WO2023100864A1

WO2023100864A1 - Adhesive layer and/or bonding agent layer

Info

Publication number: WO2023100864A1
Application number: PCT/JP2022/043961
Authority: WO
Inventors: 駿飛永; 虎太朗雨宮; 大輔水野; 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: TW202335854A; KR20240116774A

Abstract

The present invention provides an adhesive layer and/or a bonding agent layer, which exhibits excellent handling properties before adhesion or bonding to a member, while exhibiting excellent flexibility after adhesion or bonding to the member.　The present invention provides an adhesive layer and/or a bonding agent layer, which is reduced in the stress by means of external stimuli. It is preferable that the stress does not increase once reduced. It is preferable that the ratio (S1(100)/S2(100)) of the stress (S1(100)) at 100% strain before application of external stimuli to the stress (S2(100)) at 100% strain after application of external stimuli is less than 0.95.

Description

Adhesive layer and/or adhesive layer

The present invention relates to a pressure-sensitive adhesive layer and/or an adhesive layer, more specifically to a pressure-sensitive adhesive layer capable of exhibiting stickiness and/or an adhesive layer capable of exhibiting adhesiveness.

Among optical devices such as displays, thin and flexible displays typified by OLED are constructed by laminating a plurality of optical films and thin layer devices. A device such as a pressure-sensitive sensor that requires flexibility is constructed by laminating a pressure-sensitive member and a substrate (Patent Document 1). Liquid curable resins, pressure-sensitive adhesives, and adhesives are selected as interlayer fillers in these laminates. An adhesive (adhesive, etc.) is 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 paste oozing out due to its own weight during storage, and the paste being chipped due to vibration or contact during transportation.

For this reason, during manufacturing, processing, storage, transportation, etc., the adhesive layer or adhesive layer has excellent handling properties before sticking or bonding to the member, and excellent flexibility during use, that is, after sticking or bonding to the member. It has been demanded.

The present invention is intended to solve such problems, and an object of the present invention is to provide a pressure-sensitive adhesive layer that has excellent handleability before adhesion or adhesion to a member and excellent flexibility after adhesion or adhesion to a member. and/or to provide an adhesive layer.

In order to solve the above problems, the present inventors made diligent efforts. As a result, the pressure-sensitive adhesive layer and the adhesive layer that reduce stress due to an external stimulus are excellent in handleability before sticking or bonding to a member, It was found that the flexibility is excellent after sticking or adhering to a member. The present invention has been completed based on these findings.

That is, the present invention provides a pressure-sensitive adhesive layer and/or an adhesive layer whose stress is reduced by an external stimulus. Since the pressure-sensitive adhesive layer or adhesive layer has the property that stress is reduced by an external stimulus, the stress can be made relatively high before applying an external stimulus, and the pressure-sensitive adhesive layer or adhesive layer before use, that is, the pressure-sensitive adhesive layer Before sticking or adhering the layer or the adhesive layer to the member, it is difficult for the glue to ooze out or to be glued off, and the handleability can be excellent. On the other hand, after the application of an external stimulus, the stress can be reduced compared to before the application, and when the adhesive layer or adhesive layer is used, that is, when the adhesive layer or adhesive layer is adhered or adhered to the member, it is flexible. It can be said that it is excellent in nature.

It is preferable that the stress does not increase after the reduction. Such a pressure-sensitive adhesive layer or the like maintains flexibility without an increase in stress when the pressure-sensitive adhesive layer or the like is adhered or adhered to a member.

The ratio [S2 (100) / S1 (100)] of the 100% strain stress (S1 (100)) before the application of the external stimulus and the 100% strain stress (S2 (100)) after the application of the external stimulus is less than 0.95 is preferred. 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 100% strain stress (S2(100)) after applying an external stimulus is preferably 10 MPa or less. Such a pressure-sensitive adhesive layer or the like is even more excellent in flexibility after application of an external stimulus.

The adhesive layer and the like are preferably used for optical applications.

The pressure-sensitive adhesive layer and/or adhesive layer of the present invention has excellent handleability before sticking or bonding to a member, and excellent flexibility after sticking or bonding to a member.

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.

[Adhesive layer, adhesive layer]
As used herein, the term "adhesive" refers to the property that two surfaces adhere to each other and can be peeled off if necessary, based on the cohesive force based on the chemical structure of the composition, when external pressure is applied (e.g., microscopic pressure). Say. 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 bonded. Moreover, in this specification, the "adhesive layer" is a laminar adhesive layer that does not have fluidity, and the "adhesive layer" is a laminar adhesive layer that does not have fluidity.

The pressure-sensitive adhesive layer and/or adhesive layer of the present invention has the property of reducing stress due to external stimulation. The stress is preferably the stress (strain stress) when the material is pulled at an arbitrary magnification, which is measured, for example, with 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.

FIG. 1 is a schematic cross-sectional view of one embodiment of the pressure-sensitive adhesive layer, etc. of the present invention. 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.

The pressure-sensitive adhesive layer, etc. of the present invention has a ratio [ S2(100)/S1(100)] is preferably less than 0.95 (for example, 0.1 or more and less than 0.95), more preferably 0.9 or less, still 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 0.01 MPa or more (for example, 0.01 to 10 MPa), more preferably It is 0.03 MPa or more (eg, 0.03 to 6 MPa), more preferably 0.05 MPa or more (eg, 0.05 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, 0.01 to 10 MPa), more preferably 6 MPa or less. (eg, 0.02 to 6 MPa), more preferably 3 MPa or less (eg, 0.03 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 pressure-sensitive 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 0.03 MPa or more (eg, 0.03 to 10 MPa), more preferably It is 0.04 MPa or more (eg, 0.04 to 4 MPa), more preferably 0.06 MPa or more (eg, 0.06 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, 0.04 to 2 MPa). Such a pressure-sensitive adhesive layer has even better flexibility after being applied with 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 0.03 MPa or more (eg, 0.03 to 10 MPa), more preferably It is 0.05 MPa or more (eg, 0.05 to 4 MPa), more preferably 0.07 MPa or more (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 of the present invention preferably has a stress (300% strain stress) (S2(300)) of 10 MPa or less (eg, 0.01 to 10 MPa) after application of an external stimulus, more preferably 4 MPa or less. (eg, 0.03 to 4 MPa), more preferably 2 MPa or less (eg, 0.04 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 ratio [S2 ( 500)/S1(500)] is preferably less than 0.950 (for example, 0.1 or more and less than 0.950), more preferably 0.8 or less, still more preferably 0.7 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 and low 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, 0.01 to 10 MPa) after application of an external stimulus, more preferably 4 MPa or less. (eg, 0.03 to 4 MPa), more preferably 2 MPa or less (eg, 0.04 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 particular, the pressure-sensitive adhesive layer or the like of the present invention has a reduced strain stress at a tensile ratio of 100%, and the ratio [S2(100)/S1(100)] is less than 0.95, or The 100% strain stress before application is preferably 0.03 to 0.4 MPa.

