Two-pack adhesive composition, method for curing two-pack adhesive composition, electrically peelable cured product, and method for peeling electrically peelable cured product

Abstract

The present invention uses a two-pack adhesive composition which is constituted from: a first agent containing at least one non-aromatic epoxy compound selected from among an aliphatic epoxy compound having a hydroxyl group and two or more epoxy groups and a cyclohexene oxide-based epoxy compound, an aromatic epoxy compound, rubber particles and an ionic liquid; and a second agent containing at least one curing agent selected from among an amine-based curing agent having two or more amino groups in the molecule, an acid anhydride-based curing agent, a phenol-based curing agent, a mercaptan-based curing agent and a polysulfide-based curing agent, and in which the ratio of the non-aromatic epoxy compound and the aromatic epoxy compound falls within a certain range.

Description

Two-component adhesive composition, method for curing a two-component adhesive composition, electropenetrating cured product, and method for removing electropenetrating cured product.

[0001] The present invention relates to a two-component adhesive composition and a method for curing the same. The present invention also relates to an electropeelable cured product and a method for removing the same.

[0002] In the fields of automobile and electronic component manufacturing, there is a growing demand for recycling, which involves disassembling and recovering parts after use. To meet this demand, adhesives that can bond materials together during the manufacturing process of automobiles and electronic components, while also possessing a certain degree of release properties when the parts are disassembled, are sometimes used.

[0003] As an adhesive that achieves the above-mentioned peelability, an adhesive that can be peeled off by applying a voltage to the adhesive layer (electro-peelable adhesive) is known. For example, Patent Document 1 describes an electro-peelable adhesive comprising a thermosetting resin precursor, a curing agent, an electrolyte, and a filler, wherein the thermal conductivity after curing is 1.0 W / m·K or higher. In the electro-peelable adhesive of Patent Document 1, the adhesive strength weakens when a voltage is applied, allowing it to be peeled off.

[0004] Japanese Patent Publication No. 2024-80122

[0005] The present invention aims to provide a two-component adhesive that exhibits excellent adhesive strength after curing and can be peeled off by applying a voltage to the cured product.

[0006] The present invention provides a two-component adhesive composition comprising at least one component comprising a first component containing at least one non-aromatic epoxy compound selected from aliphatic epoxy compounds having a hydroxyl group and two or more epoxy groups and cyclohexene oxide epoxy compounds, an aromatic epoxy compound, rubber particles and an ionic liquid, and a second component containing at least one curing agent selected from amine curing agents having two or more amino groups in the molecule, acid anhydride curing agents, phenol curing agents, mercaptan curing agents and polysulfide curing agents, wherein the non-aromatic epoxy compound is present in an amount of 60% to 95% by weight and the aromatic epoxy compound is present in an amount of 5% to 40% by weight, based on a total weight of 100% by weight of the non-aromatic epoxy compound and the aromatic epoxy compound.

[0007] Furthermore, the present invention provides a method for curing a two-component adhesive composition, comprising mixing the first and second components of the above-mentioned two-component adhesive composition, and curing the resulting mixture by heating it at 40°C or higher but less than 150°C for 30 minutes or more and 24 hours or less, or by curing it at 10°C or higher but 40°C for 24 hours or more and 120 hours or less.

[0008] Furthermore, the present invention provides an electro-removable cured product obtained by curing the above-mentioned two-component adhesive composition.

[0009] Furthermore, the present invention provides a method for removing an electropeelable cured product, which includes applying a voltage to an electropeelable cured product obtained by curing the above-mentioned two-component adhesive composition, in a second conductive object to which a first conductive object is bonded via the electropeelable cured product.

[0010] According to the present invention, it is possible to provide an adhesive composition that exhibits good adhesion and excellent electropenetration properties after curing.

[0011] Figure 1A is a schematic diagram of a composite material in which a first conductor and a second conductor are bonded together via a cured adhesive composition, viewed from the horizontal direction, with an example of a circuit in which electrode terminals are connected to the first conductor and the second conductor. Figure 1A is a schematic diagram showing the state in which the cured material is electrically peeled off from the first conductor when a voltage is applied to the composite material. Figure 2A is a schematic diagram showing the state in which the cured material is electrically peeled off from the first conductor when a voltage is applied to the composite material. Figure 3A is a schematic diagram showing the state in which the cured material is electrically peeled off from the first conductor when a voltage is applied to the composite material. Figure 4A is a schematic diagram showing the state in which the cured material is electrically peeled off from the first conductor when a voltage is applied to the composite material. Figure 5A is a schematic diagram showing the state in which the cured material is electrically peeled off from the first conductor when a voltage is applied to the composite material. Figure 6A is a schematic diagram showing the state in which the cured material is electrically peeled off from the first conductor when a voltage is applied to the composite material. Figure 7A is a schematic diagram showing the state in which the cured material is electrically peeled off from the first conductor when a voltage is applied to the composite material. This is a schematic diagram showing the state in which a voltage is applied to the composite in Figure 4A, and the cured material is electrically peeled off from the first conductor. This is a schematic diagram of the composite (test piece) prepared in the adhesion strength test, viewed from the horizontal. This is a schematic diagram of the circuit in which the electrode terminals are connected to the test piece prepared in the electropeelability test.

[0012] <Two-component adhesive composition> The two-component adhesive composition of the present invention comprises at least one component comprising a first agent containing at least one non-aromatic epoxy compound selected from aliphatic epoxy compounds having a hydroxyl group and two or more epoxy groups and cyclohexene oxide epoxy compounds, an aromatic epoxy compound, rubber particles and an ionic liquid, and a second agent containing at least one curing agent selected from amines having two or more amino groups in their molecules, acid anhydride curing agents, phenolic curing agents, mercaptan curing agents and polysulfide curing agents. Polymerization is initiated and curing occurs when the first agent and the second agent are mixed. Hereinafter, the mixture obtained by mixing the first agent and the second agent before curing will also be referred to as the "adhesive".

[0013] (Non-aromatic epoxy compounds) Aliphatic epoxy compounds having a hydroxyl group and two or more epoxy groups, and cyclohexene oxide-based epoxy compounds are collectively referred to as "non-aromatic epoxy compounds." Aliphatic epoxy compounds having a hydroxyl group and two or more epoxy groups (also called epoxy compounds having a hydroxyl group) include aliphatic polyol polyglycidyl ethers and hydroxyaliphatic carboxylic acid polyglycidyl esters. An "aliphatic polyol" is an aliphatic compound having two or more hydroxyl groups. The aliphatic portion may further have substituents other than hydroxyl groups. Examples of such substituents include alkoxy groups having 1 to 6 carbon atoms. Examples of aliphatic polyols include alkyl polyols. The alkyl in alkyl polyols is preferably an alkyl having 3 to 30 carbon atoms, and more preferably an alkyl having 3 to 16 carbon atoms. The alkyl may be linear or branched, and may have substituents other than hydroxyl groups, similar to the aliphatic compounds described above. In this specification, "polyglycidyl ether" means two or more glycidyl ethers, and examples include diglycidyl ether, triglycidyl ether, tetraglycidyl ether, pentaglycidyl ether, etc. Examples of alkyl polyol polyglycidyl ethers include glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolethane polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, castor oil modified polyglycidyl ether, propoxylated glycerin triglycidyl ether, and sorbitol polyglycidyl ether, etc. Among these, sorbitol polyglycidyl ether is preferred, sorbitol polyglycidyl ether with an epoxy equivalent of 143 to 234 g / eq is more preferred, and sorbitol polyglycidyl ether with an epoxy equivalent of 173 g / eq is particularly preferred. In this specification, "equivalent" means the value obtained by dividing the molecular weight by the number of corresponding functional groups. For example, epoxy equivalent (hereinafter also referred to as EEW) is the value obtained by dividing the molecular weight of the epoxy compound by the number of epoxy groups contained in the epoxy compound.A commercially available product is Denacol EX-614B (sorbitol polyglycidyl ether with an epoxy equivalent of 173 g / eq) (also known as EX-614B), provided by Nagase ChemteX Corporation.

