TW202402995A - Adhesive composition, adhesive sheet, and bonded body - Google Patents

Abstract

The invention relates to an adhesive composition, an adhesive sheet and a bonded body. The present invention relates to an adhesive composition comprising at least a polymer and an ionic liquid, in which an adhesive layer is formed using a composition comprising components other than the ionic liquid among the contained components, and the adhesive layer has a relative dielectric constant of 5 or more at a frequency of 100 Hz after the adhesive layer is left to stand for 3 days in an environment of 22 DEG C and 20% RH.

Description

Adhesive composition, adhesive sheet, and joint body

The present invention relates to an adhesive composition, an adhesive sheet including an adhesive layer formed from the adhesive composition, and a joint between the adhesive sheet and an adherend.

In electronic parts manufacturing steps, etc., there are increasing requirements related to secondary processing to improve yield, or reuse of parts that are disassembled and recycled after use. In order to meet such requirements, a double-sided adhesive sheet with a certain adhesion force and a certain peelability is sometimes used when joining components together in the electronic component manufacturing process.

As a double-sided adhesive sheet that achieves the above-mentioned adhesive force and releasability, there are known adhesive sheets in which an ionic liquid containing cations and anions is used as a component forming the adhesive composition, and a voltage is applied to the adhesive layer to cause peeling ( Electro-peelable adhesive sheet) (Patent Documents 1 to 3). Regarding the electro-peelable adhesive sheets of Patent Documents 1 to 3, it is believed that by application of voltage, the cations of the ionic liquid move to the cathode side to cause reduction, and the anions of the ionic liquid move to the anode side to cause oxidation, followed by the adhesion force at the interface. weaken and become easier to peel off. [Prior technical literature] [Patent Document]

Patent Document 1: Japanese Patent Application Publication No. 2010-037354 Patent Document 2: Japanese Patent No. 6097112 Patent Document 3: Japanese Patent No. 4139851

[Problem to be solved by the invention]

The electrically peelable adhesive sheet is preferably one that can firmly join the components when voltage is not applied, and can be peeled off with less force when voltage is applied. Therefore, it is preferable that the reduction rate of the adhesive force obtained by voltage application is large in the electro-peelable adhesive sheet. However, in an environment with low humidity such as winter, the reduction rate of the adhesive force obtained by voltage application becomes a problem.

The present invention was completed in view of the above, and its object is to provide an adhesive composition that can sufficiently reduce the adhesive force by application of voltage in a low-humidity environment, and to provide an adhesive layer formed from the adhesive composition. The adhesive piece. [Technical means to solve problems]

According to the research of the present inventors, the reduction rate of the adhesive force obtained by voltage application in a low-humidity environment is reduced because the moisture content of the adhesive layer decreases in a low-humidity environment and the cations and anions of the ionic liquid are less likely to move. cause. The inventors of the present invention further conducted repeated studies, and as a result obtained the following insights. First, it was found that the relative dielectric constant of components other than ionic liquid in the adhesive layer is correlated with the reduction rate of the adhesive force obtained by voltage application. By increasing the relative dielectric constant, the adhesion force obtained by voltage application can be increased. The reduction rate of the adhesion force. It was also found that when the moisture content of the adhesive layer is reduced in a low-humidity environment, if the relative dielectric constant is large, the electrical peelability is also good, that is, the reduction rate of the adhesive force obtained by voltage application is relatively small. big. Second, it was found that the ionic conductivity of the adhesive layer, the capacitance per unit area of the interface between the adhesive layer and the adherend, and the reduction rate of the adhesive force obtained by voltage application are correlated. By increasing the ionic conductivity The rate and the capacitance per unit area of the interface between the adhesive layer and the adherend can increase the reduction rate of the adhesive force obtained by voltage application. Furthermore, it was found that when the moisture content of the adhesive layer is reduced in a low-humidity environment, if the ionic conductivity and the capacitance per unit area of the interface between the adhesive layer and the adherend are large, the electrical peelability will be reduced. It is also good, that is, the reduction rate of the adhesive force obtained by voltage application is large.

An adhesive composition of the present invention based on the above-mentioned first finding contains a polymer and an ionic liquid, and an adhesive layer is formed using a composition containing components other than the ionic liquid among the components contained in the adhesive composition. And after placing the adhesive layer in an environment of 22°C and 20% RH for 3 days, the relative dielectric constant of the adhesive layer at a frequency of 100 Hz is above 5.

Another adhesive composition of the present invention based on the above second finding is one that contains a polymer and an ionic liquid. The adhesive composition is used to form an adhesive layer and is attached to an aluminum plate containing A5052P H32 in JIS H4000:2014. , after being placed in an environment of 22°C and 15% RH for 7 days, the capacitance per unit area of the interface between the adhesive layer and the aluminum plate is more than 0.9 μF/ ^cm2 , and the ionic conductivity of the adhesive layer is 10 μS /m or above.

In one aspect of the adhesive composition of the present invention, the adhesive composition is used to form an adhesive layer and attached to an aluminum plate containing A5052P H32 in JIS H4000:2014, and placed in an environment of 22°C and 15%RH. After 7 days, the capacitance per unit area of the interface between the adhesive layer and the aluminum plate can be more than 1.2 μF/cm ² , and the ion conductivity of the adhesive layer can be more than 20 μS/m.

In one aspect of the adhesive composition of the present invention, the adhesive composition may further include an ionic solid.

In one aspect of the adhesive composition of the present invention, the polymer may include an ionic polymer.

In one aspect of the adhesive composition of the present invention, the polymer may include polyester polymers, urethane polymers, and polymers having carboxyl groups, alkoxy groups, hydroxyl groups, and/or amide bonds. At least one of the group consisting of acrylic polymers.

Moreover, another adhesive composition of the present invention contains a polymer and an ionic liquid, and contains 0.5 to 30 parts by mass of the ionic liquid and 0.5 to 10 parts by mass of the ionic solid relative to 100 parts by mass of the polymer.

Furthermore, another adhesive composition of the present invention contains a polymer and an ionic liquid, and contains 0.5 to 30 parts by mass of the ionic liquid relative to 100 parts by mass of the polymer, and 0.05 to 2 parts by mass of the ionic polymer in the polymer. .

Furthermore, another adhesive composition of the present invention contains 100 parts by mass of an acrylic polymer and 0.5 to 30 parts by mass of an ionic liquid, and the polar group-containing monomers are The ratio is 0.1 to 35% by mass.

In one aspect of the present invention, the adhesive composition is used for electro-stripping.

Moreover, the adhesive sheet of this invention is equipped with the adhesive layer formed from the adhesive composition of this invention.

Furthermore, the joint body of the present invention includes an adherend having a metal adherent surface, and the adhesive sheet of the present invention, and the adhesive layer of the adhesive sheet of the present invention is bonded to the metal adherent surface. [Effects of the invention]

The adhesive composition of the present invention can also fully reduce the adhesive force by applying voltage in a low-humidity environment.

Hereinafter, the form for carrying out the present invention will be described in detail. In addition, the present invention is not limited to the embodiments described below.

[Adhesive composition] The adhesive compositions of the first and second embodiments of the present invention each contain a polymer and an ionic liquid. An adhesive layer is formed using a composition containing components other than the ionic liquid among the components contained in the adhesive composition of the first embodiment, and the adhesive layer is left in an environment of 22°C and 20% RH for 3 days. Afterwards, the relative dielectric constant of the adhesive layer at a frequency of 100 Hz is above 5. Furthermore, an adhesive layer was formed using the adhesive composition of the second embodiment and attached to an aluminum plate containing A5052P H32 in JIS H4000:2014. The adhesive was left in an environment of 22°C and 15% RH for 7 days. The capacitance per unit area of the interface between the layer and the aluminum plate is above 0.9 μF/cm ² , and the ionic conductivity of the adhesive layer is above 10 μS/m. These adhesive compositions have the property of reducing adhesive force by application of voltage, and are suitable as adhesive compositions for electrical peeling. In addition, the above-mentioned first and second embodiments are not exclusive. There are adhesive compositions that conform to any one of the first and second embodiments, and there are also adhesive compositions that conform to only one of them. As long as the adhesive composition conforms to either the first or second embodiment, the effects of the present invention will be exerted. These adhesive compositions are described below.

In addition, in this specification, the 1st and 2nd embodiment of this invention may be collectively called "this embodiment". Furthermore, in this specification, the adhesion force when voltage is not applied is sometimes referred to as "initial adhesion force". In addition, a composition containing components other than ionic liquid among the components contained in the adhesive composition may be referred to as an "adhesive composition not containing ionic liquid". Moreover, the adhesive layer formed using the adhesive composition which does not contain ionic liquid is sometimes called "the adhesive layer which does not contain ionic liquid". In addition, the property of reducing the adhesive force by voltage application is sometimes called "electro-peelability", and the property of reducing the adhesive force by voltage application is sometimes called "excellent electro-peelability", etc.

＜Components of adhesive composition＞ (polymer) The adhesive composition of this embodiment contains a polymer. In this embodiment, the polymer is not particularly limited as long as it is a common organic polymer compound, such as a polymer of monomers or a partial polymer. The monomer may be one type of monomer or a mixture of two or more types of monomers. Furthermore, the so-called partial polymer refers to a polymer in which at least a part of the monomer or monomer mixture is partially polymerized.

The polymer in this embodiment is usually used as an adhesive, and is not particularly limited as long as it has adhesive properties. Examples include acrylic polymers, rubber polymers, vinyl alkyl ether polymers, and polysiloxanes. Polymers, polyester polymers, polyamide polymers, urethane polymers, fluorine polymers, and epoxy polymers, etc. The polymer can be used alone or in combination of two or more types. In order to increase the relative dielectric constant of components other than the ionic liquid in the obtained adhesive layer, increase the ionic conductivity of the obtained adhesive layer and the capacitance per unit area of the bonding interface, and improve the electrical peelability, It is preferable that the relative dielectric constant of the polymer is large. From this point of view, it is particularly preferable that the polymer in this embodiment contains a polyester-based polymer, a urethane-based polymer, and a polymer having a carboxyl group. , at least one of the group consisting of acrylic polymers with alkoxy groups, hydroxyl groups and/or amide bonds. Polyester polymers and urethane polymers have easily polarizable hydroxyl groups at the terminals, and acrylic polymers have carboxyl groups, alkoxy groups, and/or amide bonds. Hydroxyl and/or amide bonds are easily polarized, so by using these polymers, polymers with relatively large relative dielectric constants can be obtained. The total content of the polyester polymer and the acrylic polymer having a carboxyl group, an alkoxy group, a hydroxyl group and/or an amide bond in the polymer of this embodiment is preferably 60 mass % or more, more preferably 80 mass %. %above. In addition, in particular, in order to reduce costs, productivity, and increase initial adhesive strength, the polymer in this embodiment is preferably an acrylic polymer. That is, the adhesive composition of this embodiment is preferably an acrylic adhesive composition containing an acrylic polymer as a polymer.

The acrylic polymer preferably contains a monomer unit derived from an alkyl (meth)acrylate (the following formula (1)) having an alkyl group having 1 to 14 carbon atoms. This kind of monomer unit is suitable for obtaining larger initial adhesion force. Furthermore, in order to increase the relative dielectric constant of the components of the adhesive layer other than the ionic liquid, and to increase the ionic conductivity of the obtained adhesive layer and the capacitance per unit area of the bonding interface, and to improve the electrical peelability, it is better to The carbon number of the alkyl group R ^b in the following formula (1) is preferably small, particularly preferably 8 or less, more preferably 4 or less. CH ₂ =C(R ^a )COOR ^b (1) [R ^a in formula (1) is a hydrogen atom or a methyl group, and R ^b is an alkyl group with 1 to 14 carbon atoms]

Examples of the (meth)acrylic acid alkyl ester having an alkyl group having 1 to 14 carbon atoms include: (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid propyl ester, (meth)acrylic acid propyl ester, (meth)acrylic acid alkyl ester Isopropyl acrylate, n-butyl (meth)acrylate, 2-butyl (meth)acrylate, 1,3-dimethylbutyl acrylate, amyl (meth)acrylate, (meth)acrylic acid Isoamyl ester, hexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-Ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, (meth)acrylate (Basic) n-dodecyl acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, etc. Among them, n-butyl acrylate, 2-ethylhexyl acrylate, and isononyl acrylate are preferred. The (meth)acrylic acid alkyl ester having an alkyl group having 1 to 14 carbon atoms can be used alone or in combination of two or more.

