JP7825307B2 - Electrically peelable adhesive - Google Patents

Description

The present invention relates to an electrically peelable adhesive body.The present invention relates to a method for producing an electrically peelable adhesive body.The present invention relates to a method for peeling an electrically peelable adhesive body.

Adhesives that can be peeled from an adherend by applying a voltage (hereinafter also referred to as "electrically peelable adhesives") are known. For example, Patent Document 1 describes an electrically peelable adhesive product.

Japanese Patent Application Laid-Open No. 2011-52056

The electrically peelable adhesive product described in Patent Document 1 can be electrically peeled from an insulator by forming a surface layer of adhesive material. However, to achieve good electrical peeling using the electrically peelable adhesive product described in Patent Document 1, a high voltage of approximately 100 V was required. Therefore, an object of the present invention is to provide an electrically peelable adhesive body that exhibits excellent electrical peeling properties even at low voltages.

Therefore, the following inventions [1] to [24] are provided.
[1] An electrically peelable adhesive body comprising a substrate, a first electrically peelable adhesive layer on a first surface of the substrate, and a second electrically peelable adhesive layer on a second surface of the substrate,
the first and second electrically releasing adhesive layers each comprise an electrically releasing adhesive composition including an acrylic polymer and an ionic liquid;
a conductive pattern layer having voids is formed on the surface of the first electrically releasing pressure-sensitive adhesive layer;
the first electrically releasable pressure-sensitive adhesive layer is capable of adhering to an adherend via voids in the conductive pattern layer,
The electroreleasable adhesive material, wherein the ionic liquid is a salt of a cation selected from imidazolium-based cations and an anion selected from (FSO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₂ N ^- and BF ₄ ^- .

[2] An electrically peelable adhesive body described in [1] above, wherein the conductive pattern layer comprises line portions that are lattice-shaped, linear, wavy, curved, or a combination thereof.

[3] An electrically peelable adhesive body described in [2] above, wherein the width of the line portion of the conductive pattern layer is 0.01 mm or more and 3 mm or less.

[4] An electrically peelable adhesive body described in any one of [1] to [3] above, wherein the ionic liquid is 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide and/or 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.

[5] An electrically peelable adhesive body described in any one of [1] to [4] above, wherein the voids have an area of 25% or more and 99% or less of the surface of the first electrically peelable adhesive layer.

[6] The electrically peelable pressure-sensitive adhesive body according to any one of the above [1] to [5], wherein the size of each void is 0.2 mm ² or more and 10 mm ² or less.

[7] An electrically peelable adhesive body described in any one of [1] to [6] above, wherein the thickness of the conductive pattern layer is in the range of 1 μm to 50 μm.

[8] An electrically peelable adhesive body described in any one of [1] to [7] above, wherein the conductive pattern layer contains 40% by weight or more of a metal-based conductive material.

[9] An electrically peelable adhesive body described in any one of [1] to [8] above, wherein the conductive pattern layer is formed on the surface of the second electrically peelable adhesive layer.

[10] An electrically peelable adhesive body described in any one of [1] to [9] above, wherein the thickness of the electrically peelable adhesive body is in the range of 10 μm to 300 μm.

[11] The electrically peelable pressure-sensitive adhesive body according to any one of the above [1] to [10], wherein the substrate has a basis weight of 10.0 g/ ^m2 or less and a thickness of 10 μm or more and 50 μm or less.

[12] An electrically peelable adhesive body described in any one of [1] to [11] above, wherein the content of the ionic liquid in the electrically peelable adhesive composition is 10 parts by weight or more and 90 parts by weight or less per 100 parts by weight of the acrylic polymer.

[13] An electrically peelable pressure-sensitive adhesive body described in any one of [1] to [12] above, wherein the acrylic polymer comprises a copolymer of an alkyl (meth)acrylate having an alkyl group having 1 to 8 carbon atoms, a carboxyl group-containing acrylic monomer, and/or a hydroxyl group-containing acrylic monomer.

[14] An electrically peelable adhesive body described in any one of [1] to [13] above, wherein the electrically peelable adhesive composition contains a migration promoter.

[15] An electrically disengageable adhesive material described in [14] above, wherein the migration promoter is an alkyl ether of polyethylene glycol.

[16] An electrically peelable pressure-sensitive adhesive body comprising an electrically peelable pressure-sensitive adhesive layer made of an electrically peelable pressure-sensitive adhesive composition containing an acrylic polymer and an ionic liquid, and a conductive pattern layer having voids formed on the surface of the electrically peelable pressure-sensitive adhesive layer,
the electrically releasing pressure-sensitive adhesive layer comprises an electrically releasing pressure-sensitive adhesive composition containing an acrylic polymer and an ionic liquid,
the electrically peelable pressure-sensitive adhesive layer is capable of adhering to an adherend via voids in the conductive pattern layer,
The electroreleasable adhesive material, wherein the ionic liquid is a salt of a cation selected from imidazolium-based cations and an anion selected from (FSO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₂ N ^- and BF ₄ ^- .

[17] A step of contacting a substrate with an electrically releasing pressure-sensitive adhesive composition containing an acrylic polymer and an ionic liquid to form a first electrically releasing pressure-sensitive adhesive layer and a second electrically releasing pressure-sensitive adhesive layer;
and forming a conductive pattern layer on at least the first electrically releasing pressure-sensitive adhesive layer,
The method for producing an electro-peelable adhesive material, wherein the ionic liquid is a salt of a cation selected from imidazolium-based cations and an anion selected from (FSO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₂ N ^- and BF ₄ ^- .

[18] The manufacturing method described in [17] above, wherein the conductive pattern layer is lattice-shaped and the width of the line portions of the conductive pattern layer is 0.01 mm or more and 3 mm or less.

[19] The manufacturing method described in [17] or [18] above, further comprising a step of preparing the electrically peelable pressure-sensitive adhesive composition before the step of forming the first electrically peelable pressure-sensitive adhesive layer and the second electrically peelable pressure-sensitive adhesive layer.

[20] The manufacturing method described in any one of [17] to [19] above, wherein the electrically peelable pressure-sensitive adhesive composition contains a migration promoter.

[21] A method for peeling an electro-peelable adhesive body by attaching objects to both sides of the electro-peelable adhesive body described in any one of [1] to [16] above, and then applying a voltage to the electro-peelable adhesive body.

[22] A peeling method described in [21] above, in which at least one of the objects is an insulator, and the surface having the first electrically peelable adhesive layer is attached to the insulator so that it is in contact with the surface, and then a voltage is applied to the electrically peelable adhesive.

[23] A peeling method described in [21] or [22] above, wherein the voltage is in the range of 1 V or more and 100 V or less.

[24] A peeling method described in any one of [21] to [23] above, wherein the voltage application time is in the range of 1 second or more and 600 seconds or less.

The present invention provides an electrically peelable adhesive material that has excellent electrical peeling properties even at low voltages.