[0014] Examples of hydroxyaliphatic carboxylic acid polyglycidyl esters include hydroxyaliphatic carboxylic acid polyglycidyl esters containing two or more carboxyl groups, with hydroxyalkyl carboxylic acid polyglycidyl esters containing two or more carboxyl groups being preferred. "Polyglycidyl ester" means two or more glycidyl esters, and examples include diglycidyl esters, triglycidyl esters, tetratriglycidyl esters, etc. As for the alkyl of the hydroxyalkyl carboxylic acid, alkyl groups having 2 to 30 carbon atoms are preferred, and alkyl groups having 2 to 16 carbon atoms are more preferred. The alkyl group may be linear or branched, and may further have substituents other than hydroxyl and carboxyl groups. Examples of such substituents include alkoxy groups having 1 to 6 carbon atoms. Examples of hydroxyalkyl carboxylic acid polyglycidyl esters containing two or more carboxyl groups include dihydroxydicarboxylic acid polyglycidyl ester of tartaric acid, monohydroxytricarboxylic acid polyglycidyl ester of citric acid, trihydroxyglutaric acid polyglycidyl ester, polyhydroxydicarboxylic acid polyglycidyl ester of saccharic acid, and monohydroxydicarboxylic acid polyglycidyl ester of malic acid.

[0015] When the non-aromatic epoxy compound contains only epoxy compounds having hydroxyl groups, the content of the epoxy compound having hydroxyl groups in the first agent may be, for example, 30% to 70% by weight, preferably 33% to 68% by weight, based on 100% by weight of the first agent. Also, based on 100% by weight of the total of the first and second agents, it may be, for example, 27% to 66% by weight, preferably 29% to 64% by weight. Furthermore, based on 100% by weight of the total of the epoxy compound having hydroxyl groups and aromatic epoxy compounds, the content of the epoxy compound having hydroxyl groups may be, for example, 60% to 95% by weight, preferably 61% to 93.5% by weight, and even more preferably 62% to 92.5% by weight. It is believed that the presence of epoxy compounds having hydroxyl groups, which are polar groups, in such a certain proportion as described above facilitates current flow when a voltage is applied to the cured product of the two-component adhesive composition.

[0016] In addition to or instead of the epoxy compounds having hydroxyl groups described above, cyclohexene oxide epoxy compounds can be used. Examples of cyclohexene oxide epoxy compounds include 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and bis[(3,4-epoxycyclohexyl)methyl]adipate. When the non-aromatic epoxy compound contains only cyclohexene oxide epoxy compounds, the content of the cyclohexene oxide epoxy compound is the same as the content of the epoxy compounds having hydroxyl groups described above. When the first agent contains both epoxy compounds having hydroxyl groups and cyclohexene oxide epoxy compounds, the sum of the content of both is considered the content of the non-aromatic epoxy compound. This content is the same as the content of the epoxy compounds having hydroxyl groups described above.

[0017] (Aromatic Epoxy Compounds) Aromatic epoxy compounds are compounds having at least two epoxy groups and at least one aromatic ring in their molecule. Examples of aromatic epoxy compounds include phenol-type epoxy compounds and aromatic carboxylic acid glycidyl esters. A phenol-type epoxy compound is a compound having at least two epoxy groups and a phenol skeleton in its molecule. Phenolic epoxy compounds preferably contain two or more phenol skeletons in their molecule, and examples include bisphenol-type epoxy compounds, biphenyl-type epoxy compounds, phenol novolac-type epoxy compounds, cresol novolac-type epoxy compounds, bisphenol A novolac-type epoxy compounds, and glycidyl ether-type epoxy resins such as other polyfunctional phenol-type epoxy resins. Among these, bisphenol-type epoxy compounds are preferred. Examples of bisphenol-type epoxy compounds include bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, bisphenol AD-type epoxy compounds, and bisphenol S-type epoxy compounds. Among these, bisphenol A type epoxy compounds are preferred, bisphenol A type epoxy compounds with an EEW of 245 to 330 g / eq are more preferred, and bisphenol A type epoxy compounds with an EEW of about 301 g / eq are particularly preferred. The aromatic epoxy compound may also be in the form of a solution in which rubber particles described later are dispersed or dissolved, i.e., a rubber particle dispersion described later.

[0018] As aromatic carboxylic acid glycidyl esters, glycidyl esters having six or more carbon atoms and a divalent or greater aromatic ring are preferred, and examples include diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, and triglycidyl trimellitic acid.

[0019] The content of the aromatic epoxy compound in the first agent is, for example, 4% by weight or more and less than 25% by weight, preferably 5% by weight or more and 24% by weight or less, based on 100% by weight of the first agent. Also, the content of the aromatic epoxy compound relative to 100% by weight of the total of the first and second agents is, for example, 3% by weight or more and less than 23.5% by weight, preferably 4% by weight or more and 23% by weight or less. Furthermore, relative to 100% by weight of the total of the non-aromatic epoxy compound and the aromatic epoxy compound, the content of the aromatic epoxy compound is, for example, 5% by weight or more and 40% by weight or less, preferably 6.5% by weight or more and 39% by weight or less, and more preferably 7.5% by weight or more and 38% by weight or less. The proportion of the aromatic epoxy compound relative to 100% by weight of the rubber particle dispersion described later is, for example, greater than 55% by weight and 75% by weight or less, preferably 60% by weight or more and 70% by weight or less.

[0020] The total content of non-aromatic epoxy compounds and aromatic epoxy compounds in the first agent is, for example, 50% to 80% by weight, preferably 52% to 75% by weight, based on 100% by weight of the first agent.