The ratio of alkyl (meth)acrylate having an alkyl group having 1 to 14 carbon atoms relative to all monomer components constituting the acrylic polymer (100% by mass) is not particularly limited, but is preferably 70% by mass or more. More preferably, it is 80 mass % or more, and still more preferably, it is 85 mass % or more. If the ratio of the acrylic polymer is 70% by mass or more, a large initial adhesive force can be easily obtained.

As the acrylic polymer, in order to modify the cohesive force, heat resistance, cross-linkability, etc., it is preferable that in addition to monomer units derived from alkyl (meth)acrylate having an alkyl group having 1 to 14 carbon atoms, and contains monomer units derived from polar group-containing monomers copolymerizable therewith. The monomer unit can provide cross-linking points, which is suitable for obtaining greater initial adhesion strength. Furthermore, the relative dielectric constant of the components other than the ionic liquid in the adhesive layer is increased, and the ionic conductivity of the obtained adhesive layer and the capacitance per unit area of the bonded interface are increased, thereby improving the electrical peelability. In particular, it is also preferred to include monomer units derived from polar group-containing monomers.

Examples of the polar group-containing monomer include carboxyl group-containing monomers, alkoxy group-containing monomers, hydroxyl group-containing monomers, cyano group-containing monomers, vinyl group-containing monomers, and aromatic vinyl groups. Monomers, amide-containing monomers, amide-imide-containing monomers, amine-containing monomers, epoxy-containing monomers, vinyl ether monomers, N-acrylamide group-containing monomers, sulfonate-containing monomers Monomers containing phosphoric acid groups, monomers containing acid anhydride groups, etc. Among them, in terms of excellent cohesion properties, carboxyl group-containing monomers, alkoxy group-containing monomers, hydroxyl group-containing monomers, and amide group-containing monomers are preferred, and carboxyl group-containing monomers are particularly preferred. . Carboxyl-containing monomers are particularly suitable for obtaining greater initial adhesion. The polar group-containing monomer can be used alone or in combination of two or more types.

Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, and fumaric acid. , crotonic acid, and methacrylic acid, etc. Acrylic is particularly preferred. The carboxyl group-containing monomer can be used alone or in combination of two or more types.

Examples of the alkoxy group-containing monomer include methoxy group-containing monomers and ethoxy group-containing monomers. Examples of the methoxy group-containing monomer include 2-methoxyethyl acrylate.

Examples of the hydroxyl-containing monomer include: (meth)acrylic acid 2-hydroxyethyl ester, (meth)acrylic acid 2-hydroxypropyl ester, (meth)acrylic acid 4-hydroxybutyl ester, (meth)acrylic acid 6 -Hydroxyhexyl ester, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclo)acrylate Hexyl) methyl ester, N-hydroxymethyl (meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether, etc. . Particularly preferred are 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. The hydroxyl group-containing monomer can be used alone or in combination of two or more types.

Examples of the amide group-containing monomer include acrylamide, methacrylamide, N-vinylpyrrolidone, N,N-dimethylacrylamide, and N,N-dimethylmethacrylamide. Acrylamide, N,N-diethylacrylamide, N,N-diethylmethacrylamide, N,N'-methylenebisacrylamide, N,N-dimethylamine Propyl acrylamide, N,N-dimethylaminopropyl methacrylamide, and diacetone acrylamide, etc. The amide group-containing monomer can be used alone or in combination of two or more types.

Examples of the cyano group-containing monomer include acrylonitrile, methacrylonitrile, and the like.

Examples of the vinyl group-containing monomer include vinyl esters such as vinyl acetate, vinyl propionate, and vinyl laurate, and vinyl acetate is particularly preferred.

Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrenes.

Examples of the monomer containing a maleimide group include: cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and Icon acyl imine etc.

Examples of the amine group-containing monomer include: (meth)aminoethyl acrylate, (meth)acrylic acid N,N-dimethylaminoethyl ester, and (meth)acrylic acid N,N-dimethylaminoethyl ester. Methylaminopropyl ester, etc.

Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, and allyl glycidyl ether.

Examples of vinyl ether monomers include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, and the like.

The ratio of the polar group-containing monomer to all monomer components (100 mass %) constituting the acrylic polymer is preferably 0.1 mass % or more and 35 mass % or less. The upper limit of the ratio of the polar group-containing monomer is more preferably 25 mass%, further preferably 20 mass%, and the lower limit is more preferably 0.5 mass%, further preferably 1 mass%, and particularly preferably 2 mass%. If the ratio of the polar group-containing monomer is 0.1% by mass or more, cohesion is easily obtained, so that paste residue is less likely to occur on the surface of the adherend after peeling off the adhesive layer, and the electrical peelability is improved. In addition, if the ratio of the polar group-containing monomer is 35% by mass or less, it is easy to prevent the adhesive layer from being excessively adhered to the adherend and causing re-peeling. In particular, if the content is 2 mass % or more and 20 mass % or less, it is easy to achieve both peelability from the adherend and adhesion between the adhesive layer and other layers.

In addition, as the monomer component constituting the acrylic polymer, a polyfunctional monomer may be included in order to introduce a cross-linked structure into the acrylic polymer and easily obtain the required cohesive force.

Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and neopentyl glycol di(meth)acrylate. (Meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate ) acrylate, divinylbenzene, and N,N'-methylene bisacrylamide, etc. The polyfunctional monomer can be used alone or in combination of two or more types.

The content of the polyfunctional monomer relative to all monomer components (100 mass%) constituting the acrylic polymer is preferably 0.1 mass% or more and 15 mass% or less. The upper limit of the content of the polyfunctional monomer is more preferably 10% by mass, and the lower limit is more preferably 3% by mass. If the content of the polyfunctional monomer is 0.1% by mass or more, the flexibility and adhesiveness of the adhesive layer can be easily improved, which is preferable. If the content of the polyfunctional monomer is 15% by mass or less, the cohesive force will not become too high and appropriate adhesion will be easily obtained.

Polyester-based polymers typically contain polycarboxylic acids such as dicarboxylic acids or their derivatives (hereinafter also referred to as "polycarboxylic acid monomers"), and polyhydric alcohols such as diols or their derivatives (hereinafter referred to as "polycarboxylic acid monomers"). A polymer with a structure in which alcohol monomers are condensed.

The polycarboxylic acid monomer is not particularly limited, and examples thereof include adipic acid, azelaic acid, dimer acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid. Carboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, dodecylsuccinic anhydride, fumaric acid, succinic acid, dodecanedioic acid Acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, etc., maleic acid, maleic anhydride, itaconic acid, citraconic acid, and their derivatives, etc. The polyvalent carboxylic acid monomer can be used alone or in combination of two or more types.

The polyol monomer is not particularly limited, and for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1 ,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diol Ethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,5-pentanediol, 2-ethyl-2-butylpropanediol, 1,9-nonanediol, 2-methyloctanediol alcohol, 1,10-decanediol, and their derivatives, etc. The polyol monomer can be used alone or in combination of two or more types.

Moreover, the polymer of this embodiment may contain an ionic polymer. Ionic polymers are polymers with ionic functional groups. By including an ionic polymer in the polymer, the relative dielectric constant of the polymer is increased and the electrical stripping property is improved. When the polymer contains an ionic polymer, the content of the ionic polymer is preferably 0.05 parts by mass or more and 2 parts by mass or less based on 100 parts by mass of the polymer.

In this embodiment, the polymer can be obtained by (co)polymerizing monomer components. The polymerization method is not particularly limited, and examples thereof include solution polymerization, emulsion polymerization, block polymerization, suspension polymerization, photopolymerization (active energy ray polymerization), and the like. In particular, from the viewpoint of cost and productivity, the solution polymerization method is preferred. In the case of copolymerization, the polymer may be any of random copolymers, block copolymers, alternating copolymers, graft copolymers, etc.

The solution polymerization method is not particularly limited, and examples thereof include a method in which a monomer component, a polymerization initiator, etc. are dissolved in a solvent, and the polymerization is performed by heating to obtain a polymer solution containing the polymer.

As the solvent used in the solution polymerization method, various common solvents can be used. Examples of such solvents (polymerization solvents) include aromatic hydrocarbons such as toluene, benzene, and xylene; esters such as ethyl acetate and n-butyl acetate; and aliphatic hydrocarbons such as n-hexane and n-heptane. alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; ketones such as methyl ethyl ketone and methyl isobutyl ketone and other organic solvents. The solvent can be used alone or in combination of two or more types.

The usage amount of the solvent is not particularly limited, but is preferably 10 parts by mass or more and 1000 parts by mass or less based on all the monomer components constituting the polymer (100 parts by mass). The upper limit of the usage amount of the solvent is more preferably 500 parts by mass, and the lower limit is more preferably 50 parts by mass.

The polymerization initiator used in the solution polymerization method is not particularly limited, and examples thereof include peroxide-based polymerization initiators, azo-based polymerization initiators, and the like. The peroxide-based polymerization initiator is not particularly limited, and examples thereof include peroxycarbonate, peroxyketone, peroxyketal, hydrogen peroxide, dialkyl peroxide, diyl peroxide, and peroxide. Oxygen esters, etc., more specifically, include: benzoyl peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, dicumyl peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, and 1,1-bis(tert-butylperoxy)cyclododecane, etc. The azo polymerization initiator is not particularly limited, and examples thereof include: 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'- Azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylpropionate)dimethyl ester, 2,2'-azobis(4-methoxy- 2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4,4-trimethylpentane ), 4,4'-azobis-4-cyanovaleric acid, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-( 5-Methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine)disulfate, 2,2'-azobis( N,N'-dimethyleneisobutylamidine) hydrochloride, and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate, etc. The polymerization initiator can be used alone or in combination of two or more types.

The usage amount of the polymerization initiator is not particularly limited, but is preferably 0.01 parts by mass or more and 5 parts by mass or less based on all the monomer components constituting the polymer (100 parts by mass). The upper limit of the usage amount of the polymerization initiator is more preferably 3 parts by mass, and the lower limit is more preferably 0.05 parts by mass.

The heating temperature during polymerization by heating by the solution polymerization method is not particularly limited, but is, for example, 50°C or more and 80°C or less. The heating time is not particularly limited, but is, for example, 1 hour or more and 24 hours or less.

The weight average molecular weight of the polymer is not particularly limited, but is preferably 100,000 or more and 5,000,000 or less. The upper limit of the weight average molecular weight is more preferably 4 million, more preferably 3 million, and the lower limit is more preferably 200,000, more preferably 300,000. If the weight average molecular weight is more than 100,000, it can effectively prevent the reduction of cohesive force and the occurrence of paste residue on the surface of the adherend after peeling off the adhesive layer. In addition, if the weight average molecular weight is 5 million or less, the problem of insufficient wettability of the adherend surface after peeling off the adhesive layer can be effectively suppressed.

