TW202136447A - Adhesive sheet - Google Patents

Abstract

Provided is an adhesive sheet that can be adhered to a fragile adherend such as a gas barrier layer of an OLED, that, even if the need for re-attachment arises, can be detached and adhered again without damaging the adherend, and in which the adhesive power greatly reduces through irradiation with light after a manufacturing process, to enable easy detachment. The adhesive sheet according to the present invention is provided with a substrate, a first adhesive agent layer, and a second adhesive agent layer. The first adhesive agent layer and the second adhesive agent layer are layered on the substrate in this order. The first adhesive agent layer contains a crosslinked resin (A), and a gas generating agent (B) that generates gas when being irradiated with light. The second adhesive agent layer contains an urethane resin (D). The crosslinked resin (A) is a reaction product between a functional group-including resin (A-1) and a curing agent (A-2). Then urethane resin (D) is a reaction product between a urethane prepolymer (D-1) and a curing agent (D-2).

Description

Adhesive sheet

The present invention relates to adhesive sheets.

In the manufacturing steps of optical or electronic components, in order to prevent surface damage during processing, assembly, inspection, transportation, etc., a surface protective film is generally attached. Such a surface protection film will be peeled from the optical component or the electronic component at the time when the surface protection is not required.

In such an optical component or electronic component to which a surface protection film is attached, when the surface protection film is to be peeled off as described above, it is important that only between the surface protection film and the optical component or electronic component The interface can be peeled off smoothly.

However, when optical components or electronic components are equipped with easily breakable components such as thin glass or barrier film, when trying to peel off the surface protection film that has been attached, the easily damaged components may be damaged due to the peeling force. situation. Even in the case of using a conventional surface protective film with light peeling properties, it may be damaged.

As technical means to solve these problems, various adhesive sheets have been proposed. Patent Document 1 discloses an adhesive sheet having an adhesive formed of an adhesive composition, the adhesive composition including a base polymer and a silicone-based additive and/or a fluorine-based additive, and the adhesive sheet is provided with ultra-lightweight Use peelable surface protection film.

In addition, Patent Documents 2 and 3 describe adhesive tapes for processing electronic parts having high adhesiveness and releasability. Specifically, an adhesive tape is disclosed, in which the adhesive layer is composed of a two-layer structure of an inner layer and an outer layer, the inner layer contains a gas generating agent that generates gas by stimulation, and the outer layer contains a A sclerosing adhesive that is irritated for cross-linking. [Prior technical literature] [Patent literature]

[Patent Document 1] Japanese Patent Application Publication No. 2017-160422 [Patent Document 2] Japanese Patent Application Publication No. 2010-202833 [Patent Document 3] Japanese Patent Application Publication No. 2019-70104

[The problem to be solved by the invention]

In recent years, OLED (Organic Light Emitting Diode) has been thinned. In this manufacturing step, an adhesive sheet is used as a protective film for the gas barrier layer. The gas barrier layer is a very fragile physical property. If the adhesive sheet must be re-attached due to misalignment, there is a problem that the gas barrier layer will be damaged when the adhesive sheet is peeled off.

In addition, when the adhesive sheet is peeled from the gas barrier layer after the specified processing is completed, if the conventional adhesive sheet is used, the peeling force is too strong, and there is also a problem of damaging the gas barrier layer.

The present invention is an invention made in view of the above-mentioned circumstances. The subject is to provide an adhesive sheet that can be used without damaging the adherend even if it is in a situation where it is necessary to reattach the adherend whose physical properties are fragile. Perform peeling. Furthermore, the problem is to provide an adhesive sheet that can significantly reduce the adhesive force by light irradiation when surface protection is not required, and can be easily peeled off from a fragile adherend. [Means to solve the problem]

That is, the adhesive sheet of the same aspect of the present invention relates to the following matters. [1]. An adhesive sheet, characterized in that it has: a substrate, a first adhesive layer, and a second adhesive layer, and the first adhesive layer and the second adhesive layer are sequentially laminated on the substrate　　The aforementioned first adhesive layer contains a crosslinked resin (A) and a gas generator (B) that generates gas by light irradiation, and 　　The aforementioned second adhesive layer contains a urethane resin (D), The aforementioned crosslinked resin (A) is a reaction product of a resin (A-1) containing multiple functional groups and a hardener (A-2), and the aforementioned urethane resin (D) is a urethane prepolymer (D-1) Reactant with hardener (D-2).　　[2]. The adhesive sheet as described in [1], wherein the second adhesive layer further contains a multifunctional ethylenically unsaturated group-containing compound (E) and a photopolymerization initiator (F).　　[3]. The adhesive sheet as described in [1] or [2], wherein the aforementioned urethane prepolymer (D-1) is a reaction product of polyol and polyisocyanate. [4]. The adhesive sheet as described in [3], wherein the aforementioned polyol is a polyol having two or more hydroxyl groups in one molecule, and the aforementioned polyisocyanate is a polyol having two or three isocyanate groups in one molecule. Isocyanate.　　[5]. The adhesive sheet as described in any one of [1] to [4], wherein the second adhesive layer further contains a fluorine-containing compound (G).　　[6]. The adhesive sheet as described in any one of [1] to [5], wherein the second adhesive layer further contains a carboxylic acid ester (H).　　[7]. The adhesive sheet as described in any one of [1] to [6], wherein the aforementioned resin (A-1) is a (meth)acrylic resin containing a hydroxyl group. [8]. The adhesive sheet as described in [7], wherein the total constituent unit of the hydroxyl-containing (meth)acrylic resin contains 0.5-20% by mass derived from the hydroxyl-containing (meth)acrylate unit.　　[9]. The adhesive sheet as described in [7] or [8], wherein the glass transition temperature (Tg) of the hydroxyl-containing (meth)acrylic resin is -60~-10°C.　　[10]. The adhesive sheet as described in any one of [1] to [9], wherein the first adhesive layer further contains a photosensitizer (C). [11]. The adhesive sheet as described in any one of [1] to [10], wherein the peel force measured under the following conditions is 3.0N/25mm or less, and the measurement conditions are: sample size: length 25mm×width 100mm; Adhesive body: glass; measuring temperature: 25℃; peeling speed: 2400mm/min; measuring mode: 180° peeling. [12]. A manufacturing method of OLED, including: 　　 the steps of attaching the adhesive sheet as described in any one of [1]~[11] to the gas barrier layer of the OLED, and 　　 using light to irradiate the The step of peeling the adhesive sheet from the gas barrier layer. [Effects of the invention]

The adhesive sheet of the present invention can obtain a certain adhesive force to the adherend by making the second adhesive layer adhere to the adherend, and can well protect the adherend during the specified steps such as processing operations. The surface of the adhesive. After the above-specified steps are completed, the adhesive sheet can be easily peeled off from the adherend by irradiating the adhesive sheet with light. Furthermore, the adhesive force is sufficiently low even when the light is not irradiated, and even if it is necessary to reattach the adherend, it can be reattached without damaging the adherend. .

[Best form to implement the invention]

Hereinafter, the adhesive sheet of the present invention will be described in detail. However, the present invention is not limited to the embodiments shown below. The adhesive sheet of this embodiment includes a substrate, a first adhesive layer, and a second adhesive layer, and the first adhesive layer and the second adhesive layer are sequentially laminated on the substrate.

(Substrate) 　　 The adhesive sheet of this embodiment has a sheet-like substrate. As the material of the base material, conventional materials can be appropriately selected and used. Since light irradiation to the adhesive sheet is performed from the substrate side, it is preferable to use a resin sheet made of a transparent resin material as the substrate.

Examples of resin materials include polyolefins such as polyethylene (PE) and polypropylene (PP); polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polynaphthalene Polyesters such as ethylene dicarboxylate; polyvinyl chloride (PVC); polyimide (PI); polyphenylene sulfide (PPS); ethylene-vinyl acetate (EVA); polytetrafluoroethylene (PTFE), etc. . Among these resin materials, in order to obtain an adhesive sheet having moderate flexibility, it is preferable to use one or more selected from PE, PP, and PET. The resin material used as the base material may be only one type, or two or more types may be mixed and used.

When a resin sheet is used as the base material, the resin sheet may be a single layer or a multilayer structure of two or more layers (for example, a three-layer structure). In the resin sheet having a multilayer structure, the resin material constituting each layer may be a resin material containing only one type, or may contain two or more types of resin materials.

When a resin sheet is used as the base material, it can be manufactured by appropriately using conventionally known sheet forming methods (for example, extrusion molding, T-die molding, blow molding, etc., or uniaxial or biaxial stretching molding, etc.).

The thickness of the substrate can be appropriately selected in accordance with the application of the adhesive sheet, the material of the substrate, and the like. When a resin sheet is used as the substrate, the thickness of the substrate is preferably 10 to 1000 μm, and more preferably 50 to 300 μm. If the thickness of the substrate is 10 μm or more, the rigidity (strength) of the adhesive sheet will increase. Therefore, when the adhesive sheet is attached to the adherend, there is a tendency that it is difficult to crease the adhesive sheet, and it is difficult to float between the adhesive sheet and the adherend. In addition, if the thickness of the base material is 10 μm or more, the adhesive sheet attached to the adherend can be easily peeled from the adherend, and the workability (handling, handling) becomes better. If the thickness of the substrate is 1000 μm or less, the adhesive sheet will have moderate flexibility and workability will become better.