[0021] (Rubber Particles) Rubber particles may be particles containing or made of a polymer having rubber elasticity. Rubber particles may also be core-shell type particles. Core-shell type particles are particles having a core portion containing or made of a polymer having rubber elasticity, and a shell layer covering the core portion. The shell layer may be one layer or two or more layers. Core-shell type particles are preferred as rubber particles. The shell layer preferably contains a polymer different from the core portion. In this specification, core-shell type particles having a core portion made of a polymer having rubber elasticity are also referred to as "core-shell type rubber particles." Examples of polymers for the core portion of core-shell type rubber particles include diene-based rubber-like polymers, silicone-based rubber-like polymers, aromatic vinyl-based rubber-like polymers, and vinyl cyanide-based rubber-like polymers. Among these, diene-based rubber-like polymers are preferred. Examples of diene-based rubber-like polymers include polymers of butadiene, isoprene, and / or chloroprene. Among these, polymers of butadiene are preferred, polybutadiene is more preferred, and cross-linked butadiene rubber is particularly preferred. Examples of polymers for the shell layer of core-shell type rubber particles include polymers obtained by polymerizing at least one monomer selected from acrylic acid ester monomers, methacrylic acid ester monomers, and aromatic vinyl monomers, or silicone resin. From the viewpoint of compatibility with epoxy compounds, acrylic copolymers are preferred as the polymer for the shell layer. More preferably, the rubber particles are core-shell type rubber particles having a core made of crosslinked butadiene rubber and a shell layer made of an acrylic copolymer.

[0022] Core-shell type rubber particles, in which the core is a diene-based rubbery polymer, can be used in the form of a fine powder. In this case, it is desirable to disperse the fine powder of the core-shell type rubber particles as uniformly as possible in the epoxy compound to prevent the formation of aggregates or clumps. Alternatively, a rubber particle dispersion may be prepared by pre-dispersing core-shell type rubber particles, in which the core is a diene-based rubbery polymer, in an epoxy compound, and this rubber particle dispersion may be used by blending it with other epoxy compounds. In the rubber particle dispersion, the epoxy compound for dispersing the core-shell type rubber particles, in which the core is a diene-based rubbery polymer, is preferably liquid at 25°C. Examples of such epoxy compounds include epoxy compounds having hydroxyl groups and aromatic epoxy compounds. Among these, aromatic epoxy compounds are preferred, and bisphenol A type epoxy compounds are even more preferred. The content of the diene-based rubbery polymer per 100% by weight of the rubbery particle dispersion is not particularly limited, but may be, for example, 25% by weight or more and less than 45% by weight, preferably 30% by weight or more and 40% by weight or less.

[0023] Examples of commercially available rubber particle dispersions include the Kaneka Corporation's KaneAce MX series (e.g., MX-150, MX-153, MX-257, MX-154). Among these, KaneAce MX-154 (bisphenol A type epoxy dispersion with a core-shell rubber particle concentration of 40% by weight) (also known as MX-154) is preferred.

[0024] The average particle size of the rubber particles is preferably 1 nm to 300 nm in volume average particle diameter, more preferably 20 nm to 200 nm, and particularly preferably 50 nm to 150 nm. The volume average particle diameter can be measured using a NanoTrac particle size distribution analyzer (Nikkiso Co., Ltd.).

[0025] With respect to 100% by weight of the first agent, the upper limit of the content of rubber particles in the first agent can be, for example, 18% by weight, 16% by weight, 13% by weight, 10% by weight, and the lower limit can be, for example, 2% by weight, 3% by weight, 5% by weight, 7% by weight. The values of the upper limit and the lower limit can be arbitrarily combined. As combinations, for example, it is 2% by weight or more and 18% by weight or less, 3% by weight or more and 16% by weight or less, and preferably 3.5% by weight or more and 13% by weight or less. With respect to 100% by weight in total of the first agent and the second agent, the upper limit of the content of rubber particles can be, for example, 17% by weight, 15% by weight, 12.5% by weight, 9.5% by weight, and the lower limit can be 1.5% by weight, 2.5% by weight, 4.5% by weight, 6.0% by weight. The values of the upper limit and the lower limit can be arbitrarily combined. As combinations, for example, it is 1.5% by weight or more and 17% by weight or less, preferably 2.5% by weight or more and 15% by weight or less, and more preferably 4.5% by weight or more and 12.5% by weight or less. By the rubber particles being present in the composition at a certain ratio, the adhesion strength before application of the cured product can be increased.

[0026] (Ionic liquid) An ionic liquid is a salt that is liquid at room temperature and contains a cation and an anion, and is also called a room temperature molten salt. The ionic liquid has properties such as nonflammability, nonvolatility, and chemical stability. In the present invention, the ionic liquid has an ionic conductivity of 10 -4 S / cm or more and 10 -1 S / cm or less. By having an ionic conductivity within this range, the property of peeling off by applying a voltage can be sufficiently imparted to the adhesive composition. The ionic conductivity is more preferably 10 -3 S / cm or more and 10 -1 S / cm or less. The ionic conductivity can be measured, for example, by the AC impedance method using a 1260 frequency response analyzer manufactured by Solartron. Examples of the ionic liquid include the following formula (1).

[0027] (In the formula, R 1 is a divalent or trivalent hydrocarbon group having 2 or more and 8 or less carbon atoms which may contain a hetero atom, and N in the formula +forms a ring together with, the hydrocarbon group may contain a substituent, the substituent is an alkyl group or an alkoxy group having 1 to 4 carbon atoms, R 2 and R 3 are the same or different and are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (however, when the nitrogen atom forms a double bond with an adjacent carbon atom, R 3 does not exist), X - is Br - , AlCl4 - , Al2Cl7 - , NO3 - , BF4 - , PF6 - , CH3COO - , CF3COO - , CF3SO3 - , (CF3SO2)2N - , (FSO2)2N - , (CF3SO2)3C - , AsF6 - , SbF6 - , F(HF) n - , CF3(CF2)3SO3 - , (CF3CF2SO2)2N - and CF3CF2COO - is an anion selected from)

[0028] In the above formula, the ring composed of R 1 and N + includes a ring in which at least one carbon atom constituting a hydrocarbon ring such as a saturated alicyclic hydrocarbon such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane and cyclooctane, and an unsaturated cyclic hydrocarbon such as cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclopentadiene and benzene is replaced by a nitrogen atom. Examples of the heteroatom include N, O, S, P, etc., and preferably N. R 1The alkyl group having 1 to 4 carbon atoms as the substituent includes, for example, a methyl group, an ethyl group, a propyl group, and a butyl group. The alkoxy group having 1 to 4 carbon atoms includes, for example, a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. The alkyl group or alkoxy group having 3 to 4 carbon atoms includes structural isomers. The alkyl group having 1 to 6 carbon atoms includes, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. The alkyl group having 3 to 8 carbon atoms includes structural isomers.

[0029] The ionic liquid is preferably a salt containing a cation selected from a pyridinium-based cation and an imidazolium-based cation and an anion selected from (FSO2)2N - and (CF3SO2)2N - from the viewpoint of improving the electrical peelability. In the present invention, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (also referred to as EMI-FSI), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (also referred to as EMI-TFSI), 1-hexylpyridinium bis(trifluoromethanesulfonyl)imide are more preferable, and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide is particularly preferable.

[0030] The ionic liquid is available from Daiichi Kogyo Seiyaku, Kanto Chemical, Koei Chemical Industry, etc. For example, EMI-FSI and EMI-TFSI can be obtained from Daiichi Kogyo Seiyaku, 1-hexylpyridinium bis(trifluoromethanesulfonyl)imide can be obtained from Koei Chemical Industry, and 1-hexylpyridinium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide can be obtained from Kanto Chemical. The combinations of cations and anions contained in EMI-FSI and EMI-TFSI are as follows.