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) in a strain curve (stress at break if broken) of 0.07 MPa or more, more preferably, before applying an external stimulus. It is 0.1 MPa or more, more preferably 0.2 MPa or more. When the stress peak strength is 0.07 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 0.01 to 1.0 MPa after application of an external stimulus. More preferably 0.03 to 0.8 MPa, still more preferably 0.04 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.

As described above, the pressure-sensitive adhesive layer and the like of the present invention have the property of reducing stress due to external stimuli. Examples of the pressure-sensitive adhesive layer or the like having such properties include a pressure-sensitive adhesive layer or the like containing a polymer having a degradable bond in the molecule that is cleaved by an external stimulus. The above polymer may contain only one type, or may contain two or more types. In this specification, a polymer having a degradable bond that can be cleaved by an external stimulus in its molecule may be referred to as "polymer (A)". The degradable bond may be of only one type, or may be of two or more types.

Degradable bonds in the polymer (A) include bonds that can be cleaved by an external stimulus and then recombined (reversible degradable bonds) and bonds that are cleaved by an external stimulus and then not recombined (irreversible bonds). degradable bond). When the degradable bond possessed by the polymer (A) is a reversible bond, the pressure-sensitive adhesive layer or the like of the present invention further contains a compound that suppresses recombination. In the present specification, the polymer (A) having the reversible degradable bond in the molecule is referred to as "polymer (A1)", the polymer having the irreversible degradable bond in the molecule is referred to as "polymer (A2)", A compound that suppresses recombination is sometimes referred to as a "recombination-suppressing compound (B)".

The external stimulus is appropriately selected according to the stress reduction means, and includes active energy ray irradiation, heat, and the like. In particular, when the polymer (A) is a thermosetting resin or an active energy ray-curable resin, the polymer ( It is preferably an external stimulus that is different from the type of curability when A) has curability. Specifically, the external stimulus is preferably active energy ray irradiation when the polymer (A) is a thermosetting resin, and preferably heat when the polymer (A) 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.

As the reversible degradable bond in the polymer (A1), a known or commonly used bond can be applied, preferably a bond that is cleaved as a radical, particularly preferably a disulfide bond (-SS-).

As the irreversibly degradable bond in the polymer (A2), a known or commonly used bond can be applied, preferably a bond containing a nitrobenzyl group. In this case, it is easy to introduce an irreversible degradable bond into the polymer. The bond containing the nitrobenzyl group is preferably an ester bond formed by nitrobenzyl alcohol (preferably 2-nitrobenzyl alcohol) and a carboxylic acid having a polymerizable functional group.

Examples of the polymer (A) include thermoplastic resins, thermosetting resins, and active energy ray-curable resins. 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.

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.

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 the pressure-sensitive adhesive layer and the like.

There are various types of acrylic resin designs depending on the purpose. Accordingly, it is preferable to appropriately select the monomer species, copolymerization composition ratio, molecular weight, molecular weight distribution, cross-linking agent, compounding composition ratio, and the like.

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 content ratio is preferably 30% by mass or less, more 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 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.

In the pressure-sensitive adhesive layer, etc. of the present invention, the polymer (A) preferably forms 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 (A) is preferably a polymer in which a network structure is formed by bonding or entanglement between molecules. A pressure-sensitive adhesive layer or the like having such a structure forms a network structure through polymer-to-polymer bonding or polymer-to-polymer entanglement, and can have an appropriate degree of hardness. , the polymer structure is shredded and the flexibility is improved.

"Molecules are entangled with each other" refers to the 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 a cross-linking reaction with each other. are preferably intertwined to form a structure. Such a configuration is suitable for an adhesive layer or the like that is relatively soft before application of an external stimulus because no covalent bond is involved.

The state in which the molecular chains form a long molecule 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. In such a structure, since the molecular chains are covalently bonded to each other, a relatively hard adhesive layer can be formed. Suitable for adhesive layers with different properties.

The polymer (A1) is preferably a thermosetting resin. The polymer (A1), which is a thermosetting resin, may be a resin in which a thermosetting resin and a thermoplastic resin are entangled to form a network structure. Epoxy resin is preferable as the thermosetting resin. When the polymer (A1) contains an epoxy-based resin, the epoxy-based resin is a resin containing at least an epoxy-based monomer and a compound (a1) described later as a monomer component constituting the resin, and/or a compound (a1) is It is preferable to use a resin in which epoxy-based resins are cross-linked by acting as a cross-linking agent. An acrylic resin is preferable as the thermoplastic resin. In this specification, the above-mentioned "crosslinking agent" refers to a compound capable of forming crosslinks of a resin, and is sometimes referred to as a "curing agent".

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

When the adhesive layer or the like of the present invention contains a thermosetting resin as the polymer (A1), the content of the thermosetting resin is not particularly limited. From the viewpoint of imparting hardness, it is preferably 3 to 95% by mass, more preferably 5 to 90% by mass, and still more preferably 6 to 85% by mass with respect to 100% by mass of the total amount of the adhesive layer of the present invention. is. When the adhesive layer 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. be. When the pressure-sensitive adhesive layer 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, and still more preferably 6 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 pressure-sensitive adhesive layer or the like of the present invention contains a thermoplastic resin, the content ratio of the thermoplastic resin is not particularly limited, but the pressure-sensitive adhesive layer or the like is provided with appropriate initial hardness and hardness after external stimulation. Therefore, it is preferably 50% by mass or more, more preferably 70% by mass or more, based on 100% by mass of the total amount of the pressure-sensitive adhesive layer and the like of the present invention. 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.

When the adhesive layer or the like of the present invention contains a thermoplastic resin as the polymer (A1), the content of the thermoplastic resin is 20 to 97% by mass with respect to 100% by mass of the total amount of the adhesive layer or the like of the present invention. is preferred, more preferably 50 to 95% by mass, and still more preferably 70 to 93% by mass. When the adhesive layer 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. , 0% by mass.

When the pressure-sensitive adhesive layer or the like of the present invention contains a thermoplastic resin as the polymer (A2), the content of the thermoplastic resin is 50% by mass or more with respect to 100% by mass of the total amount of the pressure-sensitive adhesive layer or the like of the present invention. It is preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

The pressure-sensitive adhesive layer, etc. of the present invention preferably has a shear storage modulus (G') that is reduced by an external stimulus (especially active energy ray irradiation). Such a pressure-sensitive adhesive layer or the like is improved in flexibility by an external stimulus. Also, it is preferable that the shear storage modulus (G') does not increase after the decrease.

The pressure-sensitive adhesive layer or the like of the present invention preferably has a shear storage modulus (G') at 25° C. before application of an external stimulus of 1.0×10 ³ to 1.0×10 ⁸ Pa, more preferably 1.0×10 ⁴ to 1.0×10 ⁷ Pa, more preferably 1.0×10 ⁴ to 1.0×10 ⁶ Pa, particularly preferably 2.0×10 ⁴ to 1.0×10 ⁵ Pa is. The pressure-sensitive adhesive layer and the like having the above-mentioned shear storage elastic modulus have appropriate hardness before application of an external stimulus, and are excellent in handleability.

