Adhesives and / or adhesives

Abstract

To provide an adhesive layer and / or a binder that allows its flexibility to be improved by an external stimulus at any timing, or an adhesive and / or a binder that can form the adhesive and the binder.SOLUTION: Provided is an adhesive and / or a binder that contains: a polymer having, in the molecules thereof, an irreversibly degradable bond that is broken by an external stimulus and not subsequently bound again; and / or a compound that can introduce the irreversibly degradable bond to the polymer. The irreversibly degradable bond preferably includes a nitrobenzyl group.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to adhesives and / or adhesives, more specifically, an adhesive layer capable of exhibiting tackiness, an adhesive layer capable of exhibiting adhesion, a composition capable of forming the adhesive layer (adhesive composition), and a composition capable of forming the adhesive layer (adhesive composition). [Background technology]

[0002] Among optical devices such as displays, thin, flexible displays, such as OLEDs, are constructed by laminating multiple optical films or thin-layer devices. Furthermore, devices requiring flexibility, such as pressure-sensitive sensors, are constructed by laminating a pressure-sensitive member and a substrate (Patent Document 1). Liquid curing resins, adhesives, and other adhesives are selected as interlayer fillers in these laminates. Adhesives and other adhesives (such as adhesives) are preferred from the viewpoints of improving workability, preventing warping due to curing shrinkage, and improving flexibility through stress distribution.

[0003] The above-mentioned adhesives, etc., play a function of dispersing and mitigating stress generated by bending and folding, particularly in flexible members, and this function is said to be expressed more efficiently the more flexible the adhesive, etc. is (Patent Document 2), and therefore flexible adhesives, etc. are used. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2012-159463 [Patent Document 2] Japanese Patent Publication No. 2020-109177 [Overview of the project] [Problems that the invention aims to solve]

[0005] On the one hand, flexible adhesives and the like deform significantly even under slight stress. For example, when cutting with a punching blade, glue bleeding, glue chipping, and process contamination caused by these may occur, and problems may arise during the manufacturing and processing of adhesives and the like. In addition, in such adhesives and the like, glue bleeding may occur due to their own weight during storage, and problems such as glue chipping may occur due to vibration and contact during transportation.

[0006] Therefore, adhesives and adhesives that have a certain degree of hardness during manufacturing, processing, storage, transportation, etc. and have flexibility when used on members are required.

[0007] The present invention is for solving such problems, and its object is to provide an adhesive and / or an adhesive whose flexibility can be improved by an external stimulus at an arbitrary timing, or an adhesive and / or an adhesive that can form the adhesive or the adhesive.

Means for Solving the Problems

[0008] As a result of intensive efforts to solve the above problems, the present inventors have found that, according to an adhesive layer and an adhesive layer containing a polymer having a bond that irreversibly cleaves by an external stimulus, the flexibility is improved by an external stimulus at an arbitrary timing. The present invention has been completed based on these findings.

[0009] That is, the present invention provides an adhesive and / or an adhesive (such as an adhesive) containing a polymer having an irreversible degradable bond in its molecule that cleaves upon an external stimulus and then does not recombine, and / or a compound capable of introducing the irreversible degradable bond into the polymer.

[0010] When the above-mentioned adhesive or the like contains a polymer having the above-mentioned irreversible decomposable bond, the irreversible decomposable bond contained in the polymer is decomposed by an external stimulus. As a result, the structure of the polymer in the adhesive or the like is fragmented, and the flexibility is improved. Further, when the above-mentioned adhesive or the like contains a compound capable of introducing the above-mentioned reversible decomposable bond into the above-mentioned polymer, the above-mentioned irreversible decomposable bond can be introduced into the above-mentioned polymer by causing the above-mentioned compound to act as, for example, a monomer component or a crosslinking agent.

[0011] The irreversible decomposable bond is preferably a bond containing a nitrobenzyl group. In this case, it is easy to introduce an irreversible decomposable bond into the polymer.

[0012] The above-mentioned polymer is preferably a thermoplastic resin and / or a thermosetting resin. An adhesive or the like containing a thermoplastic resin can exhibit adhesiveness that adheres by, for example, external pressure. An adhesive or the like containing a thermosetting resin can adhere to an adherend by curing, for example, by heating.

[0013] The above-mentioned polymer is preferably a polymer that forms a network structure by bonding or entanglement of molecules or a polymer that can form the above-mentioned network structure. An adhesive or the like having such a configuration can form a network structure by bonding or entanglement of polymers, and can have an appropriate hardness. When the irreversible decomposable bond formed by an external stimulus is decomposed, the polymer structure is fragmented and the flexibility is improved.

[0014] The above-mentioned adhesive or the like is preferably used for optical applications.

Advantages of the Invention

[0015] The adhesive and / or the bonding agent of the present invention can improve the flexibility by applying an external stimulus at an arbitrary timing.

Brief Description of the Drawings

[0016] [Figure 1]This diagram shows a schematic cross-sectional view of an adhesive sheet or adhesive sheet 10 with a release liner, in which the adhesive layer or bonding layer 1 of the present invention is formed on a release liner 2. [Modes for carrying out the invention]

[0017] [Adhesives, bonding agents] In this specification, "adhesion" refers to the property of two surfaces adhering tightly to each other based on cohesive forces derived from the chemical structure of the composition in response to external pressure (e.g., minute pressure), and being able to be separated if necessary. In contrast, "bonding" refers to the property of two surfaces being firmly joined together by a chemical reaction (curing) of the composition, producing a cured product, and not being intended to be separated. Furthermore, in this specification, "adhesive" may be a non-fluid layered adhesive layer, or a fluid adhesive composition for forming the above-mentioned adhesive layer. Similarly, "adhesive" may be a non-fluid layered adhesive layer, or a fluid adhesive composition for forming the above-mentioned adhesive layer.

[0018] The adhesive and / or bonding agent of the present invention contains at least a polymer having irreversibly degradable bonds within its molecule that break upon external stimuli and do not subsequently recombine, and / or a compound capable of introducing the above irreversibly degradable bonds into the polymer. In this specification, the above polymer may be referred to as "polymer (A)," and the compound capable of introducing the above irreversibly degradable bonds into the polymer may be referred to as "compound (B)." In this specification, "adhesive and / or bonding agent" may be referred to as "adhesive, etc."

[0019] The external stimulus that triggers the cleavage reaction of the irreversibly degradable bond described above is appropriately selected according to the type of irreversibly degradable bond, and examples include irradiation with active energy rays and heat. In particular, from the viewpoint that the thermosetting reaction or active energy ray curing reaction and the cleavage can be caused separately when polymer (A) is a thermosetting resin or an active energy ray curable resin, it is preferable that the external stimulus is different from the type of curability when polymer (A) is curable. Specifically, when polymer (A) is a thermosetting resin, irradiation with active energy rays is preferred, and when polymer (A) is an active energy ray curable resin, heat is preferred.

[0020] The above-mentioned active energy rays are not particularly limited, but 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. The irradiation energy, irradiation time, and irradiation method of the active energy rays are not particularly limited. 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.

[0021] As the irreversibly degradable bond mentioned above, known or conventional bonds can be applied, and preferably a bond containing a nitrobenzyl group. In this case, it is easy to introduce an irreversibly degradable bond into the polymer. As the bond containing a nitrobenzyl group mentioned above, an ester bond formed between nitrobenzyl alcohol (preferably 2-nitrobenzyl alcohol) and a carboxylic acid having a polymerizable functional group is preferred.

