WO2023100861A1

WO2023100861A1 - Pressure-sensitive adhesive and/or adhesive

Info

Publication number: WO2023100861A1
Application number: PCT/JP2022/043957
Authority: WO
Inventors: 駿飛永; 武史仲野; 智史岩田
Original assignee: 日東電工株式会社
Priority date: 2021-11-30
Filing date: 2022-11-29
Publication date: 2023-06-08
Also published as: TW202330856A

Abstract

The present invention provides a pressure-sensitive adhesive and/or an adhesive which can be more flexibly changed by an external stimulus at an arbitrary timing. Provided is a release liner-equipped pressure-sensitive adhesive sheet and/or adhesive sheet 10 comprising: a pressure-sensitive adhesive layer and/or adhesive layer 1 that includes the following component (a) and component (b); and a release liner 2. Component (a): a polymer that has, in the molecule thereof, a reversibly degradable bond which can be split by an external stimulus and then re-bond thereafter, and/or a compound capable of introducing the reversibly degradable bond into a polymer. Component (b): a compound that inhibits the re-bonding.

Description

Adhesives and/or Adhesives

The present invention relates to pressure sensitive adhesives and/or adhesives, and more specifically to pressure sensitive adhesives and/or adhesives that become flexible upon application of an external stimulus at any timing.

Among optical devices such as displays, thin and flexible displays represented by OLED are constructed by laminating a plurality of optical films and thin layer devices. A device that requires flexibility, such as a pressure sensor, is also constructed by stacking a pressure-sensitive member and a substrate (Patent Document 1). Liquid curable resins, pressure-sensitive adhesives, and adhesives are selected for these interlayer fillers. Pressure-sensitive adhesives and adhesives (adhesive agents, etc.) are preferably used.

The pressure-sensitive adhesive or the like has a function of dispersing and relieving the stress generated by bending/folding, especially in a flexible member, and it is said that the more flexible the pressure-sensitive adhesive or the like, the more efficiently the function is expressed (Patent Document 2) A flexible adhesive or the like is used.

JP 2012-159463 A JP 2020-109177 A

On the other hand, flexible adhesives, etc., can be greatly deformed even with a small amount of stress. Problems can arise at times. In addition, such an adhesive or the like may cause problems such as the adhesive being squeezed out due to its own weight during storage, and the adhesive being chipped due to vibration or contact during transportation.

Therefore, there is a demand for pressure-sensitive adhesives and adhesives that have a certain degree of hardness during manufacturing, processing, storage, transportation, etc., and that have flexibility when used for components.

The present invention is intended to solve such problems, and its object is to form a pressure-sensitive adhesive and / or adhesive, or the pressure-sensitive adhesive or adhesive that can improve flexibility by external stimulation at any timing. An object of the present invention is to provide a pressure-sensitive adhesive and/or an adhesive that can be used.

In order to achieve the above object, the present inventors have made diligent efforts, and as a result, have developed a pressure-sensitive adhesive layer and an adhesive layer containing a polymer having a bond that is cleaved by an external stimulus and a compound that suppresses recombination after the cleavage. According to the findings, it was found that external stimulation improves flexibility at arbitrary timing. The present invention has been completed based on these findings.

The present invention provides a pressure-sensitive adhesive and/or an adhesive (such as a pressure-sensitive adhesive) containing components (a) and (b).
Component (a): a polymer having a reversible degradable bond in its molecule that can be cleaved by an external stimulus and then rebonded, and/or a compound capable of introducing the reversible degradable bond into the polymer Component (b): the above Compounds that inhibit recombination

When the pressure-sensitive adhesive or the like contains a polymer having a reversible degradable bond in the molecule as the component (a), the reversible degradable bond contained in the polymer is reduced by an external stimulus by also containing the component (b). is decomposed, and recombination after cleavage is suppressed by the component (b). As a result, the structure of the polymer in the pressure-sensitive adhesive or the like is shredded to improve the flexibility. In addition, when the pressure-sensitive adhesive or the like contains a compound capable of introducing the reversibly degradable bond into the polymer as the component (a), the compound can act as, for example, a monomer component or a cross-linking agent to cause the reversible decomposition in the polymer. Sexual bonding can be introduced.

Also, the reversible degradable bond is preferably a disulfide bond.

Also, the component (b) is preferably a radical scavenger.

Also, the polymer is preferably a thermoplastic resin and/or a thermosetting resin. A pressure-sensitive adhesive or the like containing a thermoplastic resin is capable of exerting adhesiveness such that it adheres under pressure from the outside, for example. A pressure-sensitive adhesive or the like containing a thermosetting resin can be adhered to an adherend by being cured by heating, for example.

In addition, the polymer is preferably a polymer in which a network structure is formed by bonding or entanglement between molecules. Adhesives having such a structure form a network structure through polymer-to-polymer bonding or polymer-to-polymer entanglement, and can have moderate hardness, and reversible degradable bonds formed by external stimuli are decomposed. This shreds the polymer structure and improves flexibility.

In addition, the adhesive and the like are preferably used for optical applications.

The pressure-sensitive adhesive and/or adhesive according to the present invention can improve flexibility by applying an external stimulus at any time.

1 shows a schematic cross-sectional view of a release liner-attached pressure-sensitive adhesive sheet or adhesive sheet 10 in which a pressure-sensitive adhesive layer or adhesive layer 1 of the present invention is formed on a release liner 2. FIG.

[Adhesives, Adhesives]
“Adhesion” refers to the property that two surfaces adhere to each other and can be peeled off if necessary due to the cohesive force based on the chemical structure of the composition when external pressure is applied (for example, minute pressure). On the other hand, "adhesion" refers to the property of chemically reacting (curing) the composition to form a cured product, which is not intended to be peeled off, and which allows two surfaces to be firmly joined together. Further, in the present specification, the "adhesive" may be a layered adhesive layer having no fluidity, and is an adhesive composition having fluidity for forming the adhesive layer. good too. Similarly, the "adhesive" may be a laminar adhesive layer that does not have fluidity, or it may be an adhesive composition that has fluidity for forming the adhesive layer.

The pressure-sensitive adhesive and/or adhesive of the present invention contains the following components (a) and (b).
Component (a): a polymer having a reversible degradable bond in its molecule that can be cleaved by an external stimulus and then rebonded, and/or a compound capable of introducing the reversible degradable bond into the polymer Component (b): the above Compounds that inhibit recombination

Degradable bonds that are cleaved by the application of an external stimulus are classified into reversible degradable bonds that can be rebonded after cleavage and irreversible degradable bonds in which the cleavage reaction proceeds irreversibly and does not rebond. In the present invention, the polymer in component (a) is a compound having a reversible degradable bond. The polymer in component (a) may be referred to as "polymer (a1)", and the compound capable of introducing the reversible degradable bond into the polymer may be referred to as "compound (a2)". In this specification, "adhesive and/or adhesive" may be referred to as "adhesive or the like".

In addition, the external stimulus that causes the cleavage reaction of the reversible degradable bond is appropriately selected according to the type of reversible degradable bond in component (a), and is not particularly limited, but includes active energy ray irradiation and heat. In particular, when the polymer (a1) is a thermosetting resin or an active energy ray-curable resin, the polymer ( When a1) has curability, it is preferably an external stimulus that is different from the type of curability. Specifically, the external stimulus is preferably active energy ray irradiation when the polymer (a1) is a thermosetting resin, and preferably heat when the polymer (a1) is an active energy ray-curable resin.

The active energy rays are not particularly limited, but include ionizing radiation such as α-rays, β-rays, γ-rays, neutron beams and electron beams, ultraviolet light and visible light. Ultraviolet rays are particularly preferred. The irradiation energy, irradiation time, irradiation method, etc. of the active energy ray are not particularly limited. Examples of light sources for ultraviolet light or visible light irradiation include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, and LED lamps.

The polymer (a1) can be obtained using the compound (a2). The compound (a2) includes, for example, a monomer component, an oligomer component, a cross-linking agent, a curing agent, etc., having the reversible degradable bond. That is, the polymer (a1) may contain a structural unit derived from a monomer component and/or an oligomer component having a reversible degradable bond, and may contain structural units derived from the cross-linking agent and/or the curing agent. You can When the compound (a2) is a monomer component or an oligomer component, the above monomer component or oligomer component is polymerized or copolymerized with another monomer component to obtain the polymer (a1) having the above reversible degradable bond.

The compound (a2) preferably does not have an aromatic ring from the viewpoint of suppressing coloration of adhesives and the like over time. On the other hand, as the compound (a2), one having an aromatic ring may be preferable when adjusting other properties such as refractive index.