[0031]

[0032]

[0033] The ionic liquid content in the first agent can be, for example, 40%, 35%, and 30% by weight at the upper limit, and 25%, 20%, and 15% by weight at the lower limit, relative to 100% by weight of the first agent. The combination can be 15% to 40% by weight, preferably 20% to 35% by weight. The ionic liquid content can be, for example, 38%, 33%, and 28.5% by weight at the upper limit, and 22.5%, 18%, and 13.5% by weight at the lower limit, relative to 100% by weight of the total of the first and second agents. The combination can be 13.5% to 38% by weight, preferably 18% to 33% by weight.

[0034] (Amine-based curing agents having two or more amino groups in the molecule) Examples of amine-based curing agents having two or more amino groups in the molecule in the second agent (hereinafter also referred to as amine-based curing agents) include polyamine compounds having two or more primary amino groups and heterocyclic compounds having two or more amino groups. Examples of polyamine compounds having two or more primary amino groups include aliphatic polyamine compounds having two or more primary amino groups, aromatic polyamine compounds having two or more primary amino groups, and alicyclic polyamine compounds having two or more primary amino groups.

[0035] As an aliphatic polyamine compound having two or more primary amino groups, a polyamine compound having two or more primary amino groups and an alkyl main chain having 2 to 12 carbon atoms is preferred. Examples include ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,3-diaminobutane, 1,4-diaminobutane, 2,2-dimethyl-1,3-propanediamine, 1,5-pentanediamine, 1,5-diamino-2-methylpentane, 1,3-pentanediamine, 1,6-hexanediamine, 2,5-dimethyl-1,6-hexanediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine. Among these, triethylenetetramine (also known as TETA) is preferred.

[0036] Aromatic polyamine compounds having two or more primary amino groups preferably have one or more benzene rings. Examples include m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 2,2'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 2,4-tolylenediamine, 2,6-tolylenediamine, m-xylylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0037] As alicyclic polyamine compounds having two or more primary amino groups, polyamine compounds having a cycloalkyl group with 6 to 12 carbon atoms are preferred, and examples include 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, bis(4-amino-3-ethylcyclohexyl)methane, bis(4-amino-3,5-dimethylcyclohexyl)methane, bis(4-amino-3-ethyl-5-methylcyclohexyl)methane, 1,4-diamino-3,6-diethylcyclohexane, isophoronediamine, menthanediamine, and 1,3-bisaminocyclohexane.

[0038] Examples of heterocyclic compounds having two or more amino groups include heterocyclic amines and imidazole compounds having an amidine skeleton. Examples of heterocyclic amines having an amidine skeleton include diazabicyclononene and diazabicycloundecene. Among these, diazabicycloundecene (also called DBU) is preferred. Examples of imidazole compounds include imidazole compounds having an electron-withdrawing group at the 1-position, such as 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole (also called 2E4MZ-CN), 1-(cyanomethyl)-2-ethyl-4-methylimidazole, and 1-cyano-2-ethyl-4-methylimidazole. Among these, 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole is preferred.

[0039] The content of the amine-based curing agent in the second agent is not particularly limited, but is 6.0% by weight or more and 10% by weight or less, and preferably 7% by weight or more and 8% by weight or less, relative to 100% by weight of the total of the first agent and the second agent.

[0040] In further embodiments, an amine-based curing agent may be mixed with the first agent to form a one-component adhesive composition. Since the one-component adhesive composition is a mixture of the first and second agents, the components and their content should be referenced to those of the two-component adhesive composition.

[0041] (Curing agents other than amine-based curing agents) In addition to or instead of amine-based curing agents, acid anhydride-based curing agents, phenol-based curing agents, mercaptan-based curing agents, polysulfide-based curing agents, etc., can be used. Examples of acid anhydride-based curing agents include carboxylic acid anhydride-based curing agents, and preferably aromatic carboxylic acid anhydride-based curing agents. Examples of acid anhydride-based curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, 4-methylphthalic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, and hexahydrophthalic anhydride. Examples of phenol-based curing agents include phenol novolac resin and cresol novolac resin. As the mercaptan-based curing agent, liquid polymercaptans having primary or secondary thiols are preferred, such as trimethylolpropanetris(3-mercaptopropionate), 2,2-bis[[(3-mercaptopropionyl)oxy]methyl]trimethylenebis[3-mercaptopropionate], dipentaerythritol hexakis(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptobutyrate) (product name: Karenz MT PE1). The content of acid anhydride-based curing agents, phenol-based curing agents, mercaptan-based curing agents, and polysulfide-based curing agents is the same as the content of the amine-based curing agents mentioned above.

[0042] (Other Additives) In the two-component adhesive composition of the present invention, other additives may be added to the first and / or second component, to the extent that they do not impair the electropenetrating properties of the cured product. Examples of other additives include fillers, corrosion inhibitors, fillers, plasticizers, anti-aging agents, antioxidants, pigments (dyes), flame retardants, solvents, surfactants (leveling agents), rust inhibitors, adhesion-enhancing resins, and antistatic agents.

[0043] (Filler) The adhesive composition of the present invention may contain a filler in the first agent. Examples of fillers include metal compounds, carbon-based materials, titanates, glass, and natural raw material particles. Among these, carbon-based materials and glass are preferred. As carbon-based materials, carbides and materials consisting only of carbon are preferred. Examples of carbides include silicon carbide, boron carbide, and nitrogen carbide. Examples of materials consisting only of carbon include carbon black, carbon tubes, carbon nanotubes, carbon fibers, and diamond. When a filler is included in the first agent, for example, it may be 0.1 parts by weight or more and less than 15 parts by weight per 100 parts by weight of the total of each epoxy compound. Alternatively, the adhesive composition of the present invention does not contain a filler. For example, even if the adhesive composition of the present invention does not contain a filler (especially a non-conductive filler), insufficient adhesive properties or viscosity problems will not occur.

[0044] (Corrosion Inhibitor) The first component of the adhesive composition of the present invention may optionally contain a corrosion inhibitor for the purpose of suppressing metal corrosion. The corrosion inhibitor is useful when the metal is a conductive adherend. The corrosion inhibitor is not particularly limited, and known corrosion inhibitors can be used. Examples include carbodiimide compounds, adsorption-type inhibitors, and chelate-forming metal deactivators. These can be used alone or in combination of two or more corrosion inhibitors.

[0045] Examples of carbodiimide compounds include 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, 1-ethyl-3-tert-butylcarbodiimide, N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide, N,N'-di-tert-butylcarbodiimide, 1,3-bis(p-tolyl)carbodiimide, and polycarbodiimide resins using these as monomers. These carbodiimide compounds can be used individually or in combination of two or more. When a carbodiimide compound is included in the first agent, the content is, for example, 0.01 parts by weight or more and 20 parts by weight or less per 100 parts by weight of the total of each epoxy compound.