The pressure-sensitive adhesive layer, etc. of the present invention preferably has a shear storage modulus (G') at 50° C. before application of an external stimulus of 1.0×10 ³ to 5.0×10 ⁷ Pa, more preferably 7.0×10 ³ to 1.0×10 ⁶ Pa, more preferably 1.0×10 ⁴ to 1.0×10 ⁵ Pa. The pressure-sensitive adhesive layer or the like having the above-mentioned shear storage modulus has appropriate hardness before application of an external stimulus and is excellent in handleability even when the temperature is slightly increased due to the environment.

The pressure-sensitive adhesive layer, etc. of the present invention preferably has a shear storage modulus (G') at 85° C. before application of an external stimulus of 1.0×10 ² to 1.0×10 ⁶ Pa, more preferably 1.0×10 ³ to 1.0×10 ⁵ Pa, more preferably 5.0×10 ³ to 1.0×10 ⁵ Pa. The pressure-sensitive adhesive layer or the like having the above-mentioned shear storage modulus has appropriate hardness before application of an external stimulus even when applied in a high-temperature environment, for example, and is excellent in handleability.

The pressure-sensitive adhesive layer, etc. of the present invention preferably has a shear storage modulus (G') at 25° C. after application of an external stimulus of 1.0×10 ² to 5.0×10 ⁶ Pa, more preferably 1.0×10 ³ to 5.0×10 ⁵ Pa, more preferably 3.0×10 ³ to 1.0×10 ⁵ Pa, particularly preferably 5.0×10 ³ to 5.0×10 ⁴ Pa is. When the shear storage elastic modulus is within the above range, the pressure-sensitive adhesive layer or the like of the present invention is more 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, etc. of the present invention preferably has a shear storage modulus (G') at 50° C. after application of an external stimulus of 1.0×10 ² to 1.0×10 ⁶ Pa, more preferably 5.0×10 ² to 3.0×10 ⁵ Pa, more preferably 1.0×10 ³ to 1.0×10 ⁵ Pa, particularly preferably 2.0×10 ³ to 8.0×10 ⁴ Pa is. When the shear storage elastic modulus is within the above range, after application of an external stimulus, for example, when the temperature is slightly increased due to the environment, the flexibility, step conformability, adhesion, etc. are superior.

The pressure-sensitive adhesive layer, etc. of the present invention preferably has a shear storage modulus (G') at 85° C. after application of an external stimulus of 1.0×10 ² to 8.0×10 ⁵ Pa, more preferably 3.0×10 ² to 1.0×10 ⁵ Pa, more preferably 5.0×10 ² to 1.0×10 ⁵ Pa, particularly preferably 1.0×10 ² to 7.0×10 ⁴ Pa is. When the shear storage elastic modulus is within the above range, after application of an external stimulus, for example, when subjected to a high-temperature environment, the film is more excellent in flexibility, step followability, adhesion, and the like.

The pressure-sensitive adhesive layer, etc. of the present invention has a ratio of the shear storage modulus (G') at 25°C before applying an external stimulus to the shear storage modulus (G') at 25°C after applying an external stimulus [after applying an external stimulus / before application of external stimulus] is preferably less than 0.95 (eg, 0.01 or more and less than 0.95), more preferably 0.8 or less (eg, 0.05 to 0.8), still more preferably 0.7 or less (eg 0.1 to 0.7), particularly preferably 0.6 or less (eg 0.2 to 0.6). In this case, there is a tendency that the flexibility, step followability, and adhesion of the pressure-sensitive adhesive layer, etc. at around room temperature before and after the application of the external stimulus change more greatly.

The pressure-sensitive adhesive layer, etc. of the present invention has a ratio of the shear storage modulus (G') at 50 ° C. before applying an external stimulus to the shear storage modulus (G') at 50 ° C. after applying an external stimulus [after applying an external stimulus / before application of external stimulus] is preferably less than 0.95 (eg, 0.01 or more and less than 0.95), more preferably 0.8 or less (eg, 0.05 to 0.8), still more preferably 0.7 or less (eg 0.1 to 0.7), particularly preferably 0.6 or less (eg 0.2 to 0.6). In this case, there is a tendency that the flexibility, step followability, and adhesiveness of the pressure-sensitive adhesive layer, etc. at around 50° C. change more significantly before and after applying an external stimulus.

The pressure-sensitive adhesive layer, etc. of the present invention has a ratio of the shear storage modulus (G') at 85°C before applying an external stimulus to the shear storage modulus (G') at 85°C after applying an external stimulus [after applying an external stimulus / before application of external stimulus] is preferably less than 0.95 (eg, 0.01 or more and less than 0.95), more preferably 0.8 or less (eg, 0.05 to 0.8), still more preferably 0.7 or less (eg 0.1 to 0.7), particularly preferably 0.6 or less (eg 0.2 to 0.6). In this case, there is a tendency that the flexibility, step followability, and adhesion of the pressure-sensitive adhesive layer, etc. under high-temperature environments change more significantly before and after the application of the external stimulus.

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

The hardness is preferably Young's modulus, which is measured, for example, with a tensile compression tester. That is, the pressure-sensitive adhesive layer of the present invention has a 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, 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 or the like having the above Young's modulus has an 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 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 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.

Although the thickness of the pressure-sensitive adhesive layer of the present invention is not particularly limited, it is, for example, about 5 to 250 μm, more preferably 7 to 200 μm, even more preferably 10 to 100 μm, particularly preferably 10 to 50 μm.

The polymer (A) can be obtained using a compound (sometimes referred to as "compound (a)") capable of introducing the degradable bond into the polymer. The compound (a) includes, for example, a monomer component, an oligomer component, a cross-linking agent, and the like having the decomposable bond. That is, the polymer (A) may contain a structural unit derived from a monomer component and/or an oligomer component having a degradable bond, and may contain a structural portion derived from the cross-linking agent. When the compound (a) is a monomer component or an oligomer component, the polymer (A) having the decomposable bond is obtained by polymerizing the above monomer component or oligomer component or copolymerizing it with another monomer component. Only one kind of the compound (a) may be used, or two or more kinds thereof may be used.

When the compound (a) is a monomer component or an oligomer component, the decomposable bond may be present in the portion constituting the side chain in the polymer (A), or may be present in the portion constituting the main chain. good. When the side chain is present in the portion constituting the side chain, it is preferable from the viewpoint that stress is less likely to be applied 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 degradable bond is cleaved, the flexibility is further improved, and a large change in physical properties can be exhibited.

