Adhesive layer and / or bonding layer

Abstract

This invention provides an adhesive layer and / or bonding agent layer that exhibits excellent operability before being bonded to or attached to a component and excellent flexibility after being bonded to or attached to the component. This invention also provides an adhesive layer and / or bonding agent layer whose stress is reduced due to external stimuli. Preferably, the stress does not increase after being reduced. The ratio of 100% strain stress before external stimulus (S1(100)) to 100% strain stress after external stimulus (S2(100)) [S1(100) / S2(100)] is preferably less than 0.95.

Description

Technical Field

[0001] The present invention relates to an adhesive layer and / or a bonding agent layer, and more specifically to an adhesive layer capable of exerting adhesive properties and / or a bonding agent layer capable of exerting bonding properties. Prior Technology

[0002] In optical devices such as displays, thin, flexible displays, represented by OLEDs (Organic Light-Emitting Diodes), are constructed by laminating multiple optical films or thin-layer devices. Furthermore, devices requiring flexibility, such as pressure sensors, are constructed by laminating a pressure-sensing member and a substrate (Patent Document 1). As the interlayer filler in these laminates, liquid curing resins or adhesives / adhesives are preferred. From the viewpoints of improved workability, reduced warping due to curing shrinkage, and improved flexibility obtained through stress dispersion, adhesives / adhesives (such as adhesives) are preferable.

[0003] The aforementioned adhesives, especially in flexible components, play a role in dispersing and mitigating the stress caused by bending and folding. The softer the adhesive, the more efficiently this function can be performed (Patent Document 2). Therefore, soft adhesives are used. Previous technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2012-159463 Patent Document 2: Japanese Patent Application Publication No. 2020-109177 Summary of the Invention

[0005] [The problem the invention aims to solve]

[0006] On the other hand, soft adhesives can sometimes deform significantly due to minute stresses, causing problems during manufacturing and processing. For example, when cutting with a die, adhesive may overflow or be missing, leading to contamination. Furthermore, these adhesives can sometimes overflow due to their own weight during storage or be missing due to vibration or contact during handling.

[0007] Therefore, there is a need for an adhesive layer or bonding agent layer that exhibits excellent operability before being bonded or attached to a component during manufacturing, processing, storage, and handling, and excellent flexibility during use, i.e., after being bonded or attached to the component.

[0008] The present invention is intended to solve this problem, and its object is to provide an adhesive layer and / or bonding layer that has excellent operability before being adhered to or bonded to a component and excellent flexibility after being adhered to or bonded to the component. [Technical means to solve the problem]

[0009] In order to solve the above-mentioned problems, the inventors conducted extensive research and discovered that adhesive layers and bonding agent layers whose stress is reduced due to external stimuli exhibit excellent workability before being bonded to or attached to a component, and excellent flexibility after being bonded to or attached to the component. This invention is based on these insights and knowledge.

[0010] In other words, the present invention provides an adhesive layer and / or bonding layer whose stress is reduced due to external stimuli. By giving the adhesive layer or bonding layer the property of reducing stress due to external stimuli, the stress is relatively high before the external stimulus is applied. Before using the adhesive layer or bonding layer, that is, before the adhesive layer or bonding layer is adhered to or bonded to the component, paste overflow or paste loss is less likely to occur, resulting in excellent workability. On the other hand, after the external stimulus is applied, the stress is lower than before the application, resulting in excellent flexibility when using the adhesive layer or bonding layer, that is, when the adhesive layer or bonding layer is adhered to or bonded to the component.

[0011] Ideally, the stress should not increase after being reduced. When this type of adhesive layer is bonded or attached to a component, the stress will not increase, thus maintaining flexibility.

[0012] The ratio of 100% strain stress before external stimulation (S1(100)) to 100% strain stress after external stimulation (S2(100)) [S2(100) / S1(100)] is preferably less than 0.95. This type of adhesive layer exhibits the ability to further reduce relatively weak tensile stress by applying external stimulation, resulting in lower rebound force during tension, making it suitable for applications with relatively low loads, such as folding components.

[0013] The 100% strain stress (S2(100)) after external stimulation is preferably below 10 MPa. This adhesive layer exhibits even better flexibility after external stimulation.

[0014] The aforementioned adhesive layer is preferably used for optical applications. [Effects of the Invention]

[0015] The adhesive layer and / or bonding agent layer of the present invention have excellent operability before being bonded or attached to a component, and excellent flexibility after being bonded or attached to a component. Simple Explanation of the Diagram

[0016] Figure 1 shows a cross-sectional schematic diagram of an adhesive sheet or bonding sheet 10 with a release liner on which the adhesive layer or bonding layer 1 of the present invention is formed. Implementation

[0017] [Adhesive layer, bonding agent layer] In this specification, "adhesive" refers to the property that, by means of external pressure (e.g., minute pressure), based on the cohesive force of the composition's chemical structure, two surfaces are brought into close contact and can be peeled off as needed. In contrast, "adhesive" refers to the property that, upon chemical reaction (hardening), the composition produces a hardened material that is not expected to peel off, allowing two surfaces to be firmly bonded. Furthermore, in this specification, "adhesive layer" refers to a non-flowing layer of adhesive, and "adhesive layer" refers to a non-flowing layer of adhesive.

[0018] The adhesive layer and / or bonding agent layer of the present invention have the property of reducing stress due to external stimuli. The aforementioned stress is preferably, for example, the stress (strain stress) under tension at any ratio, measured by a tensile-compression testing machine. The stress (strain stress) under tension at the aforementioned specific ratio only needs to be reduced at at least one ratio. Preferably, the strain stress is reduced at at least one point within the range of 100% to 500% of the tensile ratio, and more preferably, the strain stress is reduced at one or more tensile ratios selected from the group consisting of 100%, 200%, 300%, and 500%. Hereinafter, preferred ranges of stress at each tensile ratio are described, but these values ​​are preferred ranges assuming no fracture occurs at each tensile ratio.

[0019] Ideally, the stress should not increase after being reduced. This type of adhesive layer, when bonded or attached to a component, will not increase stress and will maintain flexibility.

[0020] Figure 1 is a cross-sectional schematic diagram of one embodiment of the adhesive layer of the present invention. The adhesive layer or bonding agent layer 1 shown in Figure 1 is deposited on the release surface of the release liner 2 to form an adhesive sheet or bonding agent sheet 10 with a release liner attached.

[0021] The ratio of the stress (100% strain stress) (S1(100)) before the application of external stimulus to the stress (100% strain stress) (S2(100)) after the application of external stimulus in the adhesive layer of the present invention [S2(100) / S1(100)] is preferably less than 0.95 (e.g., more than 0.1 and less than 0.95), more preferably less than 0.9, and even more preferably less than 0.8. Such an adhesive layer exhibits the ability to further reduce relatively weak tensile stress by applying external stimulus, resulting in lower rebound force during tension, making it suitable for applications with relatively low loads, such as foldable components.

[0022] The stress (100% strain stress) (S1(100)) of the adhesive layer of the present invention before the application of external stimulus is preferably 0.01 MPa or more (e.g., 0.01 to 10 MPa), more preferably 0.03 MPa or more (e.g., 0.03 to 6 MPa), and even more preferably 0.05 MPa or more (e.g., 0.05 to 3 MPa). After the application of external stimulus, the flexibility of such an adhesive layer is further improved.

[0023] The stress (100% strain stress) (S2(100)) of the adhesive layer of the present invention after being subjected to external stimulation is preferably 10 MPa or less (e.g., 0.01 to 10 MPa), more preferably 6 MPa or less (e.g., 0.02 to 6 MPa), and even more preferably 3 MPa or less (e.g., 0.03 to 3 MPa). This adhesive layer, after being subjected to external stimulation, exhibits even better flexibility.

[0024] The ratio of the stress (200% strain stress) (S1(200)) before the application of external stimulus to the stress (200% strain stress) (S2(200)) after the application of external stimulus in the adhesive layer of the present invention [S2(200) / S1(200)] is preferably less than 0.95 (e.g., more than 0.1 and less than 0.95), more preferably less than 0.8, and even more preferably less than 0.7. Such an adhesive layer exhibits the ability to further reduce relatively weak tensile stress by applying external stimulus, resulting in lower rebound force during tension, making it suitable for applications with relatively low loads, such as foldable components.

[0025] The stress (200% strain stress) (S1(200)) of the adhesive layer of the present invention before the application of external stimulus is preferably 0.03 MPa or more (e.g., 0.03 to 10 MPa), more preferably 0.04 MPa or more (e.g., 0.04 to 4 MPa), and even more preferably 0.06 MPa or more (e.g., 0.06 to 2 MPa). After the application of external stimulus, the flexibility of this adhesive layer is further improved.

[0026] The stress (200% strain stress) (S2(200)) of the adhesive layer of the present invention after being subjected to external stimuli is preferably 10 MPa or less (e.g., 0.01 to 10 MPa), more preferably 4 MPa or less (e.g., 0.03 to 4 MPa), and even more preferably 2 MPa or less (e.g., 0.04 to 2 MPa). This adhesive layer exhibits even better flexibility after being subjected to external stimuli.

[0027] The ratio of the stress (300% strain stress) (S1(300)) before the application of external stimulus to the stress (300% strain stress) (S2(300)) after the application of external stimulus in the adhesive layer of the present invention [S2(300) / S1(300)] is preferably less than 0.950 (e.g., more than 0.1 and less than 0.950), more preferably less than 0.8, and even more preferably less than 0.7. Such an adhesive layer exhibits the characteristic of reducing tensile stress by applying external stimulus, making it suitable for applications with relatively low loads, such as foldable components.

[0028] The stress (300% strain stress) (S1(300)) of the adhesive layer of the present invention before external stimulation is preferably 0.03 MPa or more (e.g., 0.03 to 10 MPa), more preferably 0.05 MPa or more (e.g., 0.05 to 4 MPa), and even more preferably 0.07 MPa or more (e.g., 0.07 to 2 MPa). After external stimulation is applied, the flexibility of this adhesive layer is further improved.

[0029] The stress (300% strain stress) (S2(300)) of the adhesive layer of the present invention after being subjected to external stimulation is preferably 10 MPa or less (e.g., 0.01 to 10 MPa), more preferably 4 MPa or less (e.g., 0.03 to 4 MPa), and even more preferably 2 MPa or less (e.g., 0.04 to 2 MPa). This adhesive layer, after being subjected to external stimulation, exhibits even better flexibility.

[0030] The ratio of the stress (500% strain stress) (S1(500)) of the adhesive layer before the external stimulus is applied to the stress (500% strain stress) (S2(500)) after the external stimulus is applied [S2(500) / S1(500)] is preferably less than 0.950 (e.g., more than 0.1 and less than 0.950), more preferably less than 0.8, and even more preferably less than 0.7. This type of adhesive layer exhibits the ability to reduce relatively strong tensile stress by applying external stimulus, and has a lower rebound force during tension, making it suitable for applications with relatively high or low loads, such as foldable (especially rollable or other winding) components.

[0031] The stress (500% strain stress) (S1(500)) of the adhesive layer of the present invention before the application of external stimulus is preferably 0.05 MPa or more (e.g., 0.05 to 10 MPa), more preferably 0.07 MPa or more (e.g., 0.07 to 4 MPa), and even more preferably 0.1 MPa or more (e.g., 0.1 to 2 MPa). After the application of external stimulus, the flexibility of such an adhesive layer is further improved.

[0032] The stress (500% strain stress) (S2(500)) of the adhesive layer of the present invention after being subjected to external stimulation is preferably 10 MPa or less (e.g., 0.01 to 10 MPa), more preferably 4 MPa or less (e.g., 0.03 to 4 MPa), and even more preferably 2 MPa or less (e.g., 0.04 to 2 MPa). This adhesive layer, after being subjected to external stimulation, exhibits even better flexibility.

[0033] The adhesive layer of the present invention is preferably such that the strain stress is reduced at a stretch ratio of 100%, and the ratio [S2(100) / S1(100)] does not reach 0.95, or the strain stress at 100% before external stimulation is 0.03~0.4 MPa.

[0034] Furthermore, the adhesive layer of the present invention may also have the following properties: the peak intensity (peak stress intensity) or fracture point stress in the stress-strain curve decreases due to external stimuli.

[0035] The peak stress intensity (or fracture point stress in the case of fracture) of the adhesive layer of the present invention in the stress-strain curve before the application of external stimulus is preferably 0.07 MPa or more, more preferably 0.1 MPa or more, and even more preferably 0.2 MPa or more. If the above-mentioned peak stress intensity is 0.07 MPa or more, the adhesive layer has appropriate hardness before the application of external stimulus, resulting in better workability.

[0036] The peak strength (peak stress intensity, or fracture point stress in the case of fracture) of the adhesive layer of the present invention in the stress-strain curve after external stimulation is preferably 0.01~1.0 MPa, more preferably 0.03~0.8 MPa, and even more preferably 0.04~0.5 MPa. If the above-mentioned peak stress intensity is within the above range, the flexibility, step follower, and adhesion are better after external stimulation is applied.