The weight average molecular weight is measured by gel permeation chromatography (GPC). More specifically, for example, the trade name "HLC-8220GPC" (manufactured by Tosoh Corporation) can be used as a GPC measurement device under the following conditions. The measurement is performed below and calculated using the standard polystyrene conversion value. (Weight average molecular weight measurement conditions) ・Sample concentration: 0.2 mass% (tetrahydrofuran solution) ・Sample injection volume: 10 μL ・Sample column: TSKguardcolumn SuperHZ-H (1 piece) + TSKgel SuperHZM-H (2 pieces) ・Reference column: TSKgel SuperH-RC (1 piece) ・Eluent: Tetrahydrofuran (THF) ・Flow rate: 0.6 mL/min ・Detector: Differential Refractometer (RI) ・Column temperature (measurement temperature): 40℃

The glass transition temperature (Tg) of the polymer is not particularly limited, but it is preferably 0°C or lower because the decrease in initial adhesive strength can be suppressed. It is more preferably -10°C or lower, and still more preferably -20°C or lower. Moreover, it is particularly preferable if it is -40°C or lower, because the reduction rate of the adhesive force obtained by voltage application becomes particularly large, and it is most preferably -50°C or lower.

The glass transition temperature (Tg) can be calculated based on the following formula (Y) (Fox formula), for example. 1/Tg=W1/Tg1+W2/Tg2+・・・+Wn/Tgn(Y) [In formula (Y), Tg represents the glass transition temperature of the polymer (unit: K), and Tgi (i=1, 2,・・・n) represents the glass transition temperature when monomer i forms a homopolymer (unit: K), Wi(i=1, 2,・・・n) represents the mass fraction of monomer i in all monomer components] The above formula (Y) is a calculation formula when the polymer is composed of n types of monomer components such as monomer 1, monomer 2,..., and monomer n.

Furthermore, the glass transition temperature when forming a homopolymer refers to the glass transition temperature of the homopolymer of the monomer, and refers to the glass transition temperature when only a certain monomer (sometimes referred to as "monomer X") is used as a monomer component. Glass transition temperature (Tg) of the polymer formed. Specifically, numerical values are listed in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc, 1989). In addition, the glass transition temperature (Tg) of a homopolymer which is not described in this document refers to the value obtained by the following measurement method, for example. That is, into a reactor equipped with a thermometer, a stirrer, a nitrogen introduction pipe and a reflux condenser, 100 parts by mass of monomer mass parts, stirring for 1 hour while introducing nitrogen gas. After removing the oxygen in the polymerization system in this way, the temperature was raised to 63°C and allowed to react for 10 hours. Then, it was cooled to room temperature, and a homopolymer solution with a solid content concentration of 33% by mass was obtained. Then, the homopolymer solution was cast-coated on a release liner and dried to prepare a test sample (sheet-shaped homopolymer) with a thickness of about 2 mm. Then, weigh about 1 to 2 mg of the test sample and place it in an aluminum open tank, and use a temperature modulation DSC (Differential Scanning Calorimeter) (trade name "Q-2000" TA Instruments company), the reversing heat flow (specific heat component) behavior of the homopolymer was obtained in a nitrogen atmosphere of 50 ml/min at a heating rate of 5°C/min. Referring to JIS-K-7121, a straight line equidistant in the vertical axis direction from a straight line obtained by extending the reference line of the low-temperature side and the high-temperature side of the obtained reversible heat flow, and the step-like change part of the glass transfer The curves intersect, and the temperature at the intersection is set as the glass transition temperature (Tg) when the homopolymer is produced.

The polymer content in the adhesive composition of this embodiment is preferably 50 mass % or more and 99.9 mass % or less relative to the total amount of the adhesive composition (100 mass %), and the upper limit is more preferably 99.5 mass %. , more preferably 99 mass%, and the lower limit is more preferably 60 mass%, further preferably 70 mass%.

(ionic liquid) The ionic liquid system in this embodiment is composed of a pair of anions and cations, and is not particularly limited as long as it is a molten salt that is liquid at 25° C. (normal temperature molten salt). Examples of anions and cations are listed below. Among the ionic substances obtained by combining these, those that are liquid at 25°C are ionic liquids, and those that are solid at 25°C are the following ionic solids and are not ionic liquids.

Examples of the anions of the ionic liquid include: (FSO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₂ N ^- , (CF ₃ CF ₂ SO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₃ C ^- , Br ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , NO ₃ ^- , BF ₄ ^- , PF ₆ ^- , CH ₃ COO ^- , CF ₃ COO ^- , CF ₃ CF ₂ CF ₂ COO ^- , CF ₃ SO ₃ ^- , CF ₃ (CF ₂ ) ₃ SO ₃ ^- , AsF ₆ ^- , SbF ₆ ^- , and F(HF) _n ^- , etc. Among them, as anions, (FSO ₂ ) _2n ^- [bis(fluorosulfonyl)imide anion], (CF ₃ SO ₂ ) _2n ^- [bis(trifluoromethanesulfonyl)imide anion], etc. The anion of the sulfonyl imine compound is preferable in that it is chemically stable and suitable for improving the electrical stripping properties.

Regarding the cations in the ionic liquid, nitrogen-containing onium, sulfur-containing onium, and phosphorus-containing onium cations are preferred in terms of chemical stability and being suitable for improving the electrical stripping properties, and imidazolium-based cations are more preferred. , ammonium, pyrrolidinium, and pyridinium cations.

Examples of imidazolium-based cations include 1-methylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, and 1-butyl-3 -Methylimidazolium cation, 1-pentyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-heptyl-3-methylimidazolium cation, 1-octyl- 3-methylimidazolium cation, 1-nonyl-3-methylimidazolium cation, 1-undecyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation , 1-tridecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1-pentadecyl-3-methylimidazolium cation, 1-hexadecan Alkyl-3-methylimidazolium cation, 1-heptadecyl-3-methylimidazolium cation, 1-octadecyl-3-methylimidazolium cation, 1-undecyl-3- Methylimidazolium cation, 1-benzyl-3-methylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, and 1,3-bis(dodecyl)imidazolium cation wait.

Examples of pyridinium-based cations include 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, and 1-butyl-4-methylpyridinium cation. , and 1-octyl-4-methylpyridinium cation, etc.

Examples of the pyrrolidinium-based cation include 1-ethyl-1-methylpyrrolidinium cation and 1-butyl-1-methylpyrrolidinium cation.

Examples of ammonium-based cations include tetraethylammonium cation, tetrabutylammonium cation, methyltrioctylammonium cation, tetradecyltrihexylammonium cation, glycidyltrimethylammonium cation, and trimethylamine Ethyl acrylate cation, etc.

As the ionic liquid, from the viewpoint of increasing the reduction rate of the adhesive force when a voltage is applied, it is preferable to select a cation having a molecular weight of 160 or less as a constituent cation, and it is particularly preferable to select a cation containing the above-mentioned (FSO ₂ ) ₂ N ^- [bis (Fluorosulfonyl)imide anion] or (CF ₃ SO ₂ ) ₂ N ^- [bis (trifluoromethanesulfonyl) imide anion], and ionic liquids of cations with a molecular weight of less than 160. Examples of cations having a molecular weight of 160 or less include: 1-methylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl- 3-methylimidazolium cation, 1-pentyl-3-methylimidazolium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1 -Butyl-4-methylpyridinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-butyl-1-methylpyrrolidinium cation, tetraethylammonium cation, glycidyltris Methyl ammonium cation, and trimethylaminoethyl acrylate cation, etc.

Furthermore, cations represented by the following formulas (2-A) to (2-D) are also preferred as cations in the ionic liquid. [Chemical 1]

R ¹ in formula (2-A) represents a hydrocarbon group with 4 to 10 carbon atoms (preferably a hydrocarbon group with 4 to 8 carbon atoms, more preferably a hydrocarbon group with 4 to 6 carbon atoms), and may also contain a heteroatom. R ² and R ³ are the same or different, and represent a hydrogen atom or a hydrocarbon group with 1 to 12 carbon atoms (preferably a hydrocarbon group with 1 to 8 carbon atoms, more preferably a hydrocarbon group with 2 to 6 carbon atoms, even more preferably a hydrocarbon group with 2 to 4 carbon atoms) hydrocarbyl), which may also contain heteroatoms. Among them, when a nitrogen atom forms a double bond with an adjacent carbon atom, R ³ does not exist.

R ⁴ in formula (2-B) represents a hydrocarbon group with 2 to 10 carbon atoms (preferably a hydrocarbon group with 2 to 8 carbon atoms, more preferably a hydrocarbon group with 2 to 6 carbon atoms), and may also contain heteroatoms, R ⁵ , R ⁶ , and R ⁷ are the same or different, and represent a hydrogen atom or a hydrocarbon group with 1 to 12 carbon atoms (preferably a hydrocarbon group with 1 to 8 carbon atoms, more preferably a hydrocarbon group with 2 to 6 carbon atoms, and even more preferably Hydrocarbon groups with numbers 2 to 4) may also contain heteroatoms.

R ⁸ in the formula (2-C) represents a hydrocarbon group with 2 to 10 carbon atoms (preferably a hydrocarbon group with 2 to 8 carbon atoms, more preferably a hydrocarbon group with 2 to 6 carbon atoms), and may also contain heteroatoms. R ⁹ , R ¹⁰ , and R ¹¹ are the same or different, and represent a hydrogen atom or a hydrocarbon group with 1 to 16 carbon atoms (preferably a hydrocarbon group with 1 to 10 carbon atoms, more preferably a hydrocarbon group with 1 to 8 carbon atoms), and may also contain hetero atom.

In formula ^{( 2} - ^D ) ^, The hydrocarbon group of 14 is more preferably a hydrocarbon group with 1 to 10 carbon atoms, further preferably a hydrocarbon group with 1 to 8 carbon atoms, especially a hydrocarbon group with 1 to 6 carbon atoms), and may also contain heteroatoms. However, when X is a sulfur atom, R ¹² does not exist.

The molecular weight of the cations in the ionic liquid is, for example, 500 or less, preferably 400 or less, more preferably 300 or less, further preferably 250 or less, particularly preferably 200 or less, and most preferably 160 or less. Also, it is usually 50 or more. It is believed that the cations in the ionic liquid have the property of moving toward the cathode side in the adhesive layer when a voltage is applied, and tend to be near the interface between the adhesive layer and the adherend. Therefore, in the present invention, the adhesion force during voltage application decreases relative to the initial adhesion force, resulting in electrical peelability. A cation with a smaller molecular weight of 500 or less is suitable in terms of making it easier for the cation to move to the cathode side in the adhesive layer and increasing the reduction rate of the adhesive force when a voltage is applied.

Examples of commercially available ionic liquids include "ELEXCEL AS-110", "ELEXCEL MP-442", "ELEXCEL IL-210", "ELEXCEL MP-471" and "ELEXCEL MP-471" manufactured by Daiichi Industrial Pharmaceutical Co., Ltd. "ELEXCEL MP-456", "ELEXCEL AS-804", "HMI-FSI" manufactured by Mitsubishi Materials Co., Ltd., "CIL-312" and "CIL-313" manufactured by JAPAN CARLIT Co., Ltd., etc.

The ionic conductivity of the ionic liquid is preferably 0.1 mS/cm or more and 10 mS/cm or less. The upper limit of the ion conductivity is more preferably 5 mS/cm, further preferably 3 mS/cm, and the lower limit is more preferably 0.3 mS/cm, further preferably 0.5 mS/cm. By having the ion conductivity within this range, the adhesive force can be sufficiently reduced even at a relatively low voltage. Furthermore, the ion conductivity can be measured by the AC (Alternating Current, AC) impedance method using, for example, a 1260 frequency response analyzer manufactured by Solartron Corporation.

The content (preparation amount) of the ionic liquid in the adhesive composition of this embodiment is preferably 0.5 parts by mass or more based on 100 parts by mass of the polymer from the viewpoint of reducing the adhesive force during voltage application. From the viewpoint of improving the initial adhesive strength, it is preferably 30 parts by mass or less. From the same viewpoint, it is more preferably 20 parts by mass or less, further preferably 15 parts by mass or less, particularly preferably 10 parts by mass or less, and most preferably 5 parts by mass or less. Moreover, it is more preferably 0.6 parts by mass or more, still more preferably 0.8 parts by mass or more, particularly preferably 1.0 parts by mass or more, and most preferably 1.5 parts by mass or more.