In order to improve the adhesion between the substrate and the first adhesive layer, surface treatment may be applied to the surface of the substrate on the side of the first adhesive layer. The surface treatment includes, for example, corona discharge treatment, acid treatment, ultraviolet irradiation treatment, plasma treatment, primer coating, and the like.

(First adhesive layer) The adhesive sheet of this embodiment has a first adhesive layer on the substrate. The first adhesive layer contains a crosslinked resin (A) and a gas generating agent (B) that generates gas by light irradiation. The aforementioned crosslinked resin (A) is a reaction product of a functional group-containing resin (A-1) and a hardener (A-2). Not only the crosslinked resin (A) and the gas generating agent (B), but the first adhesive layer may further contain a photosensitizer (C). In addition, the aforementioned functional group-containing resin (A-1) is preferably a hydroxyl group-containing (meth)acrylic resin.

The thickness of the first adhesive layer is preferably set to 1-100 μm, more preferably 5 to 80 μm, more preferably 10 to 70 μm. The thickness of the first adhesive layer may also be 40-65 μm. If the thickness of the first adhesive layer is 1 μm or more, the uniformity of the thickness of the first adhesive layer becomes good. On the other hand, if the thickness of the first adhesive layer is 100 μm or less, when a solvent is used to form the first adhesive layer, since the solvent can be easily removed, it is preferable.

"Crosslinked resin (A)" "Crosslinked resin (A) is a resin containing multiple functional groups (A-1) (hereinafter also referred to as "functional group-containing resin (A-1)") and a hardener (A- 2) The reactant. The aforementioned crosslinked resin (A) is preferably a cured product of a functional group-containing resin (A-1) and a curing agent (A-2). As said functional group, a hydroxyl group, a carboxyl group, an epoxy group, etc. are mentioned, Among them, a hydroxyl group is preferable.

"Resin containing functional groups (A-1)" "Resin containing functional groups (A-1) is not particularly limited as long as it has a plurality of functional groups, but preferably contains (meth)acrylic acid A resin, and this (meth)acrylic resin contains the structural unit derived from the monomer containing a functional group. In particular, it is preferable to include a (meth)acrylic resin, and that the (meth)acrylic resin includes a structural unit derived from a (meth)acrylate containing a hydroxyl group. In this specification, the "(meth)acrylic resin" refers to a resin having 60 mol% or more of a structural unit derived from a (meth)acrylic monomer. The glass transition temperature (Tg) of the functional group-containing resin (A-1) is preferably -80~0°C, more preferably -70~-5°C, more preferably -60~-10°C. The glass transition temperature (Tg) can also be -60~-35℃. If the glass transition temperature (Tg) of the functional group-containing resin (A-1) is -80°C or higher, the adhesiveness between the first adhesive layer and the second adhesive layer becomes even better. In addition, if the glass transition temperature (Tg) of the functional group-containing resin (A-1) is 0°C or less, it is difficult to cause peeling at the interface between the first adhesive layer and the second adhesive layer.

The glass transition temperature (Tg) of the functional group-containing resin (A-1) is determined by the following method. 10 mg of functional group-containing resin (A-1) was taken as a sample. Use a differential scanning calorimeter (DSC) to change the sample temperature from -80°C to 200°C at a heating rate of 10°C/min. Perform differential scanning calorimeter measurement, and use the observed start temperature of endothermic glass transition as Tg . However, if two Tgs are observed, it is the average of the two Tgs.

The weight average molecular weight of the functional group-containing resin (A-1) is preferably 100,000 to 2 million, more preferably 200,000 to 1.5 million, and more preferably 300,000 to 1 million. The weight average molecular weight of the functional group-containing resin (A-1) may be 400,000 to 600,000. If the weight average molecular weight of the functional group-containing resin (A-1) is 100,000 or more, it is difficult to cause aggregation failure of the first adhesive layer. When the weight average molecular weight of the crosslinked resin (A) is 2 million or less, the viscosity of the functional group-containing resin (A-1) will not become too high, and the workability when forming the first adhesive layer is good.

The weight average molecular weight of the functional group-containing resin (A-1) was measured at room temperature using a gel permeation chromatograph (manufactured by Showa Denko Co., Ltd., Shodex (registered trademark) GPC-101), and measured at room temperature under the following conditions Calculated by polystyrene conversion. Column: Shodex (registered trademark) LF-804, manufactured by Showa Denko Corporation, Column temperature: 40°C Sample: 0.2% by mass resin in tetrahydrofuran solution Flow rate: 1ml/min Dissolving liquid: tetrahydrofuran

Examples of the functional group-containing resin (A-1) include (meth)acrylic resins, rubbers, urethane resins, and silicone resins. Among them, it is preferable to use (meth)acrylic resin as the functional group-containing resin (A-1) from the viewpoint of physical properties and economic efficiency as an adhesive. "(Meth)acrylic acid" in this embodiment refers to one or more selected from "methacrylic acid" and "acrylic acid".

The ratio of the structural unit derived from the functional group-containing monomer in the functional group-containing resin (A-1) is preferably 0.5 to 20% by mass, and more preferably 1 to 15% by mass in the total structural unit. When the above-mentioned ratio is 0.5% by mass or more, the functional group-containing resin (A-1) will sufficiently contain the structural unit derived from the functional group-containing monomer that reacts with the curing agent (A-2). As a result, when the adhesive sheet is peeled off, it is difficult to cause agglomeration failure inside the first adhesive layer. If the ratio of the structural unit derived from the functional group-containing monomer is 20% by mass or less in the total structural unit, the adhesive force is less likely to decrease due to the reaction with the hardener, and the substrate and the second adhesive can be obtained The adhesion of the layer is a good first adhesive layer.

"Hardening agent (A-2)" "As the hardening agent (A-2), it is not particularly limited as long as it has two or more functional groups reactive with hydroxyl, carboxyl or epoxy groups, and The reaction with other functional groups is not restricted. The hardener (A-2) reacts with the functional group of the functional group-containing resin (A-1) to make it crosslink, thereby enhancing the cohesive force of the first adhesive layer. The hardening reaction is performed by heating the first adhesive layer. As will be described later, after the first adhesive composition is applied to the substrate, it may be cured by heating combined with drying. The temperature of the hardening reaction will vary depending on the hardening agent (A-2) used, the type of functional group that reacts with the hardening agent, and the thickness of the first adhesive layer, and it is preferably 30-60°C. The reaction time (heating time) is preferably 24 hours to 120 hours.　　As the hardener (A-2), a polyisocyanate compound, a polyglycidyl compound, etc. can be used.

Examples of polyisocyanate compounds include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hydrogenated toluene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, and diphenyl Methane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, tetramethylxylene diisocyanate, 1,5-naphthalene diisocyanate, trihydroxy Toluene diisocyanate adduct of methylpropane, xylene diisocyanate adduct of trimethylolpropane, triphenylmethane triisocyanate, methylene bis(4-phenylmethane) triisocyanate, hexamethylene Diisocyanate trimer, isophorone diisocyanate trimer, etc.

Examples of polyglycidyl compounds include bisphenol A and epichlorohydrin type epoxy resins, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, and glycerol triglycidyl. Ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, two Acid glyceride, polyglycidyl ether, etc.

These curing agents (A-2) may be used alone or in combination of two or more kinds. When the functional group-containing resin (A-1) is a resin containing a hydroxyl group, from the viewpoint of reactivity with the hydroxyl group, a polyisocyanate compound is preferably used as the curing agent (A-2).

The content of the hardener (A-2) is preferably 0.05-10 parts by mass relative to 100 parts by mass of the resin (A-1) containing functional groups, more preferably 0.1-5 parts by mass, more preferably 0.5~ 3 parts by mass. When the content of the curing agent (A-2) is 0.05 parts by mass or more, the crosslinked resin (A) can sufficiently form a three-dimensional crosslinked structure. When the content of the curing agent (A-2) is 10 parts by mass or less, it will become a first adhesive layer with good adhesion to the base material and the second adhesive layer.

The total amount of functional groups contained in the curing agent (A-2) is preferably 0.01 to 300 moles relative to the total amount of hydroxyl, carboxyl or epoxy groups contained in the functional group-containing resin (A-1) Ear%, it is more preferable to use the content of the hardening agent (A-2) so that it becomes 0.1 to 200 mol%. If the total amount of the functional groups contained in the curing agent (A-2) is 0.01 mol% or more, sufficient cohesive force can be obtained. If the total amount of functional groups contained in the curing agent (A-2) is 300 mol% or less, even if the unreacted curing agent (A-2) remains in the first adhesive layer, it will not cause defects Influence.

(Method for manufacturing functional group-containing resin (A-1)) 　　 The functional group-containing resin can be obtained by, for example, copolymerizing raw material monomers containing (meth)acrylic monomers by a conventional polymerization method (A-1). The raw material monomer of the functional group-containing resin (A-1) may be a raw material monomer containing only one type of monomer alone, or may be a raw material monomer containing two or more types of monomers. As a polymerization method for polymerizing raw material monomers, for example, a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, an alternating copolymerization method, etc. may be mentioned. Among them, from the viewpoint of transparency and cost of the (meth)acrylic resin obtained after polymerization, it is preferable to use a solution polymerization method.