[0037] The ratio of the peak intensity of the adhesive layer, etc., before the application of external stimulus to the peak intensity of the stress-strain curve after the application of external stimulus (or the ratio of the stress at the fracture point in the case of fracture) [after application of external stimulus / before application of external stimulus] is preferably less than 0.95 (e.g., more than 0.05 and less than 0.95), more preferably less than 0.8 (e.g., 0.1 to 0.8), and even more preferably less than 0.7 (e.g., 0.3 to 0.7). In this case, there is a tendency for the flexibility, step followability, and adhesion of the adhesive layer, etc., to change more significantly before and after the application of external stimulus.

[0038] The adhesive layer of the present invention, as described above, has the property of reducing stress due to external stimuli. Examples of adhesive layers possessing this property include adhesive layers comprising polymers containing decomposable bonds within the molecule that break upon external stimulation. The polymer may contain only one type or more. Furthermore, in this specification, the polymer containing decomposable bonds within the molecule that break upon external stimulation is sometimes referred to as "polymer (A)". The decomposable bonds may be only one type or more.

[0039] Examples of decomposable bonds in polymer (A) include bonds that break upon external stimulation and can subsequently re-bond (reversible decomposable bonds) and bonds that break upon external stimulation and cannot subsequently re-bond (irreversible decomposable bonds). When the decomposable bonds in polymer (A) are reversible, the adhesive layer of the present invention further includes a compound that inhibits the re-bonding. Furthermore, in this specification, polymer (A) having the aforementioned reversible decomposable bonds within its molecule is sometimes referred to as "polymer (A1)," polymer having the aforementioned irreversible decomposable bonds within its molecule is sometimes referred to as "polymer (A2)," and the compound that inhibits the re-bonding is sometimes referred to as "re-bonding inhibitory compound (B)."

[0040] The aforementioned external stimuli are appropriately selected based on the stress reduction method, and examples include active energy line irradiation and heat. Especially when polymer (A) is a thermosetting resin or an active energy line-curing resin, from the viewpoint of being able to produce a thermosetting reaction or an active energy line-curing reaction and the aforementioned bond breaking, it is preferable to use an external stimuli of a different type of curing property than when polymer (A) is curable. Specifically, when polymer (A) is a thermosetting resin, active energy line irradiation is preferable, and when polymer (A) is an active energy line-curing resin, heat is preferable.

[0041] There are no particular limitations on the aforementioned active energy rays; examples include ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron beams, as well as ultraviolet light and visible light. Ultraviolet light is particularly preferred. There are no particular limitations on the irradiation energy, irradiation time, or irradiation method of the active energy rays. Furthermore, examples of light sources for ultraviolet or visible light irradiation include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, and LED lamps.

[0042] As for the aforementioned reversible decomposable bond in polymer (A1), known or conventional bonds can be used, preferably bonds that break free radicals, and especially disulfide bonds (-SS-).

[0043] As for the aforementioned irreversible decomposable bond in polymer (A2), known or conventional bonds can be used, preferably bonds containing nitrobenzyl groups. In this case, it is easy to introduce irreversible decomposable bonds into the polymer. As for the aforementioned bonds containing nitrobenzyl groups, ester bonds formed by nitrobenzyl alcohol (preferably 2-nitrobenzyl alcohol) and carboxylic acids having polymerizable functional groups are preferred.

[0044] Examples of polymers (A) include thermoplastic resins, thermosetting resins, and active energy line curing resins. Among these, thermoplastic resins and thermosetting resins are preferred. An adhesive layer containing a thermoplastic resin can, for example, exhibit adhesive properties that allow for close adhesion under external pressure. An adhesive layer containing a thermosetting resin can, for example, bond to the substrate by heat curing.

[0045] Examples of thermosetting resins include both thermosetting resins and resins obtained by curing the aforementioned thermosetting resins. The aforementioned thermosetting resins possess thermosetting functional groups. Preferably, the number of thermosetting functional groups in the aforementioned thermosetting resins is two or more (e.g., 2 to 4). Examples of such thermosetting resins include phenolic resins, epoxy resins, urethane resins, melamine resins, and alkyd resins.

[0046] Examples of the aforementioned thermoplastic resins include polystyrene resins, vinyl acetate resins, polyester resins, polyolefin resins (polyethylene resins, polypropylene resin compositions, etc.), polyimide resins, and acrylic resins. Among these, acrylic resins are preferred in order to impart cohesiveness and appropriate flexibility to the adhesive layer.

[0047] The design of acrylic resins varies depending on the purpose. It is best to select appropriate monomer types, copolymer composition ratios, molecular weight, molecular weight distribution, crosslinking agents, and formulation ratios based on the target values ​​of mechanical properties such as flexibility and elastic modulus, thermal properties such as glass transition point, and adhesive properties such as adhesion and bonding strength.

[0048] Acrylic resins are resins that contain acrylic monomers (monomers having a (meth)acrylic group in their molecule) as monomeric components of the resin. That is, the aforementioned acrylic resins contain structural units derived from acrylic monomers. Preferably, the aforementioned acrylic resins are polymers containing alkyl (meth)acrylates as monomeric components of the polymer. Furthermore, in this specification, "(meth)acrylate" means "acrylate" and / or "methacrylate" (either "acrylate" or "methacrylate"), and so on.

[0049] Regarding the aforementioned alkyl (meth)acrylates as essential monomeric components, alkyl (meth)acrylates having straight-chain or branched alkyl groups are preferred examples. Furthermore, only one of the aforementioned alkyl (meth)acrylates may be used, or two or more may be used.

[0050] There is no particular limitation as to alkyl methacrylates having straight-chain or branched alkyl groups, and examples include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, dibutyl methacrylate, terbutyl methacrylate, pentyl methacrylate, isoamyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, nonyl methacrylate, and iso... Nonyl acrylate, decyl acrylate, isodecyl acrylate, undecyl acrylate, dodecyl acrylate (lauryl acrylate), tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, stearyl acrylate, isostearyl acrylate, nonadecanyl acrylate, eicosyl acrylate, and other alkyl acrylates having a straight-chain or branched alkyl group having 1 to 20 carbon atoms.

[0051] As an alkyl methacrylate having a straight-chain or branched alkyl group, it is preferred to be an alkyl methacrylate having a straight-chain or branched alkyl group having 2 or more carbons (preferably 2 to 18, more preferably 2 to 5).

[0052] The content ratio of structural units derived from (meth)acrylate in the aforementioned acrylic resin is preferably 70% by mass or more, and more preferably 80% by mass or more, relative to 100% by mass of the total monomer components constituting the acrylic resin. The aforementioned content ratio is preferably 99% by mass or less, and more preferably 98% by mass or less. Furthermore, depending on the application or required properties, there may also be cases where the content ratio of structural units derived from (meth)acrylate in the acrylic resin is less than 70% by mass relative to 100% by mass of the total monomer components constituting the acrylic resin.

[0053] The aforementioned acrylic resin may also contain the aforementioned alkyl (meth)acrylate and other monomers (copolymeric monomers) capable of copolymerizing with the aforementioned alkyl (meth)acrylate as monomeric components constituting the resin. That is, the aforementioned acrylic resin may also contain copolymeric monomers as structural units. Only one type of copolymeric monomer may be used, or two or more types may be used.

[0054] Examples of the aforementioned comonomers include: carboxyl-containing monomers, hydroxyl-containing monomers, epoxy-containing monomers, ketone-containing monomers, alkoxy-containing monomers, sulfonic acid-containing monomers, phosphate-containing monomers, vinyl ester monomers, vinyl ether monomers, isocyanate-containing monomers, aromatic vinyl compounds, alicyclic monomers, (meth)acrylates containing aromatic rings, chlorine-containing monomers, nitrogen-containing monomers, etc.

[0055] The content ratio of structural units derived from copolymer monomers in the aforementioned acrylic resin is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more, relative to 100% by mass of the total monomer components constituting the acrylic resin. The aforementioned content ratio is preferably 30% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. Furthermore, depending on the application or required properties, the content ratio of structural units derived from copolymer monomers in the aforementioned acrylic resin may also be less than 0.1% by mass relative to 100% by mass of the total monomer components constituting the acrylic resin.

[0056] In the adhesive layer of the present invention, the polymer (A) preferably forms a network structure. A network structure refers to a state in which molecules are complexed together, or a state in which molecular chains are bonded together to form long and large molecules. That is, polymer (A) is preferably a polymer that forms a network structure through bonding or molecular complexation. Adhesive layers with this configuration, forming a network structure through polymer bonding or complexation, can possess moderate hardness. By using external stimuli to break down the decomposable bonds, the polymer structure breaks down, thus improving flexibility.

[0057] The term "molecular complex" refers to a state in which polymers form a network structure without covalent bonds. To form such a complex structure, it is preferable to use polymers of different types that are unlikely to undergo cross-linking reactions. From a manufacturing perspective, a complex structure formed between thermoplastic resins, or between thermosetting resins and thermoplastic resins, is preferred. Because this structure does not involve covalent bonds, it is suitable for relatively soft adhesive layers before external stimuli are applied.

[0058] The aforementioned state of long and large molecules formed by molecular chains bonded together refers to a polymer composed of a single polymer. To form such long and large molecules, it is preferable to contain a single polymer, and more preferably, the aforementioned thermosetting resin. This configuration, due to covalent bonding resulting in long and large molecular chains, enables the formation of relatively rigid adhesive layers, etc. Furthermore, since the number of sites cut by external stimuli also increases, it is more suitable for adhesive layers exhibiting a difference in flexibility before and after external stimuli.

[0059] The polymer (A1) is preferably a thermosetting resin. The polymer (A1) as a thermosetting resin can also be a resin with a network structure formed by complexing a thermosetting resin and a thermoplastic resin. As the aforementioned thermosetting resin, an epoxy resin is preferred. When the polymer (A1) contains an epoxy resin, the epoxy resin is preferably a resin that contains at least an epoxy monomer and the compound (a1) described later as monomeric components of the resin, and / or a compound (a1) acting as a crosslinking agent to crosslink the epoxy resins with each other. As the aforementioned thermoplastic resin, an acrylic resin is preferred. Furthermore, in this specification, the term "crosslinking agent" refers to a compound capable of forming crosslinks in a resin, sometimes referred to as a "curing agent."

[0060] The polymer (A2) is preferably a thermoplastic resin, and more preferably an acrylic resin. When the polymer (A2) is an acrylic resin, the acrylic resin is preferably a resin that includes at least an acrylic monomer and the compound (a2) described below as monomer components constituting the resin.

[0061] When the adhesive layer of the present invention contains a thermosetting resin as a polymer (A1), the content ratio of the thermosetting resin is not particularly limited. From the viewpoint of imparting appropriate initial hardness and hardness after external stimulation to the adhesive layer, the content ratio is preferably 3 to 95% by mass, more preferably 5 to 90% by mass, and even more preferably 6 to 85% by mass, relative to 100% of the total amount of the adhesive layer of the present invention. When the adhesive layer of the present invention contains a thermosetting resin as a base polymer, the above-mentioned content ratio is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, and even more preferably 65 to 85% by mass. When the adhesive layer of the present invention contains a thermoplastic resin as a base polymer, the above-mentioned content ratio is preferably 3 to 80% by mass, more preferably 5 to 50% by mass, and even more preferably 6 to 30% by mass. Furthermore, the amount of the thermosetting resin includes the thermosetting resin, its raw material monomers, crosslinking agents, and structural portions derived from the crosslinking agents.

[0062] When the adhesive layer of the present invention contains a thermoplastic resin, the content ratio of the thermoplastic resin is not particularly limited. From the viewpoint of imparting appropriate initial hardness and hardness after external stimulation to the adhesive layer, it is preferably 50% by mass or more, and more preferably 70% by mass or more, relative to 100% of the total amount of the adhesive layer of the present invention. Furthermore, the amount of thermoplastic resin includes the amount of thermoplastic resin, its raw material monomers, crosslinking agent, and structural portions derived from the crosslinking agent.

[0063] When the adhesive layer of the present invention contains a thermoplastic resin as a polymer (A1), the content ratio of the thermoplastic resin is preferably 20-97% by mass, more preferably 50-95% by mass, and even more preferably 70-93% by mass, relative to 100% of the total amount of the adhesive layer of the present invention. When the adhesive layer of the present invention contains a thermosetting resin as a base polymer, the content ratio is preferably 30% by mass or less, and may be 10% by mass or less, 5% by mass or less, 1% by mass or less, or even 0% by mass.

[0064] When the adhesive layer of the present invention contains a thermoplastic resin as a polymer (A2), the content ratio of the thermoplastic resin is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to 100% by mass of the total amount of the adhesive layer of the present invention.

[0065] The adhesive layer of the present invention preferably has a shear storage modulus (G') that decreases due to external stimuli (especially irradiation by active energy lines). This type of adhesive layer improves flexibility due to external stimuli. Furthermore, the shear storage modulus (G') preferably does not increase after the aforementioned decrease.

[0066] The shear storage modulus (G') of the adhesive layer of the present invention at 25°C before external stimulation is preferably 1.0 × 10³ to 1.0 × 10⁸ Pa, more preferably 1.0 × 10⁴ to 1.0 × 10⁷ Pa, further preferably 1.0 × 10⁴ to 1.0 × 10⁶ Pa, and even more preferably 2.0 × 10⁴ to 1.0 × 10⁵ Pa. Adhesive layers having the above-mentioned shear storage modulus have appropriate hardness before external stimulation is applied, resulting in excellent workability.

