consisting of polyfunctional isocyanate-based crosslinking agents and epoxy-based crosslinking agents is preferred in terms of being able to further exhibit the effects of the present invention. The crosslinking agent may be one type only, or two or more types may be used.

[0101] As the polyfunctional isocyanate-based crosslinking agent, 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, etc.) in one molecule can be used. Specific examples of the polyfunctional isocyanate 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 (for example, manufactured by Mitsui Chemicals, Inc., trade name: Takenate D101E), trimethylolpropane / hexamethylene diisocyanate trimer adduct (for example, manufactured by Tosoh Corporation, trade name: Coronate HL), and isocyanurate of hexamethylene diisocyanate (for example, Examples of suitable polyisocyanates include isocyanate adducts such as those manufactured by Tosoh Corporation under the trade name of Coronate HX; trimethylolpropane adducts of xylylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D110N), trimethylolpropane adducts of xylylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D120N), trimethylolpropane adducts of isophorone diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D140N), and trimethylolpropane adducts of hexamethylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D160N); polyether polyisocyanates, polyester polyisocyanates, and adducts of these with various polyols; and polyisocyanates multifunctionalized with isocyanurate bonds, biuret bonds, allophanate bonds, etc.

[0102] Examples of epoxy crosslinking agents (polyfunctional epoxy compounds) 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 methyl ... Examples of the epoxy crosslinking agent include diglycidyl ether, 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 the epoxy crosslinking agent include commercially available products such as "Tetrad C" (manufactured by Mitsubishi Gas Chemical Company, Inc.).

[0103] The content of the crosslinking agent in the acrylic pressure-sensitive adhesive composition (A) may be any appropriate content within a range that does not impair the effects of the present invention. In order to further exhibit the effects of the present invention, the content is preferably 0.005 to 20 parts by weight, more preferably 0.01 to 10 parts by weight, and even more preferably 0.05 to 5 parts by weight relative to the solid content (100 parts by weight) of the acrylic resin (A).

[0104] <2-2-c. Acrylic Oligomer> The acrylic pressure-sensitive adhesive composition (A) may contain an acrylic oligomer. The acrylic oligomer may be one type only, or two or more types may be used.

[0105] The content of the acrylic oligomer in the acrylic pressure-sensitive adhesive composition (A) is preferably 0 to 50 parts by weight, more preferably 0 to 40 parts by weight, and even more preferably 0 to 30 parts by weight, relative to the solid content (100 parts by weight) of the acrylic resin (A).

[0106] The weight average molecular weight of the acrylic oligomer is preferably 1,000 to 30,000, more preferably 1,000 to 20,000, still more preferably 1,500 to 10,000, and particularly preferably 2,000 to 8,000. The weight average molecular weight (Mw) can be determined in polystyrene equivalent terms by the GPC method.

[0107] The acrylic oligomer is preferably an acrylic oligomer obtained from a monomer component containing, as an essential component, a (meth)acrylic acid ester having a cyclic structure in the molecule.

[0108] The (meth)acrylic acid ester having a cyclic structure in the molecule may be of one type only, or of two or more types.

[0109] 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-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate; Examples of (meth)acrylic acid esters include (meth)acrylic acid esters having three or more aliphatic hydrocarbon rings, such as 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; and from the viewpoint of being able to further exhibit the effects of the present invention, preferred are cyclohexyl acrylate, cyclohexyl methacrylate, dicyclopentanyl acrylate, and dicyclopentanyl methacrylate.

[0110] The content of the (meth)acrylic acid ester having a cyclic structure in the molecule relative to the total amount of monomer components constituting the acrylic oligomer is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 99% by weight, even more preferably 80% by weight to 98% by weight, particularly preferably 90% by weight to 97% by weight, and most preferably 92% by weight to 97% by weight.

[0111] The monomer components constituting the acrylic oligomer may contain a carboxyl group-containing monomer. Examples of such carboxyl group-containing monomers include (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and acid anhydrides thereof (e.g., acid anhydride group-containing monomers such as maleic anhydride and itanoic anhydride). Such carboxyl group-containing monomers may be used alone or in combination of two or more.

[0112] The content of the carboxyl group-containing monomer relative to the total amount of monomer components constituting the acrylic oligomer is preferably 0 to 20% by weight, more preferably 1 to 10% by weight, even more preferably 2 to 9% by weight, particularly preferably 3 to 8% by weight, and most preferably 4 to 7% by weight.

[0113] The monomer component constituting the acrylic oligomer may contain other monomers, and such other monomers may be of only one type or of two or more types.

[0114] The content ratio of the other monomers relative to the total amount of the monomer components constituting the acrylic oligomer is preferably 0 to 50% by weight, more preferably 0 to 30% by weight, even more preferably 0 to 20% by weight, particularly preferably 0 to 10% by weight, and most preferably 0 to 5% by weight.

[0115] Examples of other monomers include (meth)acrylic acids such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, and isodecyl (meth)acrylate. alkyl esters; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate and methyl glycidyl (meth)acrylate; vinyl ester monomers such as vinyl acetate and vinyl propionate; hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate and hydroxybutyl (meth)acrylate; alkoxyalkyl (meth)acrylate monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; olefin monomers such as ethylene, propylene, isoprene and butadiene; and vinyl ether monomers such as vinyl ether.

[0116] Examples of other monomers include polyfunctional monomers such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, glycerin di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, divinylbenzene, butyl di(meth)acrylate, and hexyl di(meth)acrylate.

[0117] Examples of other monomers include nitrogen atom-containing monomers (for example, aminoalkyl (meth)acrylate monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; (N-substituted) amide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, and N-hydroxy(meth)acrylamide; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; and isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate).

[0118] The acrylic oligomer is preferably formed by polymerization from a composition containing a monomer component essentially consisting of a (meth)acrylic acid ester having a cyclic structure in the molecule, in order to further enhance the effects of the present invention. Such a composition may contain any other appropriate components in addition to the monomer component. Examples of such other components include polymerization initiators, chain transfer agents, solvents, other polymer components, crosslinking accelerators, crosslinking catalysts, silane coupling agents, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), antioxidants, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), foils, UV absorbers, antioxidants, light stabilizers, plasticizers, softeners, surfactants, antistatic agents, conductive agents, stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, and catalysts.

[0119] The explanations in the section <2-2-a. Acrylic resin (A)> can be used for the polymerization initiator, chain transfer agent, and solvent.