When compound (a2) is a cross-linking agent or curing agent, compound (a2) has a functional group (functional group (L1)) other than the reversible degradable bond. The functional group (L1) is preferably a thiol group, a carboxyl group, a hydroxy group, an amino group, an epoxy group, or an isocyanate group from the viewpoint of ensuring a certain degree of flexibility of the pressure-sensitive adhesive layer and the like with an appropriate crosslinking density. Further, the number of functional groups of the compound (a2) increases the molecular weight of the polymer (a1) after introduction into the polymer (a1), imparts a certain degree of hardness to the polymer before applying an external stimulus, and further reduces the molecular weight of the polymer after cleavage. It is preferable that the number is 2 or more from the viewpoint of allowing flexibility to be exhibited. On the other hand, if the number of functional groups increases, it will crosslink with many polymers, making it difficult to obtain the effect of cleaving the reversible degradable bond. Therefore, the number of functional groups is preferably 4 or less, more preferably 3 or less.

Examples of the compound (a2), which is the cross-linking agent or curing agent, include compounds having a disulfide bond. Examples of the compound having a disulfide bond include 4,4'-dithiodibutyric acid, 4,4'-dithiodiphenol (bis(4-hydroxyphenyl)disulfide), 2,2'-dithiodianiline, 4,4' -dithiodianiline, 3,3'-dithiodipropionic acid, and dithiodiethanol. Among these, 4,4'-dithiodibutyric acid, 4,4'-dithiodiphenol, and 4,4'-dithiodianiline are particularly preferable from the viewpoint of better solubility.

Further, in this case, the compound (a2) may be blended in the composition such as the pressure-sensitive adhesive as the raw material monomer, or the polymer (a1) containing the compound (a2) as a constituent unit may be the pressure-sensitive adhesive as the base polymer. may be blended into equivalent compositions. In the above-mentioned monomer component and oligomer component, the reversible degradable bond may be present in the portion constituting the side chain of the polymer (a1), or may be present in the portion constituting the main chain. The presence of the side chain in the portion constituting the side chain is preferable from the viewpoint that stress is less likely to be applied even when it is greatly deformed, and the handleability in the actual use temperature range (assuming room temperature) is maintained. On the other hand, when it is contained in the portion constituting the main chain, it is preferable from the viewpoint that the molecular weight of the polymer is further reduced after the reversible degradable bond is cleaved, the flexibility is further improved, and a large change in physical properties can be expressed.

Only one type of component (a) may be used, or two or more types may be used. That is, the pressure-sensitive adhesive or the like of the present invention may contain either one of the polymer (a1) or the compound (a2), or may contain both. Also, the polymer (a1) and the compound (a2) may be used alone or in combination of two or more.

The total content of one or more selected from the group consisting of the compound (a2), the structural unit derived from the compound (a2), and the structural part derived from the compound (a2) in the pressure-sensitive adhesive or the like of the present invention is In order to exhibit sufficient flexibility by being cleaved and shredded after stimulation, the total amount of the pressure-sensitive adhesive etc. of the present invention (excluding components such as organic solvents that do not remain at the time of layer formation) is 100% by mass. On the other hand, it is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and still more preferably 1.5% by mass or more. Moreover, in order to make the crosslink density appropriate and to impart appropriate flexibility to the resin before applying an external stimulus, it is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

The reversible bond is preferably a bond that is cleaved as a radical, and particularly preferably a disulfide bond (-SS-).

Examples of the polymer (a1) include thermoplastic resins, thermosetting resins, and active energy ray-curable resins. Among them, thermoplastic resins and thermosetting resins are preferred. A pressure-sensitive adhesive or the like (adhesive layer or adhesive) containing a thermoplastic resin can, for example, exert pressure-sensitive adhesiveness to adhere to it under pressure from the outside. An adhesive or the like (adhesive layer or adhesive) containing a thermosetting resin can be adhered to an adherend by being cured by heating, for example. Only one kind of polymer (a1) may be used, or two or more kinds thereof may be used.

Examples of the thermosetting resin include both resins having thermosetting properties (thermosetting resins) and resins obtained by curing the above thermosetting resins. The thermosetting resin has a thermosetting functional group. The number of thermosetting functional groups in the thermosetting resin is preferably 2 or more (for example, 2 to 4). Examples of the thermosetting resin include phenol-based resin, epoxy-based resin, urethane-based resin, melamine-based resin, and alkyd-based resin. Among them, epoxy resins are particularly preferred.

Epoxy resins include, for example, bisphenol epoxy resins, spirocyclic epoxy resins, naphthalene epoxy resins, biphenyl epoxy resins, terpene epoxy resins, glycidyl ether epoxy resins, glycidylamine epoxy resins. type resins, novolak-type epoxy resins, and the like.

Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, tetrabromobisphenol A type epoxy resin, and the like. Examples of the glycidyl ether type epoxy resin include tris(glycidyloxyphenyl)methane and tetrakis(glycidyloxyphenyl)ethane. Examples of the glycidylamine type epoxy resin include tetraglycidyldiaminodiphenylmethane. Examples of the novolak-type epoxy resins include cresol novolac-type epoxy resins, phenol novolak-type epoxy resins, α-naphthol novolac-type epoxy resins, and brominated phenol novolak-type epoxy resins.

Examples of the thermoplastic resin include polystyrene-based resin, vinyl acetate-based resin, polyester-based resin, polyolefin-based resin (polyethylene-based resin, polypropylene-based resin composition, etc.), polyimide-based resin, acrylic-based resin, and the like. Among them, acrylic resins are preferable because they can impart cohesion and appropriate flexibility to adhesives and the like.

There are various types of acrylic resin designs depending on the purpose, including mechanical properties such as flexibility and elastic modulus, thermophysical properties such as glass transition point, optical properties such as transmittance, haze, and refractive index, adhesive strength, adhesion strength, etc. It is preferable to appropriately select the monomer type, copolymerization composition ratio, molecular weight, molecular weight distribution, cross-linking agent, compounding composition ratio, etc., according to the characteristic values peculiar to the pressure-sensitive adhesive, etc., and the target value.

An acrylic resin is a resin containing an acrylic monomer (a monomer having a (meth)acryloyl group in the molecule) as a monomer component that constitutes the resin. That is, the acrylic resin contains structural units derived from acrylic monomers. The acrylic resin is preferably a polymer containing a (meth)acrylic acid alkyl ester as a monomer component constituting the polymer. In the present specification, "(meth)acrylic" means "acrylic" and/or "methacrylic" (one or both of "acrylic" and "methacrylic"), and the same applies to others. .

As the (meth)acrylic acid alkyl ester as an essential monomer component, a (meth)acrylic acid alkyl ester having a linear or branched alkyl group is preferably mentioned. In addition, only 1 type may be used for the said (meth)acrylic-acid alkyl ester, and 2 or more types may be used for it.

The (meth)acrylic acid alkyl 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, (meth) ) isopentyl acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, ( meth) isononyl acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate (lauryl (meth) acrylate), tridecyl (meth) acrylate, (meth) ) Tetradecyl acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate (stearyl (meth)acrylate), isostearyl (meth)acrylate, (meth)acrylate (Meth)acrylic acid alkyl esters having a linear or branched alkyl group having 1 to 20 carbon atoms, such as nonadecyl acrylate and eicosyl (meth)acrylate.

As the (meth)acrylic acid alkyl ester having a linear or branched alkyl group, among them, a linear or branched chain having 2 or more carbon atoms (preferably 2 to 18, more preferably 2 to 5) A (meth)acrylic acid alkyl ester having a triangular alkyl group is preferred.

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

The acrylic resin contains the (meth)acrylic acid alkyl ester and other monomers (copolymerizable monomers) copolymerizable with the (meth)acrylic acid alkyl ester as monomer components constituting the resin. good too. That is, the acrylic resin may contain a copolymerizable monomer as a structural unit. The above copolymerizable monomers may be used alone or in combination of two or more.

Examples of the copolymerizable monomer include carboxy group-containing monomers, hydroxy group-containing monomers, epoxy group-containing monomers, keto group-containing monomers, alkoxy group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, vinyl ester-based monomers, vinyl ether-based monomers, isocyanate group-containing monomers, aromatic vinyl compounds, alicyclic monomers, aromatic ring-containing (meth)acrylates, chlorine-containing monomers, nitrogen-containing monomers, and the like.

The content of structural units derived from copolymerizable monomers in the acrylic resin is preferably 0.1% by mass or more, more preferably 0%, based on the total amount of 100% by mass of the monomer components constituting the acrylic resin. .3% by mass or more. The above content is preferably 30% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. Of course, depending on the application and required properties, the content ratio of the structural units derived from the copolymerizable monomer in the acrylic resin may be It may be less than 0.1% by mass.

The content of the thermosetting resin is not particularly limited, but the total amount of the adhesive of the present invention (however, organic It is preferably 3 to 95% by mass, more preferably 5 to 90% by mass, and still more preferably 6 to 85% by mass, based on 100% by mass (excluding components such as solvents that do not remain during layer formation). When the adhesive or the like of the present invention contains a thermosetting resin as a base polymer, the content is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, and still more preferably 65 to 85% by mass. . When the adhesive or the like of the present invention contains a thermoplastic resin as a base polymer, the content is preferably 3 to 80% by mass, more preferably 5 to 50% by mass, still more preferably 7 to 30% by mass. In addition, the amount of the thermosetting resin includes the amount of the thermosetting resin, its raw material monomer, the cross-linking agent, and the structural part derived from the cross-linking agent.