[0022] Polymer (A) can be obtained using compound (B). Examples of compound (B) include monomer components, oligomer components, and crosslinking agents having the above-mentioned irreversibly degradable bonds. That is, polymer (A) may contain structural units derived from monomer components and / or oligomer components having irreversibly degradable bonds, and may also contain structural parts derived from the above-mentioned crosslinking agent. When compound (B) is a monomer component or an oligomer component, polymer (A) having the above-mentioned irreversibly degradable bonds can be obtained by polymerizing the monomer component or oligomer component or copolymerizing it with other monomer components.

[0023] When compound (B) is a monomer or oligomer component, the irreversibly decomposable bond may be present in the side chain portion of polymer (A) or in the main chain portion. Having the bond in the side chain portion is preferable because it reduces stress when significantly deformed and maintains handling properties within the actual operating temperature range (assuming room temperature). On the other hand, having the bond in the main chain portion is preferable because it further reduces the molecular weight of the polymer after the cleavage of the irreversibly decomposable bond, leading to improved flexibility and significant changes in physical properties.

[0024] Compound (B) preferably has functional groups other than the irreversibly degradable bond described above (functional group (L1)). If it has two or more functional groups (L1), compound (B) functions as a crosslinking agent. Furthermore, if the functional group (L1) is a polymerizable functional group, compound (B) functions as a monomer component or oligomer component.

[0025] Examples of polymerizable functional groups include cationic polymerizable groups, anionic polymerizable groups, and radical polymerizable groups. Among these, radical polymerizable groups are preferred. Examples of radical polymerizable groups include (meth)acryloyl groups and radical polymerizable carbon-carbon double bonds such as vinyl groups.

[0026] Other functional groups (L1) besides the polymerizable functional groups mentioned above include thiol groups, carboxyl groups, hydroxyl groups, amino groups, epoxy groups, and isocyanate groups, from the viewpoint of ensuring a moderate crosslinking density and a certain degree of flexibility in the adhesive layer, etc.

[0027] The number of functional groups in compound (B) is preferably two or more, from the viewpoint of increasing the molecular weight after introduction into polymer (A) and giving the polymer a certain degree of hardness before the application of external stimuli, while further decreasing the molecular weight of the polymer after cleavage and exhibiting flexibility. On the other hand, if the number of functional groups is large, it will crosslink with many polymers, making it difficult to obtain the effect of cleavage of irreversibly degradable bonds. Therefore, from the viewpoint of ensuring a moderate crosslinking density and a certain degree of flexibility in the adhesive layer, the number of functional groups is preferably four or less, and more preferably three or less.

[0028] As compound (B), a monomer in which a nitrobenzyl group and a polymerizable functional group are linked via a linking group (nitrobenzyl monomer) is preferred. The linking group is not particularly limited, but an ester bond is preferred. Nitrobenzyl monomers in which the linking group is an ester bond are sometimes referred to as "nitrobenzyl ester monomers." Examples of the nitrobenzyl ester monomers include esterified compounds of a compound having a nitrobenzyl alcohol skeleton and a compound having a polymerizable functional group and a carboxyl group, and esterified compounds of a compound having a nitrophenylacetic acid skeleton and a compound having a polymerizable functional group and a hydroxyl group.

[0029] Examples of compounds having the nitrobenzyl alcohol skeleton include 2-nitrobenzyl alcohol and 2-nitro-1,3-bis(hydroxymethyl)benzene. An example of a compound having the nitrophenylacetic acid skeleton is 2-nitroisophthalic acid. 2-nitro-1,3-bis((meth)acryloyloxymethylene)benzene is preferred as the nitrobenzyl ester monomer.

[0030] The above-mentioned nitrobenzyl ester monomers can be produced by esterifying a carboxylic acid having a polymerizable functional group (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.

[0031] Polymer (A) may be used alone or in combination of two or more types. Similarly, compound (B) may be used alone or in combination of two or more types. Furthermore, the adhesive, etc., of the present invention may contain only polymer (A) and compound (B), or both.

[0032] The content ratio of one or more components selected from the group consisting of compound (B), constituent units derived from compound (B), and structural parts derived from compound (B) in the adhesive of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more, based on 100% by mass of the total amount of the adhesive of the present invention (excluding components that do not remain during layer formation, such as organic solvents). Furthermore, in order to provide an appropriate crosslinking density and impart appropriate flexibility to the resin before the application of external stimuli, it is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0033] Examples of polymer (A) include thermoplastic resins, thermosetting resins, and active energy ray curable resins. Among these, thermoplastic resins and thermosetting resins are preferred. Adhesives containing thermoplastic resins (adhesive layer or adhesive layer) can exhibit adhesive properties that allow them to adhere to surfaces under external pressure, for example. Adhesives containing thermosetting resins (adhesive layer or adhesive layer) can adhere to surfaces by curing, for example, through heating.

[0034] The above-mentioned thermosetting resin can be either a thermosetting resin (thermosetting resin) or a resin obtained by curing the above-mentioned thermosetting resin. The above-mentioned thermosetting resin has thermosetting functional groups. The number of thermosetting functional groups in the above-mentioned thermosetting resin is preferably two or more (for example, 2 to 4). Examples of the above-mentioned thermosetting resin include phenolic resins, epoxy resins, urethane resins, melamine resins, alkyd resins, and the like.

[0035] Examples of the thermoplastic resins mentioned above 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 because they can impart cohesive force and appropriate flexibility to adhesives and the like.

[0036] The design of acrylic resins varies widely depending on the purpose, and it is preferable to appropriately select monomer species, copolymerization ratio, molecular weight, molecular weight distribution, crosslinking agent, and blending ratio according to the desired values ​​of mechanical properties such as flexibility and elastic modulus, thermal properties such as glass transition temperature, and adhesive properties such as tackiness and adhesion.

[0037] The acrylic resin is a resin that contains acrylic monomers (monomers having a (meth)acryloyl group in the molecule) as monomer components constituting the resin. That is, the acrylic resin contains constituent units derived from acrylic monomers. Preferably, the acrylic resin is a polymer that contains alkyl (meth)acrylate as a monomer component constituting the polymer. In this specification, "(meth)acrylic" means "acrylic" and / or "methacrylic" (either one or both of "acrylic" and "methacrylic"), and the same applies to other terms.

[0038] As the essential monomer component, the alkyl (meth)acrylate ester described above is preferably an alkyl (meth)acrylate ester having a linear or branched alkyl group. Note that one or more of the alkyl (meth)acrylate esters may be used.

[0039] The alkyl (meth)acrylate ester having a linear or branched alkyl group is not particularly limited, but examples include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, and (meth) Examples of alkyl (meth)acrylates having a linear or branched alkyl group with 1 to 20 carbon atoms include isononyl acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (stearyl (meth)acrylate), isostearyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

[0040] Among the alkyl (meth)acrylate esters having linear or branched alkyl groups, alkyl (meth)acrylate esters having linear or branched alkyl groups with 2 or more carbon atoms (preferably 2 to 18, more preferably 2 to 5) are preferred.

[0041] The content of constituent units derived from alkyl (meth)acrylate in the above acrylic resin is preferably 70% by mass or more, and more preferably 80% by mass or more, based on 100% by mass of the total amount of monomer components constituting the acrylic resin. The above content is preferably 99% by mass or less, and more preferably 98% by mass or less. Of course, depending on the application and required properties, the content of constituent units derived from alkyl (meth)acrylate in the acrylic resin may be less than 70% by mass, based on 100% by mass of the total amount of monomer components constituting the acrylic resin.

[0042] The above-mentioned acrylic resin may contain, as a monomer component of the resin, other monomers copolymerizable with the above-mentioned alkyl (meth)acrylate (copolymerizable monomer) in addition to the above-mentioned alkyl (meth)acrylate. In other words, the above-mentioned acrylic resin may contain copolymerizable monomers as constituent units. Only one type of copolymerizable monomer may be used, or two or more types may be used.