Examples of the (meth)acrylic monomer used as a raw material monomer of the functional group-containing resin (A-1) include (meth)acrylic monomers, (meth)acrylamide monomers, and the like. Examples of (meth)acrylic monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. Alkyl (meth)acrylate; (meth)acrylates containing cyclic hydrocarbon groups such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; benzyl (meth)acrylate, (meth)acrylate (Meth)acrylates containing aromatic groups such as phenoxyethyl acrylate; (meth)acrylic acid; tetrahydrofurfuryl (meth)acrylate; glycidyl (meth)acrylate, etc. Glyceryl (meth)acrylates; (meth)acrylates containing hydroxyl groups such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate.

As the (meth)acrylamide monomer, for example, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl( (Meth)acrylamide, N-hydroxyethyl (meth)acrylamide, (meth)acrylamide, etc.

As a raw material monomer for the functional group-containing resin (A-1), N-vinylpyrrolidone, N-vinylcaprolactone, and N-vinylethyl can also be used together with (meth)acrylic monomers. Amide, N-acrylomethrin, acrylonitrile, etc.

Since the first adhesive layer with good adhesion to the substrate and the second adhesive layer can be obtained, as the raw material monomer of the functional group-containing resin (A-1), selected from (meth)acrylic acid is specially used One or more of alkyl ester, (meth)acrylic acid, hydroxyl-containing (meth)acrylate, and (meth)acrylamide monomers are preferred, and it is also preferred to use methyl (meth)acrylate Ester, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, (meth)acrylate One or more of 4-hydroxybutyl acrylate, N-hydroxyethyl (meth)acrylamide, and N,N-dimethyl (meth)acrylamide.

The cross-linked resin (A) is a reaction product of the functional group-containing resin (A-1) and the curing agent (A-2). The functional group-containing resin (A-1) has a raw material monomer containing a functional group-containing monomer body. Examples of the functional group contained in the functional group-containing monomer include a hydroxyl group, a carboxyl group, and an epoxy group. Among these functional groups, since the reactivity with the hardener is high, the hydroxyl group is particularly preferred. Specifically, as the functional group-containing monomer, hydroxyl-containing (meth)acrylate selected from 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc., (meth)acrylate, ( One or more of the group of glycidyl group-containing (meth)acrylates such as meth)acrylic acid and glycidyl (meth)acrylate.

The content of the functional group-containing monomer in the raw material monomer of the functional group-containing resin (A-1) is preferably 0.5 to 20% by mass, and more preferably 1 to 15% by mass. In other words, the functional group-containing resin (A-1) preferably contains 0.5 to 20% by mass of structural units derived from the functional group-containing monomer. If the content of the functional group-containing monomer in the raw material monomer is 0.5% by mass or more, the functional group derived from the functional group-containing monomer reacts with the curing agent (A-2), and sufficient aggregation can be obtained. Strong first adhesive layer. If the content of the functional group-containing monomer in the raw material monomer is 20% by mass or less, the reaction between the functional group-containing monomer and the curing agent (A-2) will cause the adhesion of the first adhesive layer The strength is not easy to decrease, and the first adhesive layer with good adhesion to the substrate and the second adhesive layer can be obtained.

When the (meth)acrylic resin used as the functional group-containing resin (A-1) is produced by the solution polymerization method, a polymerization initiator and/or a solvent are used together with the raw material monomers as necessary. The polymerization initiator is not particularly limited, and it can be appropriately selected and used from among those skilled in the art. As the polymerization initiator, for example, 2,2'-azobis(isobutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2 ,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1 -Carboxonitrile), 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2-methylpropionic acid) dimethyl and other azo System polymerization initiator; Benzoyl peroxide, tertiary butyl hydroperoxide, di-tertiary butyl peroxide, tertiary butyl peroxy benzoate, dicumyl peroxide, 1 ,1-bis(tert-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclododecane and other peroxide systems Oil-soluble polymerization initiators such as polymerization initiators. These polymerization initiators may be used alone or in combination of two or more kinds.

The amount of the polymerization initiator used is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, more preferably 0.1 to 100 parts by mass of the raw material monomer of the functional group-containing resin (A-1) ~2 parts by mass.

As the solvent, various general solvents can be used. Examples of solvents include esters such as ethyl acetate, n-propyl acetate, and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane, Alicyclic hydrocarbons such as methylcyclohexane; organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone.　 These solvents can be used alone or in combination of two or more kinds.

"Gas generating agent (B)" "The gas generating agent (B) contained in the first adhesive layer generates gas by light irradiation.　 The gas generating agent (B) is not particularly limited, and, for example, azo compounds, azide compounds, etc. can be suitably used. Azo compounds and azide compounds generate nitrogen gas by stimulation of light, heat, and the like.

As the azo compound, for example, 2,2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis( 2-methylpropionic acid) dimethyl ester, 2,2'-azobis(N-cyclohexyl-2-methylpropionamide), 2,2'-azobis(N-butyl-2- Methylpropionamide), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis[N-(2-propylene Yl)-2-methylpropanamide], 2,2'-azobis[2-(2-imidazolin-2-yl)propane]hydrogen dichloride, 2,2'-azobis[2-( 2-imidazolin-2-yl)propane], 2,2'-azobis(2-methylpropionamidine) hydrogen dichloride, 2,2'-azobis{2-[N-(2-carboxyethyl Base) amidine] propane} and so on.

Among these azo compounds, it is preferable to use 1,1'-azobis(cyclohexane-1-carbonitrile) and 2,2'- from the viewpoint of the stability of the compound. Azobis(N-cyclohexyl-2-methylpropanamide), 2,2'-azobis(N-butyl-2-methylpropanamide), 2,2'-azobis[ 1 or 2 of 2-methyl-N-(2-hydroxyethyl)propanamide], 2,2'-azobis[N-(2-propenyl)-2-methylpropanamide] More than species.

As the azide compound, for example, 3-azidomethyl-3-methyloxetane, p-phthaloyl azide, p-tert-butyl benzoyl azide, 3-azide A polymer having an azide group, such as a glycidyl azide polymer obtained by ring-opening polymerization of methyl-3-methyloxetane. Among these azide compounds, from the viewpoint of compatibility with (meth)acrylic resins, it is preferable to use a glycidyl azide polymer.

The content of the gas generating agent (B) in the first adhesive layer is preferably 5-50 parts by mass, and more preferably 8-40 parts by mass relative to 100 parts by mass of the functional group-containing resin (A-1) , More preferably 9-25 parts by mass. When the content of the gas generating agent (B) is 5 parts by mass or more, a sufficient amount of gas can be generated by irradiating the adhesive sheet with light. As a result, the area ratio of the unevenness formed on the surface of the second adhesive layer will become sufficiently large, so that the contact area between the surface of the second adhesive layer and the adherend is greatly reduced, making it easier to peel off the adherend Of adhesive flakes. When the content of the gas generating agent (B) is 50 parts by mass or less, the precipitation of the gas generating agent (B) in the first adhesive layer can be prevented.

"Photosensitizer (C)" 　　The first adhesive layer may also contain a photosensitizer (C). The photosensitizer (C) has the effect of amplifying the light stimulating the gas generating agent (B). Therefore, by making the first adhesive layer contain the photosensitizer (C), the amount of light used when the gas is released from the gas generating agent (B) can be reduced, or light with a wider wavelength range can be used as irradiation Light to use.

The photosensitizer (C) is not particularly limited, and conventional photosensitizers can be used. Examples of photosensitizers include thioxanthone compounds and anthracene compounds. As specific examples of the thioxanthone compound, thioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, etc. can be cited.

Specific examples of the anthracene compound include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dibutoxyanthracene, 9,10-dibenzyloxyanthracene, 9,10-bis-α-methylbenzyloxyanthracene, 9,10-bis(octyloxy)anthracene, 9,10-bis(2-hydroxyethoxy)anthracene, 9,10-bis(shrinkage) Glyceryloxy)anthracene, 9,10-bis(2-vinyloxyethoxy)anthracene, 9,10-bis(p-epoxyphenylmethoxy)anthracene, 2-ethyl-9,10 -Bis(p-epoxyphenylmethoxy)anthracene, 9,10-bis(p-vinylphenylmethoxy)anthracene, etc.

Among these photosensitizers (C), when a (meth)acrylic resin is used as the functional group-containing resin (A-1), from the viewpoint of compatibility with the (meth)acrylic resin , Preferably selected from 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 9,10-dibutoxyanthracene, 9,10-bis(octyloxy)anthracene, One or more of 9,10-bis(2-hydroxyethoxy)anthracene.

The content of the photosensitizer (C) is preferably 0.03 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, more preferably 0.1 to 100 parts by mass relative to 100 parts by mass of the functional group-containing resin (A-1) 2 parts by mass. When the content of the photosensitizer (C) is 0.03 parts by mass or more, a sufficient sensitization effect can be obtained. In addition, when the content of the photosensitizer (C) is 5 parts by mass or less, the photosensitizer (C) and the functional group-containing resin (A-1) can be made uniform in the first adhesive layer To disperse. The mass ratio of gas generator (B) to photosensitizer (C) (gas generator (B): photosensitizer (C)) is preferably 200:1 to 1:1, and more preferably 100: 1~5:1, more preferably 30:1~8:1. If the mass ratio is in the aforementioned range, even if the amount of light irradiated to the adhesive sheet is small, gas can be efficiently generated from the gas generating agent (B).