The compound (a) preferably has a functional group (functional group (L1)) other than the decomposable bond. When having two or more functional groups (L1), the compound (a) functions as a cross-linking agent. Moreover, when the functional group (L1) is a polymerizable functional group, the compound (a) functions as a monomer component or an oligomer component.

Examples of the polymerizable functional groups include cationic polymerizable groups, anionic polymerizable groups, and radically polymerizable groups. Among them, a radically polymerizable group is preferred. Examples of the radically polymerizable group include radically polymerizable carbon-carbon double bonds such as (meth)acryloyl group and vinyl group.

As the functional group (L1) other than the polymerizable functional group, a thiol group, a carboxyl group, a hydroxy group, an amino group, an epoxy group, and isocyanate are used from the viewpoint of securing a certain degree of flexibility of the pressure-sensitive adhesive layer with an appropriate crosslinking density. and the like.

The number of functional groups of the compound (a) increases the molecular weight of the polymer (A) after introduction into the polymer (A), giving the polymer a certain degree of hardness before applying an external stimulus, while reducing the molecular weight of the polymer after cleavage to make it flexible. From the viewpoint of exhibiting properties, the number is preferably two or more. On the other hand, if the number of functional groups increases, it will crosslink with a large number of polymers, making it difficult to obtain the effect of cleaving the degradable bond. , the number of functional groups is preferably 4 or less, more preferably 3 or less.

Examples of the compound (a) having a reversible degradable bond (sometimes referred to as "compound (a1)") 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, dithiodiethanol and the like. Among these, 4,4'-dithiodibutyric acid, 4,4'-dithiodiphenol, and 4,4'-dithiodianiline are particularly preferred from the viewpoint of better solubility.

The compound (a1) preferably does not have an aromatic ring from the viewpoint of suppressing coloration of the pressure-sensitive adhesive layer or the like over time. On the other hand, as the compound (a1), one having an aromatic ring may be preferable when adjusting other properties such as refractive index.

As the compound (a) having an irreversible bond (sometimes referred to as "compound (a2)"), a monomer in which a nitrobenzyl group and a polymerizable functional group are bonded via a linking group (nitrobenzyl monomer) are preferred. Although the linking group is not particularly limited, an ester bond is preferable. A nitrobenzyl-based monomer in which the linking group is an ester bond is sometimes referred to as a "nitrobenzyl ester-based monomer." Examples of the nitrobenzyl ester-based monomers include, for example, an esterified product of a compound having a nitrobenzyl alcohol skeleton and a compound having a polymerizable functional group and a carboxy group, or a compound having a nitrophenylacetic acid skeleton and a polymerizable functional group and a hydroxy group. Examples include esterified products with compounds having

Examples of compounds having a nitrobenzyl alcohol skeleton include 2-nitrobenzyl alcohol and 2-nitro-1,3-bis(hydroxymethyl)benzene. Examples of compounds having a nitrophenylacetic acid skeleton include 2-nitroisophthalic acid. As the nitrobenzyl ester-based monomer, 2-nitro-1,3-bis((meth)acryloyloxymethylene)benzene is preferred.

The nitrobenzyl ester-based monomer is a carboxylic acid having a polymerizable functional group (e.g. (meth) acrylic acid) and a compound having a nitrobenzyl alcohol skeleton to esterify, a compound having a polymerizable functional group and a hydroxy group and a compound having a nitrophenylacetic acid skeleton can be esterified.

The content of the polymer (A) in the adhesive layer or the like of the present invention is preferably 50% by mass or more, more preferably 60% by mass or more, and further It is preferably 65% by mass or more, particularly preferably 70% by mass or more. In addition, the amount of the polymer (A) includes the amount of the polymer (A), its raw material monomer, the cross-linking agent, and the structural part derived from the cross-linking agent.

When the pressure-sensitive adhesive layer or the like of the present invention contains the polymer (A1), the content of the polymer (A1) in the pressure-sensitive adhesive layer or the like of the present invention is It is preferably 30 to 99% by mass, more preferably 40 to 97% by mass, even more preferably 50 to 95% by mass, and particularly preferably 70 to 95% by mass. 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 blending the cross-linking agent and the recombination-inhibiting compound (B). 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.

When the pressure-sensitive adhesive layer or the like of the present invention contains the polymer (A2), the content of the polymer (A2) in the pressure-sensitive adhesive layer or the like of the present invention is It is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more. The amount of the polymer (A2) includes the amount of the polymer (A2), its raw material monomer, the cross-linking agent, and the structural part derived from the cross-linking agent.

The content ratio of one or more selected from the group consisting of structural units derived from the compound (a1) and structural units derived from the compound (a1) in the polymer (A1) is cleaved and shredded after application of an external stimulus. From the viewpoint of exhibiting sufficient flexibility, 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 with respect to 100% by mass of the total amount of the polymer (A1). % 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. In addition, in this specification, when two or more types of polymers are entangled, the entangled polymer is converted into one polymer.

When the pressure-sensitive adhesive layer or the like of the present invention contains the polymer (A1), the content of the cross-linking agent in the pressure-sensitive adhesive layer or the like of the present invention and/or the structural portion derived from the cross-linking agent is the total amount of the polymer (A1) of 100 mass. %, preferably 0.5 to 40% by mass, more preferably 1 to 35% by mass, still more preferably 1.5 to 30% by mass. In addition, when the compound (a1) is a cross-linking agent, the content includes the amount of the compound (a1) and the structural portion derived from the compound (a1).

The content ratio of one or more selected from the group consisting of structural units derived from the compound (a2) and structural units derived from the compound (a2) in the polymer (A2) is cleaved and shredded after application of an external stimulus. From the viewpoint of exhibiting sufficient flexibility, the polymer (A2) is preferably 0.1 to 15% by mass, more preferably 0.2 to 10% by mass, and still more preferably 0 .5 to 5% by weight, particularly preferably 1 to 3% by weight.

When the pressure-sensitive adhesive layer or the like of the present invention contains the polymer (A2), the content of the cross-linking agent in the pressure-sensitive adhesive layer or the like of the present invention and/or the structural portion derived from the cross-linking agent is the total amount of the polymer (A2) of 100 mass. %, preferably 0.1 to 15% by mass, more preferably 0.2 to 10% by mass, still more preferably 0.5 to 5% by mass, and particularly preferably 1 to 3% 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).

The recombination-inhibiting compound (B) is a compound capable of suppressing recombination of cleavage of the polymer (A1) caused by an external stimulus, and is not particularly limited, but when the cleavage of the polymer (A1) generates a radical , a compound having radical scavenging ability (radical scavenger) is preferred. Examples of the radical scavenger include photoradical polymerization initiators, spin scavengers, antioxidants, polymerization inhibitors, and hydrogen donors.

Examples of the photoradical polymerization initiator include, but are not limited to, benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, Photoactive oxime photoinitiators, benzoin photoinitiators, benzyl photoinitiators, benzophenone photoinitiators, ketal photoinitiators, thioxanthone photoinitiators, acylphosphine oxide photoinitiators initiators, and the like.