(other ingredients) The adhesive composition of this embodiment may contain one or more components other than polymers and ionic liquids (hereinafter, sometimes referred to as "other components") as necessary within a range that does not impair the effects of the present invention. ”). Next, other components that may be contained in the adhesive composition of this embodiment will be described.

The adhesive composition of this embodiment may also contain an ionic additive in order to control the relative dielectric constant, ionic conductivity, and capacitance. As the ionic additive, for example, an ionic solid can be used.

Ionic solids are ionic substances that are solid at 25°C. The ionic solid is not particularly limited. For example, an ionic substance obtained by combining the anions and cations exemplified in the description of the ionic liquid may be used to obtain a solid. When the adhesive composition contains an ionic solid, the content of the ionic solid is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass based on 100 parts by mass of the polymer. or less, more preferably 5 parts by mass or less, still more preferably 2.5 parts by mass or less.

The adhesive composition of this embodiment may contain a crosslinking agent if necessary in order to improve creep properties or shear properties by crosslinking the polymer. Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, melamine-based cross-linking agents, peroxide-based cross-linking agents, urea-based cross-linking agents, and metal alkoxide-based cross-linking agents. agents, metal chelate cross-linking agents, metal salt cross-linking agents, oxazoline cross-linking agents, aziridine cross-linking agents, and amine cross-linking agents, etc. Examples of the isocyanate cross-linking agent include toluene diisocyanate, methylene bis(phenyl isocyanate), and the like. Examples of the epoxy cross-linking agent include N,N,N',N'-tetraglycidyl m-xylylenediamine, diglycidyl aniline, 1,3-bis(N,N-diglycidyl Glyceryl aminomethyl) cyclohexane and 1,6-hexanediol diglycidyl ether, etc. When a cross-linking agent is contained, the content is preferably 0.1 parts by mass or more, more preferably 0.7 parts by mass or more, and preferably 50 parts by mass or less, more preferably 10 parts by mass, based on 100 parts by mass of the polymer. parts or less, and more preferably 3 parts by mass or less. In addition, a crosslinking agent can be used individually or in combination of 2 or more types.

The adhesive composition of this embodiment may contain polyethylene glycol or tetraethylene glycol dimethyl ether if necessary in order to assist the movement of the ionic liquid when a voltage is applied. As polyethylene glycol or tetraethylene glycol dimethyl ether, those having a number average molecular weight of 100 to 6,000 can be used. When these components are contained, the content is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, further preferably 1 part by mass or more, and preferably 30 parts by mass, based on 100 parts by mass of the polymer. Parts by mass or less, more preferably 20 parts by mass or less, still more preferably 15 parts by mass or less.

In order to impart conductivity to the adhesive composition, the adhesive composition of this embodiment may contain a conductive filler if necessary. The conductive filler is not particularly limited, and generally known or customary conductive fillers can be used. For example, graphite, carbon black, carbon fiber, metal powder such as silver or copper, etc. can be used. When the conductive filler is contained, the content is preferably from 0.1 parts by mass to 200 parts by mass relative to 100 parts by mass of the polymer.

In order to suppress corrosion of the metal adherend, the adhesive composition of this embodiment may contain a preservative if necessary. The preservative is not particularly limited, and commonly known or customary preservatives can be used. For example, carbodiimide compounds, adsorption-type inhibitors, chelation-forming metal deactivators, and the like can be used. Examples of carbodiimide compounds include: 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, 1-ethyl-3-(3-dimethyl Aminopropyl) carbodiimide, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, 1-ethyl-3-tertiary Butylcarbodiimide, N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide, N,N'-di-tertiary butylcarbodiimide, 1, 3-bis(p-tolyl)carbodiimide, and polycarbodiimide resins using these as monomers. These carbodiimide compounds can be used alone or in combination of two or more. When the adhesive composition of this embodiment contains a carbodiimide compound, the content is preferably 0.01 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of the polymer. Examples of adsorption inhibitors include alkyl amines, carboxylates, carboxylic acid derivatives, alkyl phosphates, and the like. The adsorption inhibitor can be used alone or in combination of two or more types. When the adhesive composition of this embodiment contains an alkylamine as an adsorption inhibitor, the content is preferably 0.01 parts by mass or more and 20 parts by mass or less based on 100 parts by mass of the polymer. When the adhesive composition of this embodiment contains a carboxylate as an adsorption inhibitor, the content is preferably 0.01 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of the polymer. When the adhesive composition of this embodiment contains a carboxylic acid derivative as an adsorption inhibitor, the content is preferably 0.01 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of the polymer. When the adhesive composition of this embodiment contains an alkyl phosphate as an adsorption inhibitor, the content is preferably 0.01 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of the polymer. As the chelate-forming metal deactivator, for example, a triazole group-containing compound or a benzotriazole group-containing compound can be used. These have a high effect of deactivating the surface of metals such as aluminum and are not likely to affect the adhesion even if they are included in adhesive components, so they are preferred. The chelate-forming metal deactivator can be used alone or in combination of two or more types. When the adhesive composition of this embodiment contains a chelate-forming metal deactivator, the content is preferably 0.01 parts by mass or more and 20 parts by mass or less based on 100 parts by mass of the polymer. The total content (preparation amount) of the preservative is preferably 0.01 parts by mass or more and 30 parts by mass or less based on 100 parts by mass of the polymer.

The adhesive composition of this embodiment may also contain fillers, plasticizers, anti-aging agents, antioxidants, pigments (dyes), flame retardants, solvents, surfactants (leveling agents), anti-rust agents, Then various additives such as resin and antistatic agent are added. The total content of these components is not particularly limited as long as the effects of the present invention are exerted. It is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 10 parts by mass or less based on 100 parts by mass of the polymer. , more preferably 5 parts by mass or less.

Examples of fillers include silica, iron oxide, zinc oxide, aluminum oxide, titanium oxide, barium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, pyrophyllite clay, kaolin clay, and calcined clay. wait. The plasticizer can be a well-known plasticizer used in ordinary resin compositions, etc., for example, oils such as paraffin oil, processing oil, liquid polyisoprene, liquid polybutadiene, liquid polybutadiene, etc. can be used. Liquid rubber such as ethylene-propylene rubber, tetrahydrophthalic acid, azelaic acid, benzoic acid, phthalic acid, trimellitic acid, pyromellitic acid, adipic acid, sebacic acid, fumarate Diacids, maleic acid, itaconic acid, citric acid, and their derivatives, dioctyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl adipate ester, diisononyl adipate (DINA), and isodecyl succinate, etc. Examples of anti-aging agents include hindered phenol compounds, aliphatic and aromatic hindered amine compounds, and the like. Examples of antioxidants include butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and the like. Examples of the pigment include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine, iron oxide, zinc oxide, lead, cadmium, iron, cobalt, aluminum, hydrochloride, and sulfate; azo pigments, and copper phthalocyanine pigments and other organic pigments, etc. Examples of anti-rust agents include zinc phosphate, tannic acid derivatives, phosphate esters, alkaline sulfonates, and various anti-rust pigments. Examples of the adhesion-imparting agent include titanium coupling agents, zirconium coupling agents, and the like. Examples of antistatic agents generally include quaternary ammonium salts, hydrophilic compounds such as polyglycolic acid or ethylene oxide derivatives, and the like. Examples of the tackifier-imparting resin include, in addition to rosin-based tackifier-imparting resins, terpene-based tackifier-imparting resins, phenol-based tackifier-imparting resins, hydrocarbon-based tackifier-imparting resins, and ketone-based tackifier-imparting resins, polyamide-based tackifier-imparting resins, Epoxy-based adhesion-imparting resins, elastic system adhesion-imparting resins, etc. In addition, the adhesive imparting resin can be used individually or in combination of 2 or more types.

＜Relative dielectric constant of adhesive layer without ionic liquid＞ An adhesive layer (ionic liquid-free adhesive layer) is formed using a composition containing components other than ionic liquid among the components contained in the adhesive composition of the first embodiment (ionic liquid-free adhesive composition). ), and after placing the adhesive layer in an environment of 22°C and 20% RH for 3 days, the relative dielectric constant of the adhesive layer at a frequency of 100 Hz is above 5.

In addition, the above-mentioned relative dielectric constant refers to the relative dielectric constant measured in the following manner. First, the ionic liquid-free adhesive composition is evenly coated on the peeling surface of the separator whose surface has been peeled off, and then heated and dried at 130°C for 3 minutes to obtain an ion-free adhesive composition with a thickness of 30 μm. Liquid adhesive layer. Then, the obtained adhesive layer without ionic liquid was placed in an environment of 22° C. and 20% RH for 3 days. Thereafter, the relative dielectric constant was measured under the following conditions. (Measurement conditions of relative dielectric constant) Measurement method: capacitance method (device: using Agilent Technologies 4294A Precision Impedance Analyzer) Electrode composition: 12.1 mmϕ, 0.5 mm thick aluminum plate Counter electrode: 60 μm thick aluminum foil Measurement environment: 23±1℃, 52±1%RH

The relative dielectric constant of an adhesive layer that does not contain ionic liquids is related to the ease of movement of ionic liquids in an adhesive layer formed using an adhesive composition that contains ionic liquids. The greater the relative dielectric constant of the adhesive layer that does not contain ionic liquid, the easier it is for the ionic liquid to move in the adhesive layer formed by using the adhesive composition containing ionic liquid, so the adhesive force is easily reduced when a voltage is applied. The adhesive composition of the first embodiment has a relative dielectric constant of 5 at a frequency of 100 Hz after the adhesive layer containing no ionic liquid is placed in an environment of 22°C and 20% RH for 3 days. As mentioned above, it is possible to form a bond in which the adhesion force is sufficiently reduced by the application of voltage even in a low-humidity environment.

The relative dielectric constant of the adhesive layer that does not contain ionic liquids can be controlled, for example, by appropriately adjusting the polymer components in the adhesive composition or the type or content of the ionic additives within the above-mentioned appropriate range.

<Ionic conductivity of the adhesive layer and capacitance per unit area of the interface between the adhesive layer and the adherend> Regarding the adhesive composition of the second embodiment, the adhesive composition is used to form an adhesive layer and adhere to For an aluminum plate containing A5052P H32 in JIS H4000:2014, the capacitance per unit area of the interface between the adhesive layer and the aluminum plate after being placed in an environment of 22°C and 15% RH for 7 days is 0.9 μF/cm ² or more. The ionic conductivity of the adhesive layer is above 10 μS/m.

The ionic conductivity of the adhesive layer is related to the ease of movement of the ionic liquid in the adhesive layer. The greater the ionic conductivity, the easier it is for the ionic liquid to move. In addition, the capacitance per unit area of the interface between the adhesive layer and the adherend is related to the ease with which ionic liquid can exist at the interface between the adhesive layer and the adherend. The larger the capacitance is, the easier it is for ionic liquid to exist in large amounts in the adhesive. The interface between the agent layer and the adherend. Regarding the adhesive composition of the second embodiment, an adhesive layer is formed using the adhesive composition and adhered to an aluminum plate containing A5052P H32 in JIS H4000:2014, and left for 7 days in an environment of 22°C and 15% RH. The capacitance per unit area of the interface between the adhesive layer and the aluminum plate is more than 0.9 μF/ ^cm2 , and the ionic conductivity of the adhesive layer is more than 10 μS/m, so it can also form a vacuum in a low-humidity environment. Adhesion in which the adhesion force is sufficiently reduced by applying voltage. Furthermore, it is more preferable that the capacitance per unit area is 1.2 μF/cm ² or more, and the ion conductivity of the adhesive layer is 20 μS/m or more.

The above-mentioned ionic conductivity and capacitance can be controlled, for example, by appropriately adjusting the components of the polymer, the type or content of the ionic liquid, and the type or content of the ionic additive in the adhesive composition within the above-mentioned appropriate ranges.

Furthermore, the so-called ion conductivity and capacitance mentioned above refer to the ion conductivity and capacitance measured in the following manner.