FIG. 1 is a schematic diagram of an electro-releasable adhesive body (referred to as an adhesive body) viewed from the horizontal direction. 1 is a schematic diagram of an adhesive body in which voids are filled with an adhesive, as viewed from the horizontal direction. 1 is a schematic diagram of an adhesive body having conductive patterns formed on both sides, viewed from the horizontal direction. 1 is a schematic diagram of an adhesive body having conductive patterns formed on both sides and in which voids are filled with adhesive, as viewed from the horizontal direction. FIG. 1 is a plan view of an adhesive body having a grid-shaped conductive pattern layer placed on a horizontal surface and viewed from directly above. FIG. 2 is an enlarged view of a portion of a grid-shaped conductive pattern layer. FIG. 1 is a schematic diagram of an adhesive body without a substrate. This is a horizontal view of a composite (composite 1) consisting of an adhesive body, a first conductor adhered to the first electrically peelable adhesive layer of the adhesive body, and a second conductor adhered to the second electrically peelable adhesive layer. FIG. 2 is a diagram showing an example of a circuit in which electrode terminals are connected to a first conductor and a second conductor of a composite body 1. FIG. 1 is a diagram showing an example in which a voltage is applied to a composite 1. FIG. 1 is a horizontal view of a composite (composite 2) consisting of an adhesive body, an insulator adhered to the first electrically releasable adhesive layer of the adhesive body, and a first conductor adhered to the second electrically releasable adhesive layer. FIG. 10 is a diagram showing an example of a circuit in which electrode terminals are connected to the conductor and conductive pattern layer of the composite 2. FIG. 10 is a diagram showing an example in which a voltage is applied to a composite 2. 1 is an image of the conductive pattern layer of the adhesive body 1. This is a horizontal view of the structure of a composite formed by attaching an insulator to the first electrically peelable adhesive layer of any of adhesive bodies 1 to 3 and an electrical conductor to the second electrically peelable adhesive layer. 8B is a diagram showing a circuit in which electrode terminals are connected to the conductors and conductive patterns of the composite of FIG. 8A. FIG.

[Electro-peelable adhesive]
An electroreleasable adhesive (hereinafter simply referred to as an adhesive) according to one embodiment of the present invention comprises a planar substrate, a first electroreleasable adhesive layer formed on a first surface of the substrate, and a second electroreleasable adhesive layer formed on a second surface of the substrate, and has electroreleasability. "Electroreleasability" refers to the ability to separate an electrical conductor attached to the adhesive by applying a voltage to the adhesive, thereby reducing the adhesiveness of the adhesive. Furthermore, a conductive pattern layer is formed on at least the surface of the first electroreleasable adhesive layer. A schematic diagram of the structure of the adhesive is shown in FIG. 1A. In FIG. 1A, 10 denotes the electroreleasable adhesive, 11 denotes the first electroreleasable adhesive layer, 12 denotes the second electroreleasable adhesive layer, 13 denotes the substrate, 14 denotes the conductive pattern layer, and 15 denotes a gap. Although not shown in FIG. 1A, in the following drawings, 1 denotes a first electrical conductor, 2 denotes a second electrical conductor, 20 denotes an insulator, and 100 denotes a DC power source.

The adhesive body may have a conductive pattern layer formed not only on the first electrically releasable adhesive layer but also on the second electrically releasable adhesive layer. An example of such an adhesive body is shown in Figure 2A.

The first and second electrically releasing adhesive layers each contain an electrically releasing adhesive composition (hereinafter also referred to simply as the composition; the electrically releasing adhesive composition will be described later), and part or all of both sides of the adhesive body are adhesive. The adhesive body of the present invention may take the form of, for example, a double-sided sheet or double-sided tape. It is preferable that the adhesive body has an adhesive strength of 3 N/25 mm or more before the application of a voltage.

The substrate refers to a planar object onto which the composition can be applied to form an adhesive layer, or which can form an adhesive layer together with the composition. The substrate does not have to be completely flat; some or all of it may be uneven. The substrate may also have at least one through-hole. There are no particular restrictions on the substrate, as long as the adhesive layer is ionically conductive when a voltage is applied to the adhesive sheet.

Examples of the substrate include foils or plates made of metals such as aluminum, copper, silver, and gold, or alloys of these metals; plant fibers; inorganic or chemical fibers; and porous films. Of these, substrates made of fibers are preferred, and plant fibers are more preferred. Examples of substrates made of plant fibers include Western paper and Japanese paper. Examples of substrates made of inorganic or chemical fibers include nonwoven or woven fabrics such as polyester (particularly polyethylene terephthalate nonwoven fabrics), carbon fibers, and glass fibers. Examples of porous films include polyimide and polyester films. The ability of the composition to penetrate the gaps between fibers and the pores of porous films allows for the formation of a thin adhesive sheet while enabling ion conduction through the adhesive layer. The substrate is preferably made of fibers made of an insulating material. Examples of insulating fibers include plant fibers and polyester fibers.

The thickness of the substrate is not particularly limited, but is, for example, 5 μm to 50 μm, preferably 10 μm to 40 μm, and more preferably 10 μm to 30 μm. The upper limit of the substrate thickness is, for example, 50, 45, 40, 35, or 30 μm. The lower limit of the substrate thickness is, for example, 5, 7, 10, 12, or 15 μm.

The basis weight of the substrate is not particularly limited, but is, for example, 50 g/ ^m² or less, preferably ² g/m² to 30 g/ ^m² or less, more preferably 2 g/ ^m² to 20 g/ ^m² or less, more preferably 2 g/m² to 15 g/ ^m² or less, and even more preferably 2 g/m² to ¹⁰ g/ ^m² or less. The upper limit of the basis weight is, for example, 50, 40, 30 ^{, 20} , or ¹⁰ g/m². The lower limit of the basis weight is, for example, 2.0, 2.5, 3.0, 4.0, or 5.0 g/ ^m² . In particular, it is particularly preferable that the core material have a basis weight of 10.0 g/ ^m² or less and a thickness of 10 μm to 35 μm. By having such a basis weight and thickness, a thin adhesive body can be obtained without affecting the electro-separation properties.

The thickness of the adhesive is not particularly limited, but is preferably 10 μm or more and 300 μm or less, more preferably 10 μm or more and 150 μm or less, and even more preferably 10 μm or more and 100 μm or less. The upper limit of the adhesive thickness is, for example, 300, 200, or 100 μm. The lower limit of the adhesive thickness is, for example, 1, 5, 10, 15, 20, 25, or 30 μm.

The thickness of the adhesive body or substrate can be measured using a known thickness measuring device. An example of a thickness measuring device is a Peacock precision measuring instrument. Here, "thickness" refers to the average value measured using the thickness measuring device at at least five randomly selected locations on the object to be measured. The first and second electrically releasing adhesive layers are layers of the composition formed on each surface of the substrate. The adhesive layer may consist solely of the composition permeating into the substrate. In this case, the first and second electrically releasing adhesive layers refer to the adhesive portions of the substrate surface.

(Electrically Peelable Adhesive Composition)
The composition contains an acrylic polymer as a pressure-sensitive adhesive. The acrylic polymer can be obtained by polymerizing an acrylic monomer in the presence of any polymerization initiator. Any acrylic polymer can be used as a pressure-sensitive adhesive. From the viewpoint of adhesiveness, the weight-average molecular weight of the acrylic polymer is preferably 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, and even more preferably 300,000 to 3,000,000. Here, the weight-average molecular weight refers to the weight-average molecular weight converted into polystyrene. Specifically, it may be the weight-average molecular weight converted into polystyrene calculated using Shodex GPC (System 21) with tetrahydrofuran as the mobile phase. The amount of the acrylic polymer in the acrylic pressure-sensitive adhesive is not particularly limited, but is preferably 10 to 70 wt% and more preferably 20 to 50 wt% of the total weight of the pressure-sensitive adhesive.

The acrylic monomers that make up the acrylic polymer are not particularly limited, and known acrylic monomers used in pressure-sensitive adhesives can be used. Among these, alkyl (meth)acrylates are preferably included as acrylic monomers, and alkyl (meth)acrylates having an alkyl group with 1 to 14 carbon atoms are more preferred. The alkyl (meth)acrylates may account for 100% by weight of the total weight of the acrylic monomers included in the pressure-sensitive adhesive, preferably 40 to 100% by weight, more preferably 50 to 98% by weight, more preferably 70 to 98% by weight, and even more preferably 85 to 98% by weight. Note that (meth)acrylate refers to either methacrylate or acrylate.

Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and dodecyl (meth)acrylate. These alkyl (meth)acrylates may be used alone or in combination of two or more. Among these alkyl (meth)acrylates, alkyl (meth)acrylates having an alkyl group containing 1 to 8 carbon atoms are preferred, alkyl (meth)acrylates having an alkyl group containing 1 to 4 carbon atoms are more preferred, n-butyl (meth)acrylate is more preferred, and n-butyl acrylate is more preferred.

Examples of acrylic monomers other than alkyl (meth)acrylates include carboxyl group-containing (meth)acrylates such as acrylate, methacrylate, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate, and hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, (4-hydroxymethylcyclohexyl)-methyl acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate. These acrylic monomers other than alkyl (meth)acrylates may be used alone or in combination of two or more.

The amount of acrylic monomers other than alkyl (meth)acrylates is not particularly limited and may be 100% by weight of the total weight of acrylic monomers, but is preferably 1% by weight or more but less than 50% by weight, more preferably 2% by weight or more but less than 40% by weight, more preferably 3% by weight or more but less than 30% by weight, and even more preferably 3% by weight or more but less than 15% by weight.

The acrylic adhesive preferably contains, as the acrylic polymer, a copolymer of an alkyl (meth)acrylate having an alkyl group with 1 to 8 carbon atoms, a carboxyl group-containing acrylic monomer, and/or a hydroxyl group-containing acrylic monomer. When the acrylic polymer contains this copolymer, the adhesive has superior adhesive strength.

When an acrylic polymer contains a carboxyl group-containing monomer and/or a hydroxyl group-containing monomer, the total content of these two monomers is not particularly limited, but is preferably 1% by weight or more and 20% by weight or less of the total monomer amount, and more preferably 1% by weight or more and 10% by weight or less.

The glass transition temperature (Tg) of the acrylic polymer is preferably not higher than 0° C., more preferably not higher than −20° C., and even more preferably not higher than −40° C. The Tg can be calculated, for example, based on the Fox equation below.
1/Tg=(W1/Tg1)+(W2/Tg2)+・・・・・・+(Wn/Tgn)
The glass transition temperature can be measured, for example, by differential thermal analysis (DTA).

Vinyl monomers may be added to the acrylic polymer as needed. Examples of vinyl monomers include itaconic acid, maleic acid, crotonic acid, maleic anhydride, itaconic anhydride, vinyl acetate, N-vinylpyrrolidone, N-vinylcarboxylic acid amides, styrene, and N-vinylcaprolactam. These vinyl monomers may be used alone or in combination of two or more.

The acrylic polymer may be crosslinked by the action of a crosslinking agent. Examples of crosslinking agents include isocyanate-based crosslinking agents such as toluene diisocyanate and methylene bisphenyl isocyanate. The amount of crosslinking agent is preferably 0.1 to 10 parts by weight, more preferably 0.3 to 10 parts by weight, and even more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the acrylic polymer. Crosslinking the acrylic polymer can improve the creep resistance and/or shear resistance of the layer formed from the composition on a core material.

Examples of polymerization initiators used in polymer synthesis include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylpropionamidine) disulfide, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4,4-trimethylpentane), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis[2-methyl-N-(phenylmethyl)-propionamidine]dihydrochloride, and 2,2'-azobis[2-(3,4,5,6-tetrahydropyrimidin-2-yl)propionamidine]dihydrochloride. Examples of polymerization initiators include azo-based polymerization initiators such as [2-(2-imidazolin-2-yl)propane]dihydrochloride and 2,2'-azobis[2-(2-imidazolin-2-yl)propane]; persulfate-based polymerization initiators such as potassium persulfate and ammonium persulfate; peroxide-based polymerization initiators such as benzoyl peroxide, hydrogen peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclododecane, 3,3,5-trimethylcyclohexanoyl peroxide, and t-butyl peroxypivalate; and redox-based polymerization initiators composed of persulfates and sodium bisulfite. These polymerization initiators may be used alone or in combination. UV irradiation or radiation exposure may also be used. The polymerization initiator is preferably used in an amount of 0.005 to 1 part by weight per 100 parts by weight of the acrylic monomer. By using the polymerization initiator in this range, an acrylic polymer with excellent adhesive properties can be formed.

(ionic liquid)
Ionic liquids are combinations of cations and anions that are liquid at room temperature, and are also called room-temperature molten salts. Ionic liquids have properties such as non-flammability, non-volatility, and chemical stability. When a voltage is applied to an ionic liquid, anions migrate to the anode side and cations migrate to the cathode side. It is believed that the migration of anions and cations to the vicinity of the electrode, or the occurrence of an oxidation-reduction reaction of the anions or cations at the interface between the electrode and the electro-releasable pressure-sensitive adhesive composition, weakens the adhesive strength of the electro-releasable pressure-sensitive adhesive composition, resulting in improved releasability.

The ionic liquid is selected from a combination of a cation selected from imidazolium-based cations and an anion selected from (FSO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ and BF ₄ ⁻ .

Ionic liquids are available from Daiichi Kogyo Seiyaku, Kanto Chemical, Koei Chemical Industry, and others. For example, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMI-FSI) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMI-TFSI) are available from Daiichi Kogyo Seiyaku, and 1-ethyl-3-methylimidazolium hexafluorophosphate is available from Koei Chemical Industry. The combinations of cations and anions contained in EMI-FSI and EMI-TFSI are as follows:

The amount of ionic liquid contained in the electro-releasable pressure-sensitive adhesive composition is not particularly limited, but is preferably 1 to 90 parts by weight, more preferably 5 to 80 parts by weight, more preferably 5 to 50 parts by weight, more preferably 5 to 45 parts by weight, and even more preferably 5 to 35 parts by weight, per 100 parts by weight of the acrylic polymer. The upper limit of the amount of ionic liquid contained in the electro-releasable pressure-sensitive adhesive composition is, for example, 90 parts by weight, 80 parts by weight, 70 parts by weight, 60 parts by weight, 50 parts by weight, 45 parts by weight, 40 parts by weight, 35 parts by weight, or 30 parts by weight, per 100 parts by weight of the acrylic polymer. The lower limit of the amount of ionic liquid contained in the electro-releasable pressure-sensitive adhesive composition is, for example, 1 part by weight, 3 parts by weight, 5 parts by weight, 7 parts by weight, 9 parts by weight, 10 parts by weight, 15 parts by weight, or 20 parts by weight, per 100 parts by weight of the acrylic polymer. The ionic liquid may be a combination of one cation and one anion, or a combination of multiple types of cations and anions.

(Transportation promoter)
In this embodiment, the composition may contain a migration promoter that assists ion migration when a voltage is applied. Examples of the migration promoter include polyethylene glycol and alkyl ethers of polyethylene glycol, and alkyl ethers of polyethylene glycol are preferred.

The molecular weight of the migration promoter is not particularly limited, but preferably has a weight-average molecular weight of 120 to 600, more preferably 120 to 550, even more preferably 120 to 500, and even more preferably 120 to 360. The upper limit of the weight-average molecular weight of the migration promoter is, for example, 600, 580, 550, 530, 500, 470, 450, 430, 400, 370, 355, 350, or 340. The lower limit of the weight-average molecular weight of the migration promoter is, for example, 120, 125, 130, 135, 140, 145, 150, 155, 160, or 170. The weight-average molecular weight here refers to the weight-average molecular weight in terms of polystyrene.