[0046] Examples of adsorption-type inhibitors include compounds having polar groups centered around atoms with high electronegativity, such as O, N, and S, and nonpolar groups centered around C and H. Adsorption-type inhibitors may be alkylamines, carboxylates, carboxylic acid derivatives, alkyl phosphates, etc. Adsorption-type inhibitors can be used alone or in combination of two or more. When the first agent contains an adsorption-type inhibitor, the content is, for example, 0.01 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of the total of each epoxy compound in the first agent.

[0047] Examples of chelate-forming metal deactivators include triazole group-containing compounds or benzotriazole group-containing compounds. These compounds have a high deactivating effect on the surface of metals such as stainless steel and aluminum, and do not significantly affect adhesion when included in adhesive components. Chelate-forming metal deactivators can be used alone or in combination of two or more. When a chelate-forming metal deactivator is included in the first agent, the content is, for example, 0.01 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the total of each epoxy compound.

[0048] When a corrosion inhibitor is included in the first agent, the total content is preferably 0.01 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the total of each epoxy compound.

[0049] A preferred two-component adhesive composition is, for example, an alkyl polyol polyglycidyl ether, a bisphenol-type epoxy compound, a cation selected from pyridinium-based cations and imidazolium-based cations, and (FSO2)2N - and (CF3SO2)2N - It consists of a first agent comprising an ionic liquid containing an anion selected from and core-shell type rubber particles, and a second agent comprising a polyamine compound having an alkyl main chain with 2 to 12 carbon atoms.

[0050] (Method for producing a two-component adhesive composition) The method for producing a two-component adhesive composition is not particularly limited. For example, the first component can be produced by appropriately stirring a non-aromatic epoxy compound, an aromatic epoxy compound, rubber particles, an ionic liquid, and other additives as needed, using known methods. Stirring is preferably carried out using a rotation-and-revolution type mixer. A rotation-and-revolution type mixer is a machine that stirs the materials in a container by tilting the container containing the materials and causing the container to rotate and revolve at high speed. By using this mixer, the first component can be stirred more uniformly. The second component may be an amine-based curing agent itself. If the second component further contains other additives, the second component can be produced by appropriately stirring the amine-based curing agent and the other additives using known methods.

[0051] (Uses of the Two-Component Adhesive Composition) The two-component adhesive composition of the present invention can be used to bond solid objects of various materials and shapes. Bonding can be performed by first mixing the first and second components to prepare an adhesive, then applying the adhesive to the object, and finally curing the adhesive. The adhesive prepared from the two-component adhesive composition of the present invention can be used in the same way as conventional one-component epoxy adhesives. Details of the method for curing the adhesive will be described later. The shape of the object to be bonded is not particularly limited, but may be, for example, film, plate, rod, mesh, fibrous, etc. The material of the object may be either conductive or non-conductive. When electrolytically peeling off the cured product, the two-component adhesive composition of the present invention is used for bonding conductive objects. By attaching a conductive auxiliary material to a non-conductive object, the non-conductive object can also be indirectly electrolytically peeled off via the conductive auxiliary material. Any adhesive or tack (collectively referred to as "adhesive") can be used to attach the conductive auxiliary material. Examples of conductive materials include metals such as iron, aluminum, copper, silver, and gold, as well as alloys of these metals and conductive resins. Examples of non-conductive materials include resins, glass, ceramics, paper, cloth, fibers, wood, and bamboo. Examples of conductive auxiliary materials include plates, films, and meshes made of conductive materials.

[0052] Once the two-component adhesive composition of the present invention has cured, the cured material can be easily peeled off by applying a voltage. Therefore, the two-component adhesive composition of the present invention can be suitably used for bonding opaque materials that cannot be subjected to UV irradiation, or materials that are sensitive to heat. Furthermore, the two-component adhesive composition of the present invention can be suitably used for fixing materials that require high processing accuracy, or for fixing materials that are difficult to physically fix, such as thin metal plates or substrates. For example, the two-component adhesive composition of the present invention can be used for temporary fixing of components in the electronic component manufacturing process (for example, temporary fixing of wafers during dicing of LSI chips). Temporary fixing can be easily released by applying a voltage to the cured material.

[0053] The two-component adhesive composition of the present invention is also useful from the viewpoint of recycling and reuse. For example, products such as automobiles, home appliances, mobile phones, and PCs may contain parts with high scarcity value, parts that need to be safely recovered, and parts that need to be reused. If such parts are fixed in the product with the two-component adhesive composition of the present invention, the fixed parts can be easily recovered by applying a voltage to the fixed parts after the product has been discarded and recovered. Another application is the bonding of sensors to conductive objects. In this application as well, the sensors can be easily recovered by detaching them by applying a low voltage, and the sensors can be reused repeatedly, making it economical.

[0054] <Method for curing a two-component adhesive composition> In the method for curing a two-component adhesive composition of the present invention, first, a mixture (i.e., adhesive) is obtained by appropriately mixing the first and second components of the two-component adhesive composition using a known method. The components of the first and second components are as described above. Next, the obtained adhesive is cured by curing at room temperature or by heating. From the viewpoint of shortening the curing time, it is preferable to cure the adhesive by heating. As an example of the method for curing the adhesive, first, the adhesive is applied to at least a part of the surface of the first conductor, and the surface of the second conductor is brought into contact with the applied surface and overlapped to form a composite. Next, the adhesive is cured by curing the formed composite at room temperature or by heating. The thickness of the applied adhesive layer is not particularly limited and may be, for example, 0.01 mm or more and 10 mm or less. The method for heating the adhesive is not particularly limited and can be heated using known equipment such as a hot air circulation oven, an infrared heater, a heat gun, and a high-frequency induction heating device. The heating temperature is not particularly limited, but the upper limit may be, for example, less than 150°C, 120°C, and 100°C, and the lower limit may be, for example, 40°C, 50°C, 70°C, 80°C, and 90°C. If heated above 150°C, the reaction will proceed, but electrical delamination may not occur even when a voltage is applied. The heating time is not particularly limited, but the upper limit may be, for example, 24 hours, 18 hours, 12 hours, and 6 hours, and the lower limit may be 30 minutes, 1 hour, 2 hours, and 4 hours. If the heating time exceeds 24 hours, depending on the heating temperature, the reaction may proceed too much, resulting in decomposition or no reduction in adhesive strength even when a voltage is applied. If the heating time is less than 30 minutes, depending on the heating temperature, the reaction may not proceed and the adhesive may not harden. As for combinations of temperature and time in heating, for example, if the heating temperature is 50°C or higher and less than 80°C, the heating time may be longer than 2 hours and 24 hours or less. When the heating temperature is 80°C or higher but less than 120°C, the heating time may be longer than 1 hour but 2 hours or less. When the heating temperature is 120°C or higher but less than 150°C, the heating time may be 30 minutes or more but 1 hour or less. When curing at room temperature, the temperature is, for example, 10°C to 40°C, preferably 15°C to 40°C. When curing at room temperature, the time is, for example, 24 hours or more but 120 hours or less.

[0055] <Electropeelable Cured Product> The electropeelable cured product of the present invention (hereinafter also simply referred to as "cured product") is a substance obtained by curing an adhesive prepared from the two-component adhesive composition of the present invention. The curing of the adhesive is as described in the curing method above. Preferably, the cured product is formed between the surface of the first conductor and the surface of the second conductor. This allows the first conductor and the second conductor to be bonded together via the cured product. The materials of the first and second conductors are the same as those of the conductive objects described above. The materials of the first and second conductors may be the same or different.