(Manufacture of samples for measurement (composite samples)) First, the adhesive composition is evenly applied to the aluminum vapor deposition surface side of the aluminum vapor deposition PET (Polyethylene Terephthalate, polyethylene terephthalate) film 100 (trade name "Metalumy TS" manufactured by TORAY ADVANCED FILM Co., Ltd.). Furthermore, at this time, in order to bring the electrode into contact with the aluminum vapor deposition surface, a portion where the adhesive composition is not applied is provided locally. Then, the adhesive layer 200 was formed by heating and drying at 130° C. for 3 minutes, and an adhesive sheet sample was obtained. Thereafter, the adhesive surface of the obtained adhesive sheet sample was attached to the aluminum plate 300 (A5052P H32 (JIS H4000: 2014)), and a joint sample 400 having a shape as shown in Figures 5 and 6 was obtained. In addition, FIG. 5 is a side view, and FIG. 6 is a top view.

(Measurement of capacitance and ionic conductivity) When measuring capacitance and ionic conductivity, use an LCR (Inductance Capacitance Resistance) meter (such as IM3533 manufactured by Hioki Electric Co., Ltd.). First, an LCR meter is used to apply an AC voltage of 0.5 V between the aluminum plate 300 and the aluminum vapor deposition surface of the aluminum vapor deposition PET film 100, and the frequency is changed from 0.5 Hz to 200 kHz to obtain the cole-cole ) graph.

Secondly, the bulk of the adhesive layer 200 is regarded as a parallel circuit of the resistance component R _adh and the electrostatic capacitance component C _adh , and the interface of the adhesive layer 200 is regarded as a parallel circuit of the resistance component R _p and the electrostatic capacitance component C _dl , such as The equivalent circuit of the joint sample is set as shown in Figure 7, and the obtained Cole-Cole curve is fitted using the following formula (A). In addition, the resistance component R ₀ is the wiring resistance.

[Number 1]

Furthermore, in formula (A), ω is the angular frequency.

By dividing the obtained C _dl by the area A of the adhesive surface of the adhesive layer 200, the capacitance per unit area of the interface between the adhesive layer 200 and the aluminum plate 300 can be obtained.

Then, the resistance component _Radh of the bulk of the adhesive layer 200 calculated according to the formula (A) can be used, and the ion conductivity σ of the adhesive layer can be calculated using the following formula (B).

[Number 2]

Furthermore, in formula (B), l is the thickness of the adhesive layer, and A is the area of the adhesive surface of the adhesive layer 200.

<Initial adhesion force, reduction rate of adhesion force obtained by voltage application> The adhesive strength of the adhesive composition of this embodiment can be evaluated by various methods. For example, it can be evaluated by the 180° peel test described in the column of Examples.

The adhesive composition of this embodiment is formed into an adhesive sheet as described in the Example column, and the initial adhesive force measured by a 180° peel test is preferably 1.0 N/cm or more, more preferably 1.5 N/cm or more. Furthermore, it is more preferable that it is 2.0 N/cm or more, especially 2.5 N/cm or more, and most preferably 3.0 N/cm or more. If the initial bonding force is 1.0 N/cm or more, the bonding with the adherend will be sufficient and the adherend will not be easily peeled off or shifted.

In addition, the adhesive composition of this embodiment is preferably formed into an adhesive sheet as described in the Example column, and is placed in an environment with a specific temperature and humidity for a specific period. After applying a voltage of 10 V for 30 seconds, The adhesion force measured by the 180° peel test while applying a voltage of 10 V is sufficiently small compared to the initial adhesion force. That is, based on the adhesive force measured by the above method (expressed in the following equation (C) only as "adhesion force during voltage application") and the initial adhesive force, the adhesive force is calculated by the following equation (C) The reduction rate is preferably 60% or more, more preferably 70% or more, and further preferably 80% or more. The above-mentioned specific temperature and humidity and period are preferably 22°C 20%RH for 3 days, and more preferably 22°C 15%RH for 7 days. Adhesion force reduction rate (%) = {1-(Adhesion force during voltage application/initial adhesion force)}×100 (C)

Furthermore, the applied voltage and voltage application time during electrical peeling are not limited to the above, and are not particularly limited as long as the adhesive sheet can be peeled off. The appropriate ranges are shown below. The applied voltage is preferably 1 V or more, more preferably 3 V or more, and further preferably 6 V or more. Moreover, it is preferably 100 V or less, more preferably 50 V or less, further preferably 30 V or less, and particularly preferably 15 V or less. The voltage application time is preferably 60 seconds or less, more preferably 40 seconds or less, further preferably 20 seconds or less, particularly preferably 10 seconds or less. In this case, workability is excellent. In addition, the shorter the application time, the better, and it is usually 1 second or more.

＜Manufacturing method of adhesive composition＞ The adhesive composition of the present invention is not particularly limited and can be produced by properly stirring polymers, ionic liquids, additives, and optionally blended cross-linking agents, polyethylene glycol, conductive fillers, etc.

[adhesive sheet] (Composition of adhesive sheet) The adhesive sheet of this embodiment is not particularly limited as long as it has at least one adhesive layer (hereinafter also referred to as "electro-peelable adhesive layer") formed from the adhesive composition of this embodiment. The adhesive sheet of this embodiment may have an adhesive layer that does not contain ionic liquid (hereinafter, may be referred to as "other adhesive layers") other than the electrically peelable adhesive layer. In addition to the above, the adhesive sheet of this embodiment may have a base material, a conductive layer, a conductive base material, an intermediate layer, a primer layer, etc. The adhesive sheet of this embodiment may be, for example, wound in a roll shape or in a sheet shape. Furthermore, "adhesive sheet" also includes the meaning of "tape". That is, the adhesive sheet of this embodiment may be a tape-like adhesive tape.

The adhesive sheet of this embodiment may be a double-sided adhesive sheet that does not have a base material and only contains an electrically peelable adhesive layer, that is, it does not contain a base material layer (no base material). The adhesive sheet of this embodiment may be a double-sided adhesive sheet having a base material, and both sides of the base material are adhesive layers (electro-peelable adhesive layers, or other adhesive layers). Furthermore, the adhesive sheet of this embodiment may be a single-sided adhesive sheet having a base material, and only one side of the base material is an adhesive layer (electro-peelable adhesive layer, or other adhesive layer). Furthermore, the adhesive sheet of this embodiment may have a separator (release liner) for the purpose of protecting the surface of the adhesive layer, but this separator is not included in the adhesive sheet of this embodiment.

The structure of the adhesive sheet of this embodiment is not particularly limited, but preferred examples include: the adhesive sheet X1 shown in FIG. 1 , the adhesive sheet X2 showing a laminated structure in FIG. Film X3. The adhesive sheet X1 is a base-less double-sided adhesive sheet including only the electro-peelable adhesive layer 1 . The adhesive sheet X2 is a base-attached double-sided adhesive sheet composed of an adhesive layer 2, a base material 5 for energization (base material 3 and conductive layer 4), and an electrically peelable adhesive layer 1. The adhesive sheet Layer 2 consists of a double-sided adhesive sheet attached to a substrate. In the electrically conductive base material 5 of the adhesive sheets X2 and X3 shown in FIGS. 2 and 3 , the base material 3 is not necessary, and may only be the conductive layer 4 . In addition, the adhesive sheet X2 in FIG. 2 may be a single-sided adhesive sheet without the adhesive layer 2 .

The base material 3 is not particularly limited, and examples thereof include paper-based base materials such as paper, fiber-based base materials such as cloth and nonwoven fabrics, various plastics (polyolefin-based resins such as polyethylene and polypropylene, polyethylene terephthalate, etc.) Plastic base materials such as films or sheets of polyester resins such as ester, acrylic resins such as polymethyl methacrylate, etc., laminates of these, etc. The base material may be in the form of a single layer or may be in the form of multiple layers. In addition, various treatments such as backside treatment, antistatic treatment, and primer treatment can also be performed on the base material as necessary.

The conductive layer 4 is not particularly limited as long as it is a conductive layer, and may be a metal (such as aluminum, magnesium, copper, iron, tin, gold, etc.) foil or a metal plate (such as aluminum, magnesium, copper, iron, etc.) , tin, silver, etc.), a conductive polymer, etc., or a metal vapor-deposited film provided on the base material 3, etc.

There is no particular limitation on the current-carrying base material 5 as long as it has a conductive layer (electrical conduction). Examples thereof include those in which a metal layer is formed on the surface of the base material. For example, the base material exemplified above can be used. The surface has a metal layer formed by plating, chemical evaporation, sputtering and other methods. Examples of the metal layer include the metals exemplified above, metal plates, conductive polymers, and the like.

In the adhesive sheet X1, the double-sided adherend is preferably an adherend having a metal adhesive surface. In the adhesive sheet X2, it is preferable that the adhesive system on one side of the electro-peelable adhesive layer has a metal adhesive surface.

Examples of the metal adherend surface include surfaces containing electrically conductive metals, such as aluminum, copper, iron, magnesium, tin, gold, silver, lead, etc. as a main component. Among them, metals containing aluminum are preferred. face. Examples of adherends having a metal adherend surface include sheets, parts, and plates containing metals containing aluminum, copper, iron, magnesium, tin, gold, silver, lead, etc. as a main component. The adherends other than the adherends having metal adhesive surfaces are not particularly limited, and examples include fiber sheets such as paper, cloth, and nonwoven fabrics, and various plastic films or sheets.

From the viewpoint of initial adhesive strength, the thickness of the electro-peelable adhesive layer 1 is preferably 1 μm or more and 1000 μm or less. The upper limit of the thickness of the electro-peelable adhesive layer 1 is more preferably 500 μm, further preferably 100 μm, especially 30 μm, and the lower limit is more preferably 3 μm, further preferably 5 μm, especially 8 μm. . Furthermore, when the adhesive sheet is a double-sided adhesive sheet without a base material (adhesive sheet The thickness.

From the viewpoint of adhesive strength, the thickness of the adhesive layer 2 is preferably 1 μm or more and 2000 μm or less. The upper limit of the thickness of the adhesive layer 2 is more preferably 1000 μm, further preferably 500 μm, especially 100 μm, and the lower limit is more preferably 3 μm, further preferably 5 μm, especially 8 μm.

The thickness of the base material 3 is preferably 10 μm or more and 1000 μm or less. The upper limit of the thickness is more preferably 500 μm, further preferably 300 μm, especially 100 μm, and the lower limit is more preferably 12 μm, further preferably 25 μm.

The thickness of the conductive layer 4 is preferably 0.001 μm or more and 1000 μm or less. The upper limit of the thickness is more preferably 500 μm, further preferably 300 μm, further preferably 50 μm, further preferably 10 μm, and the lower limit is more preferably 0.01 μm, more preferably 0.03 μm, further preferably 0.05 μm .

The thickness of the energizing base material 5 is preferably 10 μm or more and 1000 μm or less. The upper limit of the thickness is more preferably 500 μm, further preferably 300 μm, especially 100 μm, and the lower limit is more preferably 12 μm, further preferably 25 μm.

The surface of the electrically peelable adhesive layer and other adhesive layers of the adhesive sheet of this embodiment can be protected by a separator (release liner). The separator is not particularly limited, and examples thereof include a release liner in which a surface of a base material such as paper or a plastic film (a liner base material) is treated with polysiloxane; a base material such as a paper or plastic film (a liner base material) The surface is made of a release liner laminated with polyolefin resin. The thickness of the spacer is not particularly limited, but is preferably 10 μm or more and 100 μm or less.

The thickness of the adhesive sheet of this embodiment is preferably 20 μm or more and 3000 μm or less. The upper limit of the thickness is more preferably 1000 μm, further preferably 300 μm, especially 200 μm, and the lower limit is more preferably 30 μm, further preferably 50 μm.