When the thermoplastic resin is contained, the content of the thermoplastic resin is not particularly limited. 20 to 97% by mass, more preferably 50 to 95% by mass, and still more preferably 70 to 93% by mass with respect to 100% by mass of the total amount of (excluding components such as organic solvents that do not remain during layer formation) %. When the adhesive or the like of the present invention contains a thermosetting resin as a base polymer, the content is preferably 30% by mass or less, and may be 10% by mass or less, 5% by mass or less, or 1% by mass or less. It may be 0% by mass. The amount of the thermoplastic resin includes the amount of the thermoplastic resin, its raw material monomers, the cross-linking agent, and the structural portion derived from the cross-linking agent.

The adhesive, etc. of the present invention contains a compound that suppresses recombination of reversibly degradable bonds, which is the component (b). The component (b) is not particularly limited as long as it can suppress the recombination of the cleavage of the component (a) caused by an external stimulus. compounds (radical scavengers) are preferred. Examples of the radical scavenger include photoradical polymerization initiators, spin scavengers, antioxidants, polymerization inhibitors, and hydrogen donors.

The content of the component (b) is selected from the group consisting of the compound (a2), the structural unit derived from the compound (a2), and the structural moiety derived from the compound (a2), from the viewpoint of exhibiting an appropriate recombination inhibitory effect. It is preferably 10 to 1000 parts by mass, more preferably 50 to 500 parts by mass, still more preferably 75 to 400 parts by mass, most preferably 100 parts by mass of the total amount of one or more selected is 100 to 300 parts by mass.

In addition, the pressure-sensitive adhesive or the like of the present invention may contain other components other than the components described above, if necessary. Examples of the other components include curing catalysts, cross-linking agents other than the compound (a2), cross-linking accelerators, polymerization initiators, tackifier resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), and oligomers. , anti-aging agents, fillers (metal powder, organic fillers, inorganic fillers, etc.), colorants (pigments, dyes, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubrication agents, leveling agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, granular substances, foil-shaped substances, flame retardants, silane coupling agents, ion trapping agents and the like. Only one kind of each of the other components may be used, or two or more kinds thereof may be used.

Examples of the curing catalyst include organic titanium compounds and organic zirconium compounds. Examples of the organic titanium compound include titanium alkoxide, titanium chelate, and titanium acylate. Examples of the organic zirconium compounds include zirconium alkoxides, zirconium chelates, zirconium acylates, and the like. Titanium alkoxides include tetraisopropyl titanate, tetra-normal butyl titanate, butyl titanate dimer, and tetraoctyl titanate. Titanium chelates include titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate, and titanium octylene glycolate. Titanium acylate includes titanium isostearate. Zirconium alkoxides include normal propyl zirconate and normal butyl zirconate. Zirconium chelates include zirconium tetraacetylacetonate and zirconium monoacetylacetonate. Zirconium acylate includes zirconium stearate.

The content of the curing catalyst is not particularly limited, but from the viewpoint of imparting an appropriate initial hardness to the adhesive or the like and hardness after external stimulation, the total amount of the adhesive or the like of the present invention (however, the organic solvent, etc. 0.005 to 3% by mass, more preferably 0.01 to 1% by mass, and still more preferably 0.05 to 1% by mass, based on 100% by mass (excluding components that do not remain during layer formation) .

The cross-linking agent other than the compound (a2) is not particularly limited as long as it cross-links the polymer. Examples include functional (meth)acrylates. Examples of polyfunctional (meth)acrylates include bifunctional or higher (meth)acrylic acid esters, such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, di Pentaerythritol hexa(meth)acrylate can be mentioned.

Hereinafter, preferred embodiments will be described separately for the case where the pressure-sensitive adhesive or the like of the present invention is a fluid pressure-sensitive adhesive composition or adhesive composition and the case where it is a pressure-sensitive adhesive layer or adhesive layer. In addition, in this specification, an adhesive composition and/or an adhesive composition may be called "adhesive composition etc.". Moreover, in this specification, an adhesive layer and/or an adhesive layer may be called "adhesive layer etc.".

(adhesive layer, adhesive layer)
FIG. 1 is a schematic cross-sectional view of one embodiment in which the adhesive or the like of the present invention is an adhesive layer or the like. A pressure-sensitive adhesive layer or adhesive layer 1 shown in FIG. 1 is laminated on the release-treated surface of a release liner 2 to form a pressure-sensitive adhesive sheet or adhesive sheet 10 with a release liner.

When the adhesive or the like of the present invention is an adhesive layer or the like, the adhesive layer or the like preferably contains at least the polymer (a1) and (b) components. Only one kind of polymer (a1) may be used, or two or more kinds thereof may be used.

The pressure-sensitive adhesive layer and the like may contain components other than the components described above. Examples of the above other components include those exemplified and explained as other components that may be included in the pressure-sensitive adhesive or the like of the present invention. Only one kind of each of the other components may be used, or two or more kinds thereof may be used.

The content of the polymer (a1) in the adhesive layer or the like is preferably 30 to 99% by mass, more preferably 40 to 97% by mass, more preferably 40 to 97% by mass, with respect to 100% by mass of the total amount of the adhesive layer or the like. 50 to 95% by weight, most preferably 70 to 95% by weight. When the content is 30% by mass or more, it is easy to impart adhesiveness to the pressure-sensitive adhesive layer and the like. When the content is 99% by mass or less, it is easy to design the composition by adding the cross-linking agent and component (b). In addition, when the compound (a2) is a monomer component or an oligomer component, the content ratio includes the amount of the compound (a2) and the structural units derived from the compound (a2). In addition, the amount of the polymer (a1) includes the amount of the polymer (a1), its raw material monomer, the cross-linking agent, and the structural portion derived from the cross-linking agent.

The content of the cross-linking agent and/or the structural part derived from the cross-linking agent in the adhesive layer or the like is preferably 0.5 to 50% by mass, more preferably 0.5 to 50% by mass, with respect to 100% by mass of the total amount of the polymer (a1). 1 to 35% by mass, more preferably 1.5 to 30% by mass. In addition, when the compound (a2) is a cross-linking agent, the content includes the amount of the compound (a2) and the structural portion derived from the compound (a2).

It is preferable that the adhesive layer and the like form a network structure. A network structure refers to a state in which molecules are entangled with each other, or a state in which molecular chains form a long molecule through some bond. That is, the polymer (a1) is preferably a polymer in which a network structure is formed by bonding or entanglement between molecules. The pressure-sensitive adhesive layer or the like having such a configuration forms a network structure through polymer-to-polymer bonding or polymer-to-polymer entanglement, and can have an appropriate degree of hardness. Degradation shreds the polymer structure and improves flexibility.

"Molecules are entangled with each other" refers to a state in which macromolecules form a network structure without covalent bonds. In order to form such an entangled structure, it is preferable to contain different types of polymers that are unlikely to cause cross-linking reactions, and from the viewpoint of ease of production, a state in which a thermoplastic resin and a thermosetting resin are mixed. is preferred. Such a configuration is suitable for adhesives or the like that are relatively soft before application of an external stimulus because no covalent bond is involved.

The state in which the molecular chains form long molecules through some kind of bond means that the polymer is a single macromolecular polymer. In order to form such long and large molecules, it is preferable to contain a single polymer, and it is preferable to contain the thermosetting resin described above. Such a structure can form a relatively hard adhesive, etc., because the molecular chains are covalently bonded to each other. Suitable for pressure-sensitive adhesives, etc. with different thicknesses.

The pressure-sensitive adhesive layer and/or adhesive layer of the present invention has the property that its hardness is reduced by an external stimulus. The hardness is preferably Young's modulus measured by, for example, a tensile compression tester. That is, the pressure-sensitive adhesive layer and/or adhesive layer of the present invention has the property that Young's modulus is reduced by an external stimulus.

That is, it is preferable that the pressure-sensitive adhesive layer or the like of the present invention has a lower Young's modulus after applying an external stimulus than before applying an external stimulus. Such a pressure-sensitive adhesive layer or the like is excellent in handleability before application of an external stimulus, and excellent in flexibility, impact resistance, and shape deformation resistance in a high speed range after application of an external stimulus.

The pressure-sensitive adhesive layer or the like of the present invention has a ratio of Young's modulus (E1) before application of an external stimulus to Young's modulus (E2) after application of an external stimulus [Young's modulus (E2)/Young's modulus (E1)] of 0.95. It is preferably less than (eg, 0.1 or more and less than 0.95), more preferably 0.8 or less (eg, 0.2 to 0.8), still more preferably 0.7 or less (eg, 0.3 to 0.0 .7). In this case, the pressure-sensitive adhesive layer or the like is excellent in flexibility before and after application of an external stimulus, excellent in resistance to minute deformation, and more excellent in impact resistance, shape deformation resistance in a high speed range, conformability to steps, adhesion, and the like.