[0056] The method for bonding the first conductor and the second conductor is as described in the curing method above. The thickness of the cured layer is not particularly limited and may be, for example, 0.01 mm or more and 10 mm or less. The adhesive strength of the electropeable cured product of the present invention before application is not particularly limited, but is, for example, 1.0 MPa or more, preferably 1.5 MPa or more, more preferably 3 MPa or more, and even more preferably 5 MPa or more. The method for measuring the adhesive strength of the cured product is as described in the examples described later.

[0057] <Method for removing electrolyzable cured material> The method for removing electrolyzable cured material of the present invention includes applying a voltage to an electrolyzable cured material in a composite in which a first conductor and a second conductor are bonded together via an electrolyzable cured material. The application of voltage significantly reduces the adhesive strength of the electrolyzable cured material, allowing it to be easily peeled off from the conductors. The peeling itself can be performed, for example, by peeling off the conductors with your hands or a suitable tool. Referring to Figure 1A, the application of voltage to the electrolyzable cured material 2 can be performed, for example, by connecting the terminals of a wire with terminals connected to a DC power supply 4 to the first conductor 1 and the second conductor 3, respectively, and starting the power supply. Referring to Figure 1B, the application of voltage energizes the electrolyzable cured material 2 through the first conductor 1 and the second conductor 3, allowing the electrolyzable cured material 2 to be peeled off from the conductors. In the example of Figure 1B, the electrolyzable cured material is peeled off from the first conductor, but the present invention is not limited to this example. In electrolytically cured materials to which voltage is applied, the adhesive strength decreases and peeling occurs mainly from the positive electrode side. However, whether the cured material peels from the first or second conductor depends on how the force for peeling is applied, etc.

[0058] The electropeelable cured product of the present invention can achieve electropeelability at low voltages, but this does not preclude its use at high voltages. The range of applied voltage can be determined by selecting an upper limit from, for example, 500V, 450V, 400V, 350V, 300V, 250V, 200V, 150V, 100V, 90V, 80V, 70V, 60V, and 50V, and a lower limit from 0.5V, 1V, 2V, 3V, 4V, 5V, 6V, 7V, 8V, 9V, and 10V. The range of applied voltage is preferably 1V to 200V, more preferably 20V to 120V, and even more preferably 30V to 100V. The voltage application time is not particularly limited as long as it can cause electrodelamination in the composite, but is usually 1 second to 1200 seconds, preferably 1 second to 600 seconds, more preferably 1 second to 300 seconds, even more preferably 1 second to 180 seconds, particularly preferably 1 second to 120 seconds, and particularly more preferably 30 seconds to 90 seconds. The combination of voltage and application time is, for example, 1V to 200V for 1 second to 1200 seconds, preferably 30V to 100V for 30 seconds to 90 seconds. The reduction rate of adhesive strength after application of the electropenetrating cured product of the present invention is, for example, 50% or more, preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more. The definition of the reduction rate of adhesive strength after application will be explained in the examples.

[0059] When bonding a non-conductive object and a conductive object using the adhesive composition of the present invention, the bonding can be done indirectly via a conductive auxiliary material, as described above. For example, referring to Figure 2A, first, the first conductor 1 is attached to the non-conductive object 5 as a conductive auxiliary material. The attachment is done using an adhesive 6. Then, the attached conductive auxiliary material (first conductor 1) and the second conductor 3 are bonded together using the adhesive composition of the present invention to form a cured product. As a result, the non-conductive object 5 and the second conductor 3 are bonded together via the conductive auxiliary material and the electropenetrating cured product 2, forming a composite. When peeling off the electropenetrating cured product 2 from this composite, the terminals of a wire with terminals connected to a DC power supply 4 are connected to the conductive auxiliary material (first conductor 1) and the second conductor 3, respectively, to form a circuit. Referring to Figure 2B, by applying a voltage, current is passed through the conductive auxiliary material (first conductor 1) and the second conductor 3 to the electropeelable cured product 2, allowing the electropeelable cured product 2 to be peeled off from the conductor.

[0060] By using a second conductor as a conductive auxiliary material, it is also possible to peel off the electrolyzable cured product in a composite in which a non-conductive object and a conductive object are bonded. Referring to Figure 3A, first, the second conductor 3 is attached to the non-conductive object 5 as a conductive auxiliary material. The attachment is done using an adhesive 6. Then, the attached conductive auxiliary material (second conductor 3) and the first conductor 1 are bonded together using the adhesive composition of the present invention to form a cured product. As a result, the non-conductive object 5 and the first conductor 1 are bonded together via the conductive auxiliary material and the electrolyzable cured product 2, forming a composite. To peel off the electrolyzable cured product 2 in this composite, the terminals of a wire with terminals connected to a DC power supply 4 are connected to the conductive auxiliary material (second conductor 3) and the first conductor 1, respectively, to form a circuit. Referring to Figure 3B, by applying a voltage, current is passed through the conductive auxiliary material (second conductor 3) and the first conductor 1 to the electropeelable cured product 2, allowing the electropeelable cured product 2 to be peeled off from the conductor.

[0061] In a composite formed by bonding non-conductive objects together using both the first and second conductors as conductive auxiliary materials, the electropenetrating cured product can also be peeled off. Referring to Figure 4A, first, the first conductor 1 and the second conductor 3 are attached to the non-conductive objects 5 and 5', respectively, as conductive auxiliary materials. The attachment is done using adhesive 6. Then, the first conductor 1 and the second conductor 3, which have been attached as conductive auxiliary materials, are bonded together using the adhesive composition of the present invention to form a cured product. As a result, the non-conductive objects 5 and 5' are bonded together via the first conductor 1, the electropenetrating cured product 2, and the second conductor 3, forming a composite. To peel off the electropenetrating cured product 2 in this composite, the terminals of a wire with terminals connected to a DC power supply 4 are connected to each of the first conductor 1 and the second conductor 3, which are conductive auxiliary materials, to form a circuit. Referring to Figure 4B, by applying a voltage, current is passed through the first conductor 1 and the second conductor 3 to the electropeelable cured product 2, allowing the electropeelable cured product 2 to be peeled off from the conductors.

[0062] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0063] <Preparation of Two-Component Adhesive Composition> [Example 1] 10 parts by weight of EMI-FSI (Daiichi Kogyo Seiyaku Co., Ltd.) and 10 parts by weight of MX-154 (Kaneka Corporation) were added to a container for a rotary-orbit mixer, and the mixture was uniformly stirred at room temperature using a rotary-orbit mixer (Awatori Rentaro, AR-100, Shinki Co., Ltd.). Then, 10 parts by weight of EX-614B (Nagase ChemteX Corporation) was added and stirred further to obtain 30 parts by weight of the first component. 2 parts by weight of TETA (Tokyo Chemical Industries, Ltd.) was used as the second component. [Comparative Example 1] 100 parts by weight of EX-614B was used as the first component, and 10 parts by weight of TETA was used as the second component.