[0043] Examples of the copolymerizable monomers mentioned above include carboxyl group-containing monomers, hydroxyl group-containing monomers, epoxy group-containing monomers, keto group-containing monomers, alkoxy group-containing monomers, sulfonic acid group-containing monomers, phosphate group-containing monomers, vinyl ester monomers, vinyl ether monomers, isocyanate group-containing monomers, aromatic vinyl compounds, alicyclic monomers, aromatic ring-containing (meth)acrylates, chlorine-containing monomers, nitrogen-containing monomers, and the like.

[0044] The content of constituent units derived from copolymerizable monomers in the above acrylic resin is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more, based on 100% by mass of the total amount of monomer components constituting the acrylic resin. The above content is preferably 15% by mass or less, and more preferably 10% by mass or less. Of course, depending on the application and required properties, the content of constituent units derived from copolymerizable monomers in the above acrylic resin may be less than 0.1% by mass, based on 100% by mass of the total amount of monomer components constituting the acrylic resin.

[0045] Polymer (A) is preferably a thermoplastic resin, and more preferably an acrylic resin. If polymer (A) is an acrylic resin, it is preferable that the acrylic resin contains at least an acrylic monomer and compound (B) as monomer components constituting the resin.

[0046] When the above thermoplastic resin is included, the content ratio of the thermoplastic resin is not particularly limited, but in order to impart appropriate initial hardness and hardness after external stimulation to the adhesive layer, it is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, based on 100% by mass of the total amount of the adhesive, etc. of the present invention (excluding components that do not remain during layer formation, such as organic solvents). The amount of thermoplastic resin includes the amount of the thermoplastic resin, its raw material monomers, crosslinking agent, and structural components derived from the crosslinking agent.

[0047] The adhesives of the present invention may contain other components besides those described 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, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, antioxidants, fillers (metal powders, organic fillers, inorganic fillers, etc.), colorants (pigments, dyes, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, granular materials, foil-like materials, flame retardants, silane coupling agents, ion trapping agents, and the like. Each of these other components may be used individually or in combination of two or more.

[0048] The above crosslinking agents are not particularly limited as long as they crosslink polymers, but examples include polyisocyanate compounds, epoxy compounds, polyol compounds (such as polyphenol compounds), aziridine compounds, melamine-based crosslinking agents, and polyfunctional (meth)acrylates. Examples of polyfunctional (meth)acrylates include (meth)acrylic acid esters with two or more functions, such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0049] The following describes preferred embodiments of the present invention, divided into cases where the adhesive is a fluid adhesive composition or adhesive layer and cases where it is an adhesive layer. In this specification, adhesive compositions and / or adhesive compositions may be referred to as "adhesive compositions, etc." Also, in this specification, adhesive layers and / or adhesive layers may be referred to as "adhesive layers, etc."

[0050] (Adhesive layer, bonding layer) Figure 1 is a schematic cross-sectional view of one embodiment in which the adhesive of the present invention is an adhesive layer or the like. The adhesive layer or bonding layer 1 shown in Figure 1 is laminated on the release surface of the release liner 2 to form an adhesive sheet with a release liner or bonding sheet 10.

[0051] When the adhesive of the present invention is an adhesive layer, the adhesive layer contains at least polymer (A). Polymer (A) may be one type only, or two or more types may be used.

[0052] The content of one or more components selected from the group consisting of constituent units and structural parts derived from compound (B) in polymer (A) is preferably 0.1 to 15% by mass, more preferably 0.2 to 10% by mass, even more preferably 0.5 to 5% by mass, and particularly preferably 1 to 3% by mass, based on 100% by mass of the total amount of polymer (A), from the viewpoint of exhibiting sufficient flexibility by being cleaved and shredded after the application of an external stimulus. In this specification, if two or more polymers are entangled, the entangled polymers are counted as one polymer.

[0053] The content of polymer (A) in the adhesive layer, etc., is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, based on 100% by mass of the total amount of the adhesive layer, etc. If compound (B) is a monomer component or an oligomer component, the above content includes the amount of compound (B) and the constituent units derived from compound (B). Furthermore, the amount of polymer (A) includes the amount of polymer (A), its raw material monomer, the crosslinking agent, and the structural components derived from the crosslinking agent.

[0054] The content of the crosslinking agent and / or structural components derived from the crosslinking agent in the above-mentioned adhesive layer, etc., is preferably 0.1 to 15% by mass, more preferably 0.2 to 10% by mass, even more preferably 0.5 to 5% by mass, and particularly preferably 1 to 3% by mass, based on 100% by mass of the total amount of polymer (A). If compound (B) is the crosslinking agent, the above content includes the amount of compound (B) and structural components derived from compound (B).

[0055] The adhesive layer described above may contain other components in addition to those listed above. Examples of these other components are those described and illustrated above as other components that may be included in the adhesive of the present invention. Each of these other components may be used individually or in combination of two or more.

[0056] The adhesive layer described above preferably has a base polymer that forms a network structure. A network structure refers to a state in which molecules are intertwined with each other, or in which molecular chains form long molecules through some kind of bonding. In other words, polymer (A) is preferably a polymer that has formed a network structure through bonding or intertwining of molecules. An adhesive layer having such a configuration can have a moderate hardness by forming a network structure through bonding or intertwining of polymers, and when the irreversibly decomposable bonds formed by external stimuli decompose, the polymer structure is shredded and flexibility is improved.

[0057] The term "entanglement of molecules" refers to a state in which polymers form a network structure without covalent bonds. To form such an entangled structure, it is preferable to include polymers of different types that do not easily undergo crosslinking reactions with each other, and from the viewpoint of ease of fabrication, it is preferable for thermoplastic resins to form an entangled structure. Because such a configuration does not involve covalent bonds, it is suitable for relatively flexible adhesives and the like before external stimuli are applied.

[0058] The state where the above molecular chains form a long molecule through some kind of bond indicates that it is a polymerization polymer composed of a single polymer. To form such a long molecule, it is preferable to contain a single polymer, and it is preferable to contain the above-mentioned thermosetting resin. Since the molecular chains are covalently bonded in a long manner in such a structure, a relatively hard adhesive or the like can be formed, and also, since the number of sites that are cleaved by external stimuli increases, it is suitable for an adhesive or the like that has a difference in flexibility before and after external stimuli.

[0059] It is preferable that the shear storage modulus (G’) of the above adhesive layer or the like decreases by irradiation with active energy rays. Such an adhesive or the like improves its flexibility by irradiation with active energy rays. Also, it is preferable that the above shear storage modulus (G’) does not increase after the above decrease.

[0060] The shear storage modulus (G’) of the above adhesive layer or the like at 25°C before application of external stimuli is preferably ~1.0×10 8 Pa, more preferably 1.0×10 4 ~1.0×10 7 Pa, still more preferably 1.0×10 4 ~1.0×10 6 Pa, particularly preferably 2.0×10 4 ~1.0×10 5 Pa. An adhesive layer or the like having the above shear storage modulus has an appropriate hardness before application of external stimuli and is excellent in workability such as manufacturing, processing, storage, transportation, etc.

[0061] The shear storage modulus (G’) of the above adhesive layer or the like at 50°C before application of external stimuli is preferably 3 ~5.0×10 7 Pa, more preferably 7.0×10 3 ~1.0×10 6 Pa, still more preferably 1.0×10 4 ~1.0×10 5The shear storage modulus is Pa. The adhesive layer having the above shear storage modulus maintains appropriate hardness even when the temperature rises slightly due to the environment, for example, before external stimulation is applied, and offers excellent workability in manufacturing, processing, storage, and transportation.