(Second Adhesive Layer) The adhesive sheet of this embodiment has a second adhesive layer on the surface of the first adhesive layer opposite to the substrate. The second adhesive layer contains urethane resin (D). The aforementioned urethane resin (D) is a reaction product of a urethane prepolymer (D-1) and a hardener (D-2). The second adhesive layer may further contain a polyfunctional ethylenically unsaturated group-containing compound (E) and a photopolymerization initiator (F). It may further contain a fluorine-containing compound (G) and/or carboxylic acid ester (H) as an optional component.

The thickness of the second adhesive layer is preferably 1-50 μm, more preferably 2-40 μm, more preferably 5-20 μm. If the thickness of the second adhesive layer is 1 μm or more, the uniformity of the thickness of the second adhesive layer can be made good. On the other hand, if the thickness of the second adhesive layer is 50 μm or less, when a solvent is used to form the second adhesive layer, the solvent can be easily removed, which is preferable. In addition, the thickness of the second adhesive layer is preferably thinner than the thickness of the first adhesive layer. In this case, by irradiating light on the adhesive sheet, it is easier to form irregularities on the surface of the second adhesive layer.

"Urethane resin (D)" "Urethane resin (D) is a reaction product of urethane prepolymer (D-1) and hardener (D-2). The urethane resin (D) is preferably a cured product of a urethane prepolymer (D-1) and a curing agent (D-2). The aforementioned urethane prepolymer (D-1) is preferably a reaction product of a polyol and a polyisocyanate.

"Urethane prepolymer (D-1)" "Urethane prepolymer (D-1) is a reaction product of polyol and polyisocyanate, and means that it can be transformed into the following amino groups The urethane resin of the formate resin: That is, the urethane resin in which the reaction between the two is half-progressed, and the urethane resin is further polymerized or crosslinked to obtain the urethane resin. For example, by making the urethane prepolymer have a plurality of hydroxyl groups or isocyanate groups, it may be converted to and then polymerized or crosslinked to obtain a urethane resin.

The weight average molecular weight of the urethane prepolymer (D-1) is preferably 10,000 to 500,000, more preferably 20,000 to 400,000, more preferably 50,000 to 300,000. If the weight average molecular weight of the urethane prepolymer (D-1) is 10,000 or more, when the adhesive sheet is attached to the adherend and then peeled off, the second adhesive layer is not likely to remain on the adherend superior. If the weight average molecular weight of the urethane prepolymer (D-1) is less than 500,000, the viscosity of the urethane prepolymer (D-1) will not become too high, and the workability will be good. The weight average molecular weight of the urethane prepolymer (D-1) can be measured under the same conditions as the functional group-containing resin (A-1).

The polyol used as a raw material for producing the urethane prepolymer (D-1) is not particularly limited as long as it is a polyol having two or more hydroxyl groups in one molecule. Examples include polyoxyalkylene polyols and polyester polyols. The aforementioned polyoxyalkylene polyol preferably includes a polyoxyalkylene polyol having an alkylene chain having 2 to 4 carbon atoms. Specifically, polyoxyethylene polyol, polyoxypropylene polyol, polyoxybutylene polyol, etc. are mentioned. In addition, copolymers of two or more types of alkylene polyols may also be used, and mixtures of two or more types of polyoxyalkylene polyols may also be used. The aforementioned polyester polyols include polyester polyols obtained by condensation reaction of one or more of the following carboxylic acids (dibasic acids) and one or more of the following polyols . Examples of the carboxylic acid (dibasic acid) include succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, etc. . As said polyhydric alcohol, ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylol propane, glycerol, etc. are mentioned. In addition, examples of the polyester polyol include polycaprolactones obtained by ring-opening polymerization of ε-caprolactone and a polyol. Examples of the polycaprolactones include polycaprolactone polyols that are obtained by ring-opening polymerization of one or more types of tetramethylene carbonate and hexamethylene carbonate with polyols.

As the polyol used as the raw material for the urethane prepolymer (D-1), ethylene glycol, 1,4-butanediol, butylethylpentanediol, neopentyl glycol, etc. can also be used Diols; and polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol. In addition, polyvalent amines such as ethylenediamine, N-aminoethylethanolamine, isophorone diamine, and xylene diamine may be substituted for a part of polyol and used in combination.

Among these, as the polyol, a trifunctional or higher polyol is preferable, and a trifunctional or higher polyoxyalkylene polyol or a polyester polyol is more preferable.

The number average molecular weight of the polyol used as the raw material for the urethane prepolymer (D-1) is preferably 500 to 15,000, and more preferably 800 to 10,000. If the number average molecular weight is 500 or more, the adhesive sheet will have sufficient peeling force. If the number average molecular weight is 15,000 or less, urethane bonds will be sufficiently formed in the urethane prepolymer (D-1), so the cohesive force of the second adhesive layer will increase.

The polyisocyanate used as a raw material for generating the urethane prepolymer (D-1) is not particularly limited as long as it is a polyisocyanate having two or more isocyanate groups in one molecule. Specifically, toluene diisocyanate and the hydride, xylene diisocyanate and the hydride, diphenylmethane diisocyanate and the hydride, 1,5-naphthylene diisocyanate and the hydride, six Methylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexyl diisocyanate, 1,3-bis(isocyanate methyl ) Diisocyanates such as cyclohexane and norbornane diisocyanate. These systems can be used alone or in combination of two or more types. Among them, from the viewpoint of control of light resistance and reactivity, hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and the hydrogenated compound are preferred.

The usage amount of the aforementioned polyol is not particularly limited, but in the urethane prepolymer (D-1), it is, for example, 30 to 98% by mass, and preferably 40 to 95% by mass. The amount of the polyisocyanate used is not particularly limited, but in the urethane prepolymer (D-1), it is, for example, 1 to 20% by mass, and preferably 2 to 15% by mass.

The total amount of isocyanate groups of the polyisocyanate may be less than the total amount of hydroxyl groups of the polyol. In this case, since the urethane prepolymer (D-1) becomes a compound having a hydroxyl group, a combination of a polyisocyanate compound or a polyglycidyl compound may be used as the curing agent (D-2). On the other hand, the total amount of isocyanate groups of the polyisocyanate may be more than the total amount of hydroxyl groups of the polyol. In this case, as the urethane prepolymer (D-1) becomes a compound having an isocyanate group, it is sufficient to combine a polyol compound as the hardener (D-2).

(Manufacturing method of urethane prepolymer (D-1)) The urethane prepolymer (D-1) is produced by using urethane in the presence of an inert organic solvent The catalyst is usually carried out by reacting the polyol and the polyisocyanate at 30 to 100°C for about 1 to 5 hours. The polyol and polyisocyanate which are the raw materials of the urethane prepolymer (D-1) may be used individually by 1 type, respectively, or may use 2 or more types together.

Examples of the urethane catalyst include conventional urethane catalysts such as tertiary amine compounds and organometallic compounds. As the aforementioned tertiary amine compound, for example, triethylamine, triethylenediamine, 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU), etc. may be mentioned.

Examples of the aforementioned organometallic compound include tin-based compounds and non-tin-based compounds. Examples of the tin-based compound include dibutyl tin dimaleate, dibutyl tin dilaurate, dibutyl tin diacetate, dioctyl tin oxide, dioctyl tin dilaurate, tin 2-ethylhexanoate, and the like. As the aforementioned non-tin-based compounds, for example, titanium-based dibutyl titanium dichloride, tetrabutyl titanate, etc.; lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate, etc. Lead series; iron series such as iron 2-ethylhexanoate and iron acetone; cobalt series such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc naphthenate, zinc 2-ethylhexanoate, etc. Zinc series; zirconium naphthenate, etc. Among them, dibutyltin dilaurate, tin 2-ethylhexanoate, dioctyltin dilaurate, and the like are preferably used.

The aforementioned organic solvent is not particularly limited, and conventional organic solvents can be used. Examples include ketone solvents such as methyl ethyl ketone, acetone, and methyl isobutyl ketone, ester solvents such as ethyl acetate, n-butyl acetate, and isobutyl acetate, and hydrocarbon solvents such as toluene and xylene. From the viewpoints of the solubility of the polyurethane polyol and the boiling point of the solvent, toluene is particularly preferred.

"Hardener (D-2)" "Hardener (D-2) is classified into polyisocyanate compound and polyglycidol according to the types of functional groups remaining in the urethane prepolymer (D-1) Compounds, polyol compounds, etc. are used. For example, when the urethane prepolymer (D-1) has a residual hydroxyl group, a compound having two or more functional groups reactive with the hydroxyl group is used as the hardener (D-2). Specifically, a polyisocyanate compound or a polyglycidyl compound is used. Similarly, when the urethane prepolymer (D-1) has a residual isocyanate group, a compound having two or more functional groups reactive with the isocyanate group is used as the hardener (D-2). Specifically, a polyol compound is used.

As the polyisocyanate compound and the polyglycidyl compound, the same compounds as those exemplified as the aforementioned curing agent (A-2) can be used. Among them, from the viewpoint of reactivity, the use of polyisocyanate compounds is preferred, and the use of toluene diisocyanate adducts of trimethylolpropane, hexamethylene diisocyanate trimers, and isophorone diisocyanate tripolymers are preferred. Polymers are more preferred.

As the polyol compound, the same compounds as those exemplified as the polyol used as the raw material for producing the urethane prepolymer (D-1) can be used.