[0120] The acrylic oligomer can be prepared by any appropriate polymerization method as long as the effects of the present invention are not impaired. Polymerization methods that can be used to polymerize the acrylic oligomer include, for example, solution polymerization, emulsion polymerization, bulk polymerization, and active energy ray polymerization by irradiation with ultraviolet light or the like. Representative examples include solution polymerization and active energy ray polymerization, with solution polymerization being preferred. As a monomer supply method for solution polymerization, a batch charging method in which the entire amount of the monomer components is supplied at once, a continuous supply (dropping) method, a divided supply (dropping) method, or the like can be appropriately employed. The polymerization temperature can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, and the like, and is preferably 20°C to 160°C, more preferably 30°C to 140°C, even more preferably 40°C to 120°C, and particularly preferably 50°C to 100°C.

[0121] The amount of the polymerization initiator used may be any appropriate amount as long as the effects of the present invention are not impaired. The amount of the polymerization initiator used is, for example, preferably 0.01 to 15% by weight based on the total amount of the monomer components constituting the acrylic oligomer.

[0122] The amount of the chain transfer agent used may be any appropriate amount as long as it does not impair the effects of the present invention, and is, for example, preferably 0.01 to 15% by weight based on the total amount of the monomer components constituting the acrylic oligomer.

[0123] <2-2-d. Other Components> The acrylic pressure-sensitive adhesive composition (A) may contain any appropriate other components as long as the effects of the present invention are not impaired. Examples of such other components include other polymer components, crosslinking accelerators, crosslinking retarders, crosslinking catalysts, silane coupling agents, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), fatty acid esters, silicone additives, antioxidants, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), foil-like materials, UV absorbers, antioxidants, light stabilizers, plasticizers, softeners, surfactants, antistatic agents, conductive agents, stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, and catalysts.

[0124] The content of the other components in the acrylic pressure-sensitive adhesive composition (A) is preferably 0 to 30 parts by weight, more preferably 0 to 20 parts by weight, and even more preferably 0 to 10 parts by weight, relative to the solid content (100 parts by weight) of the acrylic resin (A).

[0125] <<2-3. Acrylic Pressure-Sensitive Adhesive Composition (B)>> One embodiment of the pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive composition (B). The acrylic pressure-sensitive adhesive composition (B) contains an acrylic resin (B) as a base polymer and an ionic compound. As the ionic compound, the ionic compounds described in the section <<2-1. Ionic Compounds>> can be used.

[0126] <2-3-a. Acrylic Resin (B)> The content of the acrylic resin (B) in the acrylic pressure-sensitive adhesive composition (B) is preferably 50 wt % to 99.999 wt %, more preferably 60 wt % to 99.99 wt %, even more preferably 65 wt % to 99.9 wt %, particularly preferably 70 wt % to 99 wt %, and most preferably 72 wt % to 95 wt %, calculated as solid content.

[0127] Any appropriate acrylic resin may be used as the acrylic resin (B) as long as it does not impair the effects of the present invention. For example, the acrylic resin (A) described in the section <1-2-a. Acrylic resin (A)> may be used as the acrylic resin (B).

[0128] <2-3-b. Crosslinking agent> The acrylic pressure-sensitive adhesive composition (B) may contain a crosslinking agent. Use of a crosslinking agent can further enhance the effects of the present invention. The crosslinking agent may be of only one type, or may be of two or more types.

[0129] As the crosslinking agent, the crosslinking agents explained in the section <2-2-b. Crosslinking agent> can be used.

[0130] The content of the crosslinking agent in the acrylic pressure-sensitive adhesive composition (B) may be any appropriate content ratio within a range that does not impair the effects of the present invention. In order to further exhibit the effects of the present invention, the content ratio is preferably 0.005 to 20 parts by weight, more preferably 0.01 to 10 parts by weight, even more preferably 0.01 to 5 parts by weight, particularly preferably 0.05 to 4 parts by weight, and most preferably 0.08 to 3 parts by weight, relative to the solid content (100 parts by weight) of the acrylic resin (B).

[0131] <2-3-c. Crosslinking catalyst> The acrylic pressure-sensitive adhesive composition (B) may contain a crosslinking catalyst. The crosslinking catalyst may be one type only, or two or more types may be used.

[0132] Any appropriate crosslinking catalyst can be used as long as it does not impair the effects of the present invention, including, for example, metal-based crosslinking catalysts such as tetra-n-butyl titanate, tetraisopropyl titanate, zirconium tetraacetylacetonate, iron diacetylacetonate, butyltin oxide, and dioctyltin dilaurate.

[0133] The content of the crosslinking catalyst in the acrylic pressure-sensitive adhesive composition (B) may be any appropriate content within a range that does not impair the effects of the present invention. In order to further exhibit the effects of the present invention, the content is preferably 0.0001 to 1 part by weight relative to the solid content (100 parts by weight) of the acrylic resin (B).

[0134] <2-3-d. Photocuring agent> The acrylic pressure-sensitive adhesive composition (B) may contain a photocuring agent. The photocuring agent may be a single type or two or more types.

[0135] Examples of the photocuring agent include a photocurable monomer and a photocurable oligomer. The photocuring agent is preferably a compound having two or more ethylenically unsaturated bonds in one molecule.

[0136] The photocuring agent is preferably a compound that is compatible with the base polymer, and in this respect, it is preferably a compound that is liquid at room temperature. Furthermore, the compatibility between the base polymer and the photocuring agent is also influenced by the molecular weight of the compound, and the smaller the molecular weight, the higher the compatibility with the base polymer. Therefore, the molecular weight of the photocuring agent is preferably 1,500 or less, more preferably 1,000 or less.

[0137] The photocuring agent is preferably a polyfunctional (meth)acrylate. Examples of the polyfunctional (meth)acrylate include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, bisphenol A ethylene oxide modified di(meth)acrylate, bisphenol A propylene oxide modified di(meth)acrylate, alkanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethoxylated isocyanuric acid tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol di(meth)acrylate. acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, dipentaerythritol hexa(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerin di(meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, butadiene (meth)acrylate, isoprene (meth)acrylate.

[0138] The functional group equivalent (g / eq) of the photocuring agent is preferably 100 to 500, more preferably 130 to 450, still more preferably 150 to 450, and particularly preferably 180 to 450.

[0139] The content of the photocuring agent in the acrylic pressure-sensitive adhesive composition (B) may be any appropriate content ratio within a range that does not impair the effects of the present invention. In order to further exhibit the effects of the present invention, the content ratio is preferably 1 to 100 parts by weight, more preferably 2 to 70 parts by weight, even more preferably 3 to 50 parts by weight, particularly preferably 4 to 40 parts by weight, and most preferably 5 to 35 parts by weight, relative to the solid content (100 parts by weight) of the acrylic resin (B).

[0140] <2-3-e. Photopolymerization initiator> The acrylic pressure-sensitive adhesive composition (B) may contain a photopolymerization initiator. The photopolymerization initiator may be one type or two or more types.