[0062] The above adhesive layer, etc., has a shear storage modulus (G') of 1.0 × 10⁻¹⁰ at 85°C before the application of external stimuli. 2 ~1.0×10 6 It is preferably Pa, and more preferably 1.0 × 10 3 ~1.0×10 5 Pa, more preferably 5.0 × 10 3 ~1.0×10 5 The shear storage modulus is Pa. The adhesive layer having the above shear storage modulus has appropriate hardness even when applied in a high-temperature environment, for example, before external stimulation is applied, and is superior in terms of workability in manufacturing, processing, storage, and transportation.

[0063] The above adhesive layer, etc., has a shear storage modulus (G') of 1.0 × 10⁻¹⁰ at 25°C after external stimulation. 2 ~5.0×10 6 It is preferably Pa, and more preferably 1.0 × 10 3 ~5.0×10 5 Pa, more preferably 3.0 × 10 3 ~1.0×10 5 Pa, particularly preferably 5.0 × 10 3 ~5.0×10 4 The shear storage modulus is Pa. When the above-mentioned shear storage modulus is within the above range, the adhesive layer of the present invention exhibits superior flexibility after external stimulation, and superior step-following ability, adhesion, etc.

[0064] The above adhesive layer, etc., has a shear storage modulus (G') of 1.0 × 10⁻¹⁰ at 50°C after external stimulation. 2 ~1.0×10 6 It is preferably Pa, and more preferably 5.0 × 10 2 ~3.0×10 5 Pa, more preferably 1.0 × 10 3 ~1.0×10 5 Pa, particularly preferably 2.0 × 103 ~8.0×10 4 The shear storage modulus is Pa. When the above-mentioned shear storage modulus is within the above range, after external stimulation, for example when the temperature rises slightly due to the environment, the flexibility is superior, and properties such as step-following ability and adhesion are better.

[0065] The above adhesive layer, etc., has a shear storage modulus (G') of 1.0 × 10 at 85°C after external stimulation. 2 ~8.0×10 5 It is preferably Pa, and more preferably 3.0 × 10 2 ~1.0×10 5 Pa, more preferably 5.0 × 10 2 ~1.0×10 5 Pa, particularly preferably 1.0 × 10 2 ~7.0×10 4 The shear storage modulus is Pa. When the above-mentioned shear storage modulus is within the above range, after external stimulation, for example when subjected to a high-temperature environment, the flexibility is superior, and properties such as step-following ability and adhesion are better.

[0066] The above-mentioned adhesive layer, etc., preferably has a ratio [after external stimulation / before external stimulation] of less than 0.95 (for example, 0.01 or more and less than 0.95) of the shear storage modulus (G') at 25°C before external stimulation and the shear storage modulus (G') at 25°C after external stimulation. This ratio is more preferably 0.8 or less (for example, 0.05 to 0.8), even more preferably 0.7 or less (for example, 0.1 to 0.7), and particularly preferably 0.6 or less (for example, 0.2 to 0.6). In this case, the flexibility, step-following ability, and adhesion of the adhesive layer, etc., at or near room temperature tend to change more significantly before and after external stimulation.

[0067] The above-mentioned adhesive layer, etc., preferably has a ratio [after external stimulation / before external stimulation] of less than 0.95 (for example, 0.01 or more and less than 0.95) of the shear storage modulus (G') at 50°C before external stimulation and the shear storage modulus (G') at 50°C after external stimulation. This ratio is more preferably 0.8 or less (for example, 0.05 to 0.8), even more preferably 0.7 or less (for example, 0.1 to 0.7), and particularly preferably 0.6 or less (for example, 0.2 to 0.6). In this case, the flexibility, step-following ability, and adhesion of the adhesive layer, etc., at around 50°C tend to change more significantly before and after external stimulation.

[0068] The above-mentioned adhesive layer preferably has a ratio [after external stimulation / before external stimulation] of less than 0.95 (for example, 0.01 or more and less than 0.95) of the shear storage modulus (G') at 85°C before external stimulation and the shear storage modulus (G') at 85°C after external stimulation. This ratio is more preferably 0.8 or less (for example, 0.05 to 0.8), even more preferably 0.7 or less (for example, 0.1 to 0.7), and particularly preferably 0.6 or less (for example, 0.2 to 0.6). In this case, the flexibility, step-following ability, and adhesion of the adhesive layer under high-temperature conditions tend to change more significantly before and after external stimulation.

[0069] The adhesive layer of the present invention preferably has the property of reducing in hardness due to external stimuli. Preferably, the hardness does not increase after the reduction. Such an adhesive layer maintains its flexibility without increasing in hardness when the adhesive layer is attached or bonded to a member.

[0070] The hardness described above is preferably measured by a Young's modulus, for example, using a tensile-compression testing machine. In other words, it is preferable that the adhesive layer of the present invention has the property of reducing its Young's modulus in response to external stimuli.

[0071] In other words, it is preferable that the adhesive layer, etc., has a lower Young's modulus after the application of an external stimulus compared to the Young's modulus before the application of an external stimulus. Such an adhesive layer, etc., has excellent handling properties before the application of an external stimulus, and after the application of an external stimulus, it has superior flexibility, impact resistance, and shape deformation properties at high speeds.

[0072] The adhesive layer described above preferably has a Young's modulus (E1) of 200 MPa or less (for example, 0.03 to 200 MPa) before external stimulation. Furthermore, the adhesive layer described above preferably has a Young's modulus (E2) of 50 MPa or less (for example, 0.001 to 50 MPa) after external stimulation. The adhesive layer described above has a moderate hardness before external stimulation and is superior in workability for manufacturing, processing, storage, and transportation. Furthermore, the adhesive layer described above has excellent flexibility after external stimulation and is superior in terms of step-following ability and adhesion.

[0073] The adhesive layer described above preferably has a Young's modulus (E1) of 0.03 to 1.5 MPa before external stimulation, more preferably 0.05 to 1.0 MPa, and even more preferably 0.1 to 0.8 MPa. The adhesive layer having the above Young's modulus (E1) has appropriate hardness before external stimulation and is superior in handling.

[0074] The adhesive layer described above preferably has a Young's modulus (E2) of less than 1.0 MPa (for example, 0.001 MPa or more and less than 1.0 MPa) after external stimulation, more preferably 0.5 MPa or less (for example, 0.005 to 0.5 MPa), and even more preferably 0.3 MPa or less (for example, 0.01 to 0.3 MPa). The adhesive layer having the above Young's modulus exhibits excellent flexibility after external stimulation, and superior ability to follow steps and adhesion.

[0075] The adhesive layer described above preferably has a ratio of Young's modulus (E2) / Young's modulus (E1) to Young's modulus (E2) after external stimulation [Young's modulus (E2) / Young's modulus (E1)] of less than 0.95 (for example, 0.1 or more and less than 0.95), more preferably 0.8 or less (for example, 0.2 to 0.8), and even more preferably 0.7 or less (for example, 0.3 to 0.7). In this case, the flexibility, step-following ability, and adhesion of the adhesive layer tend to change more significantly before and after external stimulation.

[0076] The adhesive layer of the present invention preferably has the property of reducing stress in response to external stimuli. It is preferable that the stress does not increase after the reduction. Such an adhesive layer maintains its flexibility without stress increasing when the adhesive layer is attached or bonded to a member.