Examples of polyethylene glycol alkyl ethers include polyethylene glycol mono(di)methyl ether, polyethylene glycol mono(di)ethyl ether, polyethylene glycol mono(di)propyl ether, polyethylene glycol mono(di)isopropyl ether, polyethylene glycol mono(di)butyl ether, polyethylene glycol mono(di)isobutyl ether, polyethylene glycol mono(di)methyl ether, and polyethylene glycol mono(di)pentyl ether. Among these, polyethylene glycol alkyl ethers having a weight-average molecular weight of 120 to 360 are preferred, with polyethylene glycol mono(di)methyl ether having a weight-average molecular weight of 120 to 360 being more preferred. Among these, tetraethylene glycol dimethyl ether (dimethyltetraglycol), diethylene glycol dibutyl ether, triethylene glycol butylmethyl ether, dimethyltriglycol, and triethylene glycol monomethyl ether are more preferred, with tetraethylene glycol dimethyl ether being even more preferred. Polyethylene glycol alkyl ethers are available from Nippon Nyukazai Co., Ltd., Toho Chemical Industry Co., Ltd., and other companies. The polyethylene glycol alkyl ethers used may be used alone or in combination of two or more.

The amount of migration promoter contained in the composition is not particularly limited, but may be, for example, 1 to 90 parts by weight, 5 to 80 parts by weight, 5 to 50 parts by weight, 5 to 40 parts by weight, or 5 to 30 parts by weight, per 100 parts by weight of the acrylic polymer. The upper limit of the amount of migration promoter contained in the composition is, for example, 90 parts by weight, 80 parts by weight, 70 parts by weight, 60 parts by weight, 50 parts by weight, 40 parts by weight, or 30 parts by weight, per 100 parts by weight of the acrylic polymer. The lower limit of the amount of migration promoter contained in the composition is, for example, 1 part by weight, 5 parts by weight, 10 parts by weight, or 15 parts by weight, per 100 parts by weight of the acrylic polymer.

(organic solvent)
The composition may contain an organic solvent. The organic solvent is not particularly limited, and examples include known organic solvents that can be used in pressure-sensitive adhesives. The organic solvent may be either a hydrophilic or hydrophobic organic solvent. Examples of hydrophilic organic solvents include methanol, ethanol, 1-propanol, 2-propanol, n-butyl alcohol, sec-butyl alcohol, isobutanol, tert-butyl alcohol, acetonitrile, acetone, and dimethylformamide. Examples of hydrophobic organic solvents include aliphatic hydrocarbons such as hexane, heptane, and isooctane; esters such as methyl acetate, ethyl acetate, and propyl acetate; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane, chloroform, 1-chlorobutane, and chlorobenzene; ethers such as diethyl ether and t-butyl methyl ether; and ketones such as methyl ethyl ketone and methyl isobutyl ketone. These organic solvents may be used alone or in combination. When an organic solvent is used, the proportion of the organic solvent used is preferably adjusted so that the solid content of the acrylic polymer is 10% by weight or more, and more preferably adjusted so that the solid content is 20% by weight or more and 50% by weight or less.

(additives)
In addition to the above components, the composition of the present embodiment may contain additives such as conductive materials, fillers, plasticizers, antioxidants, flame retardants, colorants, surfactants, and highly water-absorbent polymers.

Conductive materials are mainly classified into carbon-based conductive materials and metal-based conductive materials. Carbon-based conductive materials include, for example, nanocarbon or carbon fiber [e.g., vapor-grown carbon fiber (VGCF) or carbon nanofiber], and more specifically, natural graphite, artificial graphite, acetylene black, ketjen black, furnace black, etc. Metal-based conductive materials include, for example, metals such as Cu, Ni, Al, Ag, Au, Pt, Zn, or Mn, or alloys of these. Conductive materials may be used alone or in combination.

Examples of fillers include silica, diatomaceous earth, alumina, zinc oxide, magnesium oxide, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, calcium silicate, talc, mica, bentonite, activated clay, glass fiber, aluminum nitride, etc. Fillers may be used alone or in combination.

Examples of plasticizers include polyols such as glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol; aliphatic polycarboxylic acid esters such as adipate esters, citrate esters, sebacate esters, azelaate esters, and maleate esters; aromatic polycarboxylic acid esters such as terephthalate esters, isophthalate esters, phthalate esters, trimellitate esters, and benzoate esters; and polyesters. Plasticizers may be used alone or in combination.

Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, lactone-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. Antioxidants may be used alone or in combination.

Examples of flame retardants include phosphorus- and halogen-containing organic compounds, bromine- or chlorine-containing organic compounds, additives such as ammonium polyphosphate, aluminum hydroxide, and antimony oxide, as well as reactive flame retardants. Flame retardants may be used alone or in combination.

Examples of colorants include inorganic pigments such as carbon black, titanium oxide, zinc oxide, iron oxide, and mica, and organic pigments such as coupling azo pigments, condensed azo pigments, anthraquinone pigments, thioindigo pigments, dioxazone pigments, and phthalocyanine pigments. Colorants may be used alone or in combination.

Examples of surfactants include anionic surfactants such as pyridinium salts, benzethonium chloride, alkylbenzenesulfonates, α-olefinsulfonates, and phosphate esters; and nonionic surfactants such as amine salts (alkylamine salts, imidazolines, etc.), sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether, and polyoxyethylene dodecyl ether. Surfactants may be used alone or in combination.

Examples of superabsorbent polymers include sodium poly(meth)acrylate, potassium poly(meth)acrylate, ammonium poly(meth)acrylate, calcium poly(meth)acrylate, magnesium poly(meth)acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, poly(meth)acrylamide, poly-N-isopropylamide, polyvinylpyrrolidone, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, or derivatives or crosslinked products thereof. Superabsorbent polymers may be used alone or in combination.

The amount of these additives (excluding adhesives other than the above-mentioned acrylic polymer) contained in the composition is not particularly limited, but can be, for example, 0.1 parts by weight or more and 200 parts by weight or less, or 1 part by weight or more and 100 parts by weight or less, per 100 parts by weight of the acrylic polymer.

The method for forming the first and second electrically releasing adhesive layers is not particularly limited. For example, they can be formed by applying the composition to a release-treated polyethylene terephthalate film (release film) or the like and then laminating the substrate thereto. After applying the composition to the release film, the composition may be heated to dry it. Another example of a formation method is to apply the composition to the substrate. The method for applying these compositions is not particularly limited. Examples include direct application with a brush or using a coating device used in the manufacture of adhesive tapes. Coating devices that can be used include spin coaters, gravure coaters, applicators, multicoats, die coaters, bar coaters, roll coaters, blade coaters, knife coaters, and spray coaters. The thickness of the first and second electrically releasing adhesive layers is not particularly limited. However, it is preferably 1 μm to 200 μm, more preferably 1 μm to 50 μm, and even more preferably 5 μm to 30 μm. When an electrically releasing adhesive layer is formed on both sides of the adhesive layer, the two electrically releasing adhesive layers may have the same thickness or different thicknesses. Furthermore, the two electrically releasing adhesive layers may have the same composition or different compositions. The surface of the adhesive body to be used may be protected by a release film, release paper, or the like until use.

(Conductive pattern layer)
The conductive pattern layer is formed on the surface of the first electrically releasing adhesive layer (or the second electrically releasing adhesive layer) and has voids. When the surface of the adhesive body having the conductive pattern layer is attached to an adherend, the first electrically releasing adhesive layer (or the second electrically releasing adhesive layer) adheres to the adherend via the voids in the conductive pattern. Here, adhesion via the voids does not mean that the voids themselves are between the adherend and the first electrically releasing adhesive layer (or the second electrically releasing adhesive layer) and cause adhesion, but rather means that the adhesive body filled in the voids adheres to the adherend.