Examples of the benzoin ether-based photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, anisole methyl ether and the like. Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 4-phenoxydichloroacetophenone, 4-(t-butyl ) and dichloroacetophenone. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one, and the like. be done. Examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. Examples of the benzoin-based photopolymerization initiator include benzoin. Examples of the benzyl-based photopolymerization initiator include benzyl. Examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. Examples of the ketal photopolymerization initiator include benzyl dimethyl ketal. Examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone. Examples of the acylphosphine oxide-based photopolymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxy phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and the like.

From the viewpoint of exhibiting an appropriate recombination-inhibiting effect, the content of the recombination-inhibiting compound (B) is determined by 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, particularly preferably 100 parts by mass with respect to 100 parts by mass in total of one or more selected from the group consisting of ~300 parts by mass.

The pressure-sensitive adhesive layer and the like of the present invention may contain other components other than the components described above, if necessary. Examples of the other components include resins other than the polymer (A), curing catalysts, cross-linking agents (including polyfunctional (meth)acrylates), cross-linking accelerators, polymerization initiators, tackifying resins (rosin derivatives, polyterpene resins , petroleum resin, oil-soluble phenol, etc.), oligomers, antioxidants, fillers (metal powder, organic fillers, inorganic fillers, etc.), coloring agents (pigments, dyes, etc.), antioxidants, plasticizers, softeners , Surfactant, Antistatic agent, Surface lubricant, Leveling agent, Light stabilizer, UV absorber, Sensitizer, Polymerization inhibitor, Granular material, Foil material, Flame retardant, Silane coupling agent, Ion trapping agent etc. 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 layer and the like and hardness after external stimulation, the total amount of the adhesive layer and the like of the present invention is 100% by mass. On the other hand, it is preferably 0.005 to 3% by mass, more preferably 0.01 to 1% by mass, still more preferably 0.05 to 1% by mass.

The above-mentioned cross-linking agent is not particularly limited as long as it cross-links the polymer. (Meth)acrylate and the like. 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 and the like.

<Adhesive composition, adhesive composition>
The adhesive layer of the present invention is formed from an adhesive composition. Also, the adhesive layer is formed from the adhesive composition. The pressure-sensitive adhesive composition and the like preferably contain at least a base polymer and/or a raw material monomer thereof. 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 polymer (A) and/or other polymers (ie polymers without degradable bonds). When the base polymer is the other polymer, the pressure-sensitive adhesive composition and the like further contain compound (a). Only one type of the base polymer may be used, or two or more types may be used.

When the base polymer is the other polymer, the pressure-sensitive adhesive composition or the like further contains compound (a). In this case, a monomer component (sometimes referred to as "monomer component (c)") having reactivity with the compound (a) may also be included. Compound (a) is reactive with the other polymer and/or monomer component (c). When the compound (a) is reactive with the other polymer, the other polymer reacts with the compound (a) 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 combine to form a network structure, and a pressure-sensitive adhesive layer or the like containing the polymer (A) is obtained. When the compound (a) and the monomer component (c) are included, the compound (a) and the monomer component (c) react with heat, active energy ray irradiation, or the like in the 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 (A) is obtained. Monomer component (c) may use only 1 type, and may use 2 or more types.

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

The above-mentioned pressure-sensitive adhesive composition mainly includes (i) a pressure-sensitive adhesive composition containing the polymer (A), (ii) a pressure-sensitive adhesive composition containing the polymer (A) and the other polymer, and (iii) the above Other polymers, compound (a), pressure-sensitive adhesive composition containing monomer component (c) as necessary, (iv) raw material monomer, compound (a), pressure-sensitive adhesive containing monomer component (c) as necessary composition and the like. When the polymer (A) is the polymer (A1), the pressure-sensitive adhesive compositions (i) to (iv) further contain the recombination inhibiting compound (B).

Therefore, polymer (A) may be a reaction product of the other polymer, compound (a), and monomer (c), and a reaction product of the other polymer and the other polymer and compound (a). It may be a polymer comprising (particularly entangled) the Moreover, when the base polymer is polymer (A), the pressure-sensitive adhesive layer and the like may contain unreacted compound (a) and/or unreacted monomer (c).

The adhesive composition and the like may contain other components other than the components described above. Examples of the other components include those exemplified and explained as other components that the pressure-sensitive adhesive layer of the present invention may contain, 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.

(Adhesive composition, etc. (M1))
The pressure-sensitive adhesive composition or the like (sometimes referred to as "pressure-sensitive adhesive composition or the like (M1)") forming the pressure-sensitive adhesive layer or the like of the present invention containing the polymer (A1) further contains the recombination inhibiting compound (B). include. The base polymer that may be contained in the pressure-sensitive adhesive composition (M1) is preferably the other polymer described above.

Examples of the base polymer 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 (a1) 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 (a1) 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 (a1) 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 (a1). 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. are 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 (a1) as a cross-linking agent. Thereby, the monomer (c) is crosslinked by the compound (a1) 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. , an isocyanate group, a (meth)acryloyl group, an amino group, an 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 groups containing 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.

When the base polymer is the other polymer, the content of the monomer component (c) in the pressure-sensitive adhesive composition (M1) is preferably 5 to 600 parts by mass with respect to 100 parts by mass of the total amount of the base polymer. , more preferably 7 to 500 parts by mass. When the other polymer is a thermosetting resin, the content is preferably 200 to 600 parts by mass, more preferably 300 to 500 parts by mass, and even more preferably 350 to 450 parts by mass. When the other polymer is a thermoplastic resin, the content is preferably 5 to 80 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 7 to 30 parts by mass.

When the base polymer is the polymer (A1), the content of the monomer component (c) in the adhesive composition (M1) 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 content of the other polymers in the adhesive composition (M1) is based on 100% by mass of the total amount of the adhesive composition (M1) (excluding components such as organic solvents that do not remain when forming the layer). is preferably 5 to 99% by mass, 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 the recombination-inhibiting compound (B) component.

The content of the cross-linking agent and/or the structural portion derived from the cross-linking agent in the pressure-sensitive adhesive composition (M1) is 0.00 parts per 100 parts by mass of the other polymer and/or monomer component (c). It is preferably 5 to 40 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 (a1) is a cross-linking agent, the content includes the amount of the compound (a1).

(Adhesive composition, etc. (M2))
The base polymer that can be included in the adhesive composition, etc. (sometimes referred to as "adhesive composition, etc. (M2)") that forms the adhesive layer, etc. of the present invention containing the polymer (A2) is, among others, the polymer (A2 ), more preferably the polymer (A2) and the above other polymers. Also, the polymer (A2) is preferably a curable resin. The curability of the curable resin is appropriately selected according to the type of the irreversibly decomposable bond, and when the irreversibly decomposable bond can be cleaved by active energy rays, it is preferably a thermosetting resin.