[0077] The stress mentioned above includes, for example, the stress (strain stress) when pulled at an arbitrary magnification, as measured by a tension-compression testing machine. The stress (strain stress) when pulled at the above specific magnification only needs to be reduced compared to the stress (strain stress) when pulled at at least one magnification. In particular, it is preferable that the strain stress is reduced at at least one point among the tensile magnifications of 100% to 500%, and it is especially preferable that the strain stress is reduced at one or more tensile magnifications selected from the group consisting of 100%, 200%, 300%, and 500%. The preferred range of stress at each tensile magnification is described below, but these values ​​are the preferred ranges when fracture does not occur at each tensile magnification.

[0078] The above adhesive layer preferably has a ratio [S2(100) / S1(100)] of the stress (100% strain stress) (S1(100)) before external stimulation is applied to the stress (100% strain stress) (S2(100)) after external stimulation is applied, which is less than 0.95 (for example, 0.1 or more and less than 0.95), more preferably 0.9 or less, and even more preferably 0.8 or less. Such an adhesive layer indicates that the relatively weak tensile stress is further reduced by the application of external stimulation, resulting in low rebound force when pulled and making it suitable for relatively low-load applications such as foldable members.

[0079] The adhesive layer described above preferably has a stress (100% strain stress) (S1(100)) of 0.01 MPa or more (e.g., 0.01 to 10 MPa) before the application of external stimuli, 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). Such an adhesive layer exhibits even greater flexibility after the application of external stimuli.

[0080] The adhesive layer described above preferably has a stress (100% strain stress) (S2(100)) of 10 MPa or less (e.g., 0.01 to 10 MPa) after external stimulation, 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). Such an adhesive layer exhibits even greater flexibility after external stimulation.

[0081] The above-mentioned adhesive layer preferably has a ratio [S2(200) / S1(200)] of the stress (200% strain stress) (S1(200)) before external stimulation is applied to the stress (200% strain stress) (S2(200)) after external stimulation is applied, which is less than 0.95 (for example, 0.1 or more and less than 0.95), more preferably 0.8 or less, and even more preferably 0.7 or less. Such an adhesive layer indicates that the relatively weak tensile stress is further reduced by the application of external stimulation, making it suitable for relatively low-load applications such as foldable members.

[0082] The adhesive layer described above preferably has a stress (200% strain stress) (S1(200)) of 0.03 MPa or higher (e.g., 0.03 to 10 MPa) before the application of external stimuli, more preferably 0.04 MPa or higher (e.g., 0.04 to 4 MPa), and even more preferably 0.06 MPa or higher (e.g., 0.06 to 2 MPa). Such an adhesive layer exhibits even greater flexibility after the application of external stimuli.

[0083] The adhesive layer described above preferably has a stress (200% strain stress) (S2(200)) of 10 MPa or less (e.g., 0.01 to 10 MPa) after external stimulation, 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). Such an adhesive layer exhibits even greater flexibility after external stimulation.

[0084] The adhesive layer described above preferably has a ratio [S2(300) / S1(300)] of the stress (300% strain stress) (S1(300)) before external stimulation is applied to the stress (300% strain stress) (S2(300)) after external stimulation is applied, which is less than 0.95 (for example, 0.1 or more and less than 0.95), more preferably 0.8 or less, and even more preferably 0.7 or less. Such an adhesive layer indicates that the tensile stress has been reduced by the application of external stimulation and is suitable for relatively low-load applications such as foldable members.

[0085] The adhesive layer described above preferably has a stress (300% strain stress) (S1(300)) of 0.03 MPa or higher (e.g., 0.03 to 10 MPa) before the application of external stimuli, more preferably 0.05 MPa or higher (e.g., 0.05 to 4 MPa), and even more preferably 0.07 MPa or higher (e.g., 0.07 to 2 MPa). Such an adhesive layer exhibits even greater flexibility after the application of external stimuli.

[0086] The adhesive layer described above preferably has a stress (300% strain stress) (S2(300)) of 10 MPa or less (e.g., 0.01 to 10 MPa) after external stimulation, 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). Such an adhesive layer exhibits even greater flexibility after external stimulation.

[0087] The above adhesive layer preferably has a ratio [S2(500) / S1(500)] of the stress (500% strain stress) (S1(500)) before external stimulation is applied to the stress (500% strain stress) (S2(500)) after external stimulation is applied, which is less than 0.95 (for example, 0.1 or more and less than 0.95), more preferably 0.8 or less, and even more preferably 0.7 or less. Such an adhesive layer indicates that the relatively strong tensile stress is reduced by the application of external stimulation, resulting in particularly low rebound force when pulled, making it suitable for relatively high-load applications such as foldable members (especially those that are wrapped around, such as rollerables).

[0088] The adhesive layer described above preferably has a stress (500% strain stress) (S1(500)) of 0.05 MPa or higher (e.g., 0.05 to 10 MPa) before the application of external stimuli, more preferably 0.07 MPa or higher (e.g., 0.07 to 4 MPa), and even more preferably 0.1 MPa or higher (e.g., 0.1 to 2 MPa). Such an adhesive layer exhibits even greater flexibility after the application of external stimuli.

[0089] The adhesive layer described above preferably has a stress (500% strain stress) (S2(500)) of 10 MPa or less (e.g., 0.01 to 10 MPa) after external stimulation, 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). Such an adhesive layer exhibits even greater flexibility after external stimulation.

[0090] Furthermore, the adhesive layer of the present invention may have the property of reducing the peak strength (stress peak intensity) and fracture stress in the stress-strain curve in response to external stimuli. Preferably, the stress peak intensity and fracture stress do not increase after the reduction.

[0091] The above-mentioned adhesive layer, etc., preferably has a peak strength (stress peak strength) of 0.07 MPa or higher in the stress-strain curve before the application of external stimuli, more preferably 0.1 MPa or higher, and even more preferably 0.2 MPa or higher. When the above-mentioned stress peak strength is 0.07 MPa or higher, the adhesive layer, etc., has appropriate hardness before the application of external stimuli, and offers excellent workability in manufacturing, processing, storage, transportation, etc.

[0092] The above-mentioned adhesive layer preferably has a peak strength (stress peak strength) of 0.01 to 1.0 MPa in the stress-strain curve after external stimulation, more preferably 0.03 to 0.8 MPa, and even more preferably 0.04 to 0.5 MPa. When the above-mentioned stress peak strength is within the above range, the flexibility is superior after external stimulation, and the ability to follow steps and adhere is further improved.

[0093] The above-mentioned adhesive layer, etc., preferably has a ratio [after external stimulation / before external stimulation] of less than 0.95 (for example, 0.05 or more and less than 0.95) of the peak intensity in the stress-strain curve before external stimulation and the peak intensity in the stress-strain curve after external stimulation. This ratio is more preferably 0.8 or less (for example, 0.1 to 0.8), and even more preferably 0.7 or less (for example, 0.3 to 0.7). In this case, the flexibility, step-following ability, and adhesion of the adhesive layer, etc., tend to change more significantly before and after external stimulation.

[0094] The thickness of the adhesive layer, etc., is not particularly limited, but is, for example, about 5 to 250 μm, more preferably 7 to 200 μm, even more preferably 10 to 100 μm, and especially preferably 10 to 50 μm.

[0095] (Removable liner) The release liner protects the adhesive and / or bonding surfaces that come into contact with the adhesive layer, etc., until use, and is peeled off when the adhesive layer, etc., is used.

[0096] Examples of substrates for the above-mentioned peel-off 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)acrylic acid copolymer film, ethylene-(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, and fluororesin film. Crosslinked films of these are also acceptable. Furthermore, laminated films of these may also be used.

[0097] It is preferable that the release surface of the above-mentioned release liner (particularly the surface in contact with the adhesive layer, etc.) is subjected to a release treatment. Examples of release agents used in the release treatment include alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax-based release agents.

[0098] The thickness of the release liner mentioned above is not particularly limited, but is, for example, about 20 to 150 μm.