The pressure-sensitive adhesive layer, etc. of the present invention preferably has a Young's modulus (E1) of 200 MPa or less (eg, 0.03 to 200 MPa) before applying an external stimulus. The pressure-sensitive adhesive layer or the like preferably has a Young's modulus (E2) of 50 MPa or less (eg, 0.001 to 50 MPa) after application of an external stimulus. The pressure-sensitive adhesive layer having the above Young's modulus has appropriate hardness before application of an external stimulus, and is excellent in workability such as manufacturing/processing, storage and transportation. In addition, the pressure-sensitive adhesive layer having the above Young's modulus is excellent in flexibility after application of an external stimulus, and is more excellent in step followability, adhesiveness, and the like.

The pressure-sensitive adhesive layer preferably has a Young's modulus (E1) of 0.03 to 1.5 MPa, more preferably 0.05 to 1.0 MPa, still more preferably 0.1 to 0 .8 MPa. The pressure-sensitive adhesive layer having the above Young's modulus (E1) has appropriate hardness before application of an external stimulus and is superior in handleability.

The above-mentioned adhesive layer preferably has a Young's modulus (E1) of 0.1 to 200 MPa, more preferably 0.3 to 100 MPa, and still more preferably 0.5 to 20 MPa before applying an external stimulus. The adhesive layer having the above Young's modulus has appropriate hardness before application of an external stimulus, and is excellent in workability such as manufacturing/processing, storage and transportation.

The pressure-sensitive adhesive layer 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), more preferably 0.5 MPa or less (for example, 0.001 MPa or more and less than 1.0 MPa) after application of an external stimulus. 005 to 0.5 MPa), more preferably 0.3 MPa or less (for example, 0.01 to 0.3 MPa). The pressure-sensitive adhesive layer having the above Young's modulus (E2) has excellent flexibility after application of an external stimulus, excellent resistance to microdeformation, impact resistance, shape deformation resistance in a high speed range, step followability, adhesion, etc. Better.

The adhesive layer preferably has a Young's modulus (E2) of 50 MPa or less (eg, 0.01 MPa or more and less than 50 MPa) after application of an external stimulus, more preferably 10 MPa or less (eg, 0.05 to 10 MPa). It is preferably 5 MPa or less (eg, 0.1 to 5 MPa). The adhesive layer having the above Young's modulus is excellent in flexibility after application of an external stimulus, and is more excellent in step followability, adhesion, and the like.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a higher breaking elongation after applying an external stimulus than before applying an external stimulus. The pressure-sensitive adhesive layer or the like does not have to be broken at 500% elongation before and after applying an external stimulus. Such a pressure-sensitive adhesive layer or the like is excellent in handleability before application of an external stimulus, and excellent in resistance to minute deformation, impact resistance, and shape deformation resistance in a high-speed range after application of an external stimulus.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a breaking elongation (B1) of 100 to 2000%, more preferably 100 to 1000%, still more preferably 120 to 900%, particularly preferably 120 to 900%, before applying an external stimulus. is 150-850%. The pressure-sensitive adhesive layer or the like having the above breaking elongation (B1) has appropriate hardness before application of an external stimulus, and is excellent in handleability.

The adhesive layer or the like of the present invention preferably has a breaking elongation (B2) after application of an external stimulus of 100 to 1300%, more preferably 130 to 1100%, still more preferably 160 to 1000%. The pressure-sensitive adhesive layer or the like having the above Young's modulus (B2) is excellent in flexibility after application of an external stimulus, excellent in resistance to minute deformation, and excellent in impact resistance and shape deformation resistance in a high speed range.

In the pressure-sensitive adhesive layer, etc. of the present invention, the ratio of the breaking elongation (B1) before applying an external stimulus to the breaking elongation (B2) after applying an external stimulus [breaking elongation (B2)/breaking elongation (B1)] is , preferably greater than 1.1 (eg, greater than 1.1 and 2.0 or less), more preferably 1.2 or greater (eg, 1.2 to 1.8), and still more preferably 1.3 or greater (eg, 1 .3 to 1.6). In this case, the pressure-sensitive adhesive layer or the like is excellent in flexibility before and after application of an external stimulus, excellent in resistance to minute deformation, and excellent in impact resistance and shape deformation resistance in a high speed range.

It is preferable that the pressure-sensitive adhesive layer, etc. of the present invention have the property of reducing stress due to an external stimulus. Preferably, the stress does not increase after reduction. Such a pressure-sensitive adhesive layer or the like does not increase stress in a state in which the pressure-sensitive adhesive layer or the like is adhered or adhered to a member, and maintains its flexibility.

Examples of the stress include the stress (distortion stress) when pulled at an arbitrary magnification, which is measured by a tension/compression tester. The stress (distortion stress) when pulled at the above-mentioned specific magnification may be reduced as long as the stress (distortion stress) when pulled at at least one magnification is reduced. Among them, it is preferable that the strain stress at at least one of the tensile ratios of 100 to 500% is reduced, and the strain at one or more tensile ratios selected from the group consisting of 100%, 200%, 300%, and 500%. A reduction in stress is particularly preferred. Preferred ranges of stress at each tensile magnification are described below, and these values are preferred ranges when no breakage occurs at each tensile magnification.

The pressure-sensitive adhesive layer or the like has a value of stress (100% strain stress) (hereinafter referred to as S1 (100)) before applying an external stimulus and a stress (100% strain stress) after applying an external stimulus (hereinafter referred to as S2 ( 100)) value ratio [S2 (100) / S1 (100)] is preferably less than 0.95 (for example, 0.1 or more and less than 0.95), more preferably 0.90 0.8 or less, more preferably 0.8 or less. Such an adhesive layer or the like shows that the relatively weak tensile stress is further reduced by applying an external stimulus, and the repulsive force when pulled is low, making it suitable for relatively low load applications such as foldable members. .

The pressure-sensitive adhesive layer or the like of the present invention preferably has a stress (100% strain stress) (S1(100)) before application of an external stimulus of 0.03 MPa or more (eg, 0.03 to 10 MPa), more preferably It is 0.05 MPa or more (eg, 0.05 to 6 MPa), more preferably 0.2 MPa or more (eg, 0.2 to 3 MPa). Such a pressure-sensitive adhesive layer or the like is even more excellent in flexibility after application of an external stimulus.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a stress (100% strain stress) (S2(100)) after application of an external stimulus of 10 MPa or less (eg, 0.03 to 10 MPa), more preferably 6 MPa or less. (eg, 0.05 to 6 MPa), more preferably 3 MPa or less (eg, 0.2 to 3 MPa). Such a pressure-sensitive adhesive layer or the like is even more excellent in flexibility after application of an external stimulus.

The pressure-sensitive adhesive layer, etc. of the present invention has a ratio [ S2(200)/S1(200)] is preferably less than 0.95 (for example, 0.1 or more and less than 0.95), more preferably 0.8 or less, still more preferably 0.7 or less . Such a pressure-sensitive adhesive layer or the like shows that the relatively weak tensile stress is further reduced by applying an external stimulus, has a low repulsive force when pulled, and is suitable for relatively low-load applications such as foldable members. .

The adhesive layer or the like of the present invention preferably has a stress (200% strain stress) (S1(200)) before application of an external stimulus of 0.05 MPa or more (eg 0.05 to 10 MPa), more preferably It is 0.1 MPa or more (eg, 0.1 to 4 MPa), more preferably 0.2 MPa or more (eg, 0.2 to 2 MPa). Such a pressure-sensitive adhesive layer or the like is even more excellent in flexibility after application of an external stimulus.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a stress (200% strain stress) (S2(200)) after application of an external stimulus of 10 MPa or less (eg, 0.01 to 10 MPa), more preferably 4 MPa or less. (eg, 0.03 to 4 MPa), more preferably 2 MPa or less (eg, 0.05 to 2 MPa). Such a pressure-sensitive adhesive layer or the like is even more excellent in flexibility after application of an external stimulus.

The pressure-sensitive adhesive layer, etc. of the present invention has a ratio [ S2(300)/S1(300)] is preferably less than 0.950 (for example, 0.1 or more and less than 0.950), more preferably 0.8 or less, still more preferably 0.7 or less . Such a pressure-sensitive adhesive layer or the like shows that the tensile stress is reduced by applying an external stimulus, and is suitable for relatively low-load applications such as foldable members.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a stress (300% strain stress) (S1(300)) before application of an external stimulus of 0.05 MPa or more (eg, 0.05 to 10 MPa), more preferably It is 0.1 MPa or more (eg, 0.1 to 4 MPa), more preferably 0.2 MPa or more (eg, 0.2 to 2 MPa). Such a pressure-sensitive adhesive layer or the like is even more excellent in flexibility after application of an external stimulus.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a stress (300% strain stress) (S2(300)) after application of an external stimulus of 10 MPa or less (eg, 0.03 to 10 MPa), more preferably 4 MPa or less. (eg, 0.05 to 4 MPa), more preferably 2 MPa or less (eg, 0.07 to 2 MPa). Such a pressure-sensitive adhesive layer or the like is even more excellent in flexibility after application of an external stimulus.