The hardener (D-2) reacts with the functional groups remaining in the urethane prepolymer (D-1) and is cross-linked to increase the cohesive force of the second adhesive layer. The hardening reaction is performed by heating the second adhesive layer. As described later, after the second adhesive composition is applied to the release film, it may be cured by heating with both drying. The temperature of the curing reaction will vary depending on the type of curing agent used, the type of functional group that reacts with the curing agent, and the thickness of the first adhesive layer, and it is preferably 30-60°C. The reaction time (heating time) is preferably 24 hours to 120 hours.

Relative to 100 parts by mass of the urethane prepolymer (D-1), the content of the hardener (D-2) is preferably 0.1-30 parts by mass, more preferably 1-20 parts by mass, and more preferably It is 5 to 15 parts by mass. When the content of the curing agent (D-2) is 0.1 parts by mass or more, the urethane resin (D) can be sufficiently formed into a cross-linked structure. If the content of the curing agent (D-2) is 30 parts by mass or less, it will become a second adhesive layer with good adhesion to the first adhesive layer and the adherend.

The total amount of functional groups contained in the hardener (D-2) is preferably 0.01 to 300 moles relative to the total amount of hydroxyl groups or isocyanate groups contained in the urethane prepolymer (D-1). Ear%, it is more preferable to use the content of the hardening agent (D-2) so that it becomes 0.1 to 200 mol%. If the total amount of the functional groups contained in the curing agent (D-2) is 0.01 mol% or more, sufficient cohesive force can be obtained. If the total amount of functional groups contained in the curing agent (D-2) is 300 mol% or less, even if the unreacted curing agent (D-2) remains in the second adhesive layer, it will not cause defects Influence.

"Multifunctional ethylenically unsaturated group-containing compound (E)" "The second adhesive layer system may include a multifunctional ethylenically unsaturated group-containing compound (E). The compound (E) containing a multifunctional ethylenically unsaturated group may be a monomer or oligomer having at least two ethylenically unsaturated groups such as (meth)acryloxy and vinyl groups, and It is not particularly limited.

As a monomer having at least two ethylenically unsaturated groups, it means a compound having a number average molecular weight of less than 1,000. For example, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl glycol hexane Di(meth)acrylate of diacid ester, hydroxytrimethylacetate neopentyl glycol di(meth)acrylate, dicyclopentyl di(meth)acrylate, caprolactone modified dicyclopentene Di(meth)acrylate, di(meth)acryloyloxyethyl isocyanate, allylated cyclohexyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, two Hydroxymethyl dicyclopentane di(meth)acrylate, ethylene oxide modified hexahydrophthalate di(meth)acrylate, neopentyl glycol modified trimethylolpropane di(methyl) Acrylate, isocyanuric acid and ethylene oxide modified triacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane three (Meth)acrylate, ginseng (meth)acryloyloxyethyl isocyanate, diglycerol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, propylene Acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, etc. These systems can be used alone, or two or more of them can be used in combination. Among them, from the viewpoint of high curability, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like are preferred.

As an oligomer having at least two ethylenically unsaturated groups, it means a compound having a number average molecular weight of 1,000 or more. For example, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, bisphenol A ethylene oxide modified two (Meth) acrylate, bisphenol A propylene oxide modified di(meth)acrylate, alkanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethoxy Alkylated isocyanuric acid triacrylate, pentaerythritol tri(meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, butadiene (meth)acrylate , Isoprene (meth)acrylate, etc. These systems can be used alone, or two or more of them can be used in combination. Among them, from the viewpoint of ease of acquisition, urethane (meth)acrylate, epoxy (meth)acrylate, and the like are preferred.

The content of the polyfunctional ethylenically unsaturated group-containing compound (E) varies depending on the molecular weight of the polyfunctional ethylenically unsaturated group-containing compound (E), the number of functional groups, and the like. The content of the polyfunctional ethylenically unsaturated group-containing compound (E) is preferably 1 to 150 parts by mass, and more preferably 5 to 100 parts by mass relative to 100 parts by mass of the urethane prepolymer (D-1) 100 parts by mass, more preferably 10-50 parts by mass. If the content of the polyfunctional ethylenically unsaturated group-containing compound (E) is 1 part by mass or more, the adhesive sheet will have sufficient peel strength, and will not cause damage when peeling from the adherend after light irradiation. The adhesive body is broken and can be easily peeled off. If the content of the polyfunctional ethylenically unsaturated group-containing compound (E) is 150 parts by mass or less, even when the adhesive sheet is reattached to the adherend, the adherend will not be damaged, and it can be removed from Peel the adhesive sheet on the adherend.

"Photopolymerization initiator (F)" "The second adhesive layer system may contain a photopolymerization initiator (F). As the photopolymerization initiator (F), for example, carbonyl-based photopolymerization initiators, thioether-based photopolymerization initiators, phosphine oxides, quinone-based photopolymerization initiators, sulfochloride )-Based photopolymerization initiator, thioxanthone-based photopolymerization initiator, etc.

As the carbonyl-based photopolymerization initiator, for example, benzophenone, benzil, benzoin, ω-bromoacetophenone, chloroacetone, acetophenone, 2,2-bis Ethoxyacetophenone, 2,2-Dimethoxy-2-phenylacetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorodiphenyl Methyl ketone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, Michele ketone, benzoin methyl ether, benzoin isobutyl ether , Benzoin-n-butyl ether, benzyl methyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-( 4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, methylbenzylcarboxylate, 2,2-diethoxyacetophenone, 4-N,N '-Dimethylacetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, etc.

As the thioether-based photopolymerization initiator, for example, diphenyl disulfide, dibenzyl disulfide (dibenzyl disulfide), tetraethylthiuram disulfide (tetraethylthiuram disulfide), tetramethylammonium monosulfide Sulfide etc. Examples of the phosphine oxides include 2,4,6-trimethylbenzyldiphenylphosphine oxide and 2,4,6-trimethylbenzylphenylethoxyphosphine. Oxide etc.

Examples of the quinone-based photopolymerization initiator include benzoquinone and anthraquinone. As the thioxanthone-based photopolymerization initiator, for example, thioxanthone-based photopolymerization initiators such as thioxanthone, 2-chlorothioxanthone, and 2-methylthioxanthone.

Only one type of these photopolymerization initiators (F) may be used alone, or two or more types may be used in combination. Among these photopolymerization initiators (F), especially from the viewpoint of solubility in organic solvents and urethane prepolymers (D-1), 1-hydroxycyclohexylbenzene is used. Cycloketone and/or 2,4,6-trimethylbenzyldiphenylphosphine oxide are preferred.

The content of the photopolymerization initiator (F) is preferably 0.1 to 10 parts by mass, and more preferably 1 to 8 parts by mass relative to 100 parts by mass of the compound (E) containing a polyfunctional ethylenically unsaturated group. If the content of the photopolymerization initiator (F) is 0.1 parts by mass or more, the second adhesive layer will be cured at a sufficiently fast curing speed by light irradiation. At the same time, the second adhesive layer after light irradiation The adhesive force will also become sufficiently small, so it is better. When the content of the photopolymerization initiator (F) is 10 parts by mass or less, when the adhesive sheet is attached to the adherend and then peeled off, the second adhesive layer is unlikely to remain on the adherend. In addition, even if the content of the photopolymerization initiator exceeds 10 parts by mass, no effect corresponding to the content of the photopolymerization initiator is seen.

"Fluorine-containing compound (G)" "The second adhesive layer may include a fluorine-containing compound (G). The fluorine-containing compound (G) is not particularly limited as long as it is a compound having fluorine. The inclusion of the fluorine-containing compound (G) improves the layering properties (wetting properties), defoaming properties (easy removal of bubbles trapped during bonding), and easy peeling properties of the adhesive sheet. Examples of the fluorine-containing compound (G) include aliphatic hydrocarbons, aromatic hydrocarbons, ethers, amines, esters, amines, and amines containing fluoroalkyl groups and/or fluorophenyl groups. Carboxylic acid esters, ureas. The fluoroalkyl group is a substituent in which a hydrogen atom such as a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, or a pentafluoroethyl group is replaced by a fluorine atom. The fluorophenyl group is a substituent in which a hydrogen atom such as a fluorophenyl group, a difluorophenyl group, and a pentafluorophenyl group is replaced by a fluorine atom.

Commercial products can also be used as the fluorine-containing compound (G). As a specific example, for example, DIC (stock) Megaface series leveling agent ("Megaface F-477", "Megaface F-552", "Megaface F-553", "Megaface F-554", "Megaface F-555", "Megaface RS-75", "Megaface F-556", "Megaface F-558", "Megaface F-570", "Megaface RS-55", "Megaface RS-56", "Megaface RS -76-NS", "Megaface RS-78", "Megaface RS-90", etc.).　 These fluorine-containing compounds (G) may be used alone as only one type, or two or more types may be used in combination.

The content of the fluorine-containing compound (G) relative to 100 parts by mass of the urethane prepolymer (D-1) is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, and more preferably It is 0.1 to 2 parts by mass. If the content of the fluorine-containing compound (G) is 0.001 parts by mass or more, the layering properties (wetting properties), defoaming properties (easy removal of bubbles trapped during lamination), and easy peeling properties of the adhesive sheet will be improved . When the content of the fluorine-containing compound (G) is 5 parts by mass or less, when the adhesive sheet is attached to the adherend and then peeled off, the fluorine-containing compound (G) can be prevented from remaining on the adherend. In addition, even if more than 5 parts by mass of the fluorine-containing compound (G) was used, the effect corresponding to the content was not seen.