The gaps between the line portions may be free of adhesive before use, or may be partially or entirely filled with adhesive, as long as they can be adhered by the first electrically releasing adhesive layer (or the second electrically releasing adhesive layer if the conductive pattern layer is formed on the second electrically releasing adhesive layer) during use. Figures 1A and 2A show examples in which no adhesive is present in the gaps before use. If no adhesive is present in the gaps before use, the electrically releasing adhesive composition will fill the gaps, for example, when pressure is applied between the adhesive and the adherend when the adhesive is attached to the adherend. Figures 1B and 2B show the state in which the electrically releasing adhesive composition has filled the gaps. In this way, the electrically releasing adhesive composition of the first electrically releasing adhesive layer (or the second electrically releasing adhesive layer) fills the gaps, making the electrically releasing adhesive composition available to come into contact with the adherend, and thus enabling the adhesive to adhere to the adherend.

The adhesive body of this embodiment induces electro-peeling by passing electricity through the conductive pattern layer when energized. Therefore, even if the adherend fixed to the surface having the conductive pattern layer is an insulator, electro-peeling can be achieved by passing electricity through the conductive pattern layer. The conductive pattern layer is formed so as to be continuous on the first electro-peeling adhesive layer (or the second electro-peeling adhesive layer). "Continuously formed" refers to the conductive pattern layer being formed without interruption on that layer. This is because, in the adhesive body, the conductive pattern layer is a region through which electricity flows when energized. If two conductive patterns exist discontinuously on the same surface, even if one conductive pattern can be energized, the other conductive pattern may not. In this case, regions where electro-peeling or no current can be passed will be created. This creates regions where electro-peeling does not occur, significantly reducing the electro-peeling properties of the adhesive body.

The shape of the conductive pattern layer is not particularly limited as long as it is formed continuously, but it is preferable that the conductive pattern layer has a combination of a certain pattern. By having a certain pattern, electricity can be uniformly applied to the adhesive body when it is energized.
The conductive pattern layer is preferably composed of line portions formed, for example, in a grid-like, linear, wavy, curved, or combination thereof, and more preferably in a grid-like line portion. Examples of adhesive bodies having a grid-like conductive pattern layer are shown in Figures 3A and 3B. Figure 3A is a view of an adhesive body having a grid-like conductive pattern layer placed on a horizontal surface and viewed from directly above. Figure 3B is an enlarged view of a portion of the adhesive body shown in Figure 3A. In Figures 3A and 3B, the areas where the grid is formed by white lines represent the conductive pattern layer and the line portions that form the conductive pattern layer, and the black dots represent gaps between the line portions of the conductive pattern layer. Forming a dense conductive pattern layer in the adhesive body in this way can further improve the electro-separation properties of the adhesive body.

While the width (line width) of the line portion of the conductive pattern layer is not particularly limited, it is preferable that the line width be uniform. The line width is preferably 0.01 mm or more and 3 mm or less, more preferably 0.02 mm or more and 2 mm or less, and even more preferably 0.02 mm or more and 1 mm or less. Having a line width within this range enables electrical peeling to be performed at a lower voltage. Note that the line width here does not refer to the length of the line portion in the direction in which the line extends, but rather the length perpendicular to the direction in which the line extends. If the line width of the conductive pattern layer is not uniform, it is preferable that the minimum and maximum line widths are substantially within the above-mentioned range. "Substantially" refers, for example, to a situation where only a small portion of the conductive pattern on the adhesive does not have the above-mentioned line width, while the rest is within the above-mentioned line width range. For example, a conductive pattern may have a terminal for electrical conduction formed in part, and this terminal portion does not satisfy the above-mentioned line width requirements.

The thickness of the conductive pattern layer is not particularly limited, but is preferably in the range of 1 μm to 50 μm, and more preferably in the range of 1 μm to 30 μm.

The shape of the voids is not particularly limited as long as a closed space is formed by the line portion. Examples of the shape of the voids include polygons such as triangles, squares, pentagons, and hexagons, circles, irregular shapes, and combinations thereof. The number of voids is also not particularly limited, but is preferably 10 to 300, and more preferably 30 to 100, per 1 ^cm2 of the adhesive body. The number of voids per 1 ^cm2 of the adhesive body is calculated by placing the adhesive body on a horizontal surface and measuring the area of the adhesive body and the number of voids when viewed from directly above.

The area ratio of the voids is not particularly limited, but it is preferable that they account for 25% to 99% of the surface area of the first electrically releasing adhesive layer (or the second electrically releasing adhesive layer if a conductive pattern layer is formed on the second electrically releasing adhesive layer), more preferably 30% to 97%, and even more preferably 40% to 95%. Note that "area" here refers to the area occupied by the voids when the adhesive body is placed on a horizontal surface and viewed from directly above. Having the void area within this range makes it possible to obtain an adhesive body that combines higher adhesion with excellent electrical releasability.

The size of the voids is not particularly limited, but the size of one void is preferably from 0.2 ^mm to ^{10 mm} , more preferably from 0.25 mm to ⁴ mm, and even more preferably from 0.4 ^mm to 2.5 ^mm . By having the void size within this range, an adhesive body can be obtained that combines higher adhesion and excellent electrical peeling properties.

The conductive pattern layer is not particularly limited as long as it is made of a conductive material. For example, the above-mentioned carbon-based conductive materials and metal-based conductive materials can be used. Of these, it is preferable that the conductive layer contains a metal-based conductive material, and more preferably that the conductive layer contains 40% or more by weight of a metal-based conductive material. It is particularly preferable that the conductive layer contains Ag as the metal-based conductive material. Specific examples of the conductive pattern layer include Cu mesh, Ag mesh, silver paste (a mixture of Ag, resin, etc.), carbon paste (a mixture of carbon-based conductive material, resin, etc.), metal cloth, conductive cloth, etched aluminum foil, metal foil, etc. Specific examples of silver paste include Dotite FA-345 manufactured by Fujikura Kasei Co., Ltd.

The conductive pattern layer may contain a resin component in addition to the carbon-based conductive material or metal-based conductive material, such as the silver paste or carbon paste mentioned above. Examples of the resin component include thermosetting resins and thermoplastic resins, with thermosetting resins being preferred. Examples of thermosetting resins include polyester resins, phenolic resins, and acrylic resins. The resin component preferably accounts for 20% by weight or less of the conductive pattern layer, more preferably 10% by weight or less, and even more preferably 5% by weight or less.

The method for forming the conductive pattern layer is not particularly limited. Examples include attaching a metal cloth to the first electrically peelable adhesive layer, forming a conductive pattern directly on the first electrically peelable adhesive layer using the above-mentioned applicator, or forming a conductive pattern on a release film using the above-mentioned applicator and then attaching it to the first electrically peelable adhesive layer.

The conductive pattern layer may have a terminal for applying a voltage to a portion thereof. The terminal may be made of the same material as that forming the conductive pattern layer, or it may be made of a different material. The terminal is preferably made of the metallic conductive material described above.

A portion of the conductive pattern layer may extend beyond the first electrically releasable adhesive layer. If this is the case, electrode terminals can be attached to the protruding conductive pattern layer, making it easier to apply electricity for electrical peeling.

There is no specific temperature requirement for peeling, but it is preferable to perform it at room temperature.