The pressure-sensitive adhesive layer or the like has a value of stress (500% strain stress) (hereinafter referred to as S1 (500)) before applying an external stimulus and a stress (500% strain stress) after applying an external stimulus (hereinafter referred to as S2 ( 500)) value ratio [S2 (500) / S1 (500)] is preferably less than 0.950 (for example, 0.1 or more and less than 0.950), more preferably 0.90 0.8 or less, more preferably 0.8 or less. Such an adhesive layer or the like shows that a relatively strong tensile stress is reduced by the application of an external stimulus, and has a low repulsive force when pulled, and can be used as a folding type (especially a winding type such as a rollable) member. Suitable for relatively high load applications.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a stress (500% strain stress) (S1(500)) before application of an external stimulus of 0.05 MPa or more (for example, 0.05 to 10 MPa), more preferably It is 0.07 MPa or more (eg, 0.07 to 4 MPa), more preferably 0.1 MPa or more (eg, 0.1 to 2 MPa). Such a pressure-sensitive adhesive layer or the like is even more excellent in flexibility after application of an external stimulus.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a stress (500% strain stress) (S2(500)) of 10 MPa or less (eg, 0.05 to 10 MPa) after application of an external stimulus, more preferably 4 MPa or less. (eg, 0.07 to 4 MPa), more preferably 2 MPa or less (eg, 0.1 to 2 MPa). Such a pressure-sensitive adhesive layer or the like is even more excellent in flexibility after application of an external stimulus.

In addition, the pressure-sensitive adhesive layer and the like of the present invention may have the property of reducing the peak strength (stress peak strength) in the stress-strain curve and the stress at break due to an external stimulus.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a peak strength (stress peak strength) (breaking point stress when broken) in a stress-strain curve before application of an external stimulus, and more preferably 1.0 MPa or more. It is 1.2 MPa or more, more preferably 1.5 MPa or more. When the stress peak strength is 1.0 MPa or more, the pressure-sensitive adhesive layer or the like has appropriate hardness before application of an external stimulus, and is excellent in handleability.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a peak strength (stress peak strength) in a stress-strain curve (stress at break when breaking) of 0.05 to 1.0 MPa after application of an external stimulus. More preferably 0.1 to 0.8 MPa, still more preferably 0.15 to 0.5 MPa. When the stress peak intensity is within the above range, the flexibility, step conformability, adhesion, etc. are more excellent after application of an external stimulus.

The pressure-sensitive adhesive layer or the like of the present invention is the stress before applying an external stimulus - the peak strength in the strain curve and the stress after applying the external stimulus - the ratio of the peak strength in the strain curve (when breaking, the ratio of the stress at break) [external After application of stimulus/before application of external stimulus] is preferably less than 0.95 (eg, 0.05 or more and less than 0.95), more preferably 0.8 or less (eg, 0.1 to 0.8), More preferably, it is 0.7 or less (eg, 0.3 to 0.7). In this case, there is a tendency that the flexibility, step followability, and adhesion of the pressure-sensitive adhesive layer, etc., change more significantly before and after the application of the external stimulus.

It is preferable that the shear storage modulus (G') of the pressure-sensitive adhesive layer or the like is lowered by irradiation with active energy rays. Flexibility of such a pressure-sensitive adhesive or the like is improved by irradiation with active energy rays. Also, it is preferable that the shear storage modulus (G') does not increase after the decrease.

The pressure-sensitive adhesive layer or the like preferably has a shear storage modulus (G') of 10 ³ to 10 ⁸ Pa at 25° C. before application of an external stimulus, more preferably 10 ⁴ to 10 ⁷ Pa, still more preferably 10 ^{4 .} ~10 ⁶ Pa. A pressure-sensitive adhesive layer or the like having such an elastic modulus has an appropriate hardness before application of an external stimulus, and is excellent in workability such as manufacturing/processing, storage and transportation.

The pressure-sensitive adhesive layer or the like preferably has a shear storage modulus (G') of 10 ² to 10 ⁶ Pa at 25° C. after application of an external stimulus, more preferably 10 ³ to 10 ⁵ Pa, still more preferably 10 ³ to 10 ⁴ Pa. When the elastic modulus after application of an external stimulus is within the above range, the pressure-sensitive adhesive layer or the like of the present invention is excellent in flexibility, step followability, adhesion, etc. after application of an external stimulus.

The thickness of the pressure-sensitive adhesive layer and the like is not particularly limited, but it is usually about 5 to 300 μm, more preferably 7 to 200 μm, even more preferably 10 to 100 μm, most preferably 10 to 50 μm.

(Release liner)
The release liner protects the adhesive surface of the adhesive layer, etc. until use, and is peeled off when the adhesive layer, etc. is used.

Examples of base materials for the 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, poly Butylene 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, A fluorine resin film or the like is used. Crosslinked films of these are also used. Furthermore, a laminated film of these may be used.

The release surface of the release liner (especially the surface in contact with the pressure-sensitive adhesive layer, etc.) is preferably subjected to a release treatment. Examples of release agents used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

Although there are no particular restrictions on the thickness of the release liner, it is usually about 20 to 150 μm.

(Adhesive composition, adhesive composition)
The pressure-sensitive adhesive layer is formed from the pressure-sensitive adhesive composition. Also, the adhesive layer is formed from the adhesive composition. Preferably, the pressure-sensitive adhesive composition or the like contains at least a base polymer and/or a raw material monomer thereof and the component (b). Among them, it is preferable to include a base polymer from the viewpoint of exhibiting adhesiveness in the pressure-sensitive adhesive layer or the like to be obtained. The base polymer is the polymer (a1) and/or other polymer (that is, a polymer having no reversible degradable bond), preferably other polymer. A base polymer that can be contained in an adhesive composition or the like is sometimes referred to as a "base polymer (p1)". Only one kind of the base polymer (p1) may be used, or two or more kinds thereof may be used.

When the base polymer (p1) is the other polymer, the pressure-sensitive adhesive composition or the like further contains the compound (a2). Moreover, in this case, a monomer component (monomer component (c)) having reactivity with the compound (a2) may be further included. The compound (a2) has reactivity with the other polymer and/or monomer component (c). When the compound (a2) is reactive with the other polymer, the other monomer reacts with the compound (a2) in the pressure-sensitive adhesive layer or the like by heat, active energy ray irradiation, or the like to form, for example, a polymer chain, The polymer chain and the other polymer are bonded to form a network structure, and a pressure-sensitive adhesive layer or the like containing the polymer (a1) is obtained. When the compound (a2) and the monomer component (c) are contained, the compound (a2) and the monomer component (c) react with heat or active energy ray irradiation in the pressure-sensitive adhesive layer or the like to form, for example, a polymer chain. The polymer chains and the above-mentioned other polymers are entangled to form a network structure, and a pressure-sensitive adhesive layer or the like containing the polymer (a1) is obtained.

When the adhesive composition or the like contains the raw material monomer, the compound (a2) is incorporated into the base polymer when the raw material monomer is polymerized to form the polymer (a1). Alternatively, the raw material monomer is polymerized to form the other polymer, which is then reacted with compound (a2) to form polymer (a1).

That is, the pressure-sensitive adhesive composition or the like mainly includes (i) the other polymer, the component (b), the compound (a2), and, if necessary, a pressure-sensitive adhesive composition or the like containing the monomer component (c), and (ii ) Raw material monomer, component (b), compound (a2), and optionally a pressure-sensitive adhesive composition containing monomer component (c), etc., (iii) pressure-sensitive adhesive composition containing polymer (a1) and component (b), etc. is mentioned.

Therefore, the polymer (a1) may be a reactant of the other polymer, compound (a2), and monomer (c). Moreover, when the base polymer (p1) is the polymer (a1), the pressure-sensitive adhesive layer and the like may contain an unreacted compound (a2) and/or an unreacted monomer (c).

Examples of the base polymer (p1) include the thermoplastic resin, the thermosetting resin, the active energy ray-curable resin, and the like. Among them, thermoplastic resins and thermosetting resins are preferred. A pressure-sensitive adhesive layer or the like containing a thermoplastic resin is capable of exerting adhesiveness such that it adheres under pressure from the outside, for example. A pressure-sensitive adhesive layer or the like containing a thermosetting resin can be adhered to an adherend by being cured by heating, for example.

As described above, the compound (a2) includes a monomer component, an oligomer component, a cross-linking agent, and the like having the reversible degradable bond. Among them, a cross-linking agent is preferable, and a cross-linking agent having a disulfide bond is more preferable.

The functional group (L1) possessed by the compound (a2) as the cross-linking agent is preferably a hydroxy group or a carboxy group from the viewpoint that the cross-linking density of the polymer (a1) is moderate.

When the compound (a2) is reactive with the other polymer, the other polymer has a functional group (L2) that can react with the functional group (L1) in the compound (a2). The functional group (L2) is appropriately selected according to the type of the functional group (L1) described above. ) acryloyl group, amino group, aldehyde group and the like.