[0064] <Adhesion Strength Test> The first agent obtained in each weight from Example 1 and Comparative Example 1 was added to a beaker, and the second agent obtained in each weight from Example 1 and Comparative Example 1 was added and stirred with a stirrer to obtain the adhesives of Example 1 and Comparative Example 1. The adhesive was applied to the longitudinal edge of a 75 mm x 25 mm, 1.0 mm thick aluminum plate that had been degreased with acetone, so that the bonding area was 25 mm x 12.5 mm and the adhesive layer was 0.16 mm thick. The longitudinal edge of another aluminum plate of the same size was bonded to the adhesive-coated surface. The bonded aluminum plates were heated in an oven (VO-320, Advantec Co., Ltd.) at 120°C for 1 hour to obtain a composite (also called a test specimen) (see Figure 5A). The adhesion strength of the test specimen was measured using a tensile testing machine (5582, Instron Japan Co., Ltd.) at 23°C and 50% RH at a tensile speed of 1 mm / min, as per JIS K6850 (1999). The measurement results are summarized in Table 1 as the adhesive strength before application.

[0065] <Electrodeposition Test> Test specimens were prepared using each adhesive in the same manner as in the adhesive strength test described above. Electrodes were attached to both ends of the longitudinal direction of each test specimen (see Figure 5B). Under conditions of 23°C and 50% RH, a voltage of 100V or 30V was applied to each test specimen for 60 seconds. The adhesive strength of the test specimens after application was measured in the same manner as in the adhesive strength test described above. The measurement results are shown in Table 1. The percentage decrease in adhesive strength is also shown in these tables. The percentage decrease in adhesive strength was calculated by dividing the difference between the adhesive strength before application and the adhesive strength after application by the adhesive strength before application. In the "Electrodeposition" column of each table, "A" was written if the percentage decrease in adhesive strength was 80% or more, "B" was written if the percentage decrease was 50% or more, and "C" was written if the percentage decrease was less than 50%. Cases with a percentage decrease in adhesive strength after application of 50% or more were designated as examples.

[0066]

[0067] Referring to the results of Example 1, the adhesive strength before application was 3.00 MPa, indicating good adhesion. After application at 30 V for 60 seconds and at 100 V for 60 seconds, the adhesive strength was 0.27 MPa (decrease rate 91%) and 0.35 MPa (decrease rate 88%), respectively, and the peelability of the cured product was also very good. This suggests that electrolysis can be performed at a voltage of at least 30 V to 100 V. On the other hand, referring to the results of Comparative Example 1, the adhesive strength before application was 6.81 MPa, but no current was conducted even when voltage was applied. This suggests that current will not be conducted unless an ionic liquid is added.

[0068] <Preparation of Two-Component Adhesive Composition> [Example 2] 12 parts by weight of EMI-FSI and 10 parts by weight of MX-154 were added to a container for a rotational mixer, and the mixture was uniformly stirred at room temperature using a rotational mixer. Then, 30 parts by weight of EX-614B was added and the mixture was stirred further to obtain 52 parts by weight of the first component. 4 parts by weight of TETA was used as the second component. [Example 3] 104 parts by weight of the first component was obtained in the same manner as in Example 2, except that 24 parts by weight of EMI-FSI were added instead of 12 parts by weight, and 70 parts by weight of EX-614B were added instead of 30 parts by weight. 8.4 parts by weight of TETA was used as the second component. [Example 4] The first agent was obtained in the same manner as in Example 2, except that 15 parts by weight of EMI-FSI was added instead of 12 parts by weight, and 20 parts by weight of MX-154 was added instead of 10 parts by weight. 4.7 parts by weight of TETA was used as the second agent. [Example 5] The first agent was obtained in the same manner as in Example 2, except that 18 parts by weight of EMI-FSI was added instead of 12 parts by weight, and 30 parts by weight of MX-154 was added instead of 10 parts by weight. 6.7 parts by weight of TETA was used as the second agent. [Comparative Example 2] The first agent was obtained in the same manner as in Example 2, except that instead of adding 30 parts by weight of EX-614B, 15 parts by weight of EX-614B and 15 parts by weight of JER828 (bisphenol A diglycidyl ether, Mitsubishi Chemical Corporation) were added. 52 parts by weight of the first agent was obtained. 4 parts by weight of TETA was used as the second agent. [Comparative Example 3] The first agent was obtained in the same manner as in Example 2, except that instead of adding 30 parts by weight of EX-614B, 21 parts by weight of EX-614B and 9 parts by weight of JER828 were added. 4 parts by weight of TETA was used as the second agent.

[0069] <Adhesion Strength Test> The adhesion strength of each test specimen was measured in the same manner as the adhesion strength test described above, except that the first and second agents obtained in Examples 2-5 and Comparative Examples 2-3 were used instead of Example 1 and Comparative Example 1. The results are summarized in Table 2 as the adhesion strength before application.

[0070] <Electrodeposition Test> The adhesive strength of each test piece was measured after application, using the same procedure as the electrodeposition test described above, except that the voltage application conditions were limited to 100V for 60 seconds. The measurement results are summarized in Table 2, which shows the adhesive strength after application. The evaluation criteria for electrodeposition were the same as described above.

[0071]

[0072] Referring to Example 2, the adhesive strength before application was 7.32 MPa, which is good adhesive strength, and was about 2.5 times stronger than that of Example 1. The adhesive strength after application at 100V for 60 seconds was 0.69 MPa (decrease rate of 91%), and the peelability of the cured product was also very good. In Examples 2 to 5 in Table 2, Example 2 had the highest adhesive strength before application, and Example 4 had the lowest. Even the lowest value was an adhesive strength of 6.27 MPa, which can be said to be good adhesive strength. In addition, in Examples 2 to 5 in Table 2, Example 5 had the lowest decrease in adhesive strength after application, with a decrease rate of 59%, which was a good result. From the results in Table 2, it was suggested that the range of rubber content in the first agent is preferably 2% to 18% by weight. Comparative Examples 2 and 3 increased the amount of JER828, a bisphenol A type epoxy, instead of reducing the proportion of EX-614B. As a result, the decrease in adhesive strength after application was 10% and 13%, which is less than the 50% decrease. Therefore, it was suggested that the proportion of bisphenol A epoxy is also important in this invention. Next, using the composition of Example 2, which had the highest strength before application and good electropeelability, we decided to conduct experiments by changing the amine-based curing agent of solution B.

[0073] <Preparation of Two-Component Adhesive Compositions> [Example 6] 52 parts by weight of the first component was prepared in the same manner as in Example 2. 4 parts by weight of DBU (Tokyo Chemical Industries, Ltd.) was used as the second component. [Comparative Example 4] 52 parts by weight of the first component was prepared in the same manner as in Example 2. 4 parts by weight of DMA (N,N-dimethylaniline, Fujifilm Wako Pure Chemical Industries, Ltd.) was used as the second component. [Comparative Example 5] 52 parts by weight of the first component was prepared in the same manner as in Example 2. 4 parts by weight of DBA (N,N-dibutylaniline, Fujifilm Wako Pure Chemical Industries, Ltd.) was used as the second component. [Example 7] 52 parts by weight of the first component was prepared in the same manner as in Example 2. 4 parts by weight of 2E4MZ-CN (Tokyo Chemical Industries, Ltd.) was used as the second component.