One embodiment of the present invention is an adhesive body comprising an electrically releasing adhesive layer made of an electrically releasing adhesive composition containing an acrylic polymer and an ionic liquid, and a conductive pattern layer having voids formed on the surface of the electrically releasing adhesive layer. A schematic diagram of the adhesive body's configuration is shown in Figure 4. In Figure 4, 10 denotes the electrically releasing adhesive body, 11 denotes the first electrically releasing adhesive layer, 14 denotes the conductive pattern layer, and 15 denotes the voids. By adhering the conductive pattern layer of this adhesive body to an insulator and the electrically releasing adhesive layer to a conductor (described below), electrical peeling by passing a current through the adhesive body becomes possible even on an insulator. Alternatively, an adhesive body having the aforementioned substrate can be formed by adhering the adhesive body to a substrate. The electrically releasing adhesive layer, conductive pattern layer, acrylic polymer, and ionic liquid are as described above.

[Method of manufacturing an electro-releasable adhesive body]
This embodiment provides a method for producing an electro-releasable adhesive body, which includes the steps of contacting a substrate with an electro-releasable adhesive composition containing an acrylic polymer and an ionic liquid to form a first electro-releasable adhesive layer and a second electro-releasable adhesive layer, and forming ^a conductive pattern layer on at least the first electro-releasable adhesive layer, wherein the ionic liquid is a salt of a cation selected from imidazolium-based cations and _an anion selected from ( _FSO2 ) _2N- ^, ( _CF3SO2 ) _2N- and _BF4- ^.
The substrate, the acrylic polymer, the ionic liquid, the electrically releasing pressure-sensitive adhesive composition, the first electrically releasing pressure-sensitive adhesive layer and the second electrically releasing pressure-sensitive adhesive layer are as described above.

Contacting a substrate with an electrically releasing adhesive composition includes, for example, allowing the electrically releasing adhesive composition to penetrate the substrate, or contacting both surfaces of the substrate with the electrically releasing adhesive composition to form a first electrically releasing adhesive layer and a second electrically releasing adhesive layer.

The method for forming the first and second electrically releasing adhesive layers is not particularly limited, and they can be formed, for example, by applying the composition to a release-treated polyethylene terephthalate film (release film) or the like and laminating a substrate thereto. After applying the composition to the release film, the composition may be heated to dry the composition. In another example, the layers can be formed by applying the composition to a substrate. The composition can be applied using the above-mentioned application device.
If the substrate is made of fibers or has holes, the attached electrically releasing adhesive composition will penetrate into the fibers or holes. At this time, the attached substrate may be pressurized. Applying pressure makes it easier for the electrically releasing adhesive composition to penetrate into the substrate. Pressure may be applied from only one side of the core material or from both sides. The adhesive layer may consist solely of the composition permeating into the substrate. In this case, the first electrically releasing adhesive layer and the second electrically releasing adhesive layer refer to the adhesive portions on the surface of the substrate.

A step of preparing an electrically peelable pressure-sensitive adhesive composition may be included before the step of contacting an electrically peelable pressure-sensitive adhesive composition containing an acrylic polymer and an ionic liquid with a substrate to form a first electrically peelable pressure-sensitive adhesive layer and a second electrically peelable pressure-sensitive adhesive layer.
The electrically peelable pressure-sensitive adhesive composition can be prepared, for example, by stirring an acrylic polymer, an ionic liquid, an optional crosslinking agent, etc. The stirring method is not particularly limited, and any known stirring method can be used. Specific examples include stirring the acrylic polymer, the ionic liquid, the migration promoter, the optional crosslinking agent, etc. using a V-type mixer or a mixer (such as a dissolver, homomixer, or planetary mixer). The above-mentioned additives may be added during stirring.

A migration promoter may be included when preparing the electroreleasable adhesive composition. The migration promoter is as described above.

[Method for removing electrically releasable adhesive material]
This embodiment also provides a method for peeling off an electro-peelable adhesive body by attaching objects to both sides of the electro-peelable adhesive body and then applying a voltage to the electro-peelable adhesive body.

The object may be a conductor or an insulator.
Examples of conductors include metal plates, metal products, or metal workbenches made of metals such as iron, aluminum, copper, silver, or gold, or alloys of these metals; metal plates, metal products, foils (thickness less than 100 μm), and plates (thickness 100 μm or more) made of metals such as iron, aluminum, copper, silver, or gold, or alloys of these metals; meshes or fabrics containing fibers mixed with or coated with these metals or alloys; resin sheets containing these metals or alloys; and resin plates with a layer containing these metals, alloys, or conductive metal oxides. Among these, materials with a resistance value of 1000 Ω/sq or less are preferred. Examples of the metal products include metal cases enclosing batteries, metal vehicle parts, electronic components such as circuit boards, etc.
Examples of insulating materials include wooden plywood, plastic products, and non-metallic work benches.

An example of an electrical peeling configuration using an adhesive is shown below. For example, a composite (composite 1) can be formed by attaching a first conductor to the first electrically peelable adhesive layer of the adhesive, and then attaching a second conductor to the second electrically peelable adhesive layer. An example of a composite is shown in Figure 5A. Figure 5A is a horizontal view of a cross section of a composite placed with the first conductor at the bottom, cut vertically (the same applies to other examples below).

Figure 5B shows composite 1 connected to a DC power supply. In Figure 5B, the terminals of the two electrodes extending from the DC power supply are connected to the first conductor and the second conductor, respectively. The DC power supply in Figure 5B is turned on and a voltage is applied. Figure 5C shows composite 1 after application. As shown in Figure 5C, electricity flows between the first conductor and the second conductor via the adhesive, allowing the second conductor to be separated from composite 1.

In this embodiment, because the electro-releasable adhesive has a conductive pattern layer, electrical peeling can be performed even when the adhesive is attached to an insulator. An example is shown in Figures 6A to 6C below. A composite (composite 2) can be formed by attaching an insulator to the first electro-releasable adhesive layer of the adhesive and a first conductor to the second electro-releasable adhesive layer. An example of a composite is shown in Figure 6A. Figure 6B shows composite 2 connected to a DC power supply. In Figure 6B, the terminals of the two electrodes extending from the DC power supply are connected to the conductive pattern layer and the first conductor, respectively. The DC power supply in Figure 6B is turned on and a voltage is applied. Figure 6C shows composite 2 after application. As shown in Figure 6C, electricity flows between the conductive pattern layer of the adhesive and the first conductor, allowing the first conductor to be separated from composite 2.

The adhesive of this embodiment can achieve electrical peeling at low voltages, but this does not preclude its use at high voltages. The range of applied voltages can be selected from, for example, 690V, 650V, 600V, 550V, 500V, 450V, 400V, 350V, 300V, 250V, 230V, 200V, 180V, 150V, 130V, 125V, 120V, 110V, 100V, 90V, 80V, 70V, 60V, 50V, 40V, and 30V for the upper limit, and 0.5V, 1V, 2V, 3V, 4V, 5V, 6V, 7V, 8V, 9V, and 10V for the lower limit. Among these, it is preferable to operate at a voltage of 1 V or more and 100 V or less, more preferably 1 V or more and 50 V or less, and even more preferably 5 V or more and 30 V or less.

The duration of voltage application is not particularly limited as long as it is capable of causing electrical peeling in the composite, but is preferably from 1 second to 600 seconds, more preferably from 1 second to 300 seconds, more preferably from 1 second to 180 seconds, and even more preferably from 1 second to 90 seconds.

The present invention will be further explained in detail below using examples and comparative examples, but the present invention is not limited by these in any way.

[Electrical peeling test using electrically peelable adhesive]
Three types of electro-releasable pressure-sensitive adhesive materials were prepared, and composites were formed by combining them with a conductor and an insulator, and an electro-releasable pressure-sensitive adhesive composition used in the composites was prepared as follows.

