Conductive adhesive

Abstract

To provide a conductive adhesive from which a cured film that is cured by heating for a short time and is excellent in bonding strength can be formed.SOLUTION: A conductive adhesive contains the following components (A) to (D): (A) an aromatic epoxy resin; (B) a microcapsule-type latent curing agent; (C) a thiol compound; and (D) one or more conductive powders selected from silver coat copper powders, silver-based powders, nickel-based powders, conductive carbon powders, copper-based powders and gold-based powders.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a conductive adhesive. In particular, it relates to a conductive adhesive that cures by short-time heating and has excellent bonding strength.

Background Art

[0002] As conductive adhesives, those with various compositions are known. For example, when fabricating circuits of electric and electronic devices, they are used for conductive connection (adhesion) of electric and electronic components in place of solder. For example, in electronic devices such as computers and mobile phones, conductive adhesives have been used to densely mount various electronic components such as LED elements, semiconductor elements, and capacitors on the same circuit board for high integration. For example, Patent Documents 1 to 3 describe conductive adhesives containing conductive powder and a resin component.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, when fabricating circuits of electric and electronic devices, the demand for conductive adhesives that cure by short-time heating has been increasing. Also, induction heating (IH) has been considered for use with substrates having low heat resistance or high heat dissipation. Many of the conventional conductive adhesives require long-time heating during heat curing, and there have been problems in using them with substrates having low heat resistance or high heat dissipation. Under such circumstances, there is a demand for a conductive adhesive that can be cured even by short-time heating and can form a cured film with excellent bonding strength. However, a conductive adhesive that satisfies these characteristics has not been known so far.

[0005] The problem to be solved by the present invention is to provide a conductive adhesive that can be cured even by short-time heating and can form a cured film with excellent bonding strength.

Means for Solving the Problems

[0006] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by a conductive adhesive having a specific composition, and have completed the present invention. Specifically, it is as follows. [Item 1] The following (A) to (D); (A) An aromatic epoxy resin, (B) A microcapsule type latent curing agent, (C) A thiol compound, and (D) One or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, conductive carbon powder, copper-based powder, and gold-based powder, A conductive adhesive containing the same. [Item 2] The conductive adhesive according to Item 1, which is for induction heating curing.

Effects of the Invention

[0007] According to the present invention, there is provided a conductive adhesive that can be cured even by short-time heating and has excellent bonding strength. Since the conductive adhesive of the present invention can form a cured film with excellent bonding strength even by short-time heating, it is useful for applications in which the conductive adhesive is cured by an induction heating (IH) method, a short-time heating method using a heating furnace (oven), a laser, a microwave, or the like to perform bonding.

Modes for Carrying Out the Invention

[0008] The conductive adhesive of the present invention (A) An aromatic epoxy resin, (B) A microcapsule type latent curing agent, (C) A thiol compound, and (D) One or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, conductive carbon powder, copper-based powder, and gold-based powder, It is a conductive adhesive containing the above. By containing the components (A) to (D), it can be a conductive adhesive capable of forming a cured film that cures by heating for a short time and has excellent bonding strength. Hereinafter, the conductive adhesive of the present invention will be described in detail.

[0009] <Component (A)> Component (A), which is a constituent component of the conductive adhesive of the present invention, is an aromatic epoxy resin. The aromatic epoxy resin is not particularly limited as long as it is an epoxy resin having one or more aromatic rings and one or more epoxy groups in the molecule. Examples of the aromatic ring include a phenyl ring, naphthalene ring, azulene ring, anthracene ring, acenaphthene ring, acenaphthylene ring, fluorene ring, phenanthrene ring, tetracene ring, pyrene ring, perylene ring, pyridine ring, pyrimidine ring, triazine ring, pyrrole ring, imidazole ring, oxazole ring, oxadiazole ring, thiadiazole ring, thiazole ring, phenoxazine ring, isoquinoline ring, benzopyran ring, indole ring, quinoline ring, carbazole ring, quinoxaline ring, furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, phenothiazine ring, pyrazole ring, etc. The aromatic ring may have one kind alone or two or more kinds. Further, these aromatic rings may have, as substituents, groups non-reactive with the epoxy group such as a halogen atom, hydrocarbon group, alkoxy group, cycloalkyloxy group, aryloxy group, aralkyloxy group, alkylthio group, cycloalkylthio group, arylthio group, aralkylthio group, acyl group, nitro group, cyano group, etc., at any number and position. The aromatic epoxy resin preferably has two or more epoxy groups.