[0099] (Adhesive composition, bonding agent composition) The adhesive layer is formed from the adhesive composition. The adhesive layer is also formed from the adhesive composition. The adhesive composition preferably contains at least a base polymer and / or its raw material monomer. The base polymer is polymer (A) and / or other polymers (i.e., polymers that do not have irreversibly degradable bonds). The base polymer may be used alone or two or more.

[0100] If the base polymer is one of the other polymers, the adhesive composition further comprises compound (B). The base polymer preferably contains polymer (A), and more preferably contains polymer (A) and the other polymers. Polymer (A) is preferably a curable resin. The curability of the curable resin is appropriately selected according to the type of irreversibly decomposable bond, and if the irreversibly decomposable bond can be cleaved by active energy rays, it is preferably a thermosetting resin.

[0101] The polymer (A), which is the curable resin described above, is preferably a resin (prepolymer) having polymerizable functional groups. When polymer (A) has polymerizable functional groups, when forming an adhesive layer, etc., polymerization of the polymerizable functional groups proceeds after application of the adhesive composition, etc., by heat or irradiation with active energy rays, and a network structure can be formed by intertwining with the other polymers. In other words, polymer (A) is preferably a polymer that can form the above network structure. The other polymers may be one type or two or more types.

[0102] If the base polymer is one of the other polymers, the adhesive composition further includes compound (B). In this case, it may also further include a monomer component (monomer component (C)) that is reactive with compound (B). Compound (B) is reactive with the other polymer and / or monomer component (C). When compound (B) is reactive with the other polymer, in the adhesive layer, etc., the other polymer and compound (B) react by heat or irradiation with active energy rays to form polymer chains, for example, and these polymer chains and the other polymer bond to form a network structure, resulting in an adhesive layer containing polymer (A). When compound (B) and monomer component (C) are included, in the adhesive layer, etc., the compound (B) and monomer component (C) react by heat or irradiation with active energy rays to form polymer chains, for example, and these polymer chains and the other polymer intertwine to form a network structure, resulting in an adhesive layer containing polymer (A).

[0103] When the above adhesive composition contains the above raw material monomer, compound (B) is incorporated into the base polymer when the above raw material monomer is polymerized, and polymer (A) is formed. Alternatively, the above raw material monomer is polymerized to form the above other polymer, and then reacted with compound (B) to form polymer (A).

[0104] Examples of the above-mentioned adhesive compositions include, primarily, (i) adhesive compositions containing polymer (A), (ii) adhesive compositions containing polymer (A) and the above-mentioned other polymers, (iii) adhesive compositions containing the above-mentioned other polymers, compound (B), and optionally monomer component (C), and (iv) adhesive compositions containing raw material monomers, compound (B), and optionally monomer component (C).

[0105] Therefore, polymer (A) may be a reaction product of the above-mentioned other polymer, compound (B), and monomer component (C), or it may be a polymer containing the above-mentioned other polymer and a reaction product of the above-mentioned other polymer and compound (a) (in particular, an intertwined polymer). Furthermore, if the base polymer contains polymer (A), the adhesive layer, etc., may contain unreacted compound (B) and / or unreacted monomer component (C).

[0106] Examples of the above-mentioned base polymers include the above-mentioned thermoplastic resin, the above-mentioned thermosetting resin, and the above-mentioned active energy ray curable resin. Among these, polymer (A) as the base polymer is preferably a curable resin, and more preferably a thermosetting resin. Among the above-mentioned other polymers, thermoplastic resins are preferred. An adhesive layer containing a thermoplastic resin can exhibit adhesiveness that allows it to adhere to surfaces under external pressure, for example. An adhesive composition containing a thermosetting resin can form a network structure by curing, for example, by heating. The above-mentioned other polymer may also be a curable resin, in which case polymer (A), which is also a curable resin, and the above-mentioned other polymer can form bonds between the two resins by heat or irradiation with active energy rays, thereby forming a network structure.

[0107] Compound (B) can be a monomer component, an oligomer component, or a crosslinking agent, as described above, that has the irreversibly decomposable bond. Among these, a monomer component (i.e., a compound having the polymerizable functional group) is preferred, more preferably the nitrobenzyl monomer, and even more preferably the nitrobenzyl ester monomer.

[0108] The content of polymer (A) in the above base polymer is preferably 10 to 90% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass, based on the total amount (100% by mass) of the base polymer. When the content is 10% by mass or more, the irreversibly degradable bonds are sufficiently cleaved by external stimuli. When the content is 90% by mass or less, appropriate tackiness and / or adhesion can be maintained even after external stimuli are applied.

[0109] The content of the other polymers in the base polymer is preferably 10 to 90% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass, based on the total amount (100% by mass) of the base polymer. If the content is 10% by mass or more, appropriate tackiness and / or adhesion can be maintained even after external stimulation. If the content is 90% by mass or less, polymer (A) can be sufficiently incorporated, thereby allowing a sufficient amount of irreversibly degradable bonds to cleave upon external stimulation.

[0110] The content of constituent units derived from compound (B) in polymer (A) 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, based on 100% by mass of the total amount of polymer (A). When the above adhesive composition contains raw material monomers that constitute the base polymer, it is preferable that the content of compound (B) in the total monomer components constituting polymer (A) is within the above range.

[0111] When polymer (A) is the above-mentioned acrylic resin, the content of constituent units derived from acrylic monomers in polymer (A) 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, based on 100% by mass of the total amount of polymer (A). When the above-mentioned adhesive composition, etc., contains raw material monomers that constitute the base polymer, it is preferable that the content of acrylic monomers in the total monomer components constituting polymer (A) is within the above range.

[0112] The content of constituent units derived from compound (B) in the above base polymer is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more, based on 100% by mass of the total amount of the base polymer, in order to allow sufficient flexibility to be exhibited by cleavage and shredding after external stimulation is applied. Furthermore, in order to provide an appropriate crosslinking density and impart appropriate flexibility to the resin before external stimulation is applied, 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 above adhesive composition, etc., contains raw material monomers that constitute the base polymer, it is preferable that the content of compound (B) in the total monomer components constituting the base polymer is within the above range.

[0113] When the base polymer is the acrylic resin, the content of constituent units derived from acrylic monomers in the base polymer is preferably 85 to 99.9% by mass, more preferably 90 to 99.8% by mass, and even more preferably 95 to 99.5% by mass, based on 100% by mass of the total amount of the base polymer. When the adhesive composition or the like contains raw material monomers that constitute the base polymer, it is preferable that the content of acrylic monomers in the total monomer components constituting the base polymer is within the above range.

[0114] The above-mentioned adhesive composition may contain other components in addition to those described above. Examples of these other components include those exemplified and described above as other components that may be included in the adhesive of the present invention, as well as solvents such as organic solvents. Each of these other components may be used individually or in combination of two or more.

[0115] The content of the base polymer in the above adhesive composition is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, based on 100% by mass of the total amount of the above adhesive composition (excluding components that do not remain after layer formation, such as organic solvents).

[0116] An embodiment of the method for manufacturing the adhesive, etc. of the present invention will now be described. For example, the adhesive sheet with a release liner or adhesive sheet 10 shown in Figure 1 can be manufactured by the following method. An adhesive composition, etc. that forms the adhesive layer, etc. 1 is applied to the base layer or the release-treated surface of the release liner 2 that has been treated with a release agent to form a coating layer. Then, the coating layer is solidified by desolvation by heating, thermal curing, or curing by irradiation with active energy rays. When irradiation with active energy rays is performed, it is done after separately bonding the release liner onto the coating layer.