[0067] The shear storage modulus (G') of the adhesive layer of the present invention at 50°C before external stimulation is preferably 1.0 × 10³ to 5.0 × 10⁷ Pa, more preferably 7.0 × 10³ to 1.0 × 10⁶ Pa, and even more preferably 1.0 × 10⁴ to 1.0 × 10⁵ Pa. Adhesive layers having the above-mentioned shear storage modulus, for example, exhibit moderate hardness even when slightly heated by environmental factors before external stimulation, resulting in excellent workability.

[0068] The shear storage modulus (G') of the adhesive layer of the present invention at 85°C before external stimulation is preferably 1.0 × 10² to 1.0 × 10⁶ Pa, more preferably 1.0 × 10³ to 1.0 × 10⁵ Pa, and even more preferably 5.0 × 10³ to 1.0 × 10⁵ Pa. Adhesive layers having the above-mentioned shear storage modulus, for example, even when exposed to high-temperature environments, exhibit moderate hardness before external stimulation, resulting in superior workability.

[0069] The shear storage modulus (G') of the adhesive layer of the present invention at 25°C after external stimulation is preferably 1.0 × 10² to 5.0 × 10⁶ Pa, more preferably 1.0 × 10³ to 5.0 × 10⁵ Pa, further preferably 3.0 × 10³ to 1.0 × 10⁵ Pa, and even more preferably 5.0 × 10³ to 5.0 × 10⁴ Pa. If the shear storage modulus is within the above range, the adhesive layer of the present invention exhibits superior flexibility, step-following properties, and adhesion after external stimulation.

[0070] The shear storage modulus (G') of the adhesive layer of the present invention at 50°C after external stimulation is preferably 1.0 × 10² to 1.0 × 10⁶ Pa, more preferably 5.0 × 10² to 3.0 × 10⁵ Pa, further preferably 1.0 × 10³ to 1.0 × 10⁵ Pa, and even more preferably 2.0 × 10³ to 8.0 × 10⁴ Pa. If the shear storage modulus is within the above range, the flexibility, step follower, and adhesion are better after external stimulation, such as when the temperature rises slightly due to the environment.

[0071] The shear storage modulus (G') of the adhesive layer of the present invention at 85°C after external stimulation is preferably 1.0 × 10² to 8.0 × 10⁵ Pa, more preferably 3.0 × 10² to 1.0 × 10⁵ Pa, further preferably 5.0 × 10² to 1.0 × 10⁵ Pa, and even more preferably 1.0 × 10² to 7.0 × 10⁴ Pa. If the shear storage modulus is within the above range, then after external stimulation, such as exposure to a high-temperature environment, the flexibility, step follow-through, and adhesion are more superior.

[0072] The ratio of the shear storage modulus (G') of the adhesive layer, etc., at 25°C before external stimulation to the shear storage modulus (G') at 25°C after external stimulation [after external stimulation / before external stimulation] is preferably less than 0.95 (e.g., 0.01 or more and less than 0.95), more preferably less than 0.8 (e.g., 0.05 to 0.8), even more preferably less than 0.7 (e.g., 0.1 to 0.7), and particularly preferably less than 0.6 (e.g., 0.2 to 0.6). In this case, the softness, step-following ability, and adhesion of the adhesive layer, etc., near room temperature tend to change more significantly before and after external stimulation.

[0073] The ratio of the shear storage modulus (G') of the adhesive layer, etc., at 50°C before external stimulation to the shear storage modulus (G') at 50°C after external stimulation [after external stimulation / before external stimulation] is preferably less than 0.95 (e.g., 0.01 or more and less than 0.95), more preferably less than 0.8 (e.g., 0.05 to 0.8), further preferably less than 0.7 (e.g., 0.1 to 0.7), and even more preferably less than 0.6 (e.g., 0.2 to 0.6). In this case, the softness, step-following ability, and adhesion of the adhesive layer, etc., around 50°C tend to change more significantly before and after external stimulation.

[0074] The ratio of the shear storage modulus (G') of the adhesive layer, etc., at 85°C before external stimulation to the shear storage modulus (G') at 85°C after external stimulation [after external stimulation / before external stimulation] is preferably less than 0.95 (e.g., 0.01 or more and less than 0.95), more preferably less than 0.8 (e.g., 0.05 to 0.8), further preferably less than 0.7 (e.g., 0.1 to 0.7), and even more preferably less than 0.6 (e.g., 0.2 to 0.6). In this case, the flexibility, step-following ability, and adhesion of the adhesive layer, etc., under high-temperature conditions tend to change more significantly before and after external stimulation.

[0075] The adhesive layer of the present invention preferably has the property that its hardness decreases due to external stimuli. Preferably, the hardness does not increase after the decrease. When such an adhesive layer is adhered to or bonded to a component, its hardness does not increase, thus maintaining its flexibility.

[0076] The aforementioned hardness is preferably, for example, Young's modulus measured by a tensile compression testing machine. That is, the adhesive layer of the present invention has the property that its Young's modulus decreases due to external stimuli.

[0077] That is, the adhesive layer of the present invention preferably has a lower Young's modulus after the external stimulus is applied, compared to the Young's modulus before the external stimulus is applied. Such an adhesive layer has excellent workability before the external stimulus is applied, and after the external stimulus is applied, it has even better flexibility, impact resistance, and resistance to shape deformation in high-speed areas.

[0078] The adhesive layer of the present invention preferably has a Young's modulus (E1) of 200 MPa or less (e.g., 0.03 to 200 MPa) before external stimulation is applied. Furthermore, the Young's modulus (E2) of the adhesive layer after external stimulation is preferably 50 MPa or less (e.g., 0.001 to 50 MPa). Adhesive layers having the above-mentioned Young's modulus have appropriate hardness before external stimulation is applied, resulting in superior workability in manufacturing, processing, storage, and handling. Furthermore, adhesive layers having the above-mentioned Young's modulus exhibit excellent flexibility, superior step-following ability, and superior adhesion after external stimulation is applied.

[0079] The Young's modulus (E1) of the adhesive layer before external stimulation is preferably 0.03~1.5 MPa, more preferably 0.05~1.0 MPa, and even more preferably 0.1~0.8 MPa. An adhesive layer with the above-mentioned Young's modulus (E1) has appropriate hardness before external stimulation is applied, resulting in superior workability.

[0080] The Young's modulus (E1) of the adhesive layer before external stimulation is preferably 0.1~200 MPa, more preferably 0.3~100 MPa, and even more preferably 0.5~20 MPa. The adhesive layer with the above-mentioned Young's modulus has appropriate hardness before external stimulation, and its workability in manufacturing, processing, storage, and handling is better.

[0081] The Young's modulus (E2) of the adhesive layer after being subjected to external stimuli is preferably less than 1.0 MPa (e.g., 0.001 MPa or more but less than 1.0 MPa), more preferably less than 0.5 MPa (e.g., 0.005 to 0.5 MPa), and even more preferably less than 0.3 MPa (e.g., 0.01 to 0.3 MPa). An adhesive layer with the above-mentioned Young's modulus (E2) exhibits excellent flexibility, excellent tolerance to minute deformations, and superior impact resistance, resistance to shape deformation in high-speed regions, step-following ability, and adhesion after being subjected to external stimuli.

[0082] The Young's modulus (E2) of the adhesive layer after external stimulation is preferably 50 MPa or less (e.g., 0.01 MPa or more but less than 50 MPa), more preferably 10 MPa or less (e.g., 0.05 to 10 MPa), and even more preferably 5 MPa or less (e.g., 0.1 to 5 MPa). Adhesive layers with the above-mentioned Young's modulus exhibit excellent flexibility, step follow-through, and adhesion after external stimulation.

[0083] The ratio of the Young's modulus (E1) of the adhesive layer, etc., before the application of external stimulus to the Young's modulus (E2) after the application of external stimulus [Young's modulus (E2) / Young's modulus (E1)] is preferably less than 0.95 (e.g., more than 0.1 and less than 0.95), more preferably less than 0.8 (e.g., 0.2 to 0.8), and even more preferably less than 0.7 (e.g., 0.3 to 0.7). In this case, the adhesive layer, etc., exhibits excellent flexibility before and after the application of external stimulus, excellent tolerance to minute deformations, and superior impact resistance, resistance to shape deformation in high-speed areas, step tracking, and adhesion.

[0084] The adhesive layer of the present invention preferably exhibits a higher elongation at break after external stimulation compared to the elongation at break before external stimulation. Furthermore, the aforementioned adhesive layer can also remain intact at 500% elongation before and after external stimulation. This type of adhesive layer exhibits excellent workability before external stimulation and excellent tolerance to minute deformations after external stimulation, with even better impact resistance and resistance to shape deformation in high-speed regions.

[0085] The elongation at break (B1) of the adhesive layer of the present invention before the application of external stimuli is preferably 100-2000%, more preferably 100-1000%, further preferably 120-900%, and even more preferably 150-850%. The adhesive layer having the above-mentioned elongation at break (B1) has appropriate hardness before the application of external stimuli, resulting in superior workability.

[0086] The elongation at break (B2) of the adhesive layer of the present invention after being subjected to external stimuli is preferably 100-1300%, more preferably 130-1100%, and even more preferably 160-1000%. The adhesive layer having the above-mentioned Young's modulus (B2) exhibits excellent flexibility, excellent tolerance to minute deformation, and even better impact resistance and resistance to shape deformation in high-speed areas after being subjected to external stimuli.

[0087] The ratio of the elongation at break (B1) of the adhesive layer, etc., before the application of external stimulus to the elongation at break (B2) after the application of external stimulus [elongation at break (B2) / elongation at break (B1)] is preferably greater than 1.1 (e.g., greater than 1.1 and less than 2.0), more preferably greater than 1.2 (e.g., 1.2 to 1.8), and even more preferably greater than 1.3 (e.g., 1.3 to 1.6). In this case, the adhesive layer, etc., exhibits excellent flexibility before and after the application of external stimulus, excellent tolerance to minute deformations, and even better impact resistance and resistance to shape deformation in high-speed areas.

[0088] The thickness of the adhesive layer, etc., in this invention is not particularly limited, for example, it is about 5 to 250 μm, more preferably 7 to 200 μm, even more preferably 10 to 100 μm, and even more preferably 10 to 50 μm.

[0089] Polymer (A) can be obtained using a compound (sometimes referred to as "compound (a)") capable of introducing the aforementioned decomposable bonds into the polymer. Examples of compound (a) include monomeric components, oligomeric components, and crosslinking agents having the aforementioned decomposable bonds. That is, polymer (A) may contain structural units derived from monomeric components and / or oligomeric components having decomposable bonds, and may also contain structural portions derived from the aforementioned crosslinking agent. When compound (a) is a monomeric component or an oligomeric component, polymer (A) having the aforementioned decomposable bonds can be obtained by polymerizing or copolymerizing the aforementioned monomeric component or oligomeric component with other monomeric components. Only one compound (a) may be used, or two or more may be used.

[0090] When compound (a) is a monomeric or oligomeric component, the aforementioned decomposable bonds can exist in the polymer (A) in either the portion constituting the side chain or the portion constituting the main chain. From the viewpoint of the portion constituting the side chain, it is preferable that the polymer is less susceptible to stress during significant deformation and that its operability is maintained within the actual operating temperature range (assuming room temperature). On the other hand, from the viewpoint of the portion constituting the main chain, it is preferable that the molecular weight of the polymer is further reduced and its flexibility is further improved after the aforementioned decomposable bonds are broken, resulting in a significant change in physical properties.

[0091] Compound (a) preferably has a functional group other than the aforementioned decomposable bond (functional group (L1)). When it has two or more functional groups (L1), compound (a) functions as a crosslinking agent. Furthermore, when the functional group (L1) is a polymerizable functional group, compound (a) functions as a monomeric component or an oligomer component.

[0092] Examples of polymerizable functional groups include cationic polymerizable groups, anionic polymerizable groups, and free radical polymerizable groups. Among these, free radical polymerizable groups are preferred. Examples of free radical polymerizable groups include (meth)acrylic acid groups, vinyl groups, and other free radical polymerizable carbon-carbon double bonds.

[0093] From the perspective of ensuring the flexibility of the adhesive layer to a certain extent, functional groups other than the aforementioned polymerizable functional groups (L1) can include thiol groups, carboxyl groups, hydroxyl groups, amino groups, epoxy groups, isocyanate groups, etc.

[0094] Regarding the number of functional groups of compound (a), from the viewpoint that introducing it into polymer (A) increases its molecular weight, imparts a certain degree of hardness to the polymer before external stimulation, and further reduces the molecular weight of the polymer after bond breaking to achieve flexibility, it is preferable to have two or more functional groups. On the other hand, if the number of functional groups increases, it will crosslink with more polymers, making it difficult to obtain the effect produced by the breaking of decomposable bonds. Therefore, from the viewpoint that the crosslinking density is appropriate to ensure the flexibility of the adhesive layer to a certain extent, the number of functional groups is preferably four or less, and more preferably three or less.

[0095] As for the aforementioned compound (a) with reversibly decomposable bonds (sometimes referred to as "compound (a1)"), examples include compounds with disulfide bonds. Examples of such compounds with disulfide bonds include 4,4'-dithiodibutyric acid, 4,4'-dithiobiphenol (bis(4-hydroxyphenyl) disulfide), 2,2'-dithiodiphenylamine, 4,4'-dithiodiphenylamine, 3,3'-dithiodipropionic acid, and dithiodiethanol. Among these, 4,4'-dithiodibutyric acid, 4,4'-dithiobiphenol, and 4,4'-dithiodiphenylamine are particularly preferred from the viewpoint of superior solubility.