Combinations of the functional group (L1) and the functional group (L2) include a carboxy group and a group containing a cyclic ether, a group containing a cyclic ether and a carboxy group, a carboxy group and an aziridyl group, an aziridyl group and a carboxy group, and a hydroxy group and isocyanate. group, isocyanate group and hydroxy group, (meth)acryloyl group and (meth)acryloyl group, hydroxy group and amino group, amino group and hydroxy group, group containing cyclic ether and hydroxy group, hydroxy group and group containing cyclic ether, etc. is mentioned. Among these, from the viewpoint of ease of reaction tracking, a combination of a carboxy group and a group containing a cyclic ether, a combination of a group containing a cyclic ether and a carboxy group, a combination of a group containing a cyclic ether and a hydroxy group, a combination of a hydroxy group and a cyclic Combinations of ether-containing groups are preferred. That is, it is preferable that the functional group (L1) is a hydroxyl group or a carboxy group, and the functional group (L2) is a group containing a cyclic ether (especially an epoxy group).

The number of functional groups (L2) in the other polymer having a functional group (L2) is 2, from the viewpoint of increasing the molecular weight after introduction into the polymer (a1) and further decreasing the molecular weight of the polymer after cleavage. It may be one or more (eg, 2 to 4). On the other hand, the number of functional groups (L2) is preferably 3 or less, more preferably 2, from the viewpoint of ensuring a certain degree of flexibility of the pressure-sensitive adhesive layer and the like with an appropriate crosslinking density.

The monomer component (c) is a compound having two or more polymerizable functional groups. The polymerizable functional group is preferably a functional group (L3) capable of reacting with the functional group (L1) of the compound (a2) as a cross-linking agent. Thereby, the monomer (c) is crosslinked by the compound (a2) while being polymerized, thereby forming a polymer chain having a reversible degradable bond in the molecule. Moreover, it is preferable that the functional group (L3) can react with the functional group (L2). The functional group (L3) is appropriately selected according to the type of the functional group (L1) or the functional group (L2) described above. Epoxy group, (meth)acryloyl group, amino group, aldehyde group and the like.

Examples of the combination of the functional group (L1) and the functional group (L3) include those exemplified and explained as the combination of the functional group (L1) and the functional group (L2) described above. Among them, from the viewpoint of ease of reaction tracking, a combination of a carboxy group and a group containing a cyclic ether, a combination of a group containing a cyclic ether and a carboxy group, a combination of a group containing a cyclic ether and a hydroxy group, and a hydroxy group and a cyclic ether Combinations of containing groups are preferred. That is, it is preferable that the functional group (L1) is a hydroxyl group or a carboxy group, and the functional group (L3) is a group containing a cyclic ether (especially an epoxy group).

The number of functional groups (L3) in the monomer component (c) is 2 or more (for example, 2 to 4). On the other hand, the number of functional groups (L3) is preferably 3 or less, more preferably 2, from the viewpoint of ensuring a certain degree of flexibility of the pressure-sensitive adhesive layer and the like with an appropriate crosslinking density.

Among them, the functional group (L3) is preferably a group having a cyclic ether group, and particularly preferably an epoxy group. That is, an epoxy compound is preferable as the monomer component (c). Such epoxy compounds include, for example, 4,4'-isopropylidenedicyclohexanol and (chloromethyl)oxirane.

The equivalent weight of the polymerizable functional group of the monomer component (c) is preferably 100 to 10,000 eq/g, more preferably 150 to 9,000 eq/g, from the viewpoint of making the crosslinked structure moderate and not too dense. Monomer component (c) may use only 1 type, and may use 2 or more types.

When the base polymer (p1) is the above other polymer, the content of the monomer component (c) in the pressure-sensitive adhesive composition or the like is 5 to 600 parts by mass with respect to 100 parts by mass of the total amount of the base polymer (p1). parts, 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 3 to 80 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 7 to 30 parts by mass.

When the base polymer (p1) is the polymer (a1), the content of the monomer component (c) in the pressure-sensitive adhesive composition or the like is 5 to 95% by mass with respect to 100% by mass of the total amount of the polymer (a1). is preferred, and more preferably 7 to 90% by mass. When the polymer (a1) is a thermosetting resin, the content is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, still more preferably 65 to 85% by mass. When the polymer (a1) is a thermoplastic resin, the content is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, still more preferably 6 to 30% by mass.

The adhesive composition and the like may contain other components other than the components described above. Examples of the above-mentioned other components include those exemplified and explained as other components that may be included in the above-described pressure-sensitive adhesive of the present invention, and solvents such as organic solvents. Only one kind of each of the other components may be used, or two or more kinds thereof may be used.

The content ratio of the other polymer in the adhesive composition etc. is 5 to 5 with respect to 100% by mass of the total amount of the adhesive composition etc. (excluding components such as organic solvents that do not remain when forming the layer) 99% by mass is preferred, more preferably 10 to 95% by mass. When the other polymer is a thermosetting resin, the content is preferably 5 to 50% by mass, more preferably 7 to 40% by mass, still more preferably 10 to 30% by mass. When the other polymer is a thermoplastic resin, the content is preferably 30 to 99% by mass, more preferably 50 to 95% by mass, still more preferably 60 to 90% by mass. When the content is 5% by mass or more, it is easy to impart adhesiveness to the pressure-sensitive adhesive layer and the like. When the content is 99% by mass or less, it is easy to design the composition by blending the cross-linking agent and component (b).

The content of the cross-linking agent and/or the structural part derived from the cross-linking agent in the pressure-sensitive adhesive composition or the like is 0.5 to 0.5 parts per 100 parts by mass of the total amount of the other polymer and/or monomer component (c). It is preferably 50 parts by mass, more preferably 1 to 35 parts by mass, still more preferably 1.5 to 30 parts by mass. In addition, when the compound (a2) is a cross-linking agent, the content includes the amount of the compound (a2).

An embodiment of the method for manufacturing the pressure-sensitive adhesive, etc. of the present invention will be described. For example, the pressure-sensitive adhesive sheet with a release liner or adhesive sheet 10 shown in FIG. 1 can be produced by the following method. After forming a coating layer by applying a pressure-sensitive adhesive layer or a pressure-sensitive adhesive composition that forms the adhesive layer 1 to the base material layer or the release-treated surface of the release liner 2, which is subjected to the release treatment, heating is performed. It can be prepared by removing the solvent, heat-curing, or curing by irradiation with active energy rays to solidify the coating layer. In addition, when performing active energy ray irradiation, it is performed after separately bonding a release liner on the coating layer.

The adhesive composition and the like may be in any form as long as it does not impair the effects of the present invention. For example, the pressure-sensitive adhesive composition may be emulsion type, solvent type (solution type), heat melting type (hot melt type), or the like. Among them, the solvent type is preferable because it is easy to obtain a pressure-sensitive adhesive layer with excellent productivity.

When the adhesive composition or the like contains the polymer (a1), the adhesive layer or the like is formed by heating when the coating layer is solidified. Further, when the pressure-sensitive adhesive composition or the like contains the other polymer and/or raw material monomer and the compound (a2), the raw material monomer is optionally removed by heating or active energy ray irradiation when solidifying the coating layer. is polymerized, and the compound (a2) forms a bond with the polymer of the raw material monomers and the other polymer to form the polymer (a1), and at the same time, the pressure-sensitive adhesive layer and the like are formed. The pressure-sensitive adhesive layer and the like may then be heated or irradiated with an active energy ray, or may be heat-cured when the polymer (a1) is a thermosetting resin. Thus, the adhesive sheet 10 with a release liner shown in FIG. 1 is obtained.

The use of the adhesive, etc. of the present invention is not particularly limited, and it can be used for any purpose. The pressure-sensitive adhesive or the like of the present invention can be used, for example, for optical applications, that is, for bonding to optical members. The pressure-sensitive adhesive or the like of the present invention is used, for example, in optical members such as electrical and electronic equipment, when various members or parts are attached (mounted) to a predetermined portion (for example, a housing or the like). It should be noted that "electrical/electronic equipment" refers to equipment corresponding to at least one of electric equipment and electronic equipment. Examples of the electric/electronic devices include image display devices such as liquid crystal displays, electroluminescence displays, and plasma displays, and mobile electronic devices. Examples of the image display device include an image display device in the portable electronic device, a display (roll display) inside and outside a vehicle such as a train or a bus, and the like.

Examples of the portable electronic devices include mobile phones, smartphones, tablet computers, notebook computers, and various wearable devices (for example, wrist wear types that are worn on the wrist like wristwatches, clips, straps, etc. that are attached to a part of the body) Modular type to be worn, eyewear type including eyeglass type (monocular type and binocular type, including head-mounted type), clothing type that can be attached to shirts, socks, hats, etc. in the form of accessories, ears such as earphones earwear type, etc.), digital cameras, digital video cameras, audio equipment (portable music players, IC recorders, etc.), calculators (calculators, etc.), portable game devices, electronic dictionaries, electronic notebooks, electronic books, in-vehicle information equipment, Examples include portable radios, portable televisions, portable printers, portable scanners, and portable modems. In this specification, the term “portable” means not only being able to be carried but also having a level of portability that allows individuals (standard adults) to relatively easily carry it. shall mean.