[0141] As the photopolymerization initiator, any appropriate photopolymerization initiator can be used as long as it does not impair the effects of the present invention. Examples of such photopolymerization initiators 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, and thioxanthone-based photopolymerization initiators.

[0142] 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, and anisole methyl ether. Examples of acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone. Examples of α-ketol-based photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Examples of aromatic sulfonyl chloride-based photopolymerization initiators include 2-naphthalenesulfonyl chloride. Examples of photoactive oxime-based photopolymerization initiators include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. Examples of benzoin-based photopolymerization initiators include benzoin. Examples of benzyl-based photopolymerization initiators include benzil. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexyl phenyl ketone. Examples of ketal-based photopolymerization initiators include benzil dimethyl ketal. Examples of thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0143] The content of the photopolymerization initiator in the acrylic pressure-sensitive adhesive composition (B) may be any appropriate content ratio within a range that does not impair the effects of the present invention. In order to further exhibit the effects of the present invention, the content ratio is preferably 0.02 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, relative to the solid content (100 parts by weight) of the acrylic resin (B).

[0144] <2-3-f. Other Components> The acrylic pressure-sensitive adhesive composition (B) may contain any appropriate other components as long as the effects of the present invention are not impaired. As such other components, the other components described in the section <2-2-d. Other Components> can be used.

[0145] The content of the other components in the acrylic pressure-sensitive adhesive composition (B) is preferably 0 to 40 parts by weight, more preferably 0 to 30 parts by weight, and even more preferably 0 to 20 parts by weight, relative to the solid content (100 parts by weight) of the acrylic resin (B).

[0146] <<2-4. Urethane-Based Pressure-Sensitive Adhesive Composition (C)>> One embodiment of the pressure-sensitive adhesive composition is a urethane-based pressure-sensitive adhesive composition (C). The urethane-based pressure-sensitive adhesive composition (C) contains a polyol as a base polymer and an ionic compound. As the ionic compound, the ionic compounds described in the section <<2-1. Ionic Compounds>> can be used.

[0147] <2-4-a. Polyol> As the polyol used as the base polymer, any suitable polyol can be used as long as it can be directly reacted with a polyfunctional isocyanate compound to produce a "one-shot type urethane polymer" within the scope of the present invention. Examples of such polyols include the polyols used as base polymers described in JP-A-2023-167113, and the description related to the polyol used as the base polymer described in JP-A-2023-167113 can be used as a description of the polyol in this specification.

[0148] The polyol preferably contains a polyol (a) having three OH groups and a number average molecular weight Mn of 300 to 100,000, from the viewpoint of further exhibiting the effects of the present invention. The polyol (a) may be one type or two or more types. The content of the polyol (a) in the polyol is preferably 5% by weight or more, more preferably 25% by weight to 100% by weight, even more preferably 50% by weight to 100% by weight, particularly preferably 70% by weight to 100% by weight, and most preferably 90% by weight to 100% by weight, from the viewpoint of further exhibiting the effects of the present invention.

[0149] The polyol (a) preferably contains a polyol (a1) having three OH groups and a number-average molecular weight Mn of 8,000 to 20,000, in order to further exhibit the effects of the present invention. The polyol (a1) may be of one type or two or more types. The number-average molecular weight Mn of the polyol (a1) is preferably 8,000 to 18,000, more preferably 8,500 to 16,000, even more preferably 8,500 to 14,000, particularly preferably 9,000 to 13,000, and most preferably 9,000 to 12,000, in order to further exhibit the effects of the present invention. The content of the polyol (a1) in the polyol is preferably 50% by weight or more, more preferably 60% to 100% by weight, even more preferably 70% to 95% by weight, particularly preferably 75% to 93% by weight, and most preferably 80% to 90% by weight, in order to further exhibit the effects of the present invention.

[0150] The polyol (a) may contain a polyol (a2) having three or more OH groups and a number-average molecular weight Mn of 5,000 or less. The polyol (a2) is preferably at least one selected from the group consisting of a polyol (triol) having three OH groups, a polyol (tetraol) having four OH groups, a polyol (pentaol) having five OH groups, and a polyol (hexaol) having six OH groups. The polyol (a2) may be one type or two or more types. The number-average molecular weight Mn of the polyol (a2) is preferably 500 to 5,000, more preferably 600 to 4,500, even more preferably 700 to 4,000, particularly preferably 800 to 3,500, and most preferably 900 to 3,300, in order to further exhibit the effects of the present invention. The content of polyol (a2) in the polyol is preferably 50% by weight or less, more preferably 0% by weight to 40% by weight, even more preferably 5% by weight to 30% by weight, particularly preferably 7% by weight to 25% by weight, and most preferably 10% by weight to 20% by weight, in terms of being able to further exhibit the effects of the present invention.

[0151] The content of the polyol (triol) having three OH groups in the polyol (a2) is preferably 80% by weight to 100% by weight, more preferably 90% by weight to 100% by weight, even more preferably 95% by weight to 100% by weight, particularly preferably 97% by weight to 100% by weight, and most preferably 99% by weight to 100% by weight, in order to further exhibit the effects of the present invention. As the polyol (triol) having three OH groups in the polyol (a2), it is preferable to use in combination two types of triols: a triol having a number average molecular weight Mn of 500 or more but less than 2000, and a triol having a number average molecular weight Mn of 2000 to 5000, in order to further exhibit the effects of the present invention. The content of the triol having a number average molecular weight Mn of 500 or more and less than 2000 in the polyol is preferably 0.01% by weight to 20% by weight, more preferably 0.05% by weight to 15% by weight, even more preferably 0.1% by weight to 10% by weight, particularly preferably 0.5% by weight to 5% by weight, and most preferably 1% by weight to 3% by weight, in order to further exhibit the effects of the present invention. The content of the triol having a number average molecular weight Mn of 2000 to 5000 in the polyol is preferably 1% by weight to 30% by weight, more preferably 2% by weight to 25% by weight, even more preferably 5% by weight to 20% by weight, particularly preferably 7% by weight to 20% by weight, and most preferably 9% by weight to 17% by weight, in order to further exhibit the effects of the present invention.

[0152] The polyol may contain a polyol having four or more OH groups and a number average molecular weight Mn of not more than 20000. The polyol having four or more OH groups and a number average molecular weight Mn of not more than 20000 may be one kind or two or more kinds.

[0153] <2-4-b. Polyfunctional isocyanate compound> The urethane-based pressure-sensitive adhesive composition (C) may contain a polyfunctional isocyanate compound. Use of a polyfunctional isocyanate compound can further enhance the effects of the present invention. The polyfunctional isocyanate compound may be one type or two or more types.