[0096] From the viewpoint of suppressing the discoloration of adhesive layers over time, it is preferable for compound (a1) to be free of aromatic rings. On the other hand, when adjusting other properties such as refractive index, it is sometimes preferable for compound (a1) to be free of aromatic rings.

[0097] As the aforementioned compound (a) having an irreversible decomposable bond (sometimes referred to as "compound (a2)"), it is preferably a monomer formed by the bonding of a nitrobenzyl group and a polymerizable functional group via a linker group (nitrobenzyl monomer). The linker group is not particularly limited, but an ester bond is preferred. Sometimes, nitrobenzyl monomers with an ester bond as the linker group are referred to as "nitrobenzyl ester monomers." Examples of nitrobenzyl ester monomers include, for example, esterifications of compounds having a nitrobenzyl alcohol skeleton and compounds having a polymerizable functional group and a carboxyl group, or esterifications of compounds having a nitrophenylacetic acid skeleton and compounds having a polymerizable functional group and a hydroxyl group, etc.

[0098] Examples of compounds having a nitrobenzyl alcohol skeleton include 2-nitrobenzyl alcohol and 2-nitro-1,3-bis(hydroxymethyl)benzene. Examples of compounds having a nitrophenylacetic acid skeleton include 2-nitroisophthalic acid. A preferred monomer for the nitrobenzyl ester system is 2-nitro-1,3-bis((meth)acryloxymethylene)benzene.

[0099] The aforementioned nitrobenzyl ester monomers can be prepared by esterifying a carboxylic acid (e.g., (meth)acrylic acid) with a compound having a nitrobenzyl alcohol skeleton, or by esterifying a compound having a polymerizable functional group and a hydroxyl group with a compound having a nitrophenylacetic acid skeleton.

[0100] The content ratio of polymer (A) in the adhesive layer of the present invention is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 65% ​​by mass or more, and particularly preferably 70% by mass or more, relative to 100% by mass of the total amount of the adhesive layer of the present invention. Furthermore, the amount of the aforementioned polymer (A) includes the amount of polymer (A), its raw material monomers, crosslinking agent, and structural portions derived from the crosslinking agent.

[0101] When the adhesive layer of the present invention contains a polymer (A1), the content ratio of the polymer (A1) in the adhesive layer of the present invention is preferably 30-99% by mass, more preferably 40-97% by mass, and even more preferably 50-95% by mass, and particularly preferably 70-95% by mass, relative to 100% of the total amount of the adhesive layer of the present invention. If the above-mentioned content ratio is 30% by mass or more, it is easy to impart adhesiveness to the adhesive layer. If the above-mentioned content ratio is 99% by mass or less, it is easy to design the composition by formulating a crosslinking agent or a rebonding inhibitor compound (B). Furthermore, the amount of the polymer (A1) includes the amount of polymer (A1), its raw material monomer, crosslinking agent, and structural portion derived from the crosslinking agent.

[0102] When the adhesive layer of the present invention contains polymer (A2), the content ratio of polymer (A2) in the adhesive layer of the present invention is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to 100% by mass of the total amount of the adhesive layer of the present invention. Furthermore, the amount of the aforementioned polymer (A2) includes the amount of polymer (A2), its raw material monomers, crosslinking agents, and structural portions derived from the crosslinking agents.

[0103] Regarding the content ratio of one or more structural units and structural parts derived from compound (a1) in polymer (A1), from the viewpoint of achieving sufficient flexibility through bond breaking and fragmentation after external stimulation, it is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 1.5% by mass or more, relative to 100% of the total amount of polymer (A1). Furthermore, to impart appropriate flexibility to the resin before external stimulation in order to achieve a suitable crosslinking density, it is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. Moreover, in this specification, when two or more polymers are complexed, the complexed polymer is treated as a single polymer.

[0104] When the adhesive layer of the present invention contains a polymer (A1), the content of the crosslinking agent and / or the structural portion derived from the crosslinking agent in the adhesive layer of the present invention is preferably 0.5 to 40% by mass, more preferably 1 to 35% by mass, and even more preferably 1.5 to 30% by mass, relative to 100% of the total amount of polymer (A1). Furthermore, when the compound (a1) is a crosslinking agent, the above content includes the amount of the compound (a1) and the structural portion derived from the compound (a1).

[0105] Regarding the proportion of one or more structural units and structural parts derived from compound (a2) in polymer (A2), from the viewpoint of achieving sufficient flexibility by imparting bond breakage and fragmentation upon external stimulation, it is preferably 0.1 to 15% by mass, more preferably 0.2 to 10% by mass, and even more preferably 0.5 to 5% by mass, and particularly preferably 1 to 3% by mass, relative to 100% of the total mass of polymer (A2).

[0106] When the adhesive layer of the present invention contains a polymer (A2), the content of the crosslinking agent and / or the structural portion derived from the crosslinking agent in the adhesive layer of the present invention is preferably 0.1 to 15% by mass, more preferably 0.2 to 10% by mass, and even more preferably 0.5 to 5% by mass, and particularly preferably 1 to 3% by mass, relative to 100% of the total mass of the polymer (A2). Furthermore, when the compound (a2) is a crosslinking agent, the above content includes the amount of the compound (a2) and the amount of the structural portion derived from the compound (a2).

[0107] The rebonding inhibitor compound (B) is a compound capable of inhibiting the rebonding of broken bonds in the polymer (A1) caused by external stimuli. There are no particular limitations, but when the polymer (A1) generates free radicals due to bond breakage, it is preferable to use a compound with free radical scavenging capabilities (free radical scavenger). Examples of such free radical scavengers include photoradical polymerization initiators, rotational scavengers, antioxidants, polymerization inhibitors, and hydrogen donors.

[0108] There are no particular limitations on the aforementioned photoradical polymerization initiators. Examples include: benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-keto alcohol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and 9-oxosulfuron-methyl-2-ethylhexylene ... Photopolymerization initiators, phosphine oxide photopolymerization initiators, etc.

[0109] 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-diphenylethane-1-one, and anisole methyl ether. Examples of acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4-(tert-butyl)dichloroacetophenone. Examples of α-ketool-based photopolymerization initiators include 2-methyl-2-hydroxyphenylacetone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropane-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 benzoin-based photopolymerization initiators include benzoin. Examples of benzoin-based photopolymerization initiators include benzoin. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. Examples of ketal-based photopolymerization initiators include benzoin dimethyl ketal. As for the above-mentioned 9-oxosulfur... Photopolymerization initiators, such as 9-oxosulfuron-methyl. 2-Chloro-9-oxysulfur 2-Methyl-9-oxosulfur 2,4-Dimethyl-9-oxosulfur Isopropyl 9-Oxysulfur 2,4-Diisopropyl-9-oxosulfur Dodecyl 9-oxosulfur Examples of phosphine oxide photopolymerization initiators include: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0110] Regarding the content of the rebonding inhibition compound (B), from the viewpoint of achieving an appropriate rebonding inhibition effect, it is preferably 10 to 1000 parts by mass, more preferably 50 to 500 parts by mass, and even more preferably 75 to 400 parts by mass, and particularly preferably 100 to 300 parts by mass, relative to a total of 100 parts by mass of one or more of the group consisting of compound (a1), structural units derived from compound (a1), and structural parts derived from compound (a1).

[0111] The adhesive layer of this invention may also include other components besides those mentioned above, as needed. Examples of these other components include resins other than polymer (A), curing catalysts, crosslinking agents (including polyfunctional (meth)acrylates), crosslinking accelerators, polymerization initiators, adhesion-improving resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, anti-aging agents, fillers (metal powders, organic fillers, inorganic fillers, etc.), colorants (pigments or dyes, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, ultraviolet absorbers, sensitizers, polymerization inhibitors, granules, foils, flame retardants, silane coupling agents, ion scavengers, etc. Only one of the above-mentioned components may be used, or two or more may be used.

[0112] Examples of curing catalysts include organotitanium compounds and organozirconium compounds. Examples of organotitanium compounds include alkyl titanium, titanium chelates, and acetyl titanium. Examples of organozirconium compounds include alkyl zirconium, zirconium chelates, and acetyl zirconium. Examples of alkyl titanium include tetraisopropyl titanate, tetrabutyl titanate, tetrabutyl titanate dimer, and tetraoctyl titanate. Examples of titanium chelates include titanium acetopyruvate, titanium tetraacetopyruvate, titanium ethyl acetopyruvate, and titanium octyl glycol. Examples of acetyl titanium include titanium isostearate. Examples of alkyl zirconium include n-propyl zirconate and n-butyl zirconate. Examples of zirconium chelates include tetraacetopyruvate and monoacetopyruvate. Examples of acetyl zirconium include zirconium stearate.

[0113] The content ratio of the aforementioned hardening catalyst is not particularly limited. From the viewpoint of imparting appropriate initial hardness and hardness after external stimulation to the adhesive layer, etc., it is preferably 0.005 to 3% by mass, more preferably 0.01 to 1% by mass, and even more preferably 0.05 to 1% by mass, relative to 100% by mass of the total amount of the adhesive layer, etc. of the present invention.

[0114] As for the aforementioned crosslinking agents, there are no particular limitations as long as they crosslink the polymer. Examples include polyisocyanate compounds, epoxy compounds, polyol compounds (polyphenolic compounds, etc.), aziridine compounds, melamine-based crosslinking agents, aziroxazoline-based crosslinking agents, and polyfunctional (meth)acrylates. As for polyfunctional (meth)acrylates, examples include (meth)acrylates with two or more functions, such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0115] <Adhesive compositions, adhesive compositions> The adhesive layer of the present invention is formed from an adhesive composition. Furthermore, the aforementioned adhesive layer is formed from the aforementioned adhesive composition. Preferably, the aforementioned adhesive composition comprises at least a base polymer and / or its raw material monomers. From the viewpoint of enabling the obtained adhesive layer to exhibit adhesive properties, it is preferable to include a base polymer. The aforementioned base polymer is polymer (A) and / or other polymers (i.e., polymers without decomposable bonds). When the aforementioned base polymer is one of the aforementioned other polymers, the aforementioned adhesive composition further comprises compound (a). Only one type of base polymer may be used, or two or more types may be used.

[0116] When the base polymer is one of the other polymers mentioned above, the adhesive composition further includes compound (a). In this case, a monomeric component (sometimes referred to as "monomeric component (c)") that is reactive with compound (a) may also be included. Compound (a) is reactive with the other polymers and / or monomeric component (c). When compound (a) is reactive with the other polymers, the other polymers react with compound (a) in the adhesive layer or the like by heat or irradiation with an active energy beam to form, for example, polymer chains. These polymer chains bond with the other polymers to form a network structure, thereby obtaining an adhesive layer or the like containing polymer (A). When the composition includes both compound (a) and monomeric component (c), the compound (a) reacts with monomeric component (c) in the adhesive layer or the like by heat or irradiation with an active energy beam to form, for example, polymer chains. These polymer chains complex with the other polymers to form a network structure, thereby obtaining an adhesive layer or the like containing polymer (A). Monomer component (c) may be used in one or more ways.

[0117] When the aforementioned adhesive composition or the like contains the aforementioned raw material monomers, compound (a) is introduced into the base polymer during the polymerization of the raw material monomers to form polymer (A). Alternatively, the aforementioned raw material monomers are polymerized to form the aforementioned other polymers, which are then reacted with compound (a) to form polymer (A).

[0118] Examples of the aforementioned adhesive compositions include: (i) adhesive compositions comprising polymer (A); (ii) adhesive compositions comprising polymer (A) and the other polymers mentioned above; (iii) adhesive compositions comprising the other polymers mentioned above, compound (a), and monomer components (c) as needed; and (iv) adhesive compositions comprising raw monomers, compound (a), and monomer components (c) as needed. Furthermore, when polymer (A) is polymer (A1), the adhesive compositions of (i) to (iv) further include a rebonding inhibitor compound (B).

[0119] Therefore, polymer (A) can be a reactant of the other polymers, compounds (a), and monomers (c) mentioned above, or it can be a polymer (especially a complexed polymer) containing the other polymers and reactants of the other polymers and compounds (a). Furthermore, when the base polymer is polymer (A), the adhesive layer, etc., may contain unreacted compounds (a) and / or unreacted monomers (c).

[0120] The aforementioned adhesive compositions may also contain other components besides those listed above. Examples of such other components include those exemplified and described as components that may be included in the adhesive layer of the present invention, or solvents such as organic solvents. Only one of the aforementioned other components may be used, or two or more may be used.

[0121] (Adhesive compositions, etc. (M1)) The adhesive composition, etc., of the present invention comprising an adhesive layer including a polymer (A1) (sometimes referred to as "adhesive composition, etc. (M1)") further comprises a rebonding inhibitor compound (B). The base polymer that the adhesive composition, etc. (M1) may contain is preferably one of the other polymers described above.

[0122] Examples of the aforementioned base polymers include the aforementioned thermoplastic resin, the aforementioned thermosetting resin, and the aforementioned active energy line curing resin. Among these, thermoplastic resin and thermosetting resin are preferred. An adhesive layer containing a thermoplastic resin can, for example, exhibit adhesiveness that allows for close adhesion under external pressure. An adhesive layer containing a thermosetting resin can, for example, bond to the substrate by heat curing.