The polymer (A2), which is the curable resin, is preferably a resin (prepolymer) having a polymerizable functional group. When the polymer (A2) has a polymerizable functional group, when forming an adhesive layer or the like, polymerization of the polymerizable functional groups proceeds by heat or active energy ray irradiation after application of the adhesive composition or the like. , can form a network structure by entangling with other polymers. That is, the polymer (A2) is preferably a polymer capable of forming the above network structure.

Examples of the base polymer include the thermoplastic resin, the thermosetting resin, the active energy ray-curable resin, and the like. The polymer (A2) as the base polymer is preferably a curable resin, more preferably a thermosetting resin. Thermoplastic resins are preferable as the other polymers. 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. An adhesive composition or the like containing a curable resin can form a network structure by being cured, for example, by heating. In addition, the other polymer may be a curable resin, and in this case, the polymer (A2), which is also a curable resin, and the other polymer form a bond between the two resins by heat, active energy ray irradiation, or the like. It becomes possible to form a network structure.

As described above, the compound (a2) includes a monomer component, an oligomer component, a cross-linking agent, and the like having the irreversibly degradable bond. Among them, the monomer component (that is, the compound having the polymerizable functional group) is preferred, the nitrobenzyl-based monomer is more preferred, and the nitrobenzyl ester-based monomer is even more preferred.

The content of the polymer (A2) in the base polymer is preferably 10 to 90% by mass, more preferably 30 to 70% by mass, more preferably 40 to 90% by mass, relative to the total amount (100% by mass) of the base polymer. 60% by mass. When the content is 10% by mass or more, a sufficient amount of the irreversible degradable bond is cleaved by an external stimulus. When the content is 90% by mass or less, appropriate tackiness and/or adhesiveness can be maintained even after application of an external stimulus.

The content of the other polymer in the base polymer is preferably 10 to 90% by mass, more preferably 30 to 70% by mass, more preferably 40 to 90% by mass, relative to the total amount (100% by mass) of the base polymer. 60% by mass. When the above content is 10% by mass or more, appropriate tackiness and/or adhesiveness can be maintained even after application of an external stimulus. When the content is 90% by mass or less, the polymer (A2) can be sufficiently blended, whereby a sufficient amount of irreversible degradable bonds are cleaved by an external stimulus.

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

When the polymer (A2) is the above acrylic resin, the content of structural units derived from acrylic monomers in the polymer (A2) is 70 to 99.8 with respect to 100% by mass of the total amount of the polymer (A2). % by mass is preferable, more preferably 85 to 99.5% by mass, and still more preferably 90 to 99.2% by mass. When the pressure-sensitive adhesive composition or the like (M2) contains raw material monomers constituting the base polymer, the content of the acrylic monomer in all the monomer components constituting the polymer (A2) is preferably within the above range.

The content of structural units derived from the compound (a2) in the base polymer is 100% by mass in the total amount of the base polymer in order to exhibit sufficient flexibility by being cleaved and shredded after application of an external stimulus. is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, still more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more. Also, in order to make the crosslink density appropriate and to impart appropriate flexibility to the resin before applying an external stimulus, the amount 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 pressure-sensitive adhesive composition or the like (M2) contains raw material monomers constituting the base polymer, the content of the compound (a2) in all the monomer components constituting the base polymer is preferably within the above range.

When the base polymer is the acrylic resin, the content of structural units derived from acrylic monomers in the base polymer is preferably 85 to 99.9% by mass with respect to 100% by mass of the total amount of the base polymer. , more preferably 90 to 99.8% by mass, more preferably 95 to 99.5% by mass. When the pressure-sensitive adhesive composition or the like (M2) contains raw material monomers constituting the base polymer, the content of the acrylic monomer in all the monomer components constituting the base polymer is preferably within the above range.

The content of the base polymer in the adhesive composition (M2) is based on 100% by mass of the total amount of the adhesive composition (M2) (excluding components such as organic solvents that do not remain during layer formation). It is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

<Release liner>
The release liner protects the pressure-sensitive adhesive surface and/or adhesive surface with which the pressure-sensitive adhesive layer or the like of the present invention comes into contact until use, and is peeled off when the pressure-sensitive adhesive layer or the like 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 etc. are mentioned. Moreover, these crosslinked films are also mentioned. 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 the thickness of the release liner is not particularly limited, it is, for example, about 20 to 150 μm.

An embodiment of the method for manufacturing the pressure-sensitive adhesive layer, 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 composition or the like for forming the pressure-sensitive adhesive layer or the like 1 to the base material layer or the release-treated surface of the release liner 2 that has been subjected to the release treatment, the solvent is removed by heating, or It can be prepared by hardening the coating layer by heat curing or curing by irradiation with active energy rays. In addition, when performing active energy ray irradiation, it is performed after bonding a separate 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 (A), 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 (a), the raw material monomer is optionally removed by heating or active energy ray irradiation when solidifying the coating layer. is polymerized, the compound (a) forms a bond with the polymer of the raw material monomers and the above-mentioned other polymer to form the polymer (A), and at the same time the pressure-sensitive adhesive layer and the like are formed. After that, the pressure-sensitive adhesive layer and the like may be heated or irradiated with an active energy ray, or when the polymer (A) is a curable resin, a curing treatment may be performed. Thus, the pressure-sensitive adhesive sheet with a release liner or adhesive sheet 10 shown in FIG. 1 is obtained.

The use of the pressure-sensitive adhesive layer, etc. of the present invention is not particularly limited, and it can be used for any purpose. The pressure-sensitive adhesive layer and the like of the present invention can be used, for example, for optical applications, that is, applications for bonding to optical members. The pressure-sensitive adhesive layer or the like of the present invention is used, for example, in optical members such as electric and electronic devices, when various members or parts are attached (mounted) to predetermined portions (for example, housings and 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 pressure-sensitive adhesive layer, etc. of the present invention has excellent handleability before being adhered or adhered to members during manufacturing, processing, storage, transportation, etc., and is excellent in flexibility after being adhered or adhered to members. For this reason, it is possible to prevent the paste from overflowing, the paste from being cut out, and the process contamination caused by these when the punching blade cuts out, for example. 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. After sticking or adhering to a member, for example, when used by being attached to a member, it should be excellent in flexibility, so that it should be excellent in adhesion (adhesive force), adhesive strength, bendability, foldability, bending resistance, etc. can be In addition, since the pressure-sensitive adhesive layer or the like of the present invention can reduce stress by external stimuli, it is possible to vary the adhesive strength and adhesive strength.

[Adhesive sheet, Adhesive sheet]
A pressure-sensitive adhesive sheet and/or an 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. These plastic materials may be used alone or in combination of two or more.

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. Further, the numerical value of each monomer component constituting the prepolymer shown in Table 3 is in parts by mass.