[0154] As the polyfunctional isocyanate compound, any suitable polyfunctional isocyanate compound can be used as long as it is a polyfunctional isocyanate compound that can be directly reacted with a polyol to produce a "one-shot type urethane polymer" within the scope of the present invention. Examples of such polyfunctional isocyanate compounds include the polyfunctional isocyanate compounds described in JP 2023-167113 A, and the description related to the polyfunctional isocyanate compound described in JP 2023-167113 A can be used as a description of the polyfunctional isocyanate compound in this specification.

[0155] When a one-shot urethane polymer is prepared by reacting a polyfunctional isocyanate compound with a polyol as a base polymer, the equivalent ratio ([NCO] / [OH]) of the isocyanate groups (NCO groups) of the polyfunctional isocyanate compound to the hydroxyl groups (OH groups) of the polyol is preferably 1.00 to 3.00, more preferably 1.10 to 2.50, even more preferably 1.20 to 2.00, and particularly preferably 1.30 to 1.90.

[0156] <2-4-c. Other Components> The urethane-based pressure-sensitive adhesive composition (C) may contain any appropriate other component within the scope of not impairing the effects of the present invention. As such other component, the other components described in the section <2-2-d. Other Components> can be used.

[0157] The content of the other components in the urethane-based pressure-sensitive adhesive composition (C) is preferably 0 to 40 parts by weight, more preferably 0 to 30 parts by weight, and even more preferably 0 to 20 parts by weight, relative to 100 parts by weight of the polyol as the base polymer.

[0158] <2-5. Urethane-Based Pressure-Sensitive Adhesive Composition (D)> One embodiment of the pressure-sensitive adhesive composition is a urethane-based pressure-sensitive adhesive composition (D). The urethane-based pressure-sensitive adhesive composition (D) contains a urethane prepolymer as a base polymer and an ionic compound. As the ionic compound, the ionic compounds described in the section <2-1. Ionic Compounds> can be used.

[0159] <2-5-a. Urethane prepolymer> As the urethane prepolymer as the base polymer, any appropriate urethane prepolymer can be used as long as it is a urethane prepolymer that can be reacted with a polyfunctional isocyanate compound to produce a "prepolymer-type urethane polymer" within the scope that does not impair the effects of the present invention. Examples of such urethane prepolymers include the urethane prepolymers used as base polymers described in JP 2023-167112 A, and the description related to the urethane prepolymer used as the base polymer described in JP 2023-167112 A can be used as a description of the urethane prepolymer in this specification.

[0160] The urethane prepolymer is preferably a polyurethane polyol, more preferably obtained by reacting a polyol with a polyfunctional isocyanate compound. The number average molecular weight Mn of the urethane prepolymer is, for example, 3,000 to 1,000,000.

[0161] The polyol includes at least one selected from the group consisting of polyester polyols and polyether polyols. Typically, the polyol is at least one selected from the group consisting of polyester polyols and polyether polyols. The polyester polyol may be of only one type, or may be of two or more types. The polyether polyol may be of only one type, or may be of two or more types.

[0162] As the polyester polyol, any polyester polyol that can be normally used in the preparation of urethane prepolymers can be used as appropriate. The molecular weight of the polyester polyol is, for example, 100 to 100,000 in terms of number average molecular weight Mn, and preferably 100 to 10,000.

[0163] The polyether polyol may be any polyether polyol that can be commonly used in the preparation of urethane prepolymers. The molecular weight of the polyether polyol is, for example, 100 to 100,000 in terms of number average molecular weight Mn, and preferably 100 to 10,000.

[0164] One embodiment of the polyol is embodiment (A), which contains both a polyester polyol and a polyether polyol. In embodiment (A), the content of the polyester polyol in the polyol is preferably 0.1 wt% to 99.9 wt%, more preferably 0.1 wt% to 80 wt%, even more preferably 0.2 wt% to 60 wt%, even more preferably 0.2 wt% to 40 wt%, particularly preferably 0.3 wt% to 30 wt%, and most preferably 0.3 wt% to 20 wt%. In embodiment (A), the content of the polyether polyol in the polyol is preferably 0.1 wt% to 99.9 wt%, more preferably 20 wt% to 99.9 wt%, even more preferably 40 wt% to 99.8 wt%, even more preferably 60 wt% to 99.8 wt%, particularly preferably 70 wt% to 99.7 wt%, and most preferably 80 wt% to 99.7 wt%.

[0165] Another embodiment of the polyol is embodiment (B) which includes a polyether polyol without including a polyester polyol.

[0166] To prepare the urethane prepolymer, the polyfunctional isocyanate compound is preferably used in an equivalent ratio such that the number of isocyanate groups (NCO groups) in the polyol is less than the number of hydroxyl groups (OH groups) in the polyol. The NCO group / OH group equivalent ratio ([NCO] / [OH]) is preferably 0.1 to 0.99, more preferably 0.2 to 0.95, and even more preferably 0.3 to 0.90.

[0167] <2-5-b. Polyfunctional isocyanate compound> The urethane-based pressure-sensitive adhesive composition (D) may contain a polyfunctional isocyanate compound. Use of a polyfunctional isocyanate compound can further enhance the effects of the present invention. The polyfunctional isocyanate compound may be one type or two or more types.

[0168] As the polyfunctional isocyanate compound, any suitable polyfunctional isocyanate compound can be used as long as it is a polyfunctional isocyanate compound that can be reacted with a urethane prepolymer to produce a "prepolymer-type urethane polymer" within the scope of the present invention. Examples of such polyfunctional isocyanate compounds include the polyfunctional isocyanate compounds described in JP 2023-167112 A, and the description related to the polyfunctional isocyanate compound described in JP 2023-167112 A can be used as a description of the polyfunctional isocyanate compound in this specification.

[0169] When a prepolymer-type urethane polymer is prepared by reacting a polyfunctional isocyanate compound with a urethane prepolymer as a base polymer, the equivalent ratio ([NCO] / [OH]) of the isocyanate groups (NCO groups) of the polyfunctional isocyanate compound to the hydroxyl groups (OH groups) of the urethane prepolymer is preferably 0.60 to 1.30, more preferably 0.70 to 1.25, even more preferably 0.75 to 1.22, and particularly preferably 0.75 to 1.20.

[0170] <2-5-c. Other Components> The urethane-based pressure-sensitive adhesive composition (D) may contain any appropriate other component within the scope of not impairing the effects of the present invention. As such other component, the other components described in the section <2-2-d. Other Components> can be used.