"Carboxylic acid ester (H)" "The second adhesive layer system may contain carboxylic acid ester (H)." The carboxylic acid ester (H) is not particularly limited as long as it is an ester compound of carboxylic acid and alcohol. As such preferable examples, esters of fatty acids with 8 to 18 carbons and linear or branched alkyl alcohols with 18 or less carbons, and polybasic acids with linear saturated hydrocarbon groups with 6 to 16 carbons are mentioned. Esters with linear or branched alkyl alcohols having 18 or less carbon atoms, esters of unsaturated fatty acids having 14 to 18 carbon atoms and polyhydric alcohols, esters of acids having branched hydrocarbon groups and polyhydric alcohols, etc.

Examples of fatty acids having 8 to 18 carbon atoms include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid. Among them, from the viewpoint of volatility, fatty acids with 10 to 18 carbon atoms are preferred, fatty acids with 16 to 18 carbon atoms are more preferred, and stearic acid is particularly preferred. As the polybasic acid having a linear saturated hydrocarbon group with 6 to 16 carbon atoms, suberic acid, sebacic acid, hexadecanedioic acid, octadecanedioic acid, etc. may be mentioned.

Examples of linear or branched alkyl alcohols having 18 or less carbon atoms include methanol, ethanol, isopropanol, hexanol, 2-ethylhexanol, decanol, stearyl alcohol, and the like. Among them, from the viewpoint of boiling point, alkyl alcohols with 2 to 12 carbons are preferred, alkyl alcohols with 4 to 10 carbons are more preferred, and hexanol and 2-ethylhexanol are particularly preferred. good.

Examples of unsaturated fatty acids having 14 to 18 carbon atoms include oleic acid, linoleic acid, and hypolinoleic acid.　　As the acid having a branched hydrocarbon group, ethylhexanoic acid, neodecanoic acid, and the like can be cited.　　As polyhydric alcohols, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc. can be mentioned.

Specific examples of the carboxylic acid ester (H) include isopropyl myristate, octyl dodecyl myristate, methyl stearate, myristyl myristate, 2-ethyl stearate Hexyl hexyl ester, cetyl ethylhexanoate, isopropyl palmitate, 2-ethylhexyl palmitate, triethylhexanoic acid, etc. These systems can be used alone, or two or more of them can be used in combination.

Relative to 100 parts by mass of the urethane prepolymer (D-1), the content of the carboxylate (H) is preferably 0.5-30 parts by mass, more preferably 3-20 parts by mass, and more preferably 5-15 parts by mass. When the content of the carboxylic acid ester (H) is 0.5 parts by mass or more, the layering properties (wettability), defoaming properties (easy removal of bubbles trapped during bonding), and easy peeling properties of the adhesive sheet will be improved. When the content of the carboxylate (H) is 30 parts by mass or less, when the adhesive sheet is attached to the adherend and then peeled off, the carboxylate (H) can be prevented from remaining on the adherend. In addition, even if it is more than 30 parts by mass of the carboxylic acid ester (H), the effect corresponding to the content is not seen.

(Release sheet) "The adhesive sheet of this embodiment" may have a release sheet (separator) on the surface of the second adhesive layer opposite to the first adhesive layer. By having the release sheet, the adhesive surface (the surface of the second adhesive layer) of the adhesive sheet can be protected until it is attached to the adherend. In addition, when an adhesive sheet is used, the release sheet can be peeled off to expose the second adhesive layer (attachment surface), and the work of pressure-bonding to the adherend can be performed efficiently.　　As the material of the release sheet, conventional materials can be appropriately selected. For example, as the material of the release sheet, a resin sheet used as a base material can be used.

The thickness of the release sheet can be appropriately selected according to the application of the adhesive sheet, the material of the release sheet, and the like. When a resin sheet is used as the release sheet, the thickness of the release sheet is preferably, for example, 5 to 300 μm, more preferably 10 to 200 μm, and more preferably 25 to 100 μm.

According to the needs, conventionally known release agents such as silicone, long-chain alkyl, fluorine, etc. can be used to apply the release surface of the release sheet (the surface that is in contact with the second adhesive layer). To be peeled off.　　 In addition, if the adhesive sheet is wound into a roll and used as an adhesive tape, peeling treatment can be applied to the surface of the substrate opposite to the first adhesive layer. In this case, the substrate will have the function of peeling off the sheet.

(Method of Manufacturing Adhesive Sheet) "The adhesive sheet of this embodiment can be manufactured by, for example, the method shown below."　　 First, prepare the first adhesive composition used to form the first adhesive layer. Using a conventional method, the resin (A-1) containing functional groups, the hardener (A-2), the gas generating agent (B), and the photosensitizer (C) contained in accordance with the requirements are used. Mix and stir to manufacture the first adhesive composition. For the purpose of viscosity adjustment, the first adhesive composition may contain a diluting solvent as needed. As the dilution solvent, the solvent used for the production of the functional group-containing resin (A-1) can be used as it is.

Next, the first adhesive composition is coated on the substrate and heated and dried to form the first adhesive layer. The heating and drying are performed at a temperature and time that are preferable for the progress of the hardening reaction. As the coating method of the first adhesive composition, a known method can be used. Specifically, for example, a gravure roll coater, a reverse roll coater, a touch roll coater, a dip roll coater, a bar coater, and a blade coater using an applicator and a conventional coater can be mentioned. Coating machine, spray coater, comma coater, direct coater, etc.

Next, the second adhesive composition for forming the second adhesive layer is prepared. Using the conventional method, by combining the urethane prepolymer (D-1), the hardener (D-2), and the polyfunctional ethylenically unsaturated group-containing compound (E ), the photopolymerization initiator (F), the fluorine-containing compound (G), and the carboxylic acid ester (H) are mixed and stirred to produce a second adhesive composition. For the purpose of viscosity adjustment, similar to the first adhesive composition, the second adhesive composition may contain a diluting solvent as needed. As the dilution solvent, the solvent used in the production of the urethane prepolymer (D-1) can be used as it is.

Next, the second adhesive composition is applied to the release surface on the release sheet and heated and dried to form a second adhesive layer. The heating and drying are performed at a temperature and time that are preferable for the progress of the hardening reaction. As the coating method of the second adhesive composition, it is possible to appropriately select and use it from the methods used as the coating method of the first adhesive composition.

Next, the first adhesive layer and the second adhesive layer are bonded together facing each other. Specifically, the first adhesive layer with the substrate side facing down is laminated, and the second adhesive layer with the sheet side facing up is peeled off and attached. Thereby, an adhesive sheet is obtained.　　 The adhesive sheet of this embodiment can also be formed into a specific shape corresponding to the shape of the adherend by a punching method or the like. In addition, the adhesive sheet of this embodiment can also be cut by winding and used as a roll-shaped adhesive tape.

In the adhesive sheet of this embodiment, the peeling force is preferably 3.0N/25mm or less, more preferably 0.01~1N/25mm, more preferably 0.05~0.25N/25mm. If the peeling force is 3.0N/25mm or less, even if it is in a situation where it must be reattached to the fragile adherend, the adherend will not be damaged.

The peel force of the adhesive sheet was measured under the following conditions.　 The adhesive sheet was cut into a size of 25mm×100mm as a sample, and attached to the glass of the adherend, and peeled at 180° at a peeling speed of 2400mm/min at 25°C. That is, the measurement conditions: Sample size: length 25mm×width 100mm; adherend: glass; measurement temperature: 25°C; peeling speed: 2400mm/min; measurement mode: 180° peeling. In addition, after light irradiation, the peeling force of the adhesive sheet is preferably less than 1/10 of that before light irradiation, more preferably less than 50%, and the peeling force is more preferably 0N/25mm.

(How to use the adhesive sheet) "If the adhesive sheet has a release sheet, peel off the release sheet during use to expose the second adhesive layer (attachment surface). Secondly, the exposed second adhesive layer and the adherend (electronic parts such as OLED) are arranged oppositely and pressure-bonded. In this way, the adhesive sheet and the adherend are closely adhered. In this state, for example, the cutting step of the adherend is performed. Then, at a stage where the adhesive sheet is not required, it is preferable to irradiate the adhesive sheet with light from the substrate side to reduce the adhesive force of the adhesive sheet and peel the adhesive sheet from the adherend.

As the light system irradiated to the adhesive sheet, it is preferable to use ultraviolet (UV). Examples of the light source used for UV irradiation include LED lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, carbon arc lamps, xenon lamps, metal halide lamps, chemical lamps, black light lamps, and the like. It is better to use LED lamps, high-pressure mercury lamps or metal halide lamps.

For the UV radiation of the adhesive sheet, if an LED lamp, a high-pressure mercury lamp or a metal halide lamp is used, 500~10000mJ/cm ² is preferred, and 1000~5000mJ/cm ² is even more preferred. If the UV irradiation amount of the adhesive sheet is 500mJ/cm ² or more, the effect of reducing the adhesive force of the adhesive sheet by UV irradiation can be sufficiently obtained. Specifically, the second adhesive layer is photocured at a sufficiently fast curing speed to increase the elastic modulus, and the adhesive force of the second adhesive layer to the adherend is sufficiently reduced. In addition, the second adhesive layer is heated by UV irradiation to fully soften the second adhesive layer. On the other hand, in the first adhesive layer, a sufficient amount of gas is generated from the gas generating agent (B). As a result, the surface of the softened second adhesive layer is pushed up, and unevenness is easily formed on the surface of the second adhesive layer. Even if the amount of UV irradiation applied to the adhesive sheet is set to 10000 mJ/cm ² or more, the effect of reducing the adhesive force of the second adhesive layer in accordance therewith cannot be obtained.