(Electrically releasing adhesive composition A)
1. Preparation of acrylic polymer
A monomer mixture consisting of 90 parts by weight of n-butyl acrylate (Mitsubishi Chemical Corporation), 6 parts by weight of methyl methacrylate (Mitsubishi Chemical Corporation), 3 parts by weight of acrylic acid (Mitsubishi Chemical Corporation), and 1 part by weight of 2-hydroxyethyl methacrylate (Nippon Shokubai Co., Ltd.) was mixed with 0.2 parts by weight of azobisisobutyronitrile (AIBN, Junsei Chemical Co., Ltd.) as a polymerization initiator and 150 parts by weight of ethyl acetate, and the mixture was heated to 85°C and polymerized for 5 hours to obtain an acrylic adhesive. The resulting acrylic adhesive contained 40% by weight of an acrylic polymer (weight-average molecular weight approximately 680,000) and had a viscosity of 6,000 mPa s.

2. Preparation of Electrically Peelable Pressure-Sensitive Adhesive Composition To 100 parts by weight of the above acrylic pressure-sensitive adhesive (including 40 parts by weight of acrylic polymer), 2 parts by weight of Takenate (registered trademark) D-101E (Mitsui Chemicals, Inc.) as an isocyanate crosslinking agent, 14 parts by weight of Elexcel (registered trademark) AS-110 (EMI-FSI: Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic liquid, and 3.5 parts by weight of dimethyl tetraglycol (Nippon Nyukazai Co., Ltd.: molecular weight approximately 220) as a migration promoter were added, and the mixture was stirred with a dissolver at room temperature for 10 minutes and allowed to stand to degas, to obtain an electrically peelable pressure-sensitive adhesive composition A (composition A).

(Electro-Releasable Adhesive Body 1: Example)
Composition A was applied to a silicone-treated polyethylene terephthalate film (hereinafter also referred to as release film) to a thickness of 35 μm and dried at 100°C for 5 minutes. A polyester nonwoven fabric [Milife (registered trademark) TY0503FE (ENEOS Techno Materials Corporation): basis weight 8.0 g/m ² , thickness 40 μm] was attached to the composition-coated surface of the dried film. Similarly, Composition A was applied to a release film to a thickness of 35 μm, and dried to prepare a film, which was then attached to the side of the nonwoven fabric where the film was not attached. The film was then left to stand at 40°C for 3 days.

A separate release film was prepared and silver paste (Dotite FA-345: Fujikura Kasei Co., Ltd.) was screen-printed onto it in a grid pattern. The grid line width was 0.2 mm, the grid (gaps) were uniformly square, and the gaps were 1.0 mm in both length and width. One of the release films from the nonwoven fabric to which Composition A had been applied was peeled off, and a release film with a grid formed on it was attached with the grid side facing the surface coated with Composition A to form a conductive pattern layer, producing electrically peelable adhesive body 1 (Adhesive Body 1). The thickness of Adhesive Body 1 excluding the film was 83 μm, and the thickness excluding the film and conductive pattern layer was 80 μm. A photograph of the conductive pattern layer of Adhesive Body 1 is shown in Figure 7.

(Electro-Releasable Adhesive 2: Example)
Electroreleasable adhesive body 2 was produced in the same manner as electroreleasable adhesive body 1, except that the line width of the lattice was 0.6 mm.

(Electrically Peelable Adhesive Composition B)
1. Preparation of Acrylic Polymer The acrylic polymer prepared in the above-mentioned preparation of acrylic polymer was used.

2. Preparation of Electrically Peelable Pressure-Sensitive Adhesive Composition To 100 parts by weight of the above acrylic pressure-sensitive adhesive (including 40 parts by weight of acrylic polymer), 2 parts by weight of Takenate (registered trademark) D-101E (Mitsui Chemicals, Inc.) as an isocyanate crosslinking agent and 17.5 parts by weight of Elexcel (registered trademark) AS-110 (EMI-FSI: Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic liquid were added, and the mixture was stirred with a dissolver at room temperature for 10 minutes and allowed to stand to degas, thereby obtaining electrically peelable pressure-sensitive adhesive composition B (composition B).

(Electro-Releasable Adhesive 3: Example)
An electrically peelable pressure-sensitive adhesive body 3 (adhesive body 3) was produced in the same manner as the above-mentioned electrically peelable pressure-sensitive adhesive body A, except for using composition B instead of composition A. The film thickness excluding the film of adhesive body 1 was 83 μm, and the film thickness excluding the film and conductive pattern layer was 80 μm.

(Electro-Releasable Adhesive 4: Comparative Example)
Electrically releasable adhesive body 4 (Adhesive body ₄ ⁾ was produced in the same manner as electrically releasable adhesive body 1, except that the ionic liquid was ₁ ^- hexylpyridinium bis( _{trifluoromethanesulfone} ) manufactured by Kanto Chemical Co., Ltd., which was not a combination of a cation selected from imidazolium-based cations and an anion selected from (FSO ₂ ) ₂ N ^- , ( _CF 3 SO 2 ) 2 N -, and BF 4 -.

(Electro-Releasable Adhesive 5: Comparative Example)
Electrically peelable adhesive body 5 (adhesive body 5) was produced in the same manner as electrically peelable adhesive body 3, except that the ionic liquid was changed to 1-hexylpyridinium bis(trifluoromethanesulfone) manufactured by Kanto Chemical Co., Ltd. and the line width of the lattice was set to 0.6 mm.

(electrical peeling test)
Several pieces of each of the adhesive bodies 1 to 5 were cut out to a size of 25 mm x 250 mm. The polyethylene terephthalate film of each cut adhesive body was peeled off, and an insulator was attached to the exposed first electrically releasable adhesive layer, and a conductor was attached to the exposed second electrically releasable adhesive layer to form a composite. The structure of this composite is shown in Figure 8A. The attached conductors and insulators, as well as their combinations, are listed in Table 1 below as Examples 1 to 6 and Comparative Examples 1 to 4. Six samples were prepared for each combination. The sizes of the attached conductors and insulators were as follows:

Al (aluminum foil): 30mm x 150mm
SUS (stainless steel plate): 30mm x 150mm
PET (polyethylene terephthalate film): 30mm x 150mm
ABS (acrylonitrile-butadiene-styrene resin plate): 30mm x 150mm
Glass (general silicate glass plate): 30mm x 150mm

Electrodes and a DC power supply were attached to the conductor and conductive pattern of each composite (Figure 8B). The voltage was adjusted using a transformer, and a voltage of 10 V was applied for 10 seconds. In this case, electro-detachment occurred at the surface where the conductor was in contact with the adhesive, causing the conductor to separate from the adhesive.

For each composite, the adhesive strength was measured before and after the application of voltage. Measurements were made using a Shimadzu Autograph (registered trademark) AGS-H, in accordance with JIS Z-0237 (2009), measuring the force (adhesive strength: N/25 mm) required to peel the conductor from the adherend at an angle of 180° at a tensile speed of 300 mm/min. The measured value was the average of three measurements for each composite combination. The measurement results are shown in Table 1.

Table 2 also shows the results of electro-peeling, which was performed on the composite combinations shown in Table 1 by connecting the power supply shown in Figure 8B with the positive and negative terminals reversed and applying a voltage of 30 V for 30 seconds. In this case, electro-peeling occurs at the surface where the adhesive and insulator are in contact. For each composite before and after applying electricity, the force required to peel the insulator from the adherend at an angle of 180° (adhesive strength: N/25 mm) at a pulling speed of 300 mm/min was measured, and the average of three measurements for each composite combination was used as the measured value.