The adhesive, etc. of the present invention can improve flexibility by applying an external stimulus at any time. For this reason, during manufacturing, processing, storage, transportation, etc., it can be made to have a certain degree of hardness and be excellent in handleability. For example, at the time of cutting with a punching blade, it is possible to prevent paste from overflowing, lack of glue, and process contamination caused by these. In addition, the glue is less likely to ooze out due to its own weight during storage, and less likely to cause glue chipping due to vibration or contact during transportation. By improving the flexibility when used by being attached to a member, it is possible to achieve excellent adhesion, adhesive strength, bendability, foldability, bending resistance, and the like. In addition, since the pressure-sensitive adhesive layer or the like of the present invention contains a polymer having an irreversible degradable bond in the molecule, it is possible to change the adhesive force and adhesion force by an external stimulus.

<Adhesive sheet, Adhesive sheet>
A pressure-sensitive adhesive layer and/or a pressure-sensitive adhesive sheet can be obtained using the pressure-sensitive adhesive layer or the like of the present invention. In addition, in this specification, an adhesive sheet and/or an adhesive sheet may be called "adhesive sheet etc.". The pressure-sensitive adhesive sheet or the like may be a so-called "substrate-less type" pressure-sensitive adhesive sheet or the like that does not have a substrate (substrate layer), or may be a type pressure-sensitive adhesive sheet or the like that has a substrate. In this specification, a "substrate-less type" pressure-sensitive adhesive sheet or the like may be referred to as a "substrate-less pressure-sensitive adhesive sheet or the like", and a type pressure-sensitive adhesive sheet or the like having a substrate may be referred to as a "substrate-attached pressure-sensitive adhesive sheet or the like." sometimes referred to as Examples of the substrate-less pressure-sensitive adhesive sheet or the like include, for example, a double-sided pressure-sensitive adhesive sheet or the like consisting only of the pressure-sensitive adhesive layer of the present invention, or the pressure-sensitive adhesive layer of the present invention and other pressure-sensitive adhesive layers (such as the pressure-sensitive adhesive layer of the present invention). A double-sided pressure-sensitive adhesive sheet made of a pressure-sensitive adhesive layer, etc., other than the above) may be mentioned. Further, the adhesive sheet with a substrate or the like is a pressure-sensitive adhesive sheet or the like containing a substrate and the adhesive layer or the like of the present invention formed on at least one surface of the substrate. A single-sided pressure-sensitive adhesive sheet or the like having the pressure-sensitive adhesive layer or the like of the present invention on either side of the substrate, a double-sided pressure-sensitive adhesive sheet or the like having the pressure-sensitive adhesive layer or the like of the present invention on both sides of the substrate, or the pressure-sensitive adhesive of the present invention on one side of the substrate Examples include a double-sided pressure-sensitive adhesive sheet having a layer or the like and having another pressure-sensitive adhesive layer or the like on the other side. In addition, the above-mentioned "base material (base material layer)" refers to a support, and when using (sticking) an adhesive sheet or the like on an adherend, This is the part where A release liner that is peeled off when using (sticking) an adhesive sheet or the like is not included in the base material.

When the pressure-sensitive adhesive sheet or the like of the present invention is a pressure-sensitive adhesive sheet or the like with a substrate, the substrate is not particularly limited. Various optical films such as a retardation plate can be used. Examples of the base material include porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and the like. Materials for the plastic film include, for example, polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyimide, Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, trade name “Arton” (cyclic olefin polymer, manufactured by JSR Corporation), trade name “Zeonor” (cyclic olefin polymer, Nippon Zeon Co., Ltd.) company) and other plastic materials such as cyclic olefin polymers. Only one kind of these plastic materials may be used, or two or more kinds thereof may be used.

Although the thickness of the base material is not particularly limited, it is preferably 10 to 150 μm, more preferably 15 to 125 μm, still more preferably 25 to 100 μm. In addition, the substrate may have either a single-layer structure or a multilayer structure. In addition, the surface of the substrate may be appropriately subjected to known and commonly used surface treatments such as physical treatments such as corona discharge treatment and plasma treatment, and chemical treatments such as undercoating treatment.

The adhesive sheet, etc. may be provided with a release liner on the surface (adhesive surface or adhesive surface) of the adhesive layer, etc. until use. When the adhesive sheet or the like is a double-sided adhesive sheet or the like, each adhesive surface or adhesive surface may be protected by two release liners, or one release liner having release surfaces on both sides. may be protected in the form of being wound into a roll (wound body). A release liner is used as a protective material such as a pressure-sensitive adhesive layer, and is peeled off when applied to an adherend. In addition, when the pressure-sensitive adhesive sheet or the like is a substrate-less pressure-sensitive adhesive sheet or the like, the release liner also serves as a support for the pressure-sensitive adhesive layer and the like. Note that the release liner does not necessarily have to be provided.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention.

Although the present invention will be described in more detail with reference to examples below, the present invention is not limited by these examples. In addition, the evaluation results indicated by "-" in Table 1 indicate that it was difficult to obtain reliable data due to the strain being too large at the draw ratio, and measurement was impossible. The evaluation results indicated by "-" in Table 2 indicate that evaluation was not performed.

Example 1
Epoxy monomer (trade name “HBE100”, manufactured by Shin Nippon Rika Co., Ltd., equivalent to monomer component (c)) 100 parts by mass, epoxy resin (trade name “1256B40”, manufactured by Mitsubishi Chemical Corporation) 25 parts by mass, curing agent As 4,4'-dithiodibutyric acid (manufactured by Tokyo Chemical Industry Co., Ltd., equivalent to compound (a2)) 20 parts by mass, a radical scavenger (trade name "Omnirad TPO H", manufactured by IGM Resins B.V., compound (b)) 25 parts by mass, 0.1 parts by mass of a curing catalyst (trade name “ZC700”, manufactured by Matsumoto Fine Chemical Co., Ltd.), and 3 parts by mass of acetylacetone (AcAc) are added to 500 parts by mass of methyl ethyl ketone, A mixed solution was prepared by mixing and stirring.
This mixed solution was applied to a 38 μm thick release liner R1 (trade name “MRF#38”, manufactured by Mitsubishi Chemical Corporation) having a release surface on one side of a polyester film, and dried in an oven at 100° C. for 5 minutes. rice field. After drying, the coated surface was covered with a 38 μm thick release liner R2 (trade name “MRE #38”, manufactured by Mitsubishi Chemical Corporation) whose one side is a release surface of a polyester film, and was heat cured. A 50 μm-thick pressure-sensitive adhesive sheet containing a curable resin (corresponding to polymer (a1)) was prepared. In this specification, the term "adhesion" refers to having properties of both stickiness and adhesiveness.

Example 2
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 1, except that the product name "jER828" (manufactured by Mitsubishi Chemical Corporation) was used as the epoxy monomer. .

Example 3
A viscosity containing a thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 2 except that the product name "Omnirad 651" (manufactured by IGM Resins B.V.) was used as a radical scavenger. An adhesive sheet was produced.

Example 4
Thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 1 except that 4,4'-dithiodiphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the curing agent. An attachment sheet was produced.

Example 5
Thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 2 except that 4,4'-dithiodiphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the curing agent. An attachment sheet was produced.

Comparative example 1
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (a1)) was produced in the same manner as in Example 1, except that no radical scavenger was used.

Comparative example 2
A pressure-sensitive adhesive sheet containing a thermosetting resin was produced in the same manner as in Example 1, except that 4,4'-ethylidenebisphenol was used as the curing agent.

Comparative example 3
A pressure-sensitive adhesive sheet containing a thermosetting resin was produced in the same manner as in Comparative Example 2, except that no radical scavenger was used.

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

100 parts by mass of the acrylic polymer (dissolved in ethyl acetate), 0.1 part by mass of a cross-linking agent (trade name "Tetrad C", manufactured by Mitsubishi Gas Chemical Co., Ltd.), epoxy monomer (trade name "HBE100", Shin Nippon Rika Co., Ltd. Company manufactured, equivalent to monomer component (c)) 100 parts by mass, curing agent (4,4′-dithiodibutyric acid, equivalent to compound (a2)) 2 parts by mass, curing catalyst (trade name “ZC700”, Matsumoto Fine Chemical Co., Ltd.) Company) 0.1 parts by mass, 3 parts by mass of acetylacetone, and 5 parts by mass of a radical scavenger (trade name "Omnirad TPO H", manufactured by IGM Resins B.V.) are added to each, mixed and stirred. A solution was prepared. This mixed solution was applied to a 38 μm thick release liner R1 (trade name “MRF#38”, manufactured by Mitsubishi Chemical Corporation) having a release surface on one side of a polyester film, and dried in an oven at 100° C. for 5 minutes. rice field. After drying, the coated surface was covered with a 38 μm thick release liner R2 (trade name “MRE #38”, manufactured by Mitsubishi Chemical Corporation) whose one side is a release surface of a polyester film, and was heat cured. A 50 μm-thick pressure-sensitive adhesive sheet containing a curable resin (corresponding to polymer (a1)) was prepared.