Especially in the case of the adhesive sheet X2 shown in FIG. 2 , the thickness of the adhesive sheet is preferably 50 μm or more and 2000 μm or less. The upper limit of the thickness is more preferably 1000 μm, further preferably 200 μm, and the lower limit is more preferably 80 μm, further preferably 100 μm.

Especially in the case of the adhesive sheet X3 shown in FIG. 3 , the thickness of the adhesive sheet is preferably 100 μm or more and 3000 μm or less. The upper limit of the thickness is more preferably 1000 μm, further preferably 300 μm, and the lower limit is more preferably 150 μm, further preferably 200 μm.

(Manufacturing method of adhesive sheet) The manufacturing method of the adhesive sheet of this embodiment can use a well-known or conventional manufacturing method. Examples of the electro-peelable adhesive layer in the adhesive sheet of this embodiment include a method of applying a solution obtained by dissolving the adhesive composition of this embodiment in a solvent as necessary on the separator, and drying and/or hardening it. wait. Examples of other adhesive layers include a method of applying a solution obtained by dissolving an adhesive composition that does not contain ionic liquids and additives in a solvent as necessary on the separator, and drying and/or hardening the solution. In addition, the solvents and spacers listed above can be used.

When coating, conventional coating machines (such as gravure roller coaters, reverse roller coaters, contact roller coaters, dip roller coaters, rod coaters, blade coaters) can be used. cloth machine, spray roller coater, etc.).

By the above method, an electrically peelable adhesive layer and other adhesive layers can be produced, and by appropriately laminating the electrically peelable adhesive layer and other adhesive layers on a base material, a conductive layer, and a current-carrying base material , the adhesive sheet of this embodiment can be produced. Furthermore, the base material, the conductive layer, and the current-carrying base material can be used instead of the spacer, and the adhesive composition can be applied to produce an adhesive sheet.

(Electrical peeling method of adhesive sheet) The adhesive sheet of this embodiment can be peeled off from the adherend by applying a voltage to the electrically peelable adhesive layer to generate a potential difference in the thickness direction of the electrically peelable adhesive layer. For example, in the case of an adherend having metal adherend surfaces on both sides of the adhesive sheet X1, peeling can be performed by applying voltage to the electrically peelable adhesive layer by energizing the metal adherend surfaces on both sides. In the adhesive sheet voltage for peeling. In the case of the adhesive sheet X3, peeling can be performed by energizing the conductive layer 4 on both sides and applying a voltage to the electrically peelable adhesive layer. It is preferable to conduct electricity supply by connecting a terminal to one end and the other end of an adhesive sheet, and applying a voltage to the entire electro-peelable adhesive layer. Furthermore, when the adherend has a metal adherent surface, the one end and the other end may also be part of the adherend having a metal adherent surface. Furthermore, during peeling, it is also possible to add water to the interface between the metal adherend surface and the electrically peelable adhesive layer and then apply voltage.

(Use of adhesive sheet) As conventional re-peeling techniques, there are adhesive layers that are hardened and peeled off by ultraviolet (UV) irradiation, or adhesive layers that are peeled off by heat. Adhesive sheets using such an adhesive layer cannot be used when ultraviolet (UV) irradiation is difficult or when the member to be adhered is damaged by heat. The adhesive sheet of this embodiment having the above-described electrically peelable adhesive layer does not use ultraviolet rays or heat, so it can be easily peeled off by applying voltage without damaging the adherend member. Therefore, the adhesive sheet of this embodiment is suitable for attaching secondary batteries (such as lithium-ion battery packs) used in mobile terminals such as smartphones, mobile phones, notebook computers, video cameras, digital cameras, etc. Fixed purpose.

In addition, examples of rigid members to be bonded to the adhesive sheet of this embodiment include silicon substrates for semiconductor wafers, sapphire substrates for LEDs (Light Emitting Diodes), SiC substrates, and metal substrates. Substrates, TFT (Thin Film Transistor, thin film transistor) substrates and color filter substrates for displays, and base substrates for organic EL (Electroluminescence, electroluminescence) panels. Examples of fragile members to be bonded to double-sided adhesive sheets include semiconductor substrates such as compound semiconductor substrates, silicon substrates for MEMS (Microelectro Mechanical System) devices, passive matrix substrates, and surfaces for smartphones. Cover glass, OGS (One Glass Solution) substrate with a touch panel sensor attached to the cover glass, organic substrates and organic-inorganic hybrid substrates with sesquioxane as the main component , flexible glass substrates for flexible displays, and graphene sheets.

[joint body] The bonded body of this embodiment has a laminated structure part, and the laminated structure part includes an adherend having a metal adherent surface, and an adhesive sheet in which an electro-peelable adhesive layer is bonded to the metal adherent surface. Examples of the adherend having a metal adherend surface include metals containing aluminum, copper, iron, magnesium, tin, gold, silver, lead, etc. as a main component. Among them, metals containing aluminum are preferred.

Examples of the bonded body of this embodiment include the following bonded body: in the case of the adhesive sheet X1, a bonded body having adherends having metal adhesive surfaces on both sides of the electro-peelable adhesive layer 1; in the case of the adhesive sheet X2 In the case of the electro-peelable adhesive layer 1 side, there is an adherend with a metal adherend surface, and in the adhesive layer 2 side there is a joint body of the adherend; in the case of the adhesive sheet X3, on both sides of the adhesive layer 2 Joints with adherends, etc. [Example]

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples. The following weight average molecular weights were measured by gel permeation chromatography (GPC) according to the method described above.

[Examples 1-1 to 1-8, Comparative Examples 1-1 to 1-5] ＜Preparation of polymer solution＞ (Preparation of acrylic polymer 1 solution) 95 parts by mass of n-butyl acrylate (BA) as the monomer component, 5 parts by mass of acrylic acid (AA), and 150 parts by mass of ethyl acetate as the polymerization solvent were put into a separable flask while introducing nitrogen gas. , stirring for 1 hour. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 1 solution having a solid content concentration of 40% by mass.

(Preparation of acrylic polymer 2 solution) 90 parts by mass of n-butyl acrylate (BA) as the monomer component, 10 parts by mass of 4-hydroxybutyl acrylate (4HBA), and 150 parts by mass of ethyl acetate as the polymerization solvent were put into a separable flask. , stirring for 1 hour while introducing nitrogen gas. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 2 solution having a solid content concentration of 30% by mass.

(Preparation of acrylic polymer 3 solution) n-butyl acrylate (BA) as the monomer component: 67 parts by mass, 2-methoxyethyl acrylate (MEA): 30 parts by mass, acrylic acid (AA): 3 parts by mass, and ethyl acetate as the polymerization solvent Ester: 150 parts by mass was put into a separable flask, and the mixture was stirred for 1 hour while introducing nitrogen gas. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 3 solution having a solid content concentration of 40% by mass.

(Preparation of acrylic polymer 4 solution) n-butyl acrylate (BA) as the monomer component: 67 parts by mass, methyl methacrylate (MMA): 33 parts by mass, and ethyl acetate as the polymerization solvent: 150 parts by mass were put into a separable flask. , while introducing nitrogen gas and stirring for 1 hour. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 4 solution having a solid content concentration of 40% by mass.

(Preparation of acrylic polymer 5 solution) n-butyl acrylate (BA) as the monomer component: 87 parts by mass, 4-hydroxybutyl acrylate (4HBA): 10 parts by mass, acrylic acid (AA): 3 parts by mass, and ethyl acetate as the polymerization solvent: 150 parts by mass was put into a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 5 solution having a solid content concentration of 30% by mass.

＜Preparation of adhesive composition＞ The acrylic polymer solution obtained above or the polymer, crosslinking agent, ionic liquid, and additive shown below were added and stirred and mixed to obtain Examples 1-1 to 1-8 and Comparative Examples 1-1 to Adhesive composition of 1-5. The amounts of each component are shown in Table 1. In addition, the values of each component in Table 1 refer to parts by mass. In addition, the compounding amount (mass parts) of the polymer means the compounding amount (mass parts) of the solid component in the polymer solution. The abbreviations of polymers, cross-linking agents, ionic liquids, and additives in Table 1 are as follows. (polymer) Vylon UR-V8700: Urethane modified polyester resin, trade name "Vylon UR-V8700", manufactured by Toyobo Corporation Vylon BX1001: Polyester resin, trade name "Vylon BX1001", manufactured by Toyobo Corporation SOMAREX 530: Anionic polyacrylamide polymer (ionic polymer), trade name "SOMAREX 530", manufactured by SOMAR Co., Ltd. (ionic liquid) AS-110: Cation: 1-ethyl-3-methylimidazolium cation, anion: bis(fluorosulfonyl)imide anion, trade name "ELEXCEL AS-110", manufactured by Daiichi Industrial Pharmaceutical Co., Ltd. (cross-linking agent) V-05: Polycarbodiimide resin, trade name "Carbodilite V-05", manufactured by Nisshinbo Chemical Co., Ltd. Takenate D110: Trimethylolpropanephenyl diisocyanate, trade name "Takenate D110N", manufactured by Mitsui Chemicals Co., Ltd. (additive) EMI-nitrate: 1-ethyl-3-methylimidazolium nitrate, manufactured by Tokyo Chemical Industry Co., Ltd. Zn-nitrate: Zinc nitrate hexahydrate, manufactured by Wako Pure Chemical Industries, Ltd. BTC-5B: barium titanate No.27776：Carbon black

＜Measurement of relative dielectric constant of adhesive layer without ionic liquid＞ Except that no ionic liquid was added, the materials were stirred and mixed in the same manner as in the above-mentioned Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-5, and the obtained ionic liquid-free Use an applicator to apply the adhesive composition to the release-treated surface of a polyethylene terephthalate separator (trade name "MRF38", manufactured by Mitsubishi Plastics Co., Ltd.) with a uniform thickness. superior. Next, heat and dry at 130°C for 3 minutes to obtain an adhesive layer without ionic liquid with a thickness of 30 μm. Then, after the obtained adhesive layer containing no ionic liquid was left in an environment of 22°C and 20% RH for 3 days, the frequency of the adhesive layer at a frequency of 100 kHz was measured under the following conditions according to JIS K6911. relative dielectric constant. (Measurement conditions) Measurement method: capacitance method (device: using Agilent Technologies 4294A Precision Impedance Analyzer) Electrode composition: 12.1 mmϕ, 0.5 mm thick aluminum plate Counter electrode: 3 oz copper plate Measurement environment: 23±1℃, 52±1%RH

＜Measurement of moisture content of electro-peelable adhesive layer＞ Using the adhesive compositions of each example, the electro-peelable adhesive layer obtained in the same manner as above was placed in an environment of 22°C and 20% RH for 3 days, and the Karl Fischer moisture vaporization-coulometric titration method was performed. (JIS K0113: 2005) Measure the moisture content of the adhesive layer. Specifically, the amount of moisture generated by heating and gasification at 200° C. for 30 minutes was measured using the Hiranuma trace moisture measuring device AQ-2100 manufactured by Hiranuma Sangyo Co., Ltd., and the ratio to the weight of the sample before heating was set. is the moisture content. That is, the moisture content is calculated by the following formula. In addition, "-" in Table 1 means not measured. Moisture content (%) = (moisture content measured by Karl Fischer/total weight of the sample before measurement) × 100

＜Evaluation＞ (Initial bonding force) The adhesive composition of each example was applied to a polyethylene terephthalate separator (trade name "MRF38", manufactured by Mitsubishi Plastics Co., Ltd.) with a peel-treated surface using an applicator to achieve a uniform thickness. on the peeled surface. Next, heat drying is performed at 130°C for 3 minutes to obtain an electrically peelable adhesive layer (adhesive sheet) with a thickness of 30 μm. Then, the obtained electro-peelable adhesive layer (adhesive sheet) was made into a sheet with a size of 10 mm × 80 mm, and a film with a metal layer (commercial product) as the base material was bonded to the side without a spacer. Named "BR1075", manufactured by TORAY ADVANCED FILM Co., Ltd., thickness 25 μm, size 10 mm × 100 mm) metal layer to make a single-sided adhesive sheet with a base material. Peel off the separator from the single-sided adhesive sheet attached to the base material, and attach the aluminum plate (A5052P H32 (JIS H4000: 2014)) as the adherend so that one end of the adhesive sheet protrudes about 2 mm from the adherend. On the peeling surface, use a 2 kg roller to push back and forth once, and place it in an environment of 23°C for 30 minutes to obtain a film including an aluminum plate/electro-peelable adhesive layer (adhesive sheet) 1'/metal layer (for electrification) Base material) 5' joint. The outline of this joint body is shown in FIG. 4 . Thereafter, a peeling tester (trade name "Variable Angle Peeling Tester YSP", manufactured by Asahi Seiko Co., Ltd.) was used to peel in the direction of the arrow in Figure 4, and a 180° peeling test was measured (tensile speed: 300 mm /min, peeling temperature 23℃). The measurement results are shown in Table 1.