[0117] The above-mentioned adhesive composition may be in any form as long as it does not impair the effects of the present invention. For example, the adhesive composition may be an emulsion type, a solvent type (solution type), a hot melt type, etc. Among these, the solvent type is preferred because it is easier to obtain an adhesive layer with excellent productivity.

[0118] If the adhesive composition contains polymer (A), the adhesive layer is formed by heating during the solidification of the coating layer. Furthermore, if the adhesive composition contains other polymers and / or raw material monomers and compound (B), the raw material monomers polymerize as needed during heating or irradiation with active energy rays during the solidification of the coating layer, and compound (B) forms bonds with the polymers of the raw material monomers and the other polymers, simultaneously forming polymer (A) and the adhesive layer. The adhesive layer may be subsequently heated or irradiated with active energy rays, or, if polymer (A) is a curable resin, a curing treatment may be performed. In this way, the adhesive sheet with a release liner or adhesive sheet 10 shown in Figure 1 is obtained.

[0119] The uses of the adhesive and the like of the present invention are not particularly limited and can be used for any purpose. The adhesive and the like of the present invention can be used, for example, in optical applications, that is, for bonding to optical components. The adhesive and the like of the present invention can be used, for example, in optical components of electrical and electronic equipment, when attaching (mounting) various components or parts to a predetermined part (for example, a housing). Note that "electrical and electronic equipment" refers to equipment that falls under at least one of electrical equipment or electronic equipment. Examples of the above electrical and electronic equipment include image display devices such as liquid crystal displays, electroluminescent displays, and plasma displays, and portable electronic devices. Examples of the above image display devices include image display devices in portable electronic devices, and displays (roll displays) inside and outside vehicles such as trains and buses.

[0120] Examples of the above-mentioned portable electronic devices include mobile phones, smartphones, tablet computers, notebook computers, various wearable devices (for example, wristwear-type devices worn on the wrist like watches, modular devices attached to a part of the body with clips or straps, eyewear-type devices including glasses (monocular and binocular types, including head-mounted types), clothing-type devices attached to shirts, socks, hats, etc. as accessories, earwear-type devices attached to the ears like earphones, etc.), digital cameras, digital video cameras, audio equipment (portable music players, IC recorders, etc.), calculators (calculators, etc.), portable game consoles, electronic dictionaries, electronic organizers, e-books, in-car information systems, portable radios, portable televisions, portable printers, portable scanners, and portable modems. In this specification, "portable" means not merely being able to carry something, but having a level of portability that allows an individual (a typical adult) to carry it relatively easily.

[0121] The adhesives of the present invention can have their flexibility improved by applying external stimuli at any time. Therefore, they can be made easy to handle by maintaining a certain degree of hardness during manufacturing, processing, storage, and transportation. For example, when cutting with a punching blade, it is possible to prevent glue overflow, glue chipping, and process contamination caused by these. Also, during storage, glue overflow is less likely to occur due to its own weight, and during transportation, glue chipping due to vibration and contact is less likely to occur. Furthermore, by improving flexibility when used by bonding to a material, excellent adhesion, bonding strength (adhesion), bendability, foldability, and bending resistance can be achieved. In addition, since the adhesive layer of the present invention contains a polymer having irreversibly decomposable bonds in its molecule, the adhesion and bonding strength can be varied by external stimuli.

[0122] <Adhesive sheets, adhesive sheets> Adhesive sheets and / or adhesive sheets can be obtained using the adhesive layer of the present invention. In this specification, adhesive sheets and / or adhesive sheets may be referred to as "adhesive sheets, etc." The above adhesive sheets, etc. may be so-called "substrate-less type" adhesive sheets, etc., which do not have a base material (substrate layer), or they may be adhesive sheets, etc., which have a base material. In this specification, "substrate-less type" adhesive sheets, etc. may be referred to as "substrate-less adhesive sheets, etc.", and adhesive sheets, etc., which have a base material may be referred to as "adhesive sheets with a base material, etc." Examples of the above substrate-less adhesive sheets, etc. include double-sided adhesive sheets, etc., which consist only of the adhesive layer of the present invention, etc., and double-sided adhesive sheets, etc., which consist of 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 above-mentioned adhesive sheet with a base material includes a base material and an adhesive layer of the present invention formed on at least one surface of the base material. Examples include a single-sided adhesive sheet having the adhesive layer of the present invention on one side of the base material, a double-sided adhesive sheet having the adhesive layer of the present invention on both sides of the base material, and a double-sided adhesive sheet having the adhesive layer of the present invention on one side of the base material and another adhesive layer on the other side. The above-mentioned "base material (base material layer)" refers to the support, which is the part that is attached to the adherend together with the adhesive layer when the adhesive sheet is used (attached) to the adherend. The release liner that is peeled off when the adhesive sheet is used (attached) is not included in the above-mentioned base material.

[0123] When the adhesive sheet of the present invention is an adhesive sheet with a substrate, the substrate is not particularly limited, but examples include plastic films, anti-reflective (AR) films, anti-glare (AG) films, polarizing plates, and various optical films such as phase difference plates. Other examples of substrates include porous materials such as paper, cloth, and nonwoven fabrics, nets, foamed sheets, and metal foils. Examples of materials for the plastic film include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetylcellulose (TAC), polysulfone, polyarylate, polyimide, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, and cyclic olefin polymers such as "Arton" (cyclic olefin polymer, manufactured by JSR Corporation) and "Zeonor" (cyclic olefin polymer, manufactured by Nippon Zeon Co., Ltd.). Note that one or more of these plastic materials may be used.

[0124] The thickness of the above substrate is not particularly limited, but is preferably 10 to 150 μm, more preferably 15 to 125 μm, and even more preferably 25 to 100 μm. The above substrate may be in the form of a single layer or multiple layers. Furthermore, the surface of the above substrate may be appropriately subjected to known and conventional surface treatments, such as physical treatments such as corona discharge treatment or plasma treatment, or chemical treatments such as undercoating.

[0125] The above-mentioned adhesive sheets, etc., may have a release liner on the surface (adhesive surface or bonding surface) of the adhesive layer, etc., until use. If the above-mentioned adhesive sheets, etc., are double-sided adhesive sheets, etc., each adhesive surface or bonding surface may be protected by two release liners, or they may be protected by a single release liner with both sides being release surfaces, in a roll-like winding form (winding body). The release liner is used as a protective material for the adhesive layer, etc., and is peeled off when attached to the substrate. Furthermore, if the above-mentioned adhesive sheets, etc., are substrate-less adhesive sheets, etc., the release liner also serves as a support for the adhesive layer, etc. Note that the release liner is not necessarily required.

[0126] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. [Examples]

[0127] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples. The values ​​for each monomer component constituting the prepolymer shown in Table 1 are in parts by mass.

[0128] 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 placed in a 5 L flask and mixed and stirred to dissolve the 2-nitroisophthalic acid. The solution was cooled to 2°C, and 0.9 M (162 mmol) of boranetetrahydrofuran complex (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise. The mixture was then heated to room temperature and stirred for 48 hours. Methanol was then added dropwise, the solvent was removed by vacuum distillation (50°C, 25 mmHg), and the solution was diluted with ethyl acetate for extraction. The organic phase was washed three times with 900 g of water. Then, 70 g of magnesium sulfate was added to the organic phase, dehydrated, filtered, and washed with ethyl acetate. The solvent of the filtrate was removed by vacuum distillation (50°C, 25 mmHg) to obtain 41 g of nitrobenzyl ester monomer precursor (slightly yellowish crystals).