[0074] <Adhesion Strength Test> Instead of the first and second agents used in Example 1 and Comparative Example 1, the first and second agents obtained in Examples 6 and 7, and Comparative Examples 4 and 5 were used. For the adhesion strength test of Example 7, the adhesion strength of the test specimens was measured in the same manner as above. For the adhesion strength tests of Example 6, Comparative Examples 4 and 5, the adhesion strength of each test specimen was measured in the same manner as above, except that the heating conditions were set to 120°C for 18 hours. These results are summarized in Table 3 as the adhesion strength before application.

[0075] <Electrodeposition Test> The adhesive strength of each test piece was measured after application, under the same conditions as above, except that the voltage application conditions were limited to 100V for 60 seconds. The measurement results are summarized in Table 3, which shows the adhesive strength after application. The evaluation criteria for electrodeposition were the same as above.

[0076]

[0077] Referring to Example 6, the adhesive strength before application was 4.30 MPa, which is higher than the 3 MPa adhesive strength before application in Example 1, indicating good adhesion. Furthermore, the adhesive strength after application at 100V for 60 seconds was 1.26 MPa (decrease rate of 71%), indicating good peelability of the cured product. Comparative Examples 4 and 5 resulted in uncured products. This suggests that the curing reaction between epoxy and amine did not proceed. In Example 7, the reduction rate of adhesive strength after application was high at 86%, indicating good peelability of the cured product. The results in Table 3 suggest that some amine compounds cannot be used as curing agents. The results in Tables 1 to 3 suggest that TETA, 2E4MZ-CN, and DBU are amine-based curing agents that exhibit good reactivity with the first agent and good peelability of the cured product. Among these, TETA showed particularly good reactivity, suggesting that amine-based curing agents having two or more primary amino groups are particularly reactive. Next, the heating time was changed with the same composition as in Example 2.

[0078] <Preparation of Two-Part Adhesive Compositions> [Examples 8-10] The first and second components of Examples 8-10 were obtained with the same composition and weight as in Example 2. <Adhesion Strength Test> The first and second components obtained in Examples 8-10 were used instead of the first and second components of Example 1 and Comparative Example 1. For the adhesion strength test of Examples 8-10, the adhesion strength of each test piece was measured in the same manner as above, except that the heating conditions were the temperature and time listed in Table 4. These results are summarized in Table 4 as the adhesion strength before application.

[0079] <Electrodeposition Test> The adhesive strength of each test piece was measured after application, using the same procedure as the electrodeposition test described above, except that the voltage application conditions were limited to 100V for 60 seconds. The measurement results are summarized in Table 4, which shows the adhesive strength after application. The evaluation criteria for electrodeposition were the same as described above.

[0080]

[0081] Referring to Examples 8, 9, and 10, the pre-treatment adhesive strengths were 4.71 MPa, 4.88 MPa, and 5.54 MPa, respectively. The pre-treatment adhesive strength tended to increase with increasing heating temperature, and the same was suggested by the results of Example 2, which was heated at 120°C for 1 hour. Referring to Examples 8, 9, and 10, the reduction rate of adhesive strength after treatment was also 85% or more, indicating very good results. Based on the results of Example 2 and Examples 8, 9, and 10, it was suggested that the curing time decreased as the heating temperature increased.

[0082] 1: First conductor, 2: Cured product of adhesive composition, 3: Second conductor, 4: DC power supply, 5, 5': Non-conductor, 6: Adhesive

Claims

1. A two-component adhesive composition comprising at least one component comprising: a first component comprising at least one non-aromatic epoxy compound selected from aliphatic epoxy compounds having a hydroxyl group and two or more epoxy groups and cyclohexene oxide epoxy compounds, an aromatic epoxy compound, rubber particles and an ionic liquid; and a second component comprising at least one curing agent selected from amine curing agents having two or more amino groups in the molecule, acid anhydride curing agents, phenolic curing agents, mercaptan curing agents and polysulfide curing agents, wherein the non-aromatic epoxy compound is present in an amount of 60% to 95% by weight and the aromatic epoxy compound is present in an amount of 5% to 40% by weight, based on a total weight of 100% by weight of the non-aromatic epoxy compound and the aromatic epoxy compound.

2. The adhesive composition according to claim 1, wherein the ionic liquid is represented by the following formula (1). (In the formula, R 1 is a divalent or trivalent hydrocarbon group having 2 to 8 carbon atoms which may contain a hetero atom. N in the formula + forms a ring together. The hydrocarbon group may contain a substituent, and the substituent is an alkyl group or an alkoxy group having 1 to 4 carbon atoms. R 2 and R 3 are the same or different and are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (however, when the nitrogen atom forms a double bond with the adjacent carbon atom, R 3 does not exist). X - is an anion selected from Br - , AlCl4 - , Al2Cl7 - , NO3 - , BF4 - , PF6 - , CH3COO - , CF3COO - , CF3SO3 - , (CF3SO2)2N - , (FSO2)2N - , (CF3SO2)3C - , AsF6 - , SbF6 - , F(HF) n - , CF3(CF2)3SO3 - , (CF3CF2SO2)2N - and CF3CF2COO - .) 3. The adhesive composition according to claim 1, wherein the ionic liquid is 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide.

4. The adhesive composition according to claim 1, wherein the aliphatic epoxy compound is at least one selected from aliphatic polyol polyglycidyl ethers and hydroxyaliphatic carboxylic acid polyglycidyl esters.

5. The adhesive composition according to claim 1, wherein the aliphatic epoxy compound is sorbitol polyglycyl ether.

6. The adhesive composition according to claim 1, wherein the amine-based curing agent is triethyltetramine.

7. The adhesive composition according to claim 1, wherein the rubber particles are core-shell type rubber particles.

8. The adhesive composition according to claim 1, wherein the rubber particles are core-shell type rubber particles having a core portion made of crosslinked butadiene rubber and a shell portion made of an acrylic copolymer.

9. The adhesive composition according to claim 1, wherein the aromatic epoxy compound is at least one selected from bisphenol-type epoxy compounds, biphenyl-type epoxy compounds, phenol novolac-type epoxy compounds, cresol novolac-type epoxy compounds, bisphenol A novolac-type epoxy compounds, and glycidyl ether-type epoxy resins.

10. A method for curing a two-component adhesive composition, comprising mixing a first agent and a second agent according to any one of claims 1 to 9, and curing the resulting mixture by heating it at 40°C or higher but less than 150°C for 30 minutes or more and 24 hours or less, or by curing it at 10°C or higher but 40°C for 24 hours or more and 120 hours or less.

11. An electropeelable cured product obtained by curing the composition according to any one of claims 1 to 9.

12. A method for removing an electropeelable cured material, comprising applying a voltage to the electropeelable cured material in a second conductive object to which a first conductive object is bonded via the electropeelable cured material described in claim 11.

13. The method according to claim 12, wherein the voltage is 1V or more and 200V or less.

14. The method according to claim 12, wherein the voltage application time is 1 second or more and 1200 seconds or less.

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