[0123] As compound (a1), examples as described above include monomeric components, oligomer components, and crosslinking agents having the aforementioned reversible decomposable bonds. Among these, crosslinking agents are preferred, and crosslinking agents having disulfide bonds are even more preferred.

[0124] Regarding the functional groups (L1) of the compound (a1) used as the crosslinking agent, from the viewpoint that the crosslinking density of the polymer (A1) becomes appropriate, hydroxyl and carboxyl groups are preferred.

[0125] When compound (a1) is reactive with the other polymers mentioned above, the other polymers have functional groups (L2) that can react with the functional groups (L1) in compound (a1). The functional group (L2) can be appropriately selected according to the type of functional group (L1), for example: carboxyl, epoxy, cyclic ether groups, aziridinyl, hydroxyl, isocyanate, (meth)acrylyl, amino, aldehyde, etc.

[0126] Examples of combinations of functional groups (L1) and (L2) include: carboxyl group and a group containing a cyclic ether, a group containing a cyclic ether and a carboxyl group, carboxyl group and aziridinyl group, aziridinyl group and carboxyl group, hydroxyl group and isocyanate group, isocyanate group and hydroxyl group, (meth)acrylyl group and (meth)acrylyl group, hydroxyl group and amino group, amino group and hydroxyl group, a group containing a cyclic ether and a hydroxyl group, and a hydroxyl group and a group containing a cyclic ether. Among these, from the viewpoint of ease of reaction tracking, combinations of carboxyl group and a group containing a cyclic ether, combinations of a group containing a cyclic ether and a carboxyl group, combinations of a group containing a cyclic ether and a hydroxyl group, and combinations of a hydroxyl group and a group containing a cyclic ether are preferred. That is, functional group (L1) is preferably hydroxyl or carboxyl, and functional group (L2) is preferably a group containing a cyclic ether (especially an epoxy group).

[0127] Regarding the number of functional groups (L2) in the aforementioned other polymers, from the viewpoint of increasing the molecular weight after introduction into polymer (a1) and further reducing the molecular weight of the polymer after bond breaking, it can be two or more (e.g., two to four). On the other hand, from the viewpoint of ensuring the flexibility of the adhesive layer to a certain extent by achieving an appropriate crosslinking density, the number of functional groups (L2) is preferably three or less, and more preferably two.

[0128] The monomer component (c) is a compound having two or more polymerizable functional groups. Preferably, the polymerizable functional group is a functional group (L3) capable of reacting with the functional group (L1) of the compound (a1) used as a crosslinking agent. In this way, the monomer (c) polymerizes while simultaneously crosslinking with the compound (a1), thereby forming a polymer chain with reversibly decomposable bonds within the molecule. Furthermore, the functional group (L3) is preferably capable of reacting with the functional group (L2). The functional group (L3) can be appropriately selected based on the type of the functional group (L1) or functional group (L2), for example, carboxyl groups, epoxy groups containing cyclic ethers, aziridinyl groups, hydroxyl groups, isocyanate groups, (meth)acrylic groups, amino groups, aldehyde groups, etc.

[0129] Examples of combinations of functional groups (L1) and (L3) include those exemplified and described above, such as combinations of functional groups (L1) and (L2). From the viewpoint of ease of reaction tracking, combinations of carboxyl groups with groups containing cyclic ethers, combinations of groups containing cyclic ethers with carboxyl groups, combinations of groups containing cyclic ethers with hydroxyl groups, and combinations of hydroxyl groups with groups containing cyclic ethers are preferred. That is, functional group (L1) is preferably hydroxyl or carboxyl, and functional group (L3) is preferably a group containing a cyclic ether (especially an epoxy group).

[0130] Regarding the number of functional groups (L3) in monomer component (c), from the viewpoint of increasing the molecular weight of the polymer (A1) after introduction and further reducing the molecular weight of the polymer after bond breaking, it can be two or more (e.g., two to four). On the other hand, from the viewpoint of ensuring the flexibility of the adhesive layer and the like to a certain extent by achieving an appropriate crosslinking density, the number of functional groups (L3) is preferably three or less, and more preferably two.

[0131] The functional group (L3) is preferably a group having a cyclic ether group, and more preferably an epoxy group. That is, the monomer component (c) mentioned above is preferably an epoxy compound. Examples of such epoxy compounds include 4,4'-isopropylidene dicyclohexanol and (chloromethyl)ethylene oxide.

[0132] Regarding the equivalent amount of polymerizable functional groups of monomer component (c), from the viewpoint of achieving a moderately dense cross-linked structure, it is preferably 100~10000 eq / g, and more preferably 150~9000 eq / g.

[0133] When the base polymer is one of the other polymers mentioned above, the content of the monomer component (c) in the adhesive composition (M1) is preferably 5 to 600 parts by mass relative to 100 parts by mass of the total amount of the base polymer, more preferably 7 to 500 parts by mass. When the other polymer is a thermosetting resin, the content is preferably 200 to 600 parts by mass, more preferably 300 to 500 parts by mass, and even more preferably 350 to 450 parts by mass. When the other polymer is a thermoplastic resin, the content is preferably 5 to 80 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 7 to 30 parts by mass.

[0134] When the base polymer is polymer (A1), the content of monomer component (c) in the adhesive composition (M1) is preferably 5-95% by mass, more preferably 7-90% by mass, relative to 100% of the total polymer (A1). When polymer (A1) is a thermosetting resin, the above content ratio is preferably 50-95% by mass, more preferably 60-90% by mass, and even more preferably 65-85% by mass. When polymer (A1) is a thermoplastic resin, the above content ratio is preferably 3-50% by mass, more preferably 5-40% by mass, and even more preferably 6-30% by mass.

[0135] The content ratio of the other polymers in the adhesive composition (M1) is preferably 5-99% by mass, more preferably 10-95% by mass, relative to 100% of the total amount of the adhesive composition (M1) (excluding components such as organic solvents that do not remain during layer formation). When the other polymers are thermosetting resins, the content ratio is preferably 5-50% by mass, more preferably 7-40% by mass, and even more preferably 10-30% by mass. When the other polymers are thermoplastic resins, the content ratio is preferably 30-99% by mass, more preferably 50-95% by mass, and even more preferably 60-90% by mass. If the content ratio is 5% by mass or more, it is easy to impart adhesiveness to the adhesive layer. If the content ratio is 99% by mass or less, it is easy to design the composition by adjusting the crosslinking agent or rebonding inhibitor compound (B).

[0136] The content of the crosslinking agent and / or structural portion derived from the crosslinking agent in the adhesive composition (M1) is preferably 0.5 to 40 parts by mass, more preferably 1 to 35 parts by mass, and even more preferably 1.5 to 30 parts by mass, relative to 100 parts by mass of the total amount of the other polymer and / or monomer components (c). Furthermore, when compound (a1) is a crosslinking agent, the above content includes the amount of compound (a1).

[0137] (Adhesive compositions, etc. (M2)) The adhesive composition (sometimes referred to as "adhesive composition (M2)") that forms the adhesive layer of the present invention containing polymer (A2) may preferably contain polymer (A2), and more preferably polymer (A2) and other polymers mentioned above. Furthermore, polymer (A2) is preferably a curable resin. The curability of the curable resin can be appropriately selected according to the type of irreversible decomposable bond; when the irreversible decomposable bond can be broken by an active energy line, a thermosetting resin is preferred.

[0138] The polymer (A2) used as the aforementioned curable resin is preferably a resin (prepolymer) having polymerizable functional groups. When the polymer (A2) has polymerizable functional groups, during the formation of an adhesive layer, etc., the polymerizable functional groups are polymerized together by heat or active energy line irradiation after the adhesive composition is coated, thereby complexing with the other polymers mentioned above, thereby forming a network structure. That is, the polymer (A2) is preferably a polymer capable of forming the aforementioned network structure.

[0139] Examples of the aforementioned base polymers include the aforementioned thermoplastic resin, the aforementioned thermosetting resin, and the aforementioned active energy line curing resin. The polymer (A2) as the aforementioned base polymer is preferably a curing resin, and more preferably a thermosetting resin. Among the other polymers mentioned above, thermoplastic resins are more preferred. An adhesive layer containing a thermoplastic resin can, for example, exhibit adhesiveness achieved through pressure from the outside. An adhesive composition containing a curing resin can, for example, form a network structure by heat curing. Furthermore, the other polymers mentioned above can also be curing resins. In this case, by applying heat or active energy line irradiation, bonds can be formed between the polymer (A2), which is also a curing resin, and the other polymers mentioned above, thereby forming a network structure.

[0140] As compound (a2), examples as described above include monomeric components, oligomeric components, and crosslinking agents having the aforementioned irreversible decomposable bonds. Among these, monomeric components (i.e., compounds having polymerizable functional groups as described above) are preferred, more preferably nitrobenzyl monomers, and even more preferably nitrobenzyl ester monomers.

[0141] The content ratio of polymer (A2) in the aforementioned base polymer, relative to the total amount of the aforementioned base polymer (100% by mass), is preferably 10-90% by mass, more preferably 30-70% by mass, and even more preferably 40-60% by mass. If the content ratio is 10% by mass or more, a sufficient amount of irreversible decomposable bonds will be broken by external stimulation. If the content ratio is 90% by mass or less, adequate adhesion and / or bonding can be maintained even after external stimulation.

[0142] The content ratio of the other polymers in the aforementioned base polymer is, relative to the total amount of the aforementioned base polymer (100% by mass), preferably 10-90% by mass, more preferably 30-70% by mass, and even more preferably 40-60% by mass. If the content ratio is 10% by mass or more, adequate adhesion and / or bonding can be maintained after external stimulation. If the content ratio is 90% by mass or less, polymer (A2) can be adequately formulated, thereby allowing sufficient amounts of irreversible decomposable bonds to be broken by external stimulation.

[0143] The percentage of structural units derived from compound (a2) in polymer (A2) is preferably 0.2 to 30% by mass, more preferably 0.5 to 15% by mass, and even more preferably 0.8 to 10% by mass, relative to 100% of the total mass of polymer (A2). When the adhesive composition or the like (M2) contains raw material monomers constituting the base polymer, the percentage of compound (a2) in all monomer components constituting polymer (A2) is preferably within the above range.

[0144] When the polymer (A2) is the aforementioned acrylic resin, the content ratio of structural units derived from acrylic monomers in the polymer (A2) is preferably 70 to 99.8% by mass, more preferably 85 to 99.5% by mass, and even more preferably 90 to 99.2% by mass, relative to 100% of the total mass of the polymer (A2). When the adhesive composition, etc. (M2) contains raw material monomers constituting the base polymer, the content ratio of acrylic monomers in all monomer components constituting the polymer (A2) is preferably within the above-mentioned range.

[0145] Regarding the content ratio of structural units derived from compound (a2) in the aforementioned basic polymer, in order to achieve sufficient flexibility through bond breaking and fragmentation upon application of external stimuli, it is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more, relative to 100% by mass of the total amount of the aforementioned basic polymer. Furthermore, in order to impart appropriate flexibility to the resin before application of external stimuli in order to achieve appropriate crosslinking density, it is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. When the adhesive composition, etc. (M2), contains raw material monomers constituting the basic polymer, the content ratio of compound (a2) in all monomer components constituting the basic polymer is preferably within the above-mentioned range.

[0146] When the base polymer is the acrylic resin, the content ratio of structural units derived from acrylic monomers in the base polymer is preferably 85-99.9% by mass, more preferably 90-99.8% by mass, and even more preferably 95-99.5% by mass, relative to 100% of the total mass of the base polymer. When the adhesive composition (M2) contains raw material monomers constituting the base polymer, the content ratio of acrylic monomers in all monomer components constituting the base polymer is preferably within the above range.

[0147] The content ratio of the base polymer in the adhesive composition (M2) is 100% by mass relative to the total amount of the adhesive composition (M2) (excluding components such as organic solvents that do not remain during layer formation), preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0148] <Removing Liner> The release liner is used to protect the adjacent adhesive surfaces and / or bonding surfaces before the application of the adhesive layer of the present invention, and is removed when the adhesive layer is applied.

[0149] Examples of substrates for the aforementioned release liner include: polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate film, ionomer resin film, ethylene-(meth)acrylate copolymer film, ethylene-(meth)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluoropolymer film, etc. Crosslinked films of these types can also be used. Furthermore, laminated films of these types can also be used.

[0150] It is preferable to perform a peeling treatment on the peeling surface of the aforementioned release liner (especially the surface in contact with the aforementioned adhesive layer, etc.). Examples of release agents used for the peeling treatment include alkyd-based, polysiloxane-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

[0151] The thickness of the aforementioned release liner is not particularly limited, for example, it is about 20~150 μm.

[0152] One embodiment of the manufacturing method of the adhesive layer of the present invention will be described. For example, the adhesive sheet or bonding sheet 10 with release liner shown in FIG. 1 can be manufactured by the following method. After coating an adhesive composition or the like to form the adhesive layer 1 onto a substrate layer or the release-treated surface of the release liner 2 which has undergone release treatment, the coating layer is cured by desolvation or thermosetting by heating, or by irradiation with active energy beams. Furthermore, in the case of irradiation with active energy beams, a release liner is additionally attached to the above-mentioned coating layer before the process is carried out.