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, epoxy curing 20 parts by mass of 4,4'-dithiodibutyric acid (manufactured by Tokyo Chemical Industry Co., Ltd., equivalent to compound (a1)) as an agent, a radical scavenger (trade name "Omnirad TPO H", manufactured by IGM Resins BV, Equivalent to recombination inhibiting compound (B)) 25 parts by mass, curing catalyst (trade name “ZC700”, manufactured by Matsumoto Fine Chemicals Co., Ltd.) 0.1 parts by mass, and 3 parts by mass of acetylacetone (AcAc), respectively, 500 parts by mass of methyl ethyl ketone and mixed with stirring 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 “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 mold 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 produced in the same manner as in Example 1, except that the trade name "jER828" (manufactured by Mitsubishi Chemical Corporation) was used as the epoxy monomer. .

Example 3
Adhesive 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 attachment sheet was produced.

Example 4
Adhesive containing thermosetting resin (corresponding to polymer (A1)) in the same manner as in Example 1 except that 4,4'-dithiodiphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the epoxy curing agent. An attachment sheet was produced.

Example 5
Adhesive containing thermosetting resin (corresponding to polymer (A1)) in the same manner as in Example 2 except that 4,4'-dithiodiphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the epoxy 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 2, 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 epoxy 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. Thus, a polymer solution containing an acrylic polymer was obtained. The acrylic polymer in this polymer solution had a weight average molecular weight (Mw) of 600,000.

(Formation of Adhesive Sheet)
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", New Japan Chemical Co., Ltd. (corresponding to monomer component (c)) 100 parts by mass, epoxy curing agent (4,4′-dithiodibutyric acid, corresponding to compound (a1)) 2 parts by mass, curing catalyst (trade name “ZC700”, Matsumoto Fine Chemical Co., Ltd.) company), 3 parts by mass of acetone, and 5 parts by mass of a radical scavenger (trade name "Omnirad TPO H", manufactured by IGM Resins B.V.) were added, mixed and stirred to form a mixed 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. bottom.

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, and the mixture was stirred and mixed. A 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 produced 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 produced in the same manner as in Example 7, except that no radical scavenger was used.

Preparation example 1
(Synthesis of nitrobenzyl ester-based monomer precursor)
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 2-nitroisophthalic acid. The solution was cooled to 2° C., 0.9 M (162 mmol) of borane tetrahydrofuran complex (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise thereto, the temperature was raised to room temperature, and the mixture was stirred for 48 hours. Thereafter, methanol was added dropwise, the solvent was distilled off under reduced pressure (50° C., 25 mmHg), the residue was diluted with ethyl acetate and extracted, and the organic phase was washed with 900 g of water a total of three times. 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 distilled off under reduced pressure (50° C., 25 mmHg) to obtain 41 g of a nitrobenzyl ester monomer precursor (pale yellow crystals).

Preparation example 2
(Synthesis of nitrobenzyl ester monomer)
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, and acetone was added. / 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC hydrochloride) (manufactured by Tokyo Chemical Industry Co., Ltd.) 84.9 g while maintaining an internal temperature of 5 ° C. or less under cooling in a mixed bath of ice (574 mmol) was added in portions and mixed and stirred to carry out the reaction. After completion of the reaction, the reaction solution was directly purified by silica gel chromatography (developing solvent: dichloromethane) twice. 0.004 g of hydroquinone monomethyl ether (MEHQ) is added to the fractionated liquid, and the solvent is distilled off under reduced pressure (30°C or less, 30 mmHg), then ice-cooled to precipitate, and dried under reduced pressure at 30°C to give a nitrobenzyl ester. 11.4 g of a monomer (2-nitro-1,3-bis(acryloyloxymethylene)benzene, pale yellow crystals) was obtained.

Preparation example 3
(Synthesis of acrylic polymer P1)
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 0.2 of AIBN as a polymerization initiator. A mixture containing parts by mass 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. As a result, a polymer solution containing the acrylic polymer P1 was obtained. The weight average molecular weight (Mw) of the acrylic polymer P1 in this polymer solution was 600,000.

Example 8
(Synthesis of acrylic polymer P2)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 95 parts by mass of butyl acrylate (BA) and the nitrobenzyl ester monomer prepared in Preparation Example 2 (corresponding to compound (a2)) 5 parts by mass, trade name "C12TCSS" (manufactured by Nippon Terpene Chemical Co., Ltd.) as a chain transfer agent 2.83 parts by mass, 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator 0.28 A mixture containing parts by mass and 301 parts by mass of ethyl acetate as a solvent was stirred at 60° C. for 6 hours under a nitrogen atmosphere to carry out a polymerization reaction. As a result, a polymer solution containing acrylic polymer P2 (corresponding to polymer (A2)), which is a prepolymer having acryloyl groups, was obtained.

(Synthesis of adhesive composition)
The polymer solution containing the acrylic polymer P1 prepared in Preparation Example 3 and the polymer solution containing the acrylic polymer P2 were mixed with 100 parts by mass of the acrylic polymer P2 per 100 parts by mass of the acrylic polymer P1. The mixture was mixed at the same ratio, stirred at 2000 rpm for 5 minutes, and further stirred and defoamed at 2200 rpm for 5 minutes to prepare a pressure-sensitive adhesive composition.

(Formation of Adhesive Sheet)
The pressure-sensitive adhesive composition was applied to the release-treated surface of a polyethylene terephthalate film (trade name: "MRF38", manufactured by Mitsubishi Chemical Corporation) with a silicone-based release agent, and the thickness of the pressure-sensitive adhesive layer after drying was was applied so as to have a thickness of 25 μm, allowed to stand at room temperature for 5 minutes, and then dried at 130° C. for 3 minutes. A pressure-sensitive adhesive sheet was obtained by sufficiently volatilizing and removing ethyl acetate contained as a solvent.

Comparative example 7
(Synthesis of acrylic polymer P3)
95 parts by mass of butyl acrylate (BA), 5 parts by mass of 1,6-hexanediol diacrylate, and a commercial product as a chain transfer agent were placed in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube. Name "C12TCSS" (manufactured by Nippon Terpene Chemical Co., Ltd.) 2.83 parts by mass, 2,2'-azobisisobutyronitrile (AIBN) 0.28 parts by mass as a polymerization initiator, and ethyl acetate 301 as a solvent A mixture containing parts by mass was stirred at 60° C. for 6 hours under a nitrogen atmosphere to carry out a polymerization reaction. As a result, a polymer solution containing acrylic polymer P3, which is a prepolymer having acryloyl groups, was obtained.

(Synthesis of adhesive composition)
The polymer solution containing the acrylic polymer P1 prepared in Preparation Example 3 and the polymer solution containing the acrylic polymer P3 were mixed with 100 parts by mass of the acrylic polymer P3 per 100 parts by mass of the acrylic polymer P1. The mixture was mixed at the same ratio, stirred at 2000 rpm for 5 minutes, and further stirred and defoamed at 2200 rpm for 5 minutes to prepare a pressure-sensitive adhesive composition.