[0171] The content of the other components in the urethane-based pressure-sensitive adhesive composition (D) is preferably 0 to 40 parts by weight, more preferably 0 to 30 parts by weight, and even more preferably 0 to 20 parts by weight, relative to 100 parts by weight of the polyol as the base polymer.

[0172] <<3. Pressure-sensitive adhesive film>> A pressure-sensitive adhesive film according to an embodiment of the present invention includes a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive formed from a pressure-sensitive adhesive composition according to an embodiment of the present invention. Representative pressure-sensitive adhesive compositions according to embodiments of the present invention include the acrylic pressure-sensitive adhesive composition (A), the acrylic pressure-sensitive adhesive composition (B), the urethane pressure-sensitive adhesive composition (C), and the urethane pressure-sensitive adhesive composition (D) described above.

[0173] The pressure-sensitive adhesive is formed from a pressure-sensitive adhesive composition. The pressure-sensitive adhesive can be formed by any appropriate method as long as the effects of the present invention are not impaired. Examples of such methods include a method in which the pressure-sensitive adhesive composition is applied to any appropriate substrate, and if necessary, heated, irradiated with active energy rays (such as ultraviolet rays), dried, or the like, and then cured as necessary to form a pressure-sensitive adhesive on the substrate.

[0174] As the substrate, for example, the substrate layer or release liner explained in the section <<1. Overall Configuration>> can be used.

[0175]

[0043] As the heating and drying conditions, any appropriate conditions can be adopted as long as the effects of the present invention are not impaired. Examples of the method for applying the acrylic pressure-sensitive adhesive composition (A) include methods using a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, an air knife coater, a spray coater, a comma coater, a direct coater, and a roll brush coater.

[0176] The pressure-sensitive adhesive film according to an embodiment of the present invention includes a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive. The pressure-sensitive adhesive film according to an embodiment of the present invention typically includes a pressure-sensitive adhesive layer and a substrate layer as described in Section «1. Overall Configuration». The pressure-sensitive adhesive film according to an embodiment of the present invention may include a release liner as described in Section «1. Overall Configuration» on the surface of the pressure-sensitive adhesive layer opposite the substrate layer. The pressure-sensitive adhesive film according to an embodiment of the present invention may include, in addition to the pressure-sensitive adhesive layer and the substrate layer, any other appropriate layer as described in Section «1. Overall Configuration».

[0177] The PSA film according to the embodiment of the present invention can be produced by any suitable method, for example, a known method for producing a PSA film including a base layer and a PSA layer.

[0178] The pressure-sensitive adhesive layer included in the pressure-sensitive adhesive film according to an embodiment of the present invention may be formed by a formation method generally referred to as a "direct method," or may be formed by a formation method generally referred to as a "transfer method." The direct method is a method in which a pressure-sensitive adhesive composition according to an embodiment of the present invention is applied to a substrate layer, and if necessary, heating, irradiation with active energy rays (such as ultraviolet rays), drying, etc. are performed to form a pressure-sensitive adhesive layer. The transfer method is a method in which a pressure-sensitive adhesive composition according to an embodiment of the present invention is applied to a release paper or the like, dried, to form a pressure-sensitive adhesive layer, and the formed pressure-sensitive adhesive layer is transferred to a substrate layer.

[0179] Examples of the application method include a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, air knife coater, spray coater, comma coater, direct coater, and roll brush coater.

[0180] The pressure-sensitive adhesive film according to the embodiment of the present invention can be used for any suitable purpose. In terms of being able to effectively exhibit the effects of the present invention, the pressure-sensitive adhesive film according to the embodiment of the present invention can be preferably used for at least one selected from the group consisting of a surface protection film and a reinforcing film.

[0181] The PSA film according to the embodiment of the present invention can exhibit any appropriate peel strength (which may be expressed as adhesive strength) depending on the type of PSA composition.

[0182] The acrylic pressure-sensitive adhesive film (A) including a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive formed from the acrylic pressure-sensitive adhesive composition (A) preferably has a glass peel strength of 0.005 N / 25 mm to 50 N / 25 mm, which will be described as an evaluation in Examples and Comparative Examples below.

[0183] The acrylic pressure-sensitive adhesive film (A) including a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive formed from the acrylic pressure-sensitive adhesive composition (A) preferably has a peel strength (1) against polyimide, which will be described as an evaluation in Examples and Comparative Examples below, of 0.005 N / 25 mm to 50 N / 25 mm.

[0184] The acrylic pressure-sensitive adhesive film (B) including a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive formed from the acrylic pressure-sensitive adhesive composition (B) has a peel strength (2) from polyimide, which will be described as an evaluation in Examples and Comparative Examples below, of preferably 0.001 N / 25 mm to 1 N / 25 mm, more preferably 0.005 N / 25 mm to 0.8 N / 25 mm, even more preferably 0.01 N / 25 mm to 0.6 N / 25 mm, particularly preferably 0.015 N / 25 mm to 0.4 N / 25 mm, and most preferably 0.02 N / 25 mm to 0.2 N / 25 mm, before UV irradiation.

[0185] The acrylic pressure-sensitive adhesive film (B) including a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive formed from the acrylic pressure-sensitive adhesive composition (B) has a polyimide peel strength (2) after UV irradiation, which will be described as an evaluation in the Examples and Comparative Examples below, of preferably 1.5 N / 25 mm or more, more preferably 2 N / 25 mm or more, even more preferably 3 N / 25 mm or more, particularly preferably 4 N / 25 mm or more, and most preferably 5 N / 25 mm or more. The higher the upper limit of the polyimide peel strength (2) after UV irradiation, the better.

[0186] <<4. Optical Devices and Electronic Devices>> The pressure-sensitive adhesive films according to embodiments of the present invention are typically attached to exposed surfaces of optical or electronic components to prevent scratches on the surfaces of the optical or electronic components and to impart impact resistance during processing, assembly, inspection, transportation, etc. in the manufacturing process of optical or electronic devices, and can be suitably used for surface protection and reinforcement of optical or electronic components. An optical device according to an embodiment of the present invention includes a pressure-sensitive adhesive film according to an embodiment of the present invention. An electronic device according to an embodiment of the present invention includes a pressure-sensitive adhesive film according to an embodiment of the present invention.

[0187] <<5. Application to OCA>> The ionic compound contained in the pressure-sensitive adhesive composition according to an embodiment of the present invention can also be suitably applied to pressure-sensitive adhesives (e.g., OCA (Optical Clear Adhesive)) and anchor layers (undercoat layers) used in touch panels, displays, and the like. The ionic compound contained in the pressure-sensitive adhesive composition according to an embodiment of the present invention can be incorporated into the pressure-sensitive adhesive layer, anchor layer, or other layer in, for example, an optical laminate including a polarizing film and a pressure-sensitive adhesive layer, or an optical laminate including a polarizing film, an anchor layer, and a pressure-sensitive adhesive layer, thereby achieving both excellent antistatic properties and corrosion resistance.