In the adhesive sheet of this embodiment, a first adhesive layer and a second adhesive layer are sequentially laminated on a substrate, wherein the first adhesive layer contains at least a crosslinked resin (A) and gas generated by light irradiation The second adhesive layer contains at least a urethane resin (D). Therefore, by making the second adhesive layer adhere to the adherend, the adhesive force to the adherend can be obtained. In addition, by irradiating light on the adhesive sheet that is in close contact with the adherend, the adhesive force to the adherend is reduced. Therefore, the adhesive sheet of this embodiment can be easily peeled from the adherend by irradiating light.

The adhesive sheet of this embodiment can be suitably used in the process of processing fragile electronic products such as OLED.　 The adhesive sheet of this embodiment is attached to the fragile electronic product with a certain adhesive force. Even if it is attached to the electronic product in a temporary step, it can be peeled off without damaging the electronic product. In addition, after the end of the work, by irradiating UV, it can be peeled off naturally without applying force to the electronic product. Based on these circumstances, by using the adhesive sheet of this embodiment, it is possible to produce fragile electronic products such as OLED with high yield. For example, the method of manufacturing OLED using the adhesive sheet of this embodiment includes the following steps: attaching the adhesive sheet of this embodiment to the gas barrier layer of the OLED; The step of peeling the sheet from the aforementioned gas barrier layer. [Examples]

Hereinafter, the present invention will be further explained in detail with examples and comparative examples. However, the present invention is not limited to the following examples.　　The "%" and "parts" in the following description, unless otherwise specified, are the quality standards. By the method shown below, hydroxyl-containing (meth)acrylic resins (A-11) to (A-13) and urethane prepolymers (D-11) to (D-13) are produced .

(Synthesis Example 1) <(Meth)acrylic resin containing hydroxyl group (A-11)> 　　 In a reaction device equipped with a stirrer, a temperature regulator, a reflux cooler, a dropping funnel, and a thermometer, the following are shown in Table 1. Type and ratio (parts by mass) of polymerizable monomers and 100 parts by mass of ethyl acetate as a solvent. After heating and refluxing was started, 0.1 parts by mass of V-601 (manufactured by Fujifilm Wako Pure Chemical Industries) was added as a polymerization initiator, and the mixture was reacted at the reflux temperature of ethyl acetate for 3 hours. After that, 0.2 parts by mass of azobisisobutyronitrile dissolved in 15 parts by mass of ethyl acetate was added, and the reaction was further performed at the reflux temperature for 4 hours. Finally, 70 parts by mass of ethyl acetate was added to obtain a 35% hydroxyl-containing (meth)acrylic resin (A-11) solution with a solid content of 35%. The so-called solid content refers to the ratio (mass%) of the residual component after removing the solvent content to the hydroxyl group-containing (meth)acrylic resin (A-11) solution (mass%), which is obtained by the following method.

(Synthesis examples 2~3) <Hydroxy-containing (meth)acrylic resin (A-12), (A-13)> Except for using polymerizable monomers of the type and ratio (parts by mass) shown in Table 1, By the same method as the hydroxyl-containing (meth)acrylic resin (A-11) solution, a 35% hydroxyl-containing (meth)acrylic resin (A-12), (A-13) solution with a solid content of 35% was obtained.

(Synthesis example 4) <Urethane prepolymer (D-11)> 　　 In a reaction device equipped with a stirrer, a temperature regulator, a reflux cooler, a dropping funnel, and a thermometer, the types shown in Table 2 are fed And the ratio (parts by mass) of polyol, the type and ratio (parts by mass) shown in Table 2 polyisocyanate, 30 parts by mass of toluene, and 0.1 parts by mass of dioctyltin dilaurate, stir at 65°C~ It was allowed to react at 75°C for 6 hours. Finally, 12 parts by mass of toluene was added to obtain a urethane prepolymer (D-11) solution with a solid content of 70%.

(Synthesis examples 5~6) <Urethane prepolymers (D-12), (D-13)> 　　 Except for using polymerizable monomers of the type and ratio (parts by mass) shown in Table 2, borrow In the same way as the urethane prepolymer (D-11) solution, a solution of the urethane prepolymer (D-12) and (D-13) with a solid content of 70% was obtained.

The polymerizable single systems described in Table 1 used the compounds shown below. Dimethacrylamide, manufactured by KJ Chemical Co., Ltd., butyl acrylate, manufactured by Toagosei Co., Ltd., 2-ethylhexyl acrylate, manufactured by Toagosei Co., Ltd., manufactured by Toagosei Co., Ltd., manufactured by Toagosei Co., Ltd., manufactured by Toagosei Co., Ltd., 2-hydroxyethyl acrylate, Osaka Made by Organic Chemical Industry Co., Ltd. 4-Hydroxybutyl Acrylate Made by Osaka Organic Chemical Industry Co., Ltd. Made Acrylic Acid Made by Nippon Shokubai Co., Ltd.

The raw materials described in Table 2 used the following compounds. Polyol Propylene oxide and ethylene oxide adducts of glycerin (manufactured by Lion, number average molecular weight 2000) 　　polyol Polycaprolactone polyol (manufactured by Perstoop, product name: Capa, number average molecular weight 2000) 　　polyisocyanate Duranate D101 (manufactured by Asahi Kasei Chemical Co., Ltd.) 　　Polyisocyanate Duranate A201H (manufactured by Asahi Kasei Chemical Co., Ltd.)

The resins (A-11) to (A-13) obtained in Synthesis Examples 1 to 3 and (D-11) to (D-13) obtained in Synthesis Examples 4 to 6 described in Table 1 and Table 2 The weight average molecular weight (Mw), glass transition temperature (Tg), and solid content are measured by the methods shown below. The results are shown in Table 1 and Table 2.

<Weight average molecular weight (Mw)> 　　Using a gel permeation chromatograph (manufactured by Showa Denko Co., Ltd., Shodex (registered trademark) GPC-101), it was measured at room temperature under the following conditions and calculated in terms of polystyrene. Column: manufactured by Showa Denko Corporation, Shodex (registered trademark) LF-804 Column temperature: 40°C Sample: 0.2% by mass of resin in tetrahydrofuran solution Flow rate: 1 ml/min Dissolving solution: tetrahydrofuran

<Glass transition temperature (Tg)> 　　Measured using a differential scanning calorimeter (manufactured by Hitachi High-Tech Science Co., Ltd., DSC7000X). Specifically, 1g is taken from the (meth)acrylic resin (A-11)~(A-13) solution containing hydroxyl groups, and dried at 100°C for 10 minutes to volatilize ethyl acetate as the solvent , And as a solid point. Take 10 mg from each solid fraction. In addition, a differential scanning calorimeter (DSC) was used to change the temperature of the sample from -80°C to 200°C at a heating rate of 10°C/min to perform differential scanning calorimeter measurement, and the endotherm due to glass transfer was observed The starting temperature is the glass transition temperature (Tg). However, when two Tgs are observed, it is set as the average value of the two Tgs.

＜Solid content＞ 　　 Weigh the hydroxyl-containing (meth)acrylic resins (A-11) to (A-13) obtained in Synthesis Examples 1 to 3 and the urethanes obtained in Synthesis Examples 4 to 6 respectively. Prepolymers (D-11) to (D-13) 2g, dried at 110°C for 5 hours, and weighed again. In addition, using the mass before drying and the mass after drying, it is calculated by the following formula. Still, the solid content of hydroxyl-containing (meth)acrylic resins (A-11)~(A-13) and urethane prepolymers (D-11)~(D-13) are regarded as all It is a copolymer. Solid content (mass%)=[A/B]×100 A: mass after drying B: mass before drying

(Examples 1 to 3) "Manufacturing of the first adhesive composition (a1) to (a3)" 　　In the indoor plastic container where the active line is blocked, add 285.7 mass according to the ratio shown in Table 3 Parts of a solution of hydroxyl-containing (meth)acrylic resins (A-11) to (A-13) obtained in Synthesis Examples 1 to 3 (as a solid content of 100 parts by mass), and 1 part by mass of hardener ( A-2), the gas generating agent (B) and the photosensitizer (C) are stirred to produce the first adhesive composition (a1) to (a3).

The following codes described in Table 3 are the compounds shown below. "Coronate (registered trademark) L-45E" 45% ethyl acetate solution of toluene diisocyanate adduct of trimethylolpropane made by Nippon Polyurethane Industry Co., Ltd. "V-40" 1,1'-azobis( Cyclohexane-1-carbonitrile) ``VAm-110'' 2,2'-azobis(N-butyl-2-methylpropanamide) manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd. Fujifilm Wako Pure Chemical Industries "GAP-5003" glycidyl azide polymer manufactured by a company limited by shares manufactured by NOF Corporation "UVS-1331" 9,10-dibutoxyanthracene manufactured by Kawasaki Chemical Industry Co., Ltd., Anthracure (registered trademark) UVS-1331

(Examples 4 to 8, Comparative Examples 1 to 2) "Manufacturing of the second adhesive composition (b1) to (b7)" "In a plastic container in a room where the active line is blocked, the ratio shown in Table 4 , Add the urethane polymer (D-11) obtained in Synthesis Example 4, the urethane polymer (D-12) obtained in Synthesis Example 5, and the amine obtained in Synthesis Example 6 Any one of base format polymer (D-13), hydroxyl-containing (meth)acrylic resin (A-11), and hydroxyl-containing (meth)acrylic resin (A-12); hardener (D-2), polyfunctional ethylenically unsaturated group-containing compound (E), photopolymerization initiator (F), fluorine-containing compound (G), carboxylate (H), and stir to produce the second Adhesive composition (b1)~(b7).