[0153] The adhesive composition can be in any form as long as it does not impair the effect of the present invention. For example, the adhesive composition can be emulsion type, solvent type (solution type), hot melt type (hot melt type), etc. Among them, solvent type is preferred in terms of easily obtaining an adhesive layer with excellent production performance.

[0154] When the adhesive composition contains polymer (A), the adhesive layer is formed by heating during the curing of the coating layer. When the adhesive composition contains other polymers and / or raw material monomers and compound (a), the raw material monomers are polymerized as needed by heating during the curing of the coating layer or by irradiation with an active energy line. Compound (a) forms bonds with the polymer of the raw material monomers or the other polymers to form polymer (A), and simultaneously forms the adhesive layer. The adhesive layer can also be subsequently heated or irradiated with an active energy line, and if polymer (A) is a curable resin, a curing process can also be performed. In this manner, the adhesive sheet or bonding sheet 10 with a release liner shown in FIG. 1 can be obtained.

[0155] The uses of the adhesive layer of the present invention are not particularly limited and can be used for all applications. For example, the adhesive layer of the present invention can be used for optical applications, i.e., for bonding to optical components. For example, the adhesive layer of the present invention is used when mounting (installing) various components or parts to designated locations (e.g., housings) in optical components such as electrical and electronic machines. Furthermore, the term "electrical and electronic machine" refers to a machine that is at least one of electrical or electronic machines. Examples of such electrical and electronic machines include, for example, image display devices such as liquid crystal displays, electroluminescent displays, and plasma displays, and portable electronic devices. Examples of such image display devices include image display devices in portable electronic devices, and displays (scrolling displays) inside and outside vehicles such as trams or buses.

[0156] Examples of portable electronic devices include: mobile phones, smartphones, tablet PCs, laptop PCs, various wearable devices (such as wristwatches, modular devices worn on the wrist, including eyeglasses (monocular or binocular, and headband-type), clothing devices attached to shirts, socks, hats, etc., and earphones), digital cameras, digital camcorders, audio devices (walkmen, voice recorders, etc.), computers (calculators, etc.), portable game consoles, electronic dictionaries, electronic notebooks, e-books, in-vehicle information devices, portable radios, portable televisions, portable printers, portable scanners, and portable modems. Furthermore, in this manual, "portable" does not simply mean being able to carry; it refers to a degree of portability that is relatively easy for a person (a standard adult) to move.

[0157] The adhesive layer of this invention exhibits excellent operability before being bonded to or attached to a component during manufacturing, processing, storage, and handling, and excellent flexibility after being bonded to or attached to the component. Therefore, for example, when cutting with a die, it can prevent paste overflow or loss, thus preventing engineering contamination. Furthermore, it is less prone to paste overflow due to its own weight during storage, and less prone to paste loss due to vibration or contact during handling. Moreover, its excellent flexibility after being bonded to or attached to a component, for example, when used in close contact with the component, allows for superior adhesion, bonding strength, bendability, foldability, and bending resistance. Furthermore, since the adhesive layer of this invention can reduce stress through external stimuli, it allows for variations in adhesion or bonding strength.

[0158] [Adhesive sheet, bonding sheet] Using the adhesive layer of the present invention, adhesive sheets and / or bonding sheets can be obtained. Furthermore, in this specification, adhesive sheets and / or bonding sheets are sometimes referred to as "adhesive sheets, etc." The aforementioned adhesive sheets, etc., can be so-called "substrate-free" adhesive sheets, etc., that do not have a substrate (substrate layer), or they can be adhesive sheets, etc., that have a substrate. Furthermore, in this specification, "substrate-free" adhesive sheets, etc., are sometimes referred to as "substrate-free adhesive sheets, etc.", and sometimes adhesive sheets, etc., that have a substrate are referred to as "substrate-attached adhesive sheets, etc." Examples of the aforementioned substrate-free adhesive sheets, such as: double-sided adhesive sheets, etc., composed solely of the adhesive layer of the present invention, etc., or double-sided adhesive sheets, etc., that include the adhesive layer of the present invention, etc., and other adhesive layers, etc. (adhesive layers other than the adhesive layer of the present invention, etc.). Furthermore, the aforementioned adhesive sheet with a substrate includes an adhesive sheet containing a substrate and an adhesive layer of the present invention formed on at least one side of the substrate. Examples include: a single-sided adhesive sheet having an adhesive layer of the present invention on one side of the substrate; a double-sided adhesive sheet having an adhesive layer of the present invention on both sides of the substrate; or a double-sided adhesive sheet having an adhesive layer of the present invention on one side of the substrate and other adhesive layers on the other side. Moreover, the term "substrate (substrate layer)" refers to a support, and when the adhesive sheet is used (attached) to the adhered body, it refers to the portion attached to the adhered body together with the adhesive layer. The release liner peeled off when using (attaching) the adhesive sheet is not included in the aforementioned substrate.

[0159] When the adhesive sheet or the like used in this invention is an adhesive sheet or the like used as a substrate, the substrate is not particularly limited. Examples of such substrates include various optical films such as plastic films, anti-reflective (AR) films, anti-glare (AG) films, polarizing plates, and phase retardation plates. Furthermore, examples of such substrates include porous materials such as paper, cloth, and non-woven fabrics, meshes, foamed sheets, and metal foils. Examples of materials used for the aforementioned plastic films or the like include: polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetin (TAC), polyurethane, polyarylate, polyimide, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, and cyclic olefin polymers such as "ARTON" (a cyclic olefin polymer manufactured by JSR Corporation) and "ZEONOR" (a cyclic olefin polymer manufactured by Zeon Corporation of Japan). Furthermore, such plastic materials may be used in only one type or in two or more types.

[0160] The thickness of the aforementioned substrate is not particularly limited, but is preferably 10-150 μm, more preferably 15-125 μm, and even more preferably 25-100 μm. Furthermore, the aforementioned substrate can be in the form of a single layer or multiple layers. Also, the surface of the aforementioned substrate can be appropriately treated with known and conventional surface treatments such as physical treatments like corona discharge treatment and plasma treatment, and chemical treatments like primer treatment.

[0161] The aforementioned adhesive sheets may also have release liner provided on the surface (adhesive surface or bonding surface) of the adhesive layer until use. Furthermore, when the aforementioned adhesive sheets are double-sided adhesive sheets, each adhesive surface or bonding surface can be protected by two release liners, or a single release liner with both sides serving as release surfaces can be wound into a roll (wound body) for protection. The release liner serves as a protective material for the adhesive layer and is peeled off when attached to the adhered object. Also, when the aforementioned adhesive sheets are substrate-free adhesive sheets, the release liner also functions as a support for the adhesive layer. Alternatively, a release liner may not be provided.

[0162] The embodiments described above are for the purpose of making the present invention easier to understand, and are not intended to limit the present invention. [Example]

[0163] The present invention will now be described in more detail with reference to specific embodiments, but the invention is not limited to these embodiments in any way. Furthermore, the evaluation results indicated by "-" in Table 1 indicate that reliable data could not be obtained due to excessive strain at that elongation ratio, and therefore could not be measured. The evaluation results indicated by "-" in Table 2 indicate that no evaluation was performed. Also, the values ​​of each monomer component constituting the prepolymer shown in Table 3 are parts by mass.

[0164] Example 1 100 parts by weight of epoxy monomer (trade name "HBE100", manufactured by Shin Nippon Rika Co., Ltd., equivalent to monomer component (c)), 25 parts by weight of epoxy resin (trade name "1256B40", manufactured by Mitsubishi Chemical Co., Ltd.), 20 parts by weight of 4,4'-dithiodibutyric acid (manufactured by Tokyo Chemical Industry Co., Ltd., equivalent to compound (a1)) as an epoxy curing agent, 25 parts by weight of free radical scavenger (trade name "Omnirad TPO H", manufactured by IGM Resins BV, equivalent to rebonding inhibitor compound (B)), 0.1 parts by weight of curing catalyst (trade name "ZC700", manufactured by Matsumoto Fine Chemical Co., Ltd.), and 3 parts by weight of acetone (AcAc) were added to 500 parts by weight of methyl ethyl ketone and mixed to prepare a mixed solution. The mixed solution was coated onto a 38 μm thick release liner R1 (trade name "MRF#38", manufactured by Mitsubishi Chemical Corporation), with one side of the polyester film serving as the release surface, and dried in an oven at 100°C for 5 minutes. After drying, the coated surface was placed over the release surface of the 38 μm thick release liner R2 (trade name "MRE#38", manufactured by Mitsubishi Chemical Corporation), thereby producing an adhesive sheet with a thickness of 50 μm containing a thermosetting resin (equivalent to polymer (A1)). Furthermore, in this specification, "adhesive" refers to having both adhesive and bonding properties.

[0165] Example 2 Except for using the trade name "jER828" (manufactured by Mitsubishi Chemical Corporation) as the epoxy monomer, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) was prepared in the same manner as in Example 1.

[0166] Example 3 Except for using the trade name "Omnirad 651" (manufactured by IGM Resins BV) as a free radical scavenger, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) was prepared in the same manner as in Example 2.

[0167] Example 4 Except for using 4,4'-dithiobiphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) as an epoxy curing agent, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) was prepared in the same manner as in Example 1.

[0168] Example 5 Except for using 4,4'-dithiobiphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) as an epoxy curing agent, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) was prepared in the same manner as in Example 2.

[0169] Comparative Example 1 Except that no free radical scavenger is used, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) is prepared in the same manner as in Example 2.

[0170] Comparative Example 2 Except for using 4,4'-ethylidene bisphenol as an epoxy curing agent, an adhesive sheet containing a thermosetting resin was prepared in the same manner as in Example 1.

[0171] Comparative Example 3 Except that no free radical scavenging agent was used, an adhesive sheet containing a thermosetting resin was prepared in the same manner as in Comparative Example 2.

[0172] Example 6 (Preparation of acrylic polymers) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet, a mixture comprising 95 parts by mass of n-butyl acrylate (BA), 5 parts by mass of acrylic acid (AA), 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 122 parts by mass of ethyl acetate as a solvent was stirred at 60°C under a nitrogen atmosphere for 7 hours. This yielded a polymer solution containing an acrylic polymer. The weight average molecular weight (Mw) of the acrylic polymer in this polymer solution was 600,000.

[0173] (Formation of bonded sheets) To 100 parts by weight of the above-mentioned acrylic polymer (dissolved in ethyl acetate), 0.1 parts by weight of crosslinking agent (trade name "Tetrad C", manufactured by Mitsubishi Gas Chemical Co., Ltd.), 100 parts by weight of epoxy monomer (trade name "HBE100", manufactured by Shin Nippon Rika Co., Ltd., equivalent to monomer component (c)), 2 parts by weight of epoxy curing agent (4,4'-dithiodibutyric acid, equivalent to compound (a1)), 0.1 parts by weight of curing catalyst (trade name "ZC700", manufactured by Matsumoto Fine Chemical Co., Ltd.), 3 parts by weight of acetone, and 5 parts by weight of free radical scavenger (trade name "Omnirad TPO H", manufactured by IGM Resins BV Co., Ltd.) were added and mixed to prepare a mixed solution. The mixed solution was coated onto a 38 μm thick release liner R1 (trade name "MRF#38", manufactured by Mitsubishi Chemical Co., Ltd.) on one side of a polyester film to form the release surface, and dried in an oven at 100°C for 5 minutes. After drying, a 38 μm thick release liner R2 (trade name "MRE#38", manufactured by Mitsubishi Chemical Corporation) is used as the release side of the single side of the polyester film covered by the coating, thereby producing an adhesive sheet with a thickness of 50 μm containing thermosetting resin (equivalent to polymer (A1)).

[0174] Example 7 Except for using the trade name "jER828" (manufactured by Mitsubishi Chemical Corporation) as the epoxy monomer, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) was prepared in the same manner as in Example 6.

[0175] Comparative Example 4 A mixed solution was prepared by adding 0.1 parts by weight of a crosslinking agent (trade name "Tetrad C", manufactured by Mitsubishi Gas Chemical Co., Ltd.) to 100 parts by weight of the acrylic polymer prepared in Example 6 (dissolved in ethyl acetate) and mixing. An adhesive sheet was then prepared in the same manner as in Example 6, except that the mixed solution was used.

[0176] Comparative Example 5 Except that no free radical scavenger is used, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) is prepared in the same manner as in Example 6.

[0177] Comparative Example 6 Except that no free radical scavenger is used, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) is prepared in the same manner as in Example 7.

[0178] Preparation Example 1 (Synthesis of nitrobenzyl ester monomer precursors) Under a nitrogen atmosphere, 72 g (341 mmol) of 2-nitroisophthalic acid and 400 g of tetrahydrofuran (THF) were added to a 5 L flask, mixed, and stirred until the 2-nitroisophthalic acid dissolved. The solution was cooled to 2°C, and 0.9 M (162 mmol) of a borane tetrahydrofuran complex (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise. The mixture was then heated to room temperature and stirred for 48 hours. Subsequently, methanol was added dropwise, and the solvent was distilled off under reduced pressure (50°C, 25 mmHg). The solution was diluted with ethyl acetate and extracted. The organic phase was washed three times with 900 g of water. Then, 70 g of magnesium sulfate was added to the organic phase for dehydration, followed by filtration and washing with ethyl acetate. The solvent in the filtrate was distilled off under reduced pressure (50°C, 25 mmHg) to obtain 41 g of a nitrobenzyl ester monomer precursor (pale yellow crystals).