The reduction rates in Tables 1 and 2 were calculated based on the following formula.
Decrease rate (%) = ([Adhesive strength before printing] - [Adhesive strength after application]) / [Adhesive strength before printing]

Tables 1 and 2 show that in each of the composites of Examples 1 to 6, which used an insulator as the adherend, electrical peeling caused by the application of a voltage significantly reduced the adhesive strength. It also shows that the reduction in adhesive strength caused by the application of a voltage can occur on either side of the composite. In contrast, in Comparative Examples 1 to 4, in which the type of ionic liquid was changed to one that was not a combination of a cation selected from imidazolium-based cations and an anion selected from (FSO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₂ N ^- , and BF ₄ ^- , the adhesive strength did not decrease significantly. These results demonstrate that by using an adhesive that combines a specific ionic liquid with a conductive pattern, as in the present invention, electrical peeling is possible even when an insulator is used, and that sufficient electrical peeling can be achieved even with the application of a low voltage for a short period of time.

REFERENCE SIGNS LIST 1 First conductor 2 Second conductor 10 Electrically releasable adhesive body 11 First electrically releasable adhesive layer 12 Second electrically releasable adhesive layer 13 Base 14 Conductive pattern layer 15 Gap 20 Insulator 100 DC power source

Claims (23)

An electrically releasable adhesive body comprising a substrate, a first electrically releasable adhesive layer on a first surface of the substrate, and a second electrically releasable adhesive layer on a second surface of the substrate,
the first and second electrically releasing adhesive layers each comprise an electrically releasing adhesive composition including an acrylic polymer and an ionic liquid;
a conductive pattern layer having voids is formed on the surface of the first electrically releasing adhesive layer;
the first electrically releasable pressure-sensitive adhesive layer is capable of adhering to an adherend via voids in the conductive pattern layer,
the ionic liquid is a salt of a cation selected from imidazolium-based cations and an anion selected from (FSO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ and BF ₄ ⁻ ;
the content of the ionic liquid in the electrically peelable pressure-sensitive adhesive composition is 10 parts by weight or more and 90 parts by weight or less per 100 parts by weight of the acrylic polymer,
the voids have an area of 25 % or more and 70% or less of the surface of the first electrically releasing pressure-sensitive adhesive layer,
The size of one of the voids is 0.4 mm ² or more and 2.5 mm ² or less,
the conductive pattern layer includes a metal-based conductive material,
There are a plurality of voids in 1 cm ² of the adhesive body ,
Electrically peelable adhesive. The electro-peelable adhesive body according to claim 1, wherein the conductive pattern layer comprises line portions that are lattice-shaped, linear, wavy, curved, or a combination thereof. The electro-peelable adhesive body according to claim 2, wherein the width of the line portions of the conductive pattern layer is 0.01 mm or more and 3 mm or less. The electroreleasable adhesive material according to claim 1, wherein the ionic liquid is 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide and/or 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. 2. The electroreleasable adhesive body according to claim 1, wherein the voids occupy an area of 30 % to 70% of the surface of the first electroreleasable adhesive layer. The electro-peelable adhesive body according to claim 1, wherein the thickness of the conductive pattern layer is in the range of 1 μm to 50 μm. The electro-peelable adhesive body according to claim 1, wherein the conductive pattern layer contains 40% by weight or more of a metal-based conductive material. The electrically peelable adhesive body according to claim 1, wherein the conductive pattern layer is formed on the surface of the second electrically peelable adhesive layer. The electroreleasable adhesive body according to claim 1, wherein the thickness of the electroreleasable adhesive body is in the range of 10 μm to 300 μm. 2. The electrically peelable pressure-sensitive adhesive body according to claim 1, wherein the substrate has a basis weight of 10.0 g/m ² or less and a thickness of 10 μm or more and 50 μm or less. The electrically peelable pressure-sensitive adhesive body according to claim 1, wherein the content of the ionic liquid in the electrically peelable pressure-sensitive adhesive composition is 10 parts by weight or more and 50 parts by weight or less per 100 parts by weight of the acrylic polymer. The electrically peelable adhesive body according to claim 1, wherein the acrylic polymer comprises a copolymer of an alkyl (meth)acrylate having an alkyl group with 1 to 8 carbon atoms, a carboxyl group-containing acrylic monomer, and/or a hydroxyl group-containing acrylic monomer. The electroreleasable adhesive body according to claim 1, wherein the electroreleasable adhesive composition contains a migration promoter. The electroreleasable adhesive according to claim 13 , wherein the migration promoter is an alkyl ether of polyethylene glycol. An electrically peelable pressure-sensitive adhesive body comprising an electrically peelable pressure-sensitive adhesive layer made of an electrically peelable pressure-sensitive adhesive composition containing an acrylic polymer and an ionic liquid, and a conductive pattern layer having voids formed on the surface of the electrically peelable pressure-sensitive adhesive layer,
the electrically releasing pressure-sensitive adhesive layer comprises an electrically releasing pressure-sensitive adhesive composition containing an acrylic polymer and an ionic liquid,
the electrically peelable pressure-sensitive adhesive layer is capable of adhering to an adherend via voids in the conductive pattern layer,
the ionic liquid is a salt of a cation selected from imidazolium-based cations and an anion selected from (FSO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ and BF ₄ ⁻ ;
the content of the ionic liquid in the electrically peelable pressure-sensitive adhesive composition is 10 parts by weight or more and 90 parts by weight or less per 100 parts by weight of the acrylic polymer,
the voids have an area of 25 % or more and 70% or less of the surface of the electrically releasable pressure-sensitive adhesive layer,
The size of one of the voids is 0.4 mm ² or more and 2.5 mm ² or less,
the conductive pattern layer includes a metal-based conductive material,
There are a plurality of voids in 1 cm ² of the adhesive body ,
Electrically peelable adhesive. a step of contacting a substrate with an electrically releasing pressure-sensitive adhesive composition containing an acrylic polymer and an ionic liquid to form a first electrically releasing pressure-sensitive adhesive layer and a second electrically releasing pressure-sensitive adhesive layer;
and forming a conductive pattern layer on at least the first electrically releasing pressure-sensitive adhesive layer,
the ionic liquid is a salt of a cation selected from imidazolium-based cations and an anion selected from (FSO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ and BF ₄ ⁻ ;
the content of the ionic liquid in the electrically peelable pressure-sensitive adhesive composition is 10 parts by weight or more and 90 parts by weight or less per 100 parts by weight of the acrylic polymer,
the conductive pattern layer has voids,
the voids have an area of 25 % or more and 70% or less of the surface of the electrically releasable pressure-sensitive adhesive layer,
The size of one of the voids is 0.4 mm ² or more and 2.5 mm ² or less,
the conductive pattern layer includes a metal-based conductive material,
There are a plurality of voids in 1 cm ² of the adhesive body ,
Method for producing an electrically peelable adhesive material. The manufacturing method according to claim 16 , wherein the conductive pattern layer is in a lattice shape and the width of the line portions of the conductive pattern layer is 0.01 mm or more and 3 mm or less. The method according to claim 16 , further comprising the step of preparing the electrical release adhesive composition before the step of forming the first and second electrical release adhesive layers. The method of claim 16 , wherein the electrically releasing adhesive composition includes a migration promoter. A method for peeling an electro-peelable adhesive body, comprising attaching objects to both sides of the electro-peelable adhesive body according to any one of claims 1 to 15 , and then applying a voltage to the electro-peelable adhesive body. The peeling method according to claim 20, wherein at least one of the objects is an insulator, the surface having the electrically peelable adhesive layer is attached to the insulator so that the surface is in contact with the electrically peelable adhesive layer, and then a voltage is applied to the electrically peelable adhesive layer, and the layer is a layer having the conductive pattern layer formed on its surface . The peeling method according to claim 20 , wherein the voltage is in the range of 1 V or more and 100 V or less. The peeling method according to claim 20 , wherein the voltage application time is in the range of 1 second to 600 seconds.