[0129] Preparation Example 2 (Synthesis of nitrobenzyl ester monomers) Next, 21.0 g (115 mmol) of the above 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 placed in a 1 L flask. While cooling in an acetone / ice bath and maintaining an internal temperature of 5°C or lower, 84.9 g (574 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC hydrochloride) (manufactured by Tokyo Chemical Industry Co., Ltd.) was added in portions, and the mixture was mixed and stirred to carry out the reaction. After the reaction was complete, the reaction solution was purified twice using silica gel chromatography (developing solvent: dichloromethane). 0.004 g of hydroquinone monomethyl ether (MEHQ) was added to the preparative solution, and the solvent was removed by distillation under reduced pressure (below 30°C, 30 mmHg). Subsequently, the solution was cooled on ice to precipitate, and then dried under reduced pressure at 30°C to obtain 11.4 g of nitrobenzyl ester monomer (2-nitro-1,3-bis(acryloyloxymethylene)benzene, pale yellow crystals). The nitrobenzyl ester monomer corresponds to compound (B).

[0130] Preparation Example 3 (Synthesis of acrylic polymer P1) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, a mixture containing 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 for 7 hours under a nitrogen atmosphere to carry out a polymerization reaction. This yielded a polymer solution containing acrylic polymer P1. The weight-average molecular weight (Mw) of acrylic polymer P1 in this polymer solution was 600,000.

[0131] Example 1 (Synthesis of acrylic polymer P2) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, a mixture containing 95 parts by mass of butyl acrylate (BA), 5 parts by mass of nitrobenzyl ester monomer prepared in Preparation Example 2 (corresponding to compound (B)), 2.83 parts by mass of the trade name "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 the polymerization reaction. This yielded a polymer solution containing acrylic polymer P2 (corresponding to polymer (A)), which is a prepolymer having an acryloyl group.

[0132] (Synthesis of adhesive compositions) A polymer solution containing acrylic polymer P1 prepared in Preparation Example 3 and a polymer solution containing acrylic polymer P2 were mixed in a ratio of 100 parts by mass of acrylic polymer P1 to 100 parts by mass of acrylic polymer P2. The mixture was stirred at 2000 rpm for 5 minutes, and then stirred and defoamed at 2200 rpm for another 5 minutes to prepare a viscous adhesive composition. In this specification, "viscous adhesive" refers to having both tackiness and adhesion properties.

[0133] (Formation of adhesive sheet) The above adhesive composition was applied to the peeled surface of a polyethylene terephthalate film (product name "MRF38", manufactured by Mitsubishi Chemical Corporation) that had been peeled with a silicone-based release agent, so that the thickness of the adhesive layer after drying was 25 μm. This was left to stand at room temperature for 5 minutes, and then dried at 130°C for 3 minutes. An adhesive sheet was obtained by thoroughly volatilizing and removing the ethyl acetate contained as a solvent.

[0134] Comparative Example 1 (Synthesis of acrylic polymer P3) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, a mixture containing 95 parts by mass of butyl acrylate (BA), 5 parts by mass of 1,6-hexanediol diacrylate, 2.83 parts by mass of the trade name "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 the polymerization reaction. This yielded a polymer solution containing acrylic polymer P3, a prepolymer having acryloyl groups.

[0135] (Synthesis of adhesive compositions) A polymer solution containing acrylic polymer P1 prepared in Preparation Example 3 and a polymer solution containing the above-mentioned acrylic polymer P3 were mixed in a ratio of 100 parts by mass of acrylic polymer P1 to 100 parts by mass of acrylic polymer P3. The mixture was stirred at 2000 rpm for 5 minutes, and then stirred and defoamed at 2200 rpm for another 5 minutes to prepare an adhesive composition.

[0136] (Formation of adhesive sheet) An adhesive sheet was prepared in the same manner as in Example 1, except that the adhesive composition prepared above was used.

[0137] Comparative Example 2 (Synthesis of acrylic polymer P4) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, a mixture containing 100 parts by mass of butyl acrylate (BA), 2.83 parts by mass of the trade name "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 the polymerization reaction. This yielded a polymer solution containing acrylic polymer P4, a prepolymer having acryloyl groups.

[0138] (Synthesis of adhesive compositions) A polymer solution containing acrylic polymer P1 prepared in Preparation Example 3 and a polymer solution containing the above-mentioned acrylic polymer P4 were mixed in a ratio of 100 parts by mass of acrylic polymer P1 to 100 parts by mass of acrylic polymer P4. The mixture was stirred at 2000 rpm for 5 minutes, and then stirred and defoamed at 2200 rpm for another 5 minutes to prepare an adhesive composition.

[0139] (Formation of adhesive sheet) An adhesive sheet was prepared in the same manner as in Example 1, except that the adhesive composition prepared above was used.

[0140] <Rating> The adhesive sheets prepared in the examples and comparative examples were evaluated before and after UV irradiation, respectively. The results are shown in the table. UV irradiation was performed using the following method.

[0141] (UV irradiation) For the adhesive sheets obtained in the examples and comparative examples, with a release liner attached to the exposed adhesive surface, a UV-LED irradiation device manufactured by Quark Technology (model number "QEL-350-RU6W-CW-MY") was used, with a 365nm wavelength UV-LED lamp as the light source, and the integrated irradiation light dose in the wavelength range of 320-390nm was 8000 mJ / cm². 2 Ultraviolet irradiation was performed as a result.

[0142] (1) Shear storage modulus A sample with a thickness of approximately 1.0 mm was prepared by laminating adhesive sheets, and dynamic viscoelasticity measurements were performed 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) Transformation mode: Twist Measurement frequency: 1Hz Heating rate: 5°C / min Measurement temperature: -50~150℃ Shape: Parallel plate 8.0mmφ

[0143] (2) Tensile test A 50 μm thick adhesive sheet obtained by lamination was cut into 10 mm x 30 mm sections, and with the release liner removed, a 30 mm long strip-shaped sample was prepared. The top and bottom 10 mm portions of this sample were fixed with a chuck jig on a tensile and compression testing machine (product name "Autograph AGS-50NX", manufactured by Shimadzu Corporation), and a tensile test was performed under the conditions of a chuck distance of 10 mm and a tensile speed of 300 mm / min.

[0144] (3) Young's modulus E From the spectra obtained in the above tensile test, the change in stress σ with respect to strain ε in the elastic deformation region (E = Δσ / Δε) was calculated.

[0145] (4) Stress peak intensity In the spectra obtained from the above tensile tests, the value of the upward-convex peak was defined as the stress peak intensity.

[0146] (5) Strain stress For the spectra obtained in the above tensile test, the stress at each strain (%) was defined as the strain stress.

[0147] [Table 1] [Explanation of Symbols]

[0148] 1. Adhesive layer or adhesive layer 2. Peel-off liner 10. Adhesive sheet or adhesive sheet with release liner.

Claims

1. The polymer contains polymers that have irreversibly degradable bonds within the molecule that break upon external stimuli and do not subsequently recombine, and polymers that do not have irreversibly degradable bonds. A tack layer and / or adhesive layer having a shear storage modulus (G') of 1.0 × 10² to 5.0 × 10⁶ Pa at 25°C after external stimulation.

2. The adhesive layer and / or bonding layer according to claim 1, wherein the irreversibly decomposable bond is a bond containing a nitrobenzyl group.

3. The adhesive layer and / or bonding layer according to claim 1 or 2, wherein the polymer having the irreversibly degradable bond in its molecule is a thermoplastic resin and / or a thermosetting resin.

4. The adhesive layer and / or bonding layer according to any one of claims 1 to 3, wherein the polymer having the irreversibly degradable bond within the molecule is a polymer in which a network structure is formed by bonding or entanglement of molecules, or a polymer capable of forming the network structure.

5. An adhesive layer and / or bonding layer according to any one of claims 1 to 4, for use in optical applications.

Images