[0179] Preparation Example 2 (Synthesis of nitrobenzyl ester monomer) Next, 21.0 g (115 mmol) of the above-mentioned monomer precursor, 33.2 g (460 mmol) of acrylic acid, 9.3 g (76.7 mmol) of 4-dimethylaminopyridine (DMAP), and 210 mL of dichloromethane were added to a 1 L flask. Under cooling in an acetone / ice bath, while maintaining the internal temperature below 5°C, 84.9 g (574 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC hydrochloride) (manufactured by Tokyo Chemical Industry Co., Ltd.) was added in batches, and the mixture was stirred to carry out the reaction. After the reaction was completed, the reaction solution was purified twice directly by silica gel chromatography (developing solvent: dichloromethane). 0.004 g of hydroquinone monomethyl ether (MEHQ) was added to the fraction, and the solvent was distilled off under reduced pressure (below 30 °C, 30 mmHg). The precipitate was then cooled in an ice bath and dried under reduced pressure at 30 °C to obtain 11.4 g of nitrobenzyl ester monomer (2-nitro-1,3-bis(acryloxymethylene)benzene, pale yellow crystals).

[0180] Preparation Example 3 (Synthesis of acrylic polymer P1) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet pipe, a mixture comprising 95 parts by mass of n-butyl acrylate (BA), 5 parts by mass of acrylic acid (AA), 0.2 parts by mass of AIBN as a polymerization initiator, and 122 parts by mass of ethyl acetate as a solvent was stirred at 60°C under a nitrogen atmosphere for 7 hours to carry out a polymerization reaction. This yielded a polymer solution containing an acrylic polymer P1. The weight average molecular weight (Mw) of the acrylic polymer P1 in this polymer solution was 600,000.

[0181] Example 8 (Synthesis of acrylic polymer P2) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet pipe, a mixture comprising 95 parts by mass of butyl acrylate (BA), 5 parts by mass of the nitrobenzyl ester monomer prepared in Preparation Example 2 (equivalent to compound (a2)), 2.83 parts by mass of the chain transfer agent "C12TCSS" (manufactured by Japan Terpene Chemical Co., Ltd.), 0.28 parts by mass of the polymerization initiator 2,2'-azobisisobutyronitrile (AIBN), and 301 parts by mass of ethyl acetate as solvent was stirred at 60°C under a nitrogen atmosphere for 6 hours to carry out a polymerization reaction. This yielded a polymer solution containing an acrylic polymer P2 (equivalent to polymer (A2)) as an acrylonitrile-containing prepolymer.

[0182] (Synthesis of adhesive composition) The polymer solution containing acrylic polymer P1 prepared in Preparation Example 3 and the polymer solution containing acrylic polymer P2 were mixed at a ratio of 100 parts by mass of acrylic polymer P2 to 100 parts by mass of acrylic polymer P1. The mixture was stirred at 2000 rpm for 5 minutes, and then stirred and defoamed at 2200 rpm for 5 minutes to prepare an adhesive composition.

[0183] (Formation of bonded sheets) The above adhesive composition was applied to the release-treated surface of a polyethylene terephthalate film (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) that had undergone release treatment with a polysiloxane-based release agent, with the dried adhesive layer thickness being 25 μm. The film was left to stand at room temperature for 5 minutes, and then dried at 130°C for 3 minutes. By fully evaporating and removing the ethyl acetate contained as a solvent, an adhesive sheet was obtained.

[0184] Comparative Example 7 (Synthesis of acrylic polymer P3) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet pipe, a mixture comprising 95 parts by mass of butyl acrylate (BA), 5 parts by mass of 1,6-hexanediol diacrylate, 2.83 parts by mass of "C12TCSS" (manufactured by Nippon Terpene Chemical Co., Ltd.) as a chain transfer agent, 0.28 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 301 parts by mass of ethyl acetate as a solvent was stirred at 60°C for 6 hours under a nitrogen atmosphere to carry out a polymerization reaction. This yielded a polymer solution containing an acrylic polymer P3 as an acrylonitrile-based prepolymer.

[0185] (Synthesis of adhesive composition) The polymer solution containing acrylic polymer P1 prepared in Preparation Example 3 and the polymer solution containing acrylic polymer P3 were mixed at a ratio of 100 parts by mass of acrylic polymer P3 to 100 parts by mass of acrylic polymer P1. The mixture was stirred at 2000 rpm for 5 minutes, and then stirred and defoamed at 2200 rpm for 5 minutes to prepare an adhesive composition.

[0186] (Formation of bonded sheets) Except for using the adhesive composition described above, the adhesive sheet was prepared in the same manner as in Example 8.

[0187] Comparative Example 8 (Synthesis of acrylic polymer P4) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet pipe, a mixture comprising 100 parts by mass of butyl acrylate (BA), 2.83 parts by mass of chain transfer agent "C12TCSS" (manufactured by Nippon Terpene Chemical Co., Ltd.), 0.28 parts by mass of polymerization initiator 2,2'-azobisisobutyronitrile (AIBN), and 301 parts by mass of solvent ethyl acetate was stirred at 60°C under a nitrogen atmosphere for 6 hours to carry out a polymerization reaction. This yielded a polymer solution containing an acrylic polymer P4 as a prepolymer with acrylonitrile groups.

[0188] (Synthesis of adhesive composition) The polymer solution containing acrylic polymer P1 prepared in Preparation Example 3 and the polymer solution containing acrylic polymer P4 were mixed at a ratio of 100 parts by mass of acrylic polymer P4 to 100 parts by mass of acrylic polymer P1. The mixture was stirred at 2000 rpm for 5 minutes, and then stirred and defoamed at 2200 rpm for 5 minutes to prepare an adhesive composition.

[0189] (Formation of bonded sheets) Except for using the adhesive composition described above, the adhesive sheet was prepared in the same manner as in Example 8.

[0190] Example 9 (Preparation of acrylic polymers) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet, a mixture comprising 63 parts by mass of 2-ethylhexyl acrylate (2EHA), 15 parts by mass of N-vinylpyrrolidone (NVP), 9 parts by mass of methyl methacrylate (MMA), 13 parts by mass of hydroxyethyl acrylate (HEA), 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 122 parts by mass of ethyl acetate as a solvent was stirred at 60°C under a nitrogen atmosphere for 7 hours. This yielded a polymer solution containing acrylic polymers. The weight average molecular weight (Mw) of the acrylic polymers in this polymer solution was 600,000.

[0191] (Formation of bonded sheets) A mixed solution was prepared by adding 4 parts by weight of crosslinking agent (trade name "Takenate D110N", manufactured by Mitsui Chemicals Co., Ltd.), 1 part by weight of curing agent (4,4'-dithiodiphenylamine, equivalent to compound (a1)), 0.1 parts by weight of crosslinking catalyst (trade name "ZC700", manufactured by Matsumoto Fine Chemical Co., Ltd.), 2 parts by weight of acetoacetone (AcAc), and 4 parts by weight of free radical scavenger (trade name "Omnirad TPO H", manufactured by IGM Resins BV Co., Ltd.) to 100 parts by weight of the above-mentioned acrylic polymer (dissolved in ethyl acetate). The mixed solution was then coated onto a 38 μm thick release liner R1 (trade name "MRF#38", manufactured by Mitsubishi Chemical Co., Ltd.) on one side of a polyester film to form the release surface, and dried in an oven at 100°C for 5 minutes. After drying, a 38 μm thick release liner R2 (trade name "MRE#38", manufactured by Mitsubishi Chemical Corporation) is used as the release side of the single side of the polyester film covered by the coating, thereby producing an adhesive sheet with a thickness of 50 μm containing thermosetting resin (equivalent to polymer (A1)).

[0192] Comparative Example 9 Except that no free radical scavenger is used, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) is prepared in the same manner as in Example 9.

[0193] Example 10 (Formation of bonded sheets) To 100 parts by weight of the acrylic polymer prepared in Example 6 (dissolved in ethyl acetate), 4 parts by weight of 1,3-bis(4,5-dihydro-2-azolyl)benzene (manufactured by Tokyo Chemical Industry Co., Ltd.) as a crosslinking agent, 4 parts by weight of a curing agent (4,4'-dithiobiphenol, equivalent to compound (a1)), and 5 parts by weight of a free radical scavenger (trade name "Omnirad TPO H", manufactured by IGM Resins BV) were added and mixed to prepare a mixed solution. This mixed solution was coated onto a 38 μm thick release liner R1 (trade name "MRF#38", manufactured by Mitsubishi Chemical Co., Ltd.) on one side of a polyester film as the release surface, and dried in an oven at 100°C for 5 minutes. After drying, a 38 μm thick release liner R2 (trade name "MRE#38", manufactured by Mitsubishi Chemical Corporation) is used as the release side of the single side of the polyester film covered by the coating, thereby producing an adhesive sheet with a thickness of 50 μm containing thermosetting resin (equivalent to polymer (A1)).

[0194] Example 11 Except for the use of 4,4'-dithiodibutyric acid (equivalent to compound (a1)) as a curing agent, the adhesive sheet was prepared in the same manner as in Example 10.

[0195] Comparative Example 10 Except that no free radical scavenger is used, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) is prepared in the same manner as in Example 10.

[0196] Comparative Example 11 Except that no free radical scavenger is used, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) is prepared in the same manner as in Example 11.

[0197] Comparative Example 12 Except that no hardener is used, an adhesive sheet containing a thermosetting resin (equivalent to polymer (A1)) is prepared in the same manner as in Example 10.

[0198] <Evaluation> The adhesive sheets produced in the examples and comparative examples were evaluated before and after UV irradiation. The results are shown in the table. Furthermore, the UV irradiation was performed using the following method.

[0199] (UV irradiation) For the adhesive sheets obtained in the embodiments and comparative examples, with the exposed adhesive surface and a release liner attached, a UV-LED irradiation device (model "QEL-350-RU6W-CW-MY") manufactured by Quark Technology was used. A UV-LED lamp with a wavelength of 365 nm was used as the light source, and the cumulative irradiation light intensity in the wavelength range of 320~390 nm was set to 8000 mJ / cm 2 for ultraviolet irradiation.

[0200] (1) Shear storage elastic modulus Laminated sheets were used to prepare test specimens approximately 1.0 mm thick. Dynamic viscoelasticity was measured using the "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific under the following conditions. The shear storage modulus at 25°C, 50°C, and 80°C was then calculated. (Measurement conditions) Deformation mode: Torsion Measurement frequency: 1 Hz Heating rate: 5℃ / minute Measurement temperature: -50~150℃ Shape: Parallel plate, 8.0 mm

[0201] (2) Tensile test Cut 10 mm × 30 mm strips from the 50 μm thick adhesive sheet obtained by lamination as needed, and prepare short strips 30 mm in length with the release liner removed. Fix the top and bottom 10 mm sections of the strips using the clamping fixture of a tensile compression testing machine (product name "Autograph AGS-50NX", manufactured by Shimadzu Corporation), and conduct a tensile test at a clamping distance of 10 mm and a tensile speed of 300 mm / min.

[0202] (3) Young's modulus E Based on the spectrum obtained from the above tensile test, the change in stress σ relative to strain ε in the elastic deformation region (E=Δσ / Δε) is calculated.

[0203] (4) Fracture point stress or peak stress intensity Based on the spectrum obtained from the tensile test, the value of the peak with an upward convex shape is set as the peak stress intensity. However, in cases where the bonded sheet breaks without obtaining an upward convex peak, the fracture point stress is used.

[0204] (5) Strain stress Based on the spectrum obtained from the above tensile test, the stress at each strain (%) is set as the strain stress.