Example 7
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 6, except that the product name "jER828" (manufactured by Mitsubishi Chemical Corporation) was used as the epoxy monomer. made.

Example 8
[Preparation of acrylic polymer]
63 parts by weight of 2-ethylhexyl acrylate (2EHA), 15 parts by weight of N-vinylpyrrolidone (NVP), 9 parts by weight of methyl methacrylate (MMA), and 13 parts by weight of hydroxyethyl acrylate (HEA) are used as raw materials for the acrylic polymer. Polymerization was carried out under the same conditions as in Example 6, except that the polymer solution containing the acrylic polymer (Polymer-B) was obtained.

To 100 parts by weight of the acrylic polymer (dissolved in ethyl acetate), 4 parts by weight of an isocyanate cross-linking agent (trade name "Takenate D110N", manufactured by Mitsubishi Chemical Corporation), a curing agent (4,4'-dithiodianiline, compound (corresponding to (a2)) 1 part by mass, 0.1 part by mass of a cross-linking catalyst (trade name "ZC700", manufactured by Matsumoto Fine Chemicals Co., Ltd.), 2 parts by mass of acetylacetone, and a radical scavenger (trade name "Omnirad TPO H", IGM Resin (manufactured by B.V.) was added to each of them, and mixed and stirred to prepare a mixed solution. This mixed solution was applied to a 38 μm thick release liner R1 (trade name “MRF#38”, manufactured by Mitsubishi Chemical Corporation) having a release surface on one side of a polyester film, and dried in an oven at 100° C. for 5 minutes. rice field. After drying, the coated surface was covered with a 38 μm thick release liner R2 (trade name “MRF #38”, manufactured by Mitsubishi Chemical Corporation) whose one side is a release surface of a polyester film, and was heat cured. A 50 μm-thick pressure-sensitive adhesive sheet containing a curable resin (corresponding to polymer (a1)) was prepared.

Example 9
To 100 parts by mass of the same acrylic polymer as prepared in Example 6 (dissolved in ethyl acetate), a cross-linking agent (1,3-bis(4,5-dihydro-2-oxazolyl)benzene, hereinafter “1,3- PBO", manufactured by TCI) 4 parts by weight, a curing agent (4,4'-dithiodibutyric acid, corresponding to compound (a2)) 5 parts by weight, and a radical scavenger (trade name "Omnirad TPO H", IGM (manufactured by Resins B.V.) was added to each, and mixed and stirred to prepare a mixed solution. This mixed solution was applied to a 38 μm thick release liner R1 (trade name “MRF#38”, manufactured by Mitsubishi Chemical Corporation) having a release surface on one side of a polyester film, and dried in an oven at 100° C. for 5 minutes. rice field. After drying, the coated surface was covered with a 38 μm thick release liner R2 (trade name “MRF #38”, manufactured by Mitsubishi Chemical Corporation) whose one side is a release surface of a polyester film, and was heat cured. A 50 μm-thick pressure-sensitive adhesive sheet containing a curable resin (corresponding to polymer (a1)) was prepared.

Example 10
Thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 1 except that 4,4'-dithiodiphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the curing agent. An attachment sheet was produced.

Comparative example 4
To 100 parts by mass of the acrylic polymer prepared in Example 6 (dissolved in ethyl acetate), 0.1 part by mass of a cross-linking agent (trade name "Tetrad C", manufactured by Mitsubishi Gas Chemical Company, Inc.) was added, mixed and stirred. A mixed solution was prepared. A pressure-sensitive adhesive sheet was produced in the same manner as in Example 6, except that this mixed solution was used.

Comparative example 5
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 6, except that no radical scavenger was used.

Comparative example 6
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 7, except that no radical scavenger was used.

Comparative example 7
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 8, except that no radical scavenger was used.

Comparative example 8
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 9, except that no radical scavenger was used.

Comparative example 9
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 10, except that no radical scavenger was used.

Comparative example 10
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (a1)) was prepared in the same manner as in Example 9, except that no curing agent was used.

(UV irradiation)
For the adhesive sheets obtained in Examples and Comparative Examples, a release liner was further attached to the exposed adhesive surface, and a UV-LED irradiation device manufactured by Quark Technology Co., Ltd. (model number "QEL-350-RU6W-CW -MY”), a UV-LED lamp with a wavelength of 365 nm was used as a light source, and ultraviolet irradiation was performed with an integrated irradiation light amount of 8000 mJ/cm ² in the wavelength range of 320 to 390 nm.

<Evaluation>
The adhesive sheets obtained in Examples and Comparative Examples were evaluated as follows. The following evaluations (1) to (4) were performed before and after UV irradiation. The results are shown in the table.

(1) Tensile test Examples 1 to 5 and Comparative Examples 1 to 3
A 10 mm×30 mm piece was cut from the 50 μm-thick pressure-sensitive adhesive sheet, and a strip-shaped sample with a height of 30 mm was produced in a state in which the release liners on both sides were removed. The upper and lower 10 mm portions were fixed with a chuck jig of a tensile compression tester (trade name “Autograph AGS-50NX” manufactured by Shimadzu Corporation), and a tensile test was performed under the conditions of a distance between chucks of 10 mm and a tensile speed of 300 mm/min. rice field. The amount of strain at break was defined as elongation at break (%), and the maximum stress at break was defined as stress at break (Pa).

Examples 6-10 and Comparative Examples 4-10
A 60 mm×30 mm piece was cut from a 50 μm-thick pressure-sensitive adhesive sheet, removed from both sides of the release liner, and rolled up in the long side direction to prepare a cylindrical sample with a height of 30 mm. The upper and lower 10 mm portions were fixed with a chuck jig of a tensile compression tester (trade 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 pulling speed of 300 mm/min. rice field. The amount of strain at break was defined as elongation at break (%), and the maximum stress at break was defined as stress at break (Pa).

(2) Young's modulus E
From the spectrum obtained in the evaluation of the elastic modulus, it was calculated from the amount of change in stress σ with respect to strain ε in the elastic deformation region (E=Δσ/Δε).

(3) Breaking Point Stress or Stress Peak Strength Regarding the spectrum obtained in the above tensile test, when a convex peak value was obtained, that value was taken as the stress peak strength. However, when the pressure-sensitive adhesive sheet was broken without obtaining an upwardly convex peak, the breaking point stress was adopted.

(4) Strain stress For the spectrum obtained in the above tensile test, the stress at each strain (%) was taken as the strain stress.

Variations of the invention according to the present disclosure are described below.
[Appendix 1]
A pressure-sensitive adhesive and/or adhesive containing the following components (a) and (b).
Component (a): a polymer having a reversible degradable bond in its molecule that can be cleaved by an external stimulus and then rebonded, and/or a compound capable of introducing the reversible degradable bond into the polymer Component (b): the above Compound that suppresses recombination [Appendix 2]
The pressure-sensitive adhesive and/or adhesive according to appendix 1, wherein the reversible degradable bond is a disulfide bond.
[Appendix 3]
3. The pressure-sensitive adhesive and/or adhesive according to

appendix

1 or 2, wherein the compound that suppresses recombination is a radical scavenger.
[Appendix 4]
4. The pressure-sensitive adhesive and/or adhesive according to any one of Appendices 1 to 3, wherein the polymer is a thermoplastic resin and/or a thermosetting resin.
[Appendix 5]
5. The pressure-sensitive adhesive and/or adhesive according to any one of Appendices 1 to 4, wherein the polymer is a polymer having a network structure formed by bonding or entanglement between molecules.
[Appendix 6] The adhesive and/or adhesive according to any one of Appendices 1 to 5, which is used for optical applications.

1 PSA layer or adhesive layer 2 Release liner 10 PSA sheet or adhesive sheet with release liner

Claims

A pressure-sensitive adhesive and/or adhesive containing the following components (a) and (b).
Component (a): a polymer having a reversible degradable bond in its molecule that can be cleaved by an external stimulus and then rebonded, and/or a compound capable of introducing the reversible degradable bond into the polymer Component (b): the above Compounds that inhibit recombination
The adhesive and/or adhesive according to claim 1, wherein the reversible degradable bond is a disulfide bond.
The pressure-sensitive adhesive and/or adhesive according to claim 1 or 2, wherein the compound that suppresses recombination is a radical scavenger.
The pressure-sensitive adhesive and/or adhesive according to claim 1 or 2, wherein the polymer is a thermoplastic resin and/or a thermosetting resin.
The pressure-sensitive adhesive and/or adhesive according to claim 1 or 2, wherein the polymer is a polymer in which a network structure is formed by bonding or entanglement between molecules.
3. The pressure-sensitive adhesive and/or adhesive according to claim 1 or 2, which is used for optical applications.