[0188] The present invention will be specifically described below using examples, but the present invention is not limited to these examples. The test and evaluation methods used in the examples are as follows. The term "parts" means "parts by weight" unless otherwise specified, and the term "%" means "% by weight" unless otherwise specified.

[0189] <Measurement of surface resistance value of the surface of the pressure-sensitive adhesive layer> The release liner was peeled off from the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film to expose the pressure-sensitive adhesive layer, and a probe (manufactured by TREK, trade name: Model 152P-2P) was brought into contact with the surface of the pressure-sensitive adhesive layer in an environment of a temperature of 25°C and a relative humidity of 50%, and the surface resistance was measured using a resistivity meter (manufactured by TREK, trade name: Model 152-1) under conditions of an applied voltage of 100 V and a voltage application time of 15 seconds. The numerical value "X.E+Y" shown in the table represents "X×10 Y For example, "3.3.E+11" in the table means "3.3×10 11 " means.

[0190] <Evaluation method for corrosion resistance (1)> The adhesive film was cut into a size of 30 mm x 80 mm and pressed onto a 50 mm x 100 mm copper foil using a hand roller to prepare an evaluation sample. This evaluation sample was left for 24 hours in an environment of 60°C temperature and 90% relative humidity, and then the surface of the copper foil was visually observed. Evaluation was performed according to the following criteria. ◯: No discoloration due to corrosion was observed on the surface of the copper foil. ×: Discoloration due to corrosion was observed on the surface of the copper foil.

[0191] <Method for evaluating corrosion resistance (2)> The adhesive film was cut into a size of 30 mm x 80 mm, and pressed onto a copper foil of 50 mm x 100 mm with a hand roller. The film was then exposed to ultraviolet light (365 nm LED, cumulative light intensity 1000 mJ / cm 2 ) to photo-cure the adhesive layer, and the resultant was used as an evaluation sample. This evaluation sample was left for 24 hours in an environment of a temperature of 60°C and a relative humidity of 90%, and then the surface of the copper foil was visually observed. Evaluation was performed according to the following criteria. ◯: No discoloration due to corrosion was observed on the surface of the copper foil. Δ: Slight discoloration due to corrosion was observed in part of the surface of the copper foil. ×: Discoloration due to corrosion was observed on the surface of the copper foil.

[0192] <Glass Peel Force> The release liner was peeled off from the surface of a pressure-sensitive adhesive film cut to a size of 25 mm wide x 100 mm long, and the exposed pressure-sensitive adhesive layer side was bonded to a glass plate (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) using a 2 kg hand roller in one stroke to prepare a test sample. A tensile tester manufactured by Shimadzu Corporation under the trade name "Autograph AG-Xplus HS 6000 mm / min High-Speed ​​Model (AG-50NX plus)" was used, and the test sample was set in the tensile tester. The pressure-sensitive adhesive film was peeled from the glass plate at a tensile speed of 300 mm / min and a peel angle of 180 degrees in an environment of 25°C and 50% relative humidity, and the load at this time was measured, and the average load was taken as the glass peel force.

[0193] <Peel force to polyimide (1)> A 25 μm thick polyimide film (Ube Industries, Ltd., "Upilex 25S") was attached to a glass plate via double-sided adhesive tape (Nitto Denko Corporation, "No. 531") to obtain a polyimide film substrate for measurement. The release liner was peeled off from the surface of a 25 mm wide x 100 mm long piece of pressure-sensitive adhesive film, and the exposed pressure-sensitive adhesive layer side was attached to the polyimide film substrate for measurement using a 2 kg hand roller in one stroke to prepare a test sample. A tensile tester manufactured by Shimadzu Corporation under the trade name "Autograph AG-Xplus HS 6000 mm / min high-speed model (AG-50NX plus)" was used, and a test sample was set in the tensile tester. The load when the PSA film was peeled from the polyimide film substrate for measurement was measured at a tensile speed of 300 mm / min and a peel angle of 180 degrees in an environment of a temperature of 25°C and a relative humidity of 50%, and the average load at this time was taken as the polyimide peel force.

[0194] <Peel Force to Polyimide (2)> A 25 μm thick polyimide film (Ube Industries, Ltd., "Upilex 25S") was attached to a glass plate via double-sided adhesive tape (Nitto Denko Corporation, "No. 531") to obtain a polyimide film substrate for measurement. The release liner was peeled off from the surface of a 25 mm wide x 100 mm long piece of adhesive film cut out, and the exposed adhesive layer side was attached to the polyimide film substrate for measurement using a 2 kg hand roller in one stroke to obtain a test sample before photocuring. Ultraviolet light (365 nm LED, cumulative light amount 1000 mJ / cm) was applied from the adhesive film side (PET film substrate side) of the test sample before photocuring. 2 The pressure-sensitive adhesive layer was photocured by irradiating the sample with light, and the photocured test sample was prepared. Each test sample was set in a tensile tester manufactured by Shimadzu Corporation under the trade name "Autograph AG-Xplus HS 6000 mm / min high-speed model (AG-50NX plus)." The test sample was then measured at a temperature of 25°C, a relative humidity of 50%, a tensile speed of 300 mm / min, and a peel angle of 180° when the pressure-sensitive adhesive film was peeled from the polyimide film substrate for measurement. The average load measured was defined as the peel force to polyimide.

[0195] <Ionic Compounds Used in Examples and Comparative Examples> The ionic compounds used in the Examples and Comparative Examples are as follows: 1-hexyl-3-methylimidazolium bis(oxalate)borate 1-octyl-3-methylimidazolium bis(oxalate)borate Lithium bis(oxalate)borate 1-ethyl-3-methylimidazolium dicyanamide 1-ethyl-3-methylimidazolium p-toluenesulfonate 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide Lithium bis(trifluoromethanesulfonyl)imide

[0196] [Production Example 1]: Production of Acrylic Polymer A A reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube was charged with 95 parts by weight of butyl acrylate (BA) and 5 parts by weight of acrylic acid (AA) as monomers, 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a polymerization initiator, and 233 parts by weight of ethyl acetate as a solvent, and nitrogen gas was introduced and purged with nitrogen for about 1 hour while stirring. Thereafter, the mixture was heated to 60°C and reacted for 7 hours to obtain a solution of acrylic polymer A having a weight average molecular weight (Mw) of 600,000.