[0205] [Table 1] (Table 1) raw material Mixing quantity [parts by weight] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Epoxy monomers 100 HBE100 jER828 jER828 HBE100 jER828 jER828 HBE100 HBE100 Epoxy resins 25.0 1256B40 1256B40 1256B40 1256B40 1256B40 1256B40 1256B40 1256B40 Epoxy hardener 20.0 4,4'-Dithiodibutyric acid 4,4'-Dithiodibutyric acid 4,4'-Dithiodibutyric acid 4,4'-Dithiobiphenol 4,4'-Dithiobiphenol 4,4'-Dithiodibutyric acid 4,4'-Ethylenebisphenol 4,4'-Ethylenebisphenol Free radical scavengers 25.0 Omnirad TPO H Omnirad TPO H Omnirad 651 Omnirad TPO H Omnirad TPO H - Omnirad TPO H - hardened catalyst 0.1 ZC700 ZC700 ZC700 ZC700 ZC700 ZC700 ZC700 ZC700 AcAc 3.0 AcAc AcAc AcAc AcAc AcAc AcAc AcAc AcAc Young's Modulus [MPa] Before UV irradiation 5.175 113.058 8.618 0.833 10.172 61.358 0.852 0.918 After UV irradiation 1.957 16.566 3.535 0.528 2.364 72.200 0.963 1.010 Young's modulus ratio [after UV irradiation / before UV irradiation] 0.38 0.15 0.41 0.63 0.23 1.18 1.13 1.10 Elongation at break [%] Before UV irradiation 480 170 370 810 270 170 770 680 After UV irradiation 670 180 300 990 360 200 660 720 The ratio of elongation at break [after UV irradiation / before UV irradiation] 1.40 1.06 0.81 1.22 1.33 1.18 0.86 1.06 Fracture point stress [MPa] Before UV irradiation 5.386 9.666 5.961 2.326 3.192 11.134 2.810 3.653 After UV irradiation 5.381 5.018 2.498 1.568 2.055 12.546 2.840 4.130 The ratio of stress at the fracture point [after UV irradiation / before UV irradiation] 1.00 0.52 0.42 0.67 0.64 1.13 1.01 1.13 100% strain stress [MPa] Before UV irradiation 1.188 9.174 1.860 0.339 1.810 10.091 0.384 0.451 After UV irradiation 0.691 5.137 1.143 0.250 0.828 10.864 0.383 0.436 100% strain-stress ratio [after UV irradiation / before UV irradiation] 0.58 0.56 0.61 0.74 0.46 1.08 1.00 0.97 200% strain stress [MPa] Before UV irradiation 1.525 - 2.525 0.395 2.531 - 0.467 0.563 After UV irradiation 0.830 - 1.664 0.278 1.067 12.547 0.455 0.541 200% strain-stress ratio [after UV irradiation / before UV irradiation] 0.54 - 0.66 0.70 0.42 - 0.98 0.96 300% strain stress [MPa] Before UV irradiation 2.263 - 4.190 0.480 2.427 - 0.592 0.739 After UV irradiation 1.160 - 2.472 0.308 1.597 - 0.557 0.696 300% strain-stress ratio [after UV irradiation / before UV irradiation] 0.51 - 0.59 0.64 0.66 - 0.94 0.94 500% strain stress [MPa] Before UV irradiation - - - 0.872 - - 1.118 1.640 After UV irradiation 2.692 - - 0.419 - - 0.938 1.453 500% strain-stress ratio [after UV irradiation / before UV irradiation] - - - 0.48 - - 0.84 0.89

[0206] [Table 2] (Table 2) raw material Mixing quantity [parts by weight] Example 6 Example 7 Comparative Example 4 Comparative Example 5 Comparative Example 6 acrylic polymers 100 BA / AA BA / AA BA / AA BA / AA BA / AA Crosslinking agent 0.1 Tetrad C Tetrad C Tetrad C Tetrad C Tetrad C Epoxy monomers 10.0 HBE100 jER828 - HBE100 jER828 Epoxy hardener 2.0 4,4'-Dithiodibutyric acid 4,4'-Dithiodibutyric acid - 4,4'-Dithiodibutyric acid 4,4'-Dithiodibutyric acid hardened catalyst 0.1 ZC700 ZC700 - ZC700 ZC700 AcAc 3.0 AcAc AcAc - AcAc AcAc Free radical scavengers 5.0 Omnirad TPO H Omnirad TPO H - - - Young's Modulus [MPa] Before UV irradiation 0.106 0.121 0.128 0.107 0.112 After UV irradiation 0.087 0.099 - 0.111 0.114 Young's modulus ratio [after UV irradiation / before UV irradiation] 0.82 0.81 - 1.04 1.02 Elongation at break [%] Before UV irradiation 1070 1040 1030 1070 1070 After UV irradiation 1290 1190 - 1050 1010 The ratio of elongation at break [after UV irradiation / before UV irradiation] 1.21 1.14 - 0.98 0.94 Fracture point stress [MPa] Before UV irradiation 0.442 0.479 0.500 0.447 0.489 After UV irradiation 0.494 0.531 - 0.495 0.513 The ratio of stress at the fracture point [after UV irradiation / before UV irradiation] 1.12 1.11 - 1.11 1.05 100% strain stress [MPa] Before UV irradiation 0.062 0.079 0.090 0.069 0.078 After UV irradiation 0.062 0.070 - 0.072 0.082 100% strain-stress ratio [after UV irradiation / before UV irradiation] 0.99 0.89 - 1.04 1.04 200% strain stress [MPa] Before UV irradiation 0.081 0.104 0.119 0.092 0.106 After UV irradiation 0.081 0.094 - 0.095 0.109 200% strain-stress ratio [after UV irradiation / before UV irradiation] 0.99 0.90 - 1.03 1.03 300% strain stress [MPa] Before UV irradiation 0.094 0.120 0.135 0.107 0.122 After UV irradiation 0.091 0.107 - 0.111 0.128 300% strain-stress ratio [after UV irradiation / before UV irradiation] 0.97 0.89 - 1.03 1.04 500% strain stress [MPa] Before UV irradiation 0.126 0.162 0.173 0.145 0.165 After UV irradiation 0.114 0.135 - 0.152 0.177 500% strain-stress ratio [after UV irradiation / before UV irradiation] 0.90 0.83 - 1.05 1.08

[0207] [Table 3] (Table 3) Example 8 Comparative Example 7 Comparative Example 8 prepolymer Nitrobenzyl ester monomer 5 - - BA 95 99 100 HDDA - 1 - Shear storage elastic modulus [Pa] 25℃ Before UV irradiation 4.27×10⁴ - - After UV irradiation 2.49×10⁴ - - 50℃ Before UV irradiation 2.47×10⁴ - - After UV irradiation 8.94×10³ - - 85℃ Before UV irradiation 1.56×10⁴ - - After UV irradiation 3.98×10³ - - The ratio of shear storage modulus [after UV irradiation / before UV irradiation] 25℃ 0.58 - - 50℃ 0.36 - - 80℃ 0.26 - - Young's modulus [MPa] Before UV irradiation 0.102 0.032 0.034 After UV irradiation 0.057 0.031 0.034 Young's modulus ratio [after UV irradiation / before UV irradiation] 0.56 0.97 0.99 Peak stress intensity [MPa] Before UV irradiation 0.348 0.035 0.032 After UV irradiation 0.056 0.034 0.031 Peak stress intensity ratio [after UV irradiation / before UV irradiation] 0.16 1.00 0.97 100% strain stress [MPa] Before UV irradiation 0.066 0.025 0.022 After UV irradiation 0.041 0.025 0.022 100% strain-stress ratio [after UV irradiation / before UV irradiation] 0.62 0.99 0.98 200% strain stress [MPa] Before UV irradiation 0.089 0.031 0.029 After UV irradiation 0.052 0.031 0.029 200% strain-stress ratio [after UV irradiation / before UV irradiation] 0.59 1.00 0.98 300% strain stress [MPa] Before UV irradiation 0.106 0.033 0.030 After UV irradiation 0.055 0.033 0.030 300% strain-stress ratio [after UV irradiation / before UV irradiation] 0.51 1.00 0.99 500% strain stress [MPa] Before UV irradiation 0.162 0.033 0.030 After UV irradiation 0.052 0.033 0.030 500% strain-stress ratio [after UV irradiation / before UV irradiation] 0.32 1.00 0.97

[0208] [Table 4] (Table 4) raw material Mixing quantity [parts by weight] Example 9 Comparative Example 9 acrylic polymers 100 2EHA / HEA / NVP / MMA 2EHA / HEA / NVP / MMA Crosslinking agent 4.0 Takenate D110N Takenate D110N hardener 1.0 4,4'-Dithiodiphenylamine 4,4'-Dithiodiphenylamine Crosslinking catalyst 0.1 ZC700 ZC700 AcAc 2.0 AcAc AcAc Free radical scavengers 4.0 Omnirad TPO H - Young's Modulus [MPa] Before UV irradiation 0.287 0.248 After UV irradiation 0.215 0.274 Young's modulus ratio [after UV irradiation / before UV irradiation] 0.75 1.10 Elongation at break [%] Before UV irradiation 693 758 After UV irradiation 633 738 The ratio of elongation at break [after UV irradiation / before UV irradiation] 0.91 0.97 Fracture point stress [MPa] Before UV irradiation 1.069 1.245 After UV irradiation 0.709 1.196 The ratio of stress at the fracture point [after UV irradiation / before UV irradiation] 0.66 0.96 100% strain stress [MPa] Before UV irradiation 0.207 0.189 After UV irradiation 0.174 0.198 100% strain-stress ratio [after UV irradiation / before UV irradiation] 0.84 1.05 200% strain stress [MPa] Before UV irradiation 0.284 0.256 After UV irradiation 0.242 0.270 200% strain-stress ratio [after UV irradiation / before UV irradiation] 0.85 1.06 300% strain stress [MPa] Before UV irradiation 0.353 0.332 After UV irradiation 0.308 0.341 300% strain-stress ratio [after UV irradiation / before UV irradiation] 0.87 1.03 500% strain stress [MPa] Before UV irradiation 0.578 0.542 After UV irradiation 0.512 0.570 500% strain-stress ratio [after UV irradiation / before UV irradiation] 0.89 1.05

[0209] [Table 5] (Table 5) raw material Mixing quantity [parts by weight] Example 10 Example 11 Comparative Example 10 Comparative Example 11 Comparative Example 12 acrylic polymers 100 BA / AA BA / AA BA / AA BA / AA BA / AA Crosslinking agent 4.0 1,3-Bis(4,5-dihydro-2-azolyl)benzene 1,3-Bis(4,5-dihydro-2-azolyl)benzene 1,3-Bis(4,5-dihydro-2-azolyl)benzene 1,3-Bis(4,5-dihydro-2-azolyl)benzene 1,3-Bis(4,5-dihydro-2-azolyl)benzene hardener 1.0 4,4'-Dithiobiphenol 4,4'-Dithiodibutyric acid 4,4'-Dithiobiphenol 4,4'-Dithiodibutyric acid - Free radical scavengers 5.0 Omnirad TPO H Omnirad TPO H - - Omnirad TPO H Young's Modulus [MPa] Before UV irradiation 0.132 0.126 0.124 0.120 0.117 After UV irradiation 0.117 0.106 0.130 0.123 0.117 Young's modulus ratio [after UV irradiation / before UV irradiation] 0.89 0.84 1.05 1.03 1.00 Elongation at break [%] Before UV irradiation 1928 358 803 1003 1293 After UV irradiation 858 358 918 873 1253 The ratio of elongation at break [after UV irradiation / before UV irradiation] 0.45 1.00 1.14 0.87 0.97 Fracture point stress [MPa] Before UV irradiation 0.112 0.103 0.512 0.481 0.590 After UV irradiation 0.113 0.084 0.478 0.451 0.469 The ratio of stress at the fracture point [after UV irradiation / before UV irradiation] 1.01 0.82 0.93 0.94 0.79 100% strain stress [MPa] Before UV irradiation 0.081 0.077 0.089 0.088 0.085 After UV irradiation 0.077 0.065 0.093 0.090 0.084 100% strain-stress ratio [after UV irradiation / before UV irradiation] 0.94 0.84 1.04 1.02 1.00 200% strain stress [MPa] Before UV irradiation 0.101 0.096 0.121 0.122 0.108 After UV irradiation 0.095 0.079 0.119 0.115 0.108 200% strain-stress ratio [after UV irradiation / before UV irradiation] 0.94 0.83 0.98 0.947 1.00 300% strain stress [MPa] Before UV irradiation 0.106 0.100 0.149 0.150 0.122 After UV irradiation 0.100 0.082 0.140 0.139 0.122 300% strain-stress ratio [after UV irradiation / before UV irradiation] 0.945 0.82 0.94 0.92 1.00 500% strain stress [MPa] Before UV irradiation 0.108 - 0.227 0.199 0.155 After UV irradiation 0.103 - 0.193 0.209 0.152 500% strain-stress ratio [after UV irradiation / before UV irradiation] 0.949 - 0.85 1.05 0.98

[0210] As shown in Tables 1-5, the stress, such as 100% strain stress, of the adhesive sheet in the examples was reduced by ultraviolet irradiation. Therefore, before ultraviolet irradiation, the workability was excellent compared to after ultraviolet irradiation. On the other hand, after ultraviolet irradiation, the stress was reduced, so the flexibility was judged to be excellent.

[0211] The following describes variations of the invention. [Note 1] An adhesive layer and / or bonding agent layer whose stress is reduced due to external stimuli. [Note 2] The adhesive layer and / or bonding agent layer as described in Note 1, wherein the above stress does not increase after reduction. [Note 3] The adhesive layer and / or bonding agent layer described in Note 1 or 2, wherein the ratio of 100% strain stress before external stimulation (S1(100)) to 100% strain stress after external stimulation (S2(100)) [S2(100) / S1(100)] does not reach 0.95. [Note 4] The adhesive layer and / or bonding agent layer described in any of Notes 1 to 3 shall have a 100% strain stress (S2(100)) of less than 10 MPa after being subjected to external stimuli. [Note 5] The adhesive layer and / or bonding agent layer described in any of Notes 1 to 4 are used for optical purposes.

[0212] 1: Adhesive layer or bonding agent layer 2: Peeling off the gasket 10: Adhesive sheets or bonded sheets with release liner

Claims

1. An adhesive layer and / or bonding agent layer, wherein the stress is reduced due to external stimulation, and the ratio of 100% strain stress before external stimulation (S1(100)) to 100% strain stress after external stimulation (S2(100)) [S2(100) / S1(100)] is less than 0.

95.

2. The adhesive layer and / or bonding agent layer as claimed in claim 1, wherein the aforementioned stress does not increase after reduction.

3. The adhesive layer and / or bonding agent layer of Request 1 have a 100% strain stress (S2(100)) of less than 10 MPa after being subjected to external stimuli.

4. The adhesive layer and / or bonding agent layer of any of claims 1 to 3, which are used for optical purposes.

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