(Adhesion force during voltage application) After pushing back and forth once with a 2 kg roller, place it in an environment of 22°C and 20% RH for 3 days, and install the negative and positive electrodes of the DC current machine at α and β in Figure 4 of the joint body respectively before peeling off. A voltage of 10 V was applied to the electrode for 30 seconds, and the electrode was peeled off while the voltage was applied in this state. Except for these points, the adhesion force during voltage application was measured in the same manner as the above-mentioned measurement of the initial adhesion force. The measurement results are shown in Table 1.

(Adhesion force reduction rate) Using the initial adhesion force measured by the above method and the adhesion force during voltage application, the adhesion force reduction rate by voltage application is calculated using the following formula (C). The results are shown in Table 1. Adhesion force reduction rate (%) = {1-(Adhesion force during voltage application/initial adhesion force)}×100 (C)

[Table 1] Example 1-1 Example 1-2 Example 1-3 Comparative example 1-1 Comparative example 1-2 Comparative Example 1-3 Examples 1-4 Examples 1-5 Examples 1-6 Example 1-7 Example 1-8 Comparative Example 1-4 Comparative Example 1-5 Element polymer Acrylic polymer 1 100 100 100 100 100 100 100 Acrylic polymer 2 100 Acrylic polymer 3 100 Acrylic polymer 4 100 Acrylic polymer 5 100 Vylon UR-V8700 100 Vylon BX1001 100 SOMAREX 530 0.2 ionic liquid AS-110 5 5 5 5 5 5 5 5 5 5 5 5 5 Cross-linking agent V-05 1 1 1 1 1 1 1 0.3 Takenate D110 0.5 0.5 additives EMI-nitrate 2 Zn-nitrate 2 2 BTC-5B 2 No.27776 2 physical properties Relative dielectric constant (ε') of the adhesive layer without ionic liquid 5.6 5.4 5.5 4.3 4.6 4.7 6.5 5.8 5.1 5.2 6.4 3.9 4.3 Moisture content(%) 0.22 0.27 0.4 - - 0.15 0.35 0.32 0.13 0.23 - 0.11 0.24 Evaluation Initial bonding force (N/cm) 5.55 4.92 6.01 4.65 4.63 5.12 2.59 3.45 3.02 3.72 5.06 5 5.2 Adhesion force during voltage application (N/cm) 0.32 0.06 0.13 2.31 1.96 2.87 0.08 0.05 0.49 0.79 0.65 2.32 2.57 Adhesion force reduction rate (%) 94.2 98.9 97.8 50.4 57.6 43.9 96.9 98.6 83.8 78.8 87.2 53.6 50.6

The adhesive layer is formed by using a composition containing components other than ionic liquids in the adhesive composition, and the adhesive layer is placed in an environment of 22°C and 20% RH for 3 days. The adhesive compositions of Examples 1-1 to 1-8 in which the relative dielectric constant of the layer at a frequency of 100 Hz is above 5 have a greater reduction rate in the adhesion force obtained by voltage application.

[Examples 2-1 to 2-11, Comparative Examples 2-1 to 2-3] ＜Preparation of polymer solution＞ (Preparation of acrylic polymer 6 solution) 90 parts by mass of n-butyl acrylate (BA) as the monomer component, 10 parts by mass of acrylic acid (AA), and 150 parts by mass of ethyl acetate as the polymerization solvent were put into a separable flask while introducing nitrogen gas. , stirring for 1 hour. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 6 solution having a solid content concentration of 40% by mass.

(Preparation of acrylic polymer 7 solution) n-butyl acrylate (BA) as the monomer component: 90 parts by mass, 4-hydroxybutyl acrylate (4HBA): 7 parts by mass, acrylic acid (AA): 3 parts by mass, and ethyl acetate as the polymerization solvent: 150 parts by mass was put into a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 7 solution having a solid content concentration of 30% by mass.

(Preparation of acrylic polymer 8 solution) n-butyl acrylate (BA) as the monomer component: 94 parts by mass, 4-hydroxybutyl acrylate (4HBA): 3 parts by mass, acrylic acid (AA): 3 parts by mass, and ethyl acetate as the polymerization solvent: 150 parts by mass was put into a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 8 solution having a solid content concentration of 30% by mass.

(Preparation of acrylic polymer 9 solution) n-butyl acrylate (BA) as the monomer component: 77 parts by mass, 2-methoxyethyl acrylate (MEA): 20 parts by mass, acrylic acid (AA): 3 parts by mass, and ethyl acetate as the polymerization solvent Ester: 150 parts by mass was put into a separable flask, and the mixture was stirred for 1 hour while introducing nitrogen gas. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 9 solution having a solid content concentration of 40% by mass.

(Preparation of acrylic polymer 10 solution) n-butyl acrylate (BA) as the monomer component: 87 parts by mass, 2-methoxyethyl acrylate (MEA): 10 parts by mass, acrylic acid (AA): 3 parts by mass, and ethyl acetate as the polymerization solvent Ester: 150 parts by mass was put into a separable flask, and the mixture was stirred for 1 hour while introducing nitrogen gas. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 10 solution having a solid content concentration of 40% by mass.

＜Preparation of adhesive composition＞ The acrylic polymer solution obtained above or the above-mentioned polymer, cross-linking agent, ionic liquid, additive, or the following ionic liquid and preservative are added and stirred and mixed to obtain Examples 2-1 to 2-11 and Adhesive compositions of Comparative Examples 2-1 to 2-3. Table 2 shows the amounts of each component. (ionic liquid) 1-hexyl-pyridinium-bis(trifluorosulfonyl)imide (Preservatives, additives, cross-linking agents) Irgamet 30: N,N-bis(2-ethylhexyl)-1,2,4-triazol-1-ylmethaneamine, trade name "Irgamet 30", manufactured by BASF Irgacor DSSG: Disodium sebacate, trade name "Irgacor DSSG", manufactured by BASF Amin O: imidazoline derivative, trade name "Amin O", manufactured by BASF Corporation PEG400: Polyethylene glycol, trade name "PEG400", manufactured by Tokyo Chemical Industry Co., Ltd. Coronate L: Isocyanate compound, trade name "Coronate L", manufactured by Tosoh Co., Ltd.

<Measurement of ionic conductivity and capacitance per unit area of the adhesive layer> The adhesive composition of each example was used to prepare a measurement sample (composite sample) as follows, and the capacitance of the bonding interface and the ion conductivity of the adhesive layer were determined by the following method. The results are shown in Table 2.

(Manufacture of samples for measurement (composite samples)) First, the adhesive composition is evenly applied to the aluminum vapor deposition surface side of the aluminum vapor deposition PET film 100 (trade name "Metalumy TS" manufactured by TORAY ADVANCED FILM Co., Ltd.). Furthermore, at this time, in order to bring the electrode into contact with the aluminum vapor deposition surface, a portion where the adhesive composition is not applied is provided locally. Then, the adhesive layer 200 was formed by heating and drying at 130° C. for 3 minutes to obtain an adhesive sheet sample. Thereafter, the adhesive surface of the obtained adhesive sheet sample was attached to the aluminum plate 300 (A5052P H32 (JIS H4000: 2014)), and a joint sample 400 having a shape as shown in Figures 5 and 6 was obtained. In addition, FIG. 5 is a side view, and FIG. 6 is a top view.

(Measurement of capacitance and ionic conductivity) When measuring capacitance and ionic conductivity, use an LCR meter (such as IM3533 manufactured by Hioki Electric Co., Ltd.). First, an LCR meter is used to apply an AC voltage of 0.5 V between the aluminum plate 300 and the aluminum vapor deposition surface of the aluminum vapor deposition PET film 100, and the frequency is changed from 0.5 Hz to 200 kHz to obtain a Cole-Cole curve.

Secondly, the bulk of the adhesive layer 200 is regarded as a parallel circuit of the resistance component R _adh and the electrostatic capacitance component C _adh , and the interface of the adhesive layer 200 is regarded as a parallel circuit of the resistance component R _p and the electrostatic capacitance component C _dl , such as The equivalent circuit of the joint sample is set as shown in Figure 7, and the obtained Cole-Cole curve is fitted using the following formula (A). In addition, the resistance component R ₀ is the wiring resistance. [Number 3]

Furthermore, in formula (A), ω is the angular frequency.

By dividing the obtained C _dl by the area A of the adhesive surface of the adhesive layer 200, the capacitance per unit area of the interface between the adhesive layer 200 and the aluminum plate 300 is calculated.

Next, the resistance component _Radh of the bulk of the adhesive layer 200 calculated based on the equation (A) is used, and the ion conductivity σ of the adhesive layer is calculated using the following equation (B).

[Number 4]

Furthermore, in formula (B), l is the thickness of the adhesive layer, and A is the area of the adhesive surface of the adhesive layer 200.

＜Evaluation＞ (Initial bonding force) For the adhesive compositions in each example, an aluminum vapor-deposited PET film (trade name "Metalumy TS" manufactured by TORAY ADVANCED FILM Co., Ltd.) was used as the base material, and an adhesive layer was formed on the aluminum vapor-deposited surface. Otherwise, the same conditions were used as in the examples. 1-1 to 1-8 and Comparative Examples 1-1 to 1-5 were used to measure the initial adhesive strength in the same manner. The measurement results are shown in Table 2.

(Adhesion during voltage application after being stored in an environment of 22°C and 20%RH for 3 days) After pushing back and forth once with a 2 kg roller, place it in an environment of 22°C and 20% RH for 3 days, and install the negative and positive electrodes of the DC current machine at α and β in Figure 4 of the joint body respectively before peeling off. Apply voltage to the electrode at a voltage of 10 V for 30 seconds, and peel it off while applying voltage in this state. Except for these aspects, measure the adhesion force during voltage application in the same manner as the above-mentioned measurement of the initial adhesion force, and The electrical peelability was evaluated based on the following criteria. The measurement results are shown in Table 2. ○: The adhesive force reduction rate is 60% or more. ×: The adhesive force reduction rate does not reach 60%.

(Adhesion during voltage application after being stored in an environment of 22°C and 15%RH for 7 days) After pushing back and forth once with a 2 kg roller, place it in an environment of 22°C and 15% RH for 7 days, and install the negative and positive electrodes of the DC current machine at α and β in Figure 4 of the joint body respectively before peeling off. The electrode is applied with a voltage of 10 V for 10 seconds, and the electrode is peeled off while applying the voltage in this state. Except for these points, the adhesion force during voltage application is measured in the same manner as the above-mentioned measurement of the initial adhesion force. The measurement results are shown in Table 2.