(Formation of Adhesive Sheet)
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 8, except that the pressure-sensitive adhesive composition prepared above was used.

Comparative example 8
(Synthesis of acrylic polymer P4)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube, 100 parts by mass of butyl acrylate (BA) and the trade name "C12TCSS" (manufactured by Nippon Terpene Chemical Co., Ltd.) as a chain transfer agent. A mixture containing 2.83 parts by mass, 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 heated at 60°C for 6 hours. , and stirred under a nitrogen atmosphere to carry out a polymerization reaction. As a result, a polymer solution containing acrylic polymer P4, which is a prepolymer having acryloyl groups, was obtained.

(Synthesis of adhesive composition)
The polymer solution containing the acrylic polymer P1 prepared in Preparation Example 3 and the polymer solution containing the acrylic polymer P4 were mixed with 100 parts by mass of the acrylic polymer P4 per 100 parts by mass of the acrylic polymer P1. The mixture was mixed at the same ratio, stirred at 2000 rpm for 5 minutes, and further stirred and defoamed at 2200 rpm for 5 minutes to prepare a pressure-sensitive adhesive composition.

Example 9
(Preparation of acrylic polymer)
63 parts by weight of 2-ethylhexyl acrylate (2EHA), 15 parts by weight of N-vinylpyrrolidone (NVP), and methyl methacrylate (MMA) were placed in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube. ) 9 parts by mass, 13 parts by mass of hydroxyethyl acrylate (HEA), 0.2 parts by mass of 2,2′-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 122 parts by mass of ethyl acetate as a solvent The mixture containing parts was stirred at 60° C. for 7 hours under a nitrogen atmosphere. Thus, a polymer solution containing an acrylic polymer was obtained. The acrylic polymer in this polymer solution had a weight average molecular weight (Mw) of 600,000.

(Formation of Adhesive Sheet)
100 parts by mass of the acrylic polymer (dissolved in ethyl acetate), 4 parts by mass of a cross-linking agent (trade name "Takenate D110N", manufactured by Mitsui Chemicals, Inc.), a curing agent (4,4'-dithiodianiline, compound (a1) equivalent) 1 part by mass, 0.1 part by mass of a cross-linking catalyst (trade name “ZC700”, manufactured by Matsumoto Fine Chemical Co., Ltd.), 2 parts by mass of acetylacetone (AcAc), and a radical scavenger (trade name “Omnirad TPO H”, IGM Resins 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 “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.

Comparative example 9
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (A1)) was produced in the same manner as in Example 9, except that no radical scavenger was used.

Example 10
(Formation of Adhesive Sheet)
100 parts by mass of the acrylic polymer prepared in Example 6 (dissolved in ethyl acetate), 1,3-bis(4,5-dihydro-2-oxazolyl)benzene (manufactured by Tokyo Chemical Industry Co., Ltd.) as a cross-linking agent 4 parts by mass , a curing agent (4,4'-dithiodiphenol, corresponding to compound (a1)) 4 parts by mass, and a radical scavenger (trade name "Omnirad TPO H", manufactured by IGM Resins B.V.) 5 parts by mass. Each was added 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 “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 11
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 10, except that 4,4'-dithiodibutyric acid (corresponding to compound (a1)) was used as the curing agent.

Comparative example 10
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (A1)) was produced in the same manner as in Example 10, except that no radical scavenger was used.

Comparative example 11
A pressure-sensitive adhesive sheet containing a thermosetting resin (corresponding to polymer (A1)) was produced in the same manner as in Example 11, except that no radical scavenger was used.

Comparative example 12
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 curing agent was used.

<Evaluation>
The adhesive sheets prepared in Examples and Comparative Examples were evaluated as follows before and after UV irradiation. The results are shown in the table. In addition, UV irradiation was performed by the following method.

(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.

(1) Shear storage modulus Adhesive sheets were laminated to prepare a sample for measurement with a thickness of about 1.0 mm, and subjected to the following conditions using "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific. A dynamic viscoelasticity measurement was performed by Then, the shear storage elastic moduli at 25°C, 50°C and 80°C were calculated.
(Measurement condition)
Deformation mode: Torsion Measurement frequency: 1Hz
Heating rate: 5°C/min Measurement temperature: -50 to 150°C
Shape: Parallel plate 8.0mmφ

(2) Tensile test A 10 mm x 30 mm piece was cut from a 50 µm-thick pressure-sensitive adhesive sheet obtained by lamination as necessary, and strip samples of 30 mm in length were produced in a state in which the release liner was 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.

(3) Young's modulus E
It was calculated from the amount of change in stress σ with respect to strain ε in the elastic deformation region (E=Δσ/Δε) from the spectrum obtained in the tensile test.

(4) Breaking Point Stress or Stress Peak Strength Regarding the spectrum obtained in the above tensile test, the value of the upwardly convex peak 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.

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

As shown in Tables 1 to 5, the pressure-sensitive adhesive sheets of Examples had reduced stress such as 100% strain stress due to ultraviolet irradiation. For this reason, it was judged to be excellent in flexibility before UV irradiation because the handleability was superior to that after UV irradiation, and on the other hand, stress was reduced after UV irradiation.

Variations of the invention according to the present disclosure are described below.
[Appendix 1] A pressure-sensitive adhesive layer and/or an adhesive layer whose stress is reduced by an external stimulus.
[Appendix 2] The pressure-sensitive adhesive layer and/or adhesive layer according to Appendix 1, wherein the stress does not increase after reduction.
[Appendix 3] The ratio [S2 (100) / S1 (100)] of the 100% strain stress (S1 (100)) before the application of the external stimulus and the 100% strain stress (S2 (100)) after the application of the external stimulus is 3. The pressure-sensitive adhesive layer and/or adhesive layer according to

appendix

1 or 2, which is less than 0.95.
[Appendix 4] The pressure-sensitive adhesive layer and/or adhesive layer according to any one of Appendices 1 to 3, wherein the 100% strain stress (S2(100)) after application of an external stimulus is 10 MPa or less.
[Appendix 5] The pressure-sensitive adhesive layer and/or adhesive layer according to any one of Appendices 1 to 4, which is used for optical applications.

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

Claims

A pressure-sensitive adhesive layer and/or adhesive layer that reduces stress due to external stimuli.
The pressure-sensitive adhesive layer and/or adhesive layer according to claim 1, wherein the stress does not increase after reduction.
The ratio [S2 (100) / S1 (100)] of the 100% strain stress (S1 (100)) before the application of the external stimulus and the 100% strain stress (S2 (100)) after the application of the external stimulus is less than 0.95 The adhesive layer and/or adhesive layer according to claim 1, wherein the adhesive layer is
The pressure-sensitive adhesive layer and/or adhesive layer according to claim 1, wherein the 100% strain stress (S2(100)) after application of an external stimulus is 10 MPa or less.
The pressure-sensitive adhesive layer and/or adhesive layer according to any one of claims 1 to 4, which is used for optical purposes.