The following codes described in Table 4 are the compounds shown below. "Coronate (registered trademark) L-45E" 45% ethyl acetate solution of toluene diisocyanate adduct of trimethylolpropane "Art Resin UN-3320HS" urethane acrylate made by Nippon Polyurethane Industry Co., Ltd. ``L-TPO'' 2,4,6-trimethylbenzyl-diphenyl-phosphine oxide manufactured by Neshang Industrial Co., Ltd. ``Megaface (registered trademark) RS-56'' fluorine-containing compound manufactured by BASF Corporation DIC shares Manufactured by a limited company "Megaface (registered trademark) F-571" fluorinated compound manufactured by DIC Co., Ltd.

The numerical system of hydroxyl-containing (meth)acrylic resins (A-11) to (A-13) and urethane prepolymers (D-11) to (D-13) in Tables 3 and 4 As the content (parts by mass) of the resin solution. In addition, the numerical values in parentheses refer to hydroxyl-containing (meth)acrylic resins (A-11) to (A-13) and urethane prepolymers (D-11) to (D- 13) The content of the net weight (parts by mass).

Next, using the first adhesive composition (a1) to (a3) shown in Table 3 and the second adhesive composition (b1) to (b7) shown in Table 4, the examples were produced by the method shown below 9-18. Adhesive sheets of Comparative Examples 3-8.

(Example 9) <Manufacturing of the first adhesive layer> Using an applicator, the first adhesive composition (a1) was coated on the processing surface side of the substrate so that the film thickness after heating and drying became 60 μm. The aforementioned substrate is made of a polyethylene terephthalate (PET) sheet with a thickness of 50 μm that has been subjected to corona discharge treatment. The sheet containing the layer of the first adhesive composition (a1) was heated and dried at 80°C for 2 minutes to be cured to form the first adhesive layer. The film thickness of the first adhesive layer is determined by measuring the thickness of the PET sheet attached to the first adhesive layer using a film thickness meter, and then subtracting the thickness of the PET sheet and the base material.

<Manufacturing of the second adhesive layer> Using an applicator, apply the second adhesive composition (b1) on the coating surface of the release sheet so that the film thickness after heating and drying becomes 15 μm. The aforementioned release sheet is composed of a 75 μm-thick polyethylene terephthalate (PET) sheet coated with a release agent. The sheet containing the layer of the second adhesive composition (b1) was heated and dried at 100°C for 2 minutes to be cured to form a second adhesive layer. The film thickness of the second adhesive layer is determined by measuring the thickness of the PET sheet attached to the second adhesive layer using a film thickness meter, and then subtracting the thickness of the PET sheet and the release sheet.

<Manufacturing of Adhesive Sheet> 　　The first adhesive layer and the second adhesive layer are arranged opposite to each other, and a 1kg rubber roller (width: about 25cm) is used from the top of the peeling sheet to reciprocate for bonding. The result is The first adhesive layer, the second adhesive layer and the adhesive sheet of the release sheet are sequentially laminated on the substrate.

(Examples 10 to 18, Comparative Examples 3 to 8) Except that the first adhesive composition shown in Table 5 and Table 6 was used to form the first adhesive layer with the film thickness shown in Table 3, and the use of Table 5 and Table 6 Except that the second adhesive composition shown forms the second adhesive layer with the film thickness shown in Table 4, the adhesive sheets of Examples 10 to 18 and Comparative Examples 3 to 8 were produced in the same manner as in Example 9.

Next, for the adhesive sheets of Examples 9 to 18 and Comparative Examples 3 to 8, test pieces were prepared by the methods shown below, respectively, and the peeling force before UV irradiation and the peeling properties after UV irradiation were evaluated. The results are shown in Table 5 and Table 6.

(Method for manufacturing test piece) The adhesive sheet was cut into a size of 25 mm in length and 100 mm in width, and the peeling sheet was peeled off to expose the second adhesive layer. Next, attach the adhesive sheet to the glass plate so that the exposed second adhesive layer (measurement surface) is in contact with the glass plate, and use a 2kg rubber roller (width: about 50mm) to make a round trip. Sample before UV irradiation. In addition, an ultraviolet irradiation device (manufactured by Eyegraphics, LED lamp (365nm)) was used to perform UV irradiation on the substrate side of the sample before UV irradiation under the conditions of ^{UV illuminance 150mW/cm 2} and UV irradiation amount 3000mJ/cm ² Prepare samples after UV irradiation.

(Evaluation of peel strength before UV irradiation) 　　 Place the sample before UV irradiation for 24 hours in an environment of 25°C and humidity 50%RH. Then, in accordance with JIS Z0237, a peeling tester (manufactured by Kyowa Interface Science Co., Ltd.) was used to perform a 180° tensile test at a peeling speed of 2400mm/min, and the peeling force between the glass plate and the adhesive sheet (N/25mm) was measured . The results are shown in Table 5 and Table 6.

(Evaluation of peelability after UV irradiation) 　　 For samples after UV irradiation, the peelability of the adhesive sheet was evaluated based on the following criteria.　　"Evaluation Criteria" 　　○: When the glass plate is pulled up while the adhesive sheet is down, the adhesive sheet peels off from the glass plate.　　△: The glass plate will peel off when the adhesive sheet is pulled down and vibration is applied.　　×: Even if the glass plate is pulled up and vibration is applied while the adhesive sheet is under the state, the adhesive sheet still does not peel off from the glass plate.

As shown in Table 5, the peeling force of the adhesive sheets of Examples 9 to 18 before UV irradiation was 0.2N/25mm or less, so the peeling force before UV irradiation was sufficiently low. In addition, for the adhesive sheets of Examples 9 to 18, when the glass plate was pulled up with the adhesive sheet in the down state after UV irradiation, all the adhesive sheets peeled off from the glass plate.

In contrast, as shown in Table 6, in Comparative Examples 3 to 8, using (meth)acrylic resin as the second adhesive layer, the peeling force before UV irradiation was 4.0N/25mm or more, so it is similar to the examples. Compared with the adhesive sheets of Examples 9 to 18, the peeling force before UV irradiation was higher.

In addition, in Comparative Examples 3, 5, and 7, even if the glass plate was pulled up with the adhesive sheet under the UV irradiation, the adhesive sheet did not peel off from the glass plate.

Claims (12)

An adhesive sheet, characterized in that it has: a substrate, a first adhesive layer, and a second adhesive layer, and the first adhesive layer and the second adhesive layer are sequentially laminated on the substrate, and the first The adhesive layer contains a cross-linked resin (A) and a gas generator (B) that generates gas by light irradiation. The second adhesive layer contains urethane resin (D), and the aforementioned cross-linked resin (A) It is the reaction product of the resin (A-1) containing multiple functional groups and the hardener (A-2). The aforementioned urethane resin (D) is a urethane prepolymer (D-1) and hardening The reactant of agent (D-2). The adhesive sheet according to claim 1, wherein the second adhesive layer further contains a polyfunctional ethylenically unsaturated group-containing compound (E) and a photopolymerization initiator (F). The adhesive sheet of claim 1, wherein the aforementioned urethane prepolymer (D-1) is a reactant of polyol and polyisocyanate. The adhesive sheet of claim 3, wherein the polyol is a polyol having two or more hydroxyl groups in one molecule, and the polyisocyanate is a polyisocyanate having two or three isocyanate groups in one molecule. The adhesive sheet of claim 1, wherein the second adhesive layer further contains a fluorine-containing compound (G). The adhesive sheet according to claim 1, wherein the second adhesive layer further contains carboxylic acid ester (H). The adhesive sheet of claim 1, wherein the aforementioned resin (A-1) is a (meth)acrylic resin containing a hydroxyl group. The adhesive sheet according to claim 7, wherein the total structural unit of the hydroxyl group-containing (meth)acrylic resin contains 0.5 to 20% by mass of the structural unit derived from the hydroxyl group-containing (meth)acrylate. The adhesive sheet of claim 7, wherein the glass transition temperature (Tg) of the (meth)acrylic resin containing the hydroxyl group is -60 to -10°C. The adhesive sheet of claim 1, wherein the aforementioned first adhesive layer further contains: a photosensitizer (C). For example, the adhesive sheet of any one of claims 1 to 10, wherein the peel force measured under the following conditions is 3.0N/25mm or less, 　 measurement conditions: 　　 sample size: length 25mm × width 100mm; adherend: glass; measurement Temperature: 25°C; peeling speed: 2400mm/min; measurement mode: 180° peeling. An OLED manufacturing method includes: 　　 attaching an adhesive sheet as in any one of Claims 1 to 11 to the gas barrier layer of the OLED The step of peeling off the barrier layer.