(Adhesion force reduction rate) Using the initial adhesion force measured by the above method and the adhesion force during voltage application after being stored in an environment of 22°C and 15% RH for 7 days, the adhesion force obtained by voltage application is calculated using the following formula (C) reduction rate. The results are shown in Table 2. Adhesion force reduction rate (%) = {1-(Adhesion force during voltage application/initial adhesion force)}×100 (C)

[Table 2] Example 2-1 Example 2-2 Example 2-3 Example 2-4 Example 2-5 Comparative example 2-1 Comparative example 2-2 Comparative example 2-3 Example 2-6 Example 2-7 Example 2-8 Example 2-9 Example 2-10 Example 2-11 Element polymer Acrylic polymer 1 100 100 100 Acrylic polymer 2 Acrylic polymer 3 100 100 Acrylic polymer 5 100 Acrylic polymer 6 100 100 Acrylic polymer 7 100 Acrylic polymer 8 100 Acrylic polymer 9 100 Acrylic polymer 10 100 Vylon UR-V8700 100 Vylon BX1001 100 SOMAREX 530 0.2 0.2 0.2 0,2 0.2 0.2 ionic liquid AS-110 5 5 5 5 5 5 5 5 5 5 5 5 1-hexyl-pyridinium-bis(trifluorosulfonyl)imide 10 10 Preservatives irgamet30 0.8 0.8 0.8 0.8 0.8 0.8 0.8 IrgacorDSSG 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Amin O 3 3 3 3 3 3 additives PEG400 20 Zn-nitrate 2 2 EMI-nitrate 2 2 2 2 2 2 Cross-linking agent V-05 1 0.3 1 0.5 0.5 0.75 0.8 0.2 0.5 0.5 0.5 0.5 Coronate L 0.25 0.25 0.1 Takenate D110 0.5 Physical properties and evaluation Initial bonding force [N/cm] 6.75 5.33 4.32 6.12 5.78 2.92 6.77 5.76 5.29 4.47 2.84 2.74 2.77 3.12 After 3 days of storage at 22℃, 20%RH Electro-stripping property ○ ○ ○ ○ ○ ○ × × ○ ○ ○ ○ ○ ○ After 7 days of storage at 22℃, 15%RH Capacitance (μF/cm ² ) 1.41 0.95 1.04 0.94 0.92 0.81 0.62 0.89 1.30 1.37 1.37 1.30 1.31 1.30 Ionic conductivity (μS/m) 10.2 22.5 16.1 23.5 258.7 258.7 15.4 8.5 10.7 44.9 21.9 47.1 32.5 22.6 Adhesion force during voltage application (N/cm) 0.23 0.67 0.36 0.11 0.12 7.93 4.90 3.41 0.94 0.11 0.09 0.14 0.10 0.12 Adhesion force reduction rate (%) 96.6 87.4 91.7 98.2 97.9 -171.3 27.6 40.8 82.2 97.5 96.8 94.9 96.4 96.1

Regarding the use of an adhesive composition to form an adhesive layer and attach it to an aluminum plate containing A5052P H32 in JIS H4000:2014, the interface between the adhesive layer and the aluminum plate after being placed in an environment of 22°C and 15% RH for 7 days The adhesive composition of Examples 2-1 to 2-11 has a capacitance per unit area of 0.9 μF/cm2 ^or more and an ionic conductivity of the adhesive layer of 10 μS/m or more. The adhesive composition obtained by applying a voltage The force reduction rates are all larger.

[Examples 3-1 to 3-5] ＜Preparation of polymer solution＞ (Preparation of acrylic polymer 11 solution) 95 parts by mass of 2-methoxyethyl acrylate (MEA) and 5 parts by mass of 4-hydroxybutyl acrylate (4HBA) as monomer components were put into a separable flask and stirred while introducing nitrogen gas. hours. After removing the oxygen in the polymerization system in this way, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added, the temperature was raised to 63°C, and the reaction was carried out for 6 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer 11 solution having a solid content concentration of 30% by mass.

<Preparation of adhesive composition> The acrylic polymer solution obtained above or the above-mentioned polymer, cross-linking agent, ionic liquid, additives, or the following additives were added and stirred and mixed to obtain Examples 3-1 to 3-5 adhesive composition. Table 3 shows the amounts of each component. (Additive) ・EMIM-MeSO ₃ : ionic additive, imidazolium salt, manufactured by Tokyo Chemical Industry Co., Ltd.・EPOMIN200: Polyethylenimine, manufactured by Nippon Shokubai.

<Measurement and evaluation of ionic conductivity and capacitance per unit area of the adhesive layer> In the same manner as Examples 2-1 to 2-11 and Comparative Examples 2-1 to 2-3, the initial adhesion force and the adhesion force during voltage application after storage in an environment of 22°C and 20% RH for 3 days were measured. And the adhesive force reduction rate, the adhesive force and the adhesive force reduction rate during voltage application after being stored in an environment of 22°C and 15% RH for 7 days. In addition, in the same manner as Examples 2-1 to 2-11 and Comparative Examples 2-1 to 2-3, a measurement sample (composite sample) was prepared, and the capacitance of the bonding interface and the ion conductivity of the adhesive layer were determined. Rate. The results are shown in Table 3.

[table 3] Example 3-1 Example 3-2 Example 3-3 Example 3-4 Example 3-5 Element polymer Acrylic polymer 10 100 Acrylic polymer 11 100 100 Vylon UR-V8700 100 Vylon BX1001 100 ionic liquid AS-110 5 5 5 5 5 Preservatives irgamet30 0.8 0.8 0.8 IrgacorDSSG 0.3 0.3 0.3 Amin O 3 3 3 additives EMI-nitrate 2 2 SOMAREX 530 0.2 0.2 0.2 EMIM-MeSO ₃ 2 EPOMIN200 10 Cross-linking agent V-05 0.3 Takenate D110 0.15 Physical properties and evaluation Initial bonding force [N/cm] 6.22 6.25 6.22 2.83 1.93 After 3 days of storage at 22℃, 20%RH Adhesion force during voltage application (N/cm) 0.03 0.04 0.03 0.03 0.03 Adhesion force reduction rate (%) 99.5 99.4 99.5 98.9 98.4 After 7 days of storage at 22℃, 15%RH Capacitance (μF/cm ² ) 1.62 1.24 1.20 0.99 1.7 Ionic conductivity (μS/m) 80.0 25.0 20.0 144.0 196 Adhesion force during voltage application (N/cm) 0.07 0.05 0.09 0.13 0.01 Adhesion force reduction rate (%) 98.9 99.2 98.6 95.4 99.5

Regarding the use of an adhesive composition to form an adhesive layer and attach it to an aluminum plate containing A5052P H32 in JIS H4000:2014, the interface between the adhesive layer and the aluminum plate after being placed in an environment of 22°C and 15% RH for 7 days The adhesive compositions of Examples 3-1 to 3-5 have a capacitance per unit area of 0.9 μF/cm ^or more and an ionic conductivity of the adhesive layer of 10 μS/m or more. The adhesive composition obtained by applying a voltage The force reduction rates are all larger.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. Various changes and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Furthermore, this application is based on the Japanese patent application filed on September 3, 2018 (Japanese Patent Application No. 2018-164545) and the Japanese patent application filed on March 28, 2019 (Japanese Patent Application No. 2019). -065065), and the Japanese patent application filed on August 29, 2019 (Japanese Patent Application No. 2019-157325), the contents of which are incorporated by reference in this application.

1: Electro-peelable adhesive layer 1': Electro-peelable adhesive layer (adhesive sheet) 2: Adhesive layer 3: Base material 4: Conductive layer 5: Electric base material 5': Film with metal layer (electricity Base material) 6: Stainless steel plate 100: Aluminum vapor-deposited PET film 200: Adhesive layer 300: Aluminum plate 400: Joint sample C _adh : Electrostatic capacitance component C _dl : Electrostatic capacitance component R _adh : Resistance component R _p : Resistance component R ₀ : Resistance component X1: Adhesive sheet X2: Adhesive sheet X3: Adhesive sheet α: Part β: Part

FIG. 1 is a cross-sectional view showing an example of the adhesive sheet of the present invention. FIG. 2 is a cross-sectional view showing an example of the laminated structure of the adhesive sheet of the present invention. FIG. 3 is a cross-sectional view showing another example of the laminated structure of the adhesive sheet of the present invention. FIG. 4 is a cross-sectional view showing an outline of the 180° peel test method in the Examples. Figure 5 is a side view of a composite sample used for capacitance and ionic conductivity measurement. Figure 6 is a top view of a composite sample used for capacitance and ionic conductivity measurement. Figure 7 is an equivalent circuit diagram of a composite sample used for capacitance and ionic conductivity measurement.

1:Electro-peelable adhesive layer

X1: Adhesive sheet

Claims (11)

An adhesive composition comprising a polymer and an ionic liquid, wherein the polymer is an acrylic polymer having an alkoxy group, and the acrylic polymer is derived from an alkyl (meth)acrylate (below) The monomer unit of formula (1)), CH ₂ =C(R ^a )COOR ^b (1) R ^a in formula (1) is a hydrogen atom or a methyl group, and R ^b is an alkyl group with 1 to 8 carbon atoms. , use a composition containing components other than the ionic liquid contained in the above-mentioned adhesive composition to form an adhesive layer, and place the adhesive layer in an environment of 22°C and 20% RH for 3 days. The relative dielectric constant of the adhesive layer at a frequency of 100 Hz is above 5. An adhesive composition comprising a polymer and an ionic liquid, wherein the polymer is an acrylic polymer having an alkoxy group, and the acrylic polymer is derived from an alkyl (meth)acrylate (below) The monomer unit of formula (1)), CH ₂ =C(R ^a )COOR ^b (1) R ^a in formula (1) is a hydrogen atom or a methyl group, and R ^b is an alkyl group with 1 to 8 carbon atoms. , use the above-mentioned adhesive composition to form an adhesive layer and attach it to an aluminum plate containing A5052P H32 in JIS H4000:2014. The adhesive layer and the aluminum plate will be placed in an environment of 22°C and 15%RH for 7 days. The capacitance per unit area of the interface is above 0.9 μF/cm ² , and the ionic conductivity of the adhesive layer is above 10 μS/m. Such as the adhesive composition of claim 2, wherein the adhesive composition is used to form an adhesive layer and is attached to an aluminum plate containing A5052P H32 in JIS H4000:2014, and is placed in an environment of 22°C and 15%RH for 7 days The capacitance per unit area of the interface between the adhesive layer and the aluminum plate is then more than 1.2 μF/cm ² , and the ionic conductivity of the adhesive layer is more than 20 μS/m. The adhesive composition according to any one of claims 1 to 3, further comprising an ionic solid. The adhesive composition according to any one of claims 1 to 4, wherein the polymer includes an ionic polymer. The adhesive composition according to any one of claims 1 to 3, including 0.5 to 30 parts by mass of the ionic liquid and 0.5 to 10 parts by mass of the ionic solid relative to 100 parts by mass of the polymer. The adhesive composition according to any one of claims 1 to 3, which contains 0.5 to 30 parts by mass of the ionic liquid relative to 100 parts by mass of the above polymer, and 0.05 to 2 parts by mass of the ionic polymer in the above polymer. share. An adhesive composition, which contains 100 parts by mass of an acrylic polymer and 0.5 to 30 parts by mass of an ionic liquid, and the acrylic polymer contains monomer units derived from a polar group-containing monomer, and the above-mentioned acrylic polymer contains The monomer system of the polar group is an alkoxy group-containing monomer. The above-mentioned acrylic polymer contains a monomer unit derived from (meth)acrylic acid alkyl ester (the following formula (1)), CH ₂ =C(R ^a ) COOR ^b (1) R ^a in the formula (1) is a hydrogen atom or a methyl group, R ^b is an alkyl group having 1 to 8 carbon atoms, and the above-mentioned polar group-containing monomer constitutes the above-mentioned acrylic polymer. The ratio of all monomer components is 0.1 to 35% by mass. The adhesive composition according to any one of claims 1 to 8, which is used for electro-stripping. An adhesive sheet provided with an adhesive layer formed of the adhesive composition according to any one of claims 1 to 9. A bonded body comprising: an adherend having a metal adherent surface, and an adhesive sheet according to claim 10, wherein the adhesive layer of the adhesive sheet is bonded to the metal adherent surface.

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