[0010] Examples of the aromatic epoxy resin include biphenyl type epoxy resin, bisphenol type epoxy resin (bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, tetramethyl bisphenol A type epoxy resin, tetramethyl bisphenol F type epoxy resin, etc.), alkylene oxide modified bisphenol type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, naphthalene type epoxy resin, aromatic glycidylamine type epoxy resin (N,N-diglycidylaniline, N,N-diglycidyltoluidine, diaminodiphenylmethane type glycidylamine, aminophenol type glycidylamine, etc.), resorcinol diglycidyl ether, hydroquinone type epoxy resin, stilbene type epoxy resin, triphenolmethane type epoxy resin, triphenolpropane type epoxy resin, alkyl modified triphenolmethane type epoxy resin, triazine ring-containing epoxy resin (triglycidyl isocyanurate, monoallyl diglycidyl isocyanurate, etc.), dicyclopentadiene phenol type epoxy resin (phenol dicyclopentadiene type epoxy resin, etc.), naphthol type epoxy resin, aromatic aralkyl type epoxy resin (phenylene and / or biphenylene skeleton-containing phenol aralkyl type epoxy resin, phenylene and / or biphenylene skeleton-containing naphthol aralkyl type epoxy resin, etc.), chelate modified aromatic epoxy resin, and the like. The aromatic epoxy resin may be used alone or in combination of two or more.

[0011] In the present invention, the aromatic epoxy resin preferably contains one or more of biphenyl type epoxy resin, fluorene type epoxy resin, phenol novolak type epoxy resin, bisphenol type epoxy resin, dicyclopentadiene phenol type epoxy resin, naphthalene type epoxy resin, aromatic glycidylamine type epoxy resin, and resorcinol diglycidyl ether.

[0012] (Biphenyl type epoxy resin) The biphenyl type epoxy resin has the formula (a1) in the molecule; [Chemical formula] There is no particular limitation as long as it is an epoxy resin having one or more biphenyl skeletons represented by and one or more epoxy groups. The biphenyl type epoxy resin preferably has two or more epoxy groups.

[0013] In formula (a1), a1 and a2 are each independently an integer from 0 to 4, and R c is a substituent, and when there are a plurality of R c , they may be the same or different from each other. Examples of the substituent include a halogen atom, a hydrocarbon group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, a cycloalkylthio group, an arylthio group, an aralkylthio group, an acyl group, a nitro group, a cyano group, etc. The substituent may be a single type or two or more types.

[0014] Examples of the biphenyl type epoxy resin include glycidyl ethers of optionally substituted biphenols (for example, 3,3',5,5'-tetramethyl-4,4'-bis(glycidyloxy)-1,1'-biphenyl, 3,3',5,5'-tetra-tert-butyl-4,4'-bis(glycidyloxy)-1,1'-biphenyl, 4,4'-bis(glycidyloxy)biphenyl, 3,3'-dimethyl-4,4'-bis(glycidyloxy)biphenyl, etc.), biphenyl aralkyl epoxy resins, glycidyl ethers of alkylene oxide adducts of optionally substituted biphenols, etc., but are not limited thereto. The biphenyl type epoxy resin may be used alone or in combination of two or more.

[0015] Examples of biphenyl type epoxy resins include NC-3000, NC-3000-L, NC-3000-H, NC-3000-FH-75M, NC-3100, etc. manufactured by Nippon Kayaku Co., Ltd.; jER series (YX4000, YX4000K, YX4000H, YL6121H, YL6640, YL6677, etc.) manufactured by Mitsubishi Chemical Corporation; but are not limited to these.

[0016] (fluorene type epoxy resin) Fluorene-type epoxy resins have the formula (a2) in the molecule; [ka] There is no particular limitation as long as the epoxy resin has one or more 9,9-bisarylfluorene skeletons represented by the following formula and one or more epoxy groups: The fluorene-type epoxy resin preferably has two or more epoxy groups.

[0017] In formula (a2), Ar 1 and Ar 2 are aromatic hydrocarbon rings each of which may have a substituent independently. Examples of aromatic hydrocarbon rings include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a biphenyl ring, a binaphthyl ring, a 1-phenylnaphthalene ring, a 2-phenylnaphthalene ring, and a terphenylene ring. Among these aromatic hydrocarbon rings, a benzene ring, a naphthalene ring, and a biphenyl ring are preferred, and a benzene ring is more preferred. Ar 1 and Ar 2 Examples of the substituent that may be possessed by include a halogen atom, a hydrocarbon group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, a cycloalkylthio group, an arylthio group, an aralkylthio group, an acyl group, a nitro group, a cyano group, etc. The substituent may be one type alone or two or more types. In formula (a2), b1 is an integer from 0 to 8; R c is a substituent, R cWhen there are a plurality of them, they may be the same as or different from each other, and the substituents are the same groups as the substituents in the above-mentioned Ar 1 and Ar 2 and are the same groups as the substituents in

[0018] Examples of the fluorene-type epoxy resin include, but are not limited to, 9,9-bis(glycidyloxyphenyl)fluorenes, 9,9-bis(polyglycidyloxyphenyl)fluorenes, 9,9-bis(glycidyloxynaphthyl)fluorenes, 9,9-bis(glycidyloxy(poly)alkoxyphenyl)fluorenes, 9,9-bis(polyglycidyloxy(poly)alkoxyphenyl)fluorenes, 9,9-bis(glycidyloxy(poly)alkoxynaphthyl)fluorenes, etc. The fluorene-type epoxy resin may be used alone or in combination of two or more kinds.

[0019] Examples of 9,9-bis(glycidyloxyphenyl)fluorenes include, but are not limited to, 9,9-bis(glycidyloxyphenyl)fluorene such as 9,9-bis(4-glycidyloxyphenyl)fluorene; 9,9-bis(mono- or di-C1-C4 alkyl-glycidyloxyphenyl)fluorenes such as 9,9-bis(3-methyl-4-glycidyloxyphenyl)fluorene, 9,9-bis(3,5-dimethyl-4-glycidyloxyphenyl)fluorene; 9,9-bis(mono- or di-C6-C 10 aryl-glycidyloxyphenyl)fluorene; etc.

[0020] Examples of 9,9-bis(polyglycidyloxyphenyl)fluorenes include, but are not limited to, 9,9-bis(di- or triglycidyloxyphenyl)fluorenes such as 9,9-bis(3,4-diglycidyloxyphenyl)fluorene, 9,9-bis(3,5-diglycidyloxyphenyl)fluorene; etc.

[0021] Examples of 9,9-bis(glycidyloxynaphthyl)fluorenes include, but are not limited to, 9,9-bis(glycidyloxynaphthyl)fluorenes such as 9,9-bis(6-glycidyloxy-2-naphthyl)fluorene and 9,9-bis(5-glycidyloxy-1-naphthyl)fluorene; etc.

[0022] Examples of 9,9-bis(glycidyloxy(poly)alkoxyphenyl)fluorenes include, but are not limited to, 9,9-bis(glycidyloxy(poly)C2-C4 alkoxy-phenyl)fluorenes such as 9,9-bis[4-(2-glycidyloxyethoxy)phenyl]fluorene; 9,9-bis(mono or di C1-C4 alkyl-glycidyloxy(poly)C2-C4 alkoxy-phenyl)fluorenes such as 9,9-bis[4-(2-glycidyloxyethoxy)-3-methylphenyl]fluorene and 9,9-bis[4-(2-glycidyloxyethoxy)-3,5-dimethylphenyl]fluorene; 9,9-bis(mono or di C6-C 10 aryl-glycidyloxy(poly)C2-C4 alkoxy-phenyl)fluorene; etc.

[0023] Examples of 9,9-bis(polyglycidyloxy(poly)alkoxyphenyl)fluorenes include, but are not limited to, 9,9-bis(di or triglycidyloxy(poly)C2-C4 alkoxy-phenyl)fluorenes such as 9,9-bis(3,4-di(2-glycidyloxyethoxy)phenyl)fluorene and 9,9-bis(3,5-di(2-glycidyloxyethoxy)phenyl)fluorene; etc.

[0024] Examples of 9,9-bis(glycidyloxy(poly)alkoxynaphthyl)fluorenes