[0197] [Production Example 2]: Production of Acrylic Polymer B A reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube was charged with 91 parts by weight of 2-ethylhexyl acrylate (2EHA) and 9 parts by weight of 4-hydroxybutyl acrylate (4HBA) as monomers, 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a polymerization initiator, and 233 parts by weight of ethyl acetate as a solvent, and nitrogen gas was introduced and purged with nitrogen for about 1 hour while stirring. Thereafter, the mixture was heated to 60°C and reacted for 7 hours to obtain a solution of acrylic polymer B having a weight average molecular weight (Mw) of 600,000.

[0198] [Production Example 3]: Production of Acrylic Polymer C A reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube was charged with 90 parts by weight of n-octyl acrylate (NOAA) and 10 parts by weight of 4-hydroxybutyl acrylate (4HBA) as monomers, 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a polymerization initiator, and 233 parts by weight of ethyl acetate as a solvent, and nitrogen gas was introduced and purged with nitrogen for about 1 hour while stirring. The mixture was then heated to 60°C and reacted for 7 hours to obtain a solution of acrylic polymer C having a weight average molecular weight (Mw) of 600,000.

[0199] [Production Example 4]: Production of acrylic oligomer

[0049] A reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube was charged with 95 parts by weight of cyclohexyl methacrylate and 5 parts by weight of acrylic acid (AA) as monomers, 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a polymerization initiator, and 103.2 parts by weight of toluene as a solvent, followed by flowing nitrogen gas and nitrogen substitution for about 1 hour while stirring. The mixture was then heated to 70°C and reacted for 3 hours, and further reacted at 75°C for 2 hours to obtain a solution of an acrylic oligomer having a weight average molecular weight (Mw) of 4000.

[0200] Example 1 To the solution of acrylic polymer A obtained in Production Example 1 (100 parts by weight as the solid content of acrylic polymer A), 0.1 parts by weight of a tetrafunctional epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, trade name "Tetrad C") as a crosslinking agent, 25 parts by weight as the solid content of the acrylic oligomer obtained in Production Example 4, and 0.3 parts by weight of 1-hexyl-3-methylimidazolium bis(oxalate)borate as an ionic compound were added and mixed uniformly to prepare a pressure-sensitive adhesive composition (1). The pressure-sensitive adhesive composition (1) was applied to a 75 μm-thick polyethylene terephthalate film substrate using an applicator so that the thickness after drying would be 13 μm. After drying at 130°C for 1 minute to remove the solvent, the release-treated surface of a release liner (a 25 μm-thick polyethylene terephthalate film, one side of which was treated with a silicone release agent) was laminated to the surface to which the pressure-sensitive adhesive composition was applied. Thereafter, an aging treatment was carried out for 4 days in an atmosphere of 25°C to promote crosslinking, thereby obtaining a PSA film (1) in which the PSA layer was fixedly laminated on the polyethylene terephthalate film substrate and a release liner was temporarily attached thereon. The results are shown in Table 1.

[0201] Examples 2 to 7, Comparative Examples 1 to 7 Pressure-sensitive adhesive compositions (2) to (7), (C1) to (C7) and pressure-sensitive adhesive films (2) to (7), (C1) to (C7) were obtained in the same manner as in Example 1, except that the type and amount of ionic compound added were changed as shown in Table 1. The results are shown in Table 1.

[0202]

[0203] [Example 8] To the solution of acrylic polymer A obtained in Production Example 1 (100 parts by weight as solids of acrylic polymer A), 0.45 parts by weight of a tetrafunctional epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, trade name "Tetrad C") as a crosslinking agent, 0.2 parts by weight of zirconium tetraacetylacetonate as a crosslinking catalyst, 30 parts by weight of polyethylene glycol #200 diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "A-200") as a photocuring agent in solids, 0.3 parts by weight of Omnirad 651 (manufactured by IGM Resins) as a photopolymerization initiator, and 0.05 parts by weight of 1-hexyl-3-methylimidazolium bis(oxalate)borate as an ionic compound were added and mixed uniformly to prepare a pressure-sensitive adhesive composition (8). The pressure-sensitive adhesive composition (8) was applied using an applicator onto a 75 μm thick polyethylene terephthalate film substrate so that the thickness after drying was 13 μm. After drying at 130°C for 1 minute to remove the solvent, the release-treated surface of a release liner (a 25µm-thick polyethylene terephthalate film with one side treated with silicone release) was attached to the surface coated with the adhesive composition. Then, aging treatment was performed for 4 days in an atmosphere of 25°C to promote crosslinking, resulting in an adhesive film (8) in which the adhesive layer was fixedly laminated on the polyethylene terephthalate film substrate and the release liner was temporarily attached thereon. The results are shown in Table 2.

[0204] Examples 9 to 19, Comparative Examples 8 to 14 PSA compositions (9) to (19), (C8) to (C14) and PSA films (9) to (19), (C8) to (C14) were obtained in the same manner as in Example 8, except that the type and amount of ionic compound added were changed as shown in Table 2. The results are shown in Table 2.

[0205] [Example 20] The solution of acrylic polymer B obtained in Production Example 2 (100 parts by weight as solids of acrylic polymer B) was added with 0.1 parts by weight of an isocyanurate of hexamethylene diisocyanate (manufactured by Tosoh, trade name "Coronate HX") as a crosslinking agent, 0.02 parts by weight of iron diacetylacetonate as a crosslinking catalyst, 10 parts by weight of polyethylene glycol #200 diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "A-200") as a photocuring agent in solids, 0.3 parts by weight of Omnirad 651 (manufactured by IGM Resins) as a photopolymerization initiator, and 0.2 parts by weight of 1-hexyl-3-methylimidazolium bis (oxalate) borate as an ionic compound, and mixed uniformly to prepare a pressure-sensitive adhesive composition (20). The above-mentioned pressure-sensitive adhesive composition (20) was applied to a 75 μm thick polyethylene terephthalate film substrate using an applicator so that the thickness after drying was 13 μm. After drying at 130 ° C for 1 minute to remove the solvent, the release-treated surface of a release liner (a 25 μm thick polyethylene terephthalate film with one side treated with silicone release) was attached to the surface coated with the pressure-sensitive adhesive composition. Then, aging treatment was performed for 4 days in an atmosphere of 25 ° C to promote crosslinking, and a pressure-sensitive adhesive film (20) was obtained in which a pressure-sensitive adhesive sheet was fixedly laminated on a polyethylene terephthalate film substrate and a release liner was temporarily attached thereon. The results are shown in Table 2.

[0206] [Examples 21 and 22] Pressure-sensitive adhesive compositions (21) and (22) and pressure-sensitive adhesive films (21) and (22) were obtained in the same manner as in Example 20, except that the type of acrylic polymer and the type and amount of ionic compound added were changed as shown in Table 2. The results are shown in Table 2.

[0207]

[0208] Example 23 Into a polymerization experimental apparatus equipped with a 1 L round-bottom separable flask, a separable cover, a separating funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade, 197 parts by weight of polypropylene glycol (product name "Sannyx PP-2000" manufactured by Sanyo Chemical Industries, Ltd.), 44 parts by weight of polyester polyol (product name "Kuraray Polyol P-2010" manufactured by Kuraray Co., Ltd.), 110 parts by weight of toluene (manufactured by Tosoh Corporation) as a solvent, and 0.041 parts by weight of dibutyltin(IV) dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) as a catalyst were charged, and nitrogen substitution was carried out at room temperature for 1 hour with stirring. Thereafter, under nitrogen flow and stirring, 33.5 parts by weight of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added, and the solution temperature in the experimental apparatus was maintained at 90±2°C in a water bath while maintaining the temperature for 4 hours. Thereafter, 197 parts by weight of polypropylene glycol (product name "GP1000", manufactured by Sanyo Chemical Industries, Ltd.) was added, and the solution temperature in the experimental apparatus was maintained at 90±2°C in a water bath while maintaining the temperature for 2 hours. Thereafter, 25.4 parts by weight of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added, and the solution temperature in the experimental apparatus was maintained at 90±2°C in a water bath while maintaining the temperature for 2 hours to obtain a solution of urethane prepolymer (A). During the polymerization, toluene was added dropwise as needed to control the temperature during polymerization and to prevent a decrease in stirrability due to increased viscosity. The total amount of toluene added was 380 parts by weight. The solids concentration of the solution of urethane prepolymer (A) was 50% by weight. 100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 10 parts by weight of Salacos 913 (manufactured by The Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 1 part by weight of 1-hexyl-3-methylimidazolium bis(oxalate)borate as an antistatic agent were diluted with ethyl acetate to a total solids concentration of 50% by weight, to obtain a urethane-based pressure-sensitive adhesive composition (23).The obtained urethane-based pressure-sensitive adhesive composition (23) was applied to a 75 μm-thick polyethylene terephthalate film substrate so that the thickness after drying was 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare a pressure-sensitive adhesive layer. Next, the release-treated surface of a release liner (a 25 μm-thick polyethylene terephthalate film with one side treated with silicone release) was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a pressure-sensitive adhesive film (23). Aging was performed at room temperature for 5 days and then evaluated. The results are shown in Table 3.

[0209] Examples 24 to 26, Comparative Example 15 PSA compositions (24) to (26), (C15) and PSA films (24) to (26), (C15) were obtained in the same manner as in Example 23, except that the type of ionic compound was changed as shown in Table 3. The results are shown in Table 3.

[0210] Example 27: 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10,000), a polyol having three OH groups, 13 parts by weight of Sannix GP-3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn=3,000), a polyol having three OH groups, and 2 parts by weight of Sannix GP-1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn=1,000), a polyol having three OH groups, were used as the polyol, and Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.), a polyfunctional alicyclic isocyanate compound, was used as the polyfunctional isocyanate compound. A mixture of 18 parts by weight of a urethane-based adhesive (manufactured by Nippon Chemical Industry Co., Ltd., trade name: Narcem Ferric) and 0.04 parts by weight of a catalyst (manufactured by Nippon Chemical Industry Co., Ltd., trade name: Narcem Ferric), 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antidegradant, 30 parts by weight of a fatty acid ester (isopropyl palmitate, manufactured by Kao, trade name: Exepar IPP, Mn = 299), 1 part by weight of 1-hexyl-3-methylimidazolium bis(oxalate)borate as an antistatic agent, and 241 parts by weight of ethyl acetate as a dilution solvent was mixed and stirred with a disperser to obtain a urethane-based adhesive composition (27). The obtained urethane-based adhesive composition (27) was applied to a 75 μm thick polyethylene terephthalate film substrate to a thickness of 12 μm after drying, and then cured and dried under conditions of a drying temperature of 130°C and a drying time of 2 minutes. In this way, an adhesive layer composed of a urethane-based adhesive was prepared on the substrate. Next, the silicone-treated surface of a 25 μm thick polyester resin substrate, one side of which had been silicone-treated, was laminated to the surface of the adhesive layer to obtain a pressure-sensitive adhesive film (27). The film was aged at room temperature for 5 days and then evaluated. The results are shown in Table 3.

[0211] [Example 28, Comparative Example 16] Pressure-sensitive adhesive compositions (28), (C16) and pressure-sensitive adhesive films (28), (C16) were obtained in the same manner as in Example 27, except that the type of ionic compound was changed as shown in Table 3. The results are shown in Table 3.

[0212]

[0213] [Example 29] For each of the PSA films (1) to (28) obtained in Examples 1 to 28, the release liner was peeled off, and the PSA layer side was attached to a polarizing plate (manufactured by Nitto Denko Corporation, product name "TEG1465DUHC"), which is an optical component, to obtain an optical device.

[0214] [Example 30] For each of the PSA films (1) to (28) obtained in Examples 1 to 28, the release liner was peeled off, and the PSA layer side was attached to a conductive film (manufactured by Nitto Denko Corporation, product name "ELECRYSTA V270L-TFMP"), which is an electronic component, to obtain an electronic device.

[0215] The pressure-sensitive adhesive film of the present invention can be used for any suitable purpose, such as a surface protection film or reinforcing film to prevent scratches or impart impact resistance to the surfaces of optical or electronic components during processing, assembly, inspection, transportation, etc. in the manufacturing process of optical or electronic devices, or as a joining member for constituting optical or electronic components.

Claims

1. An adhesive composition comprising a base polymer and an ionic compound, wherein the ionic compound consists of a cationic species and an anionic species, and the anionic species is at least one selected from the group consisting of a borate anion and a dicyanamide anion.

2. The adhesive composition according to claim 1, wherein the cationic species is at least one selected from the group consisting of an onium cation and a metal cation.

3. The adhesive composition according to claim 1, wherein the borate anion does not contain both a fluorine element and a sulfur element.

4. The adhesive composition according to claim 1, wherein the base polymer is at least one selected from an acrylic resin, a polyol, and a urethane prepolymer.

5. The adhesive composition according to claim 1, wherein the amount of the ionic compound relative to 100 parts by weight of the base polymer is 0.001 to 30 parts by weight.

6. An adhesive film comprising an adhesive layer composed of an adhesive formed from the adhesive composition according to any one of claims 1 to 5.

7. The adhesive film according to claim 6, which is used for at least one selected from the group consisting of a surface protection film and a reinforcing film.

8. An optical device comprising the adhesive film according to claim 6.

9. An electronic device comprising the adhesive film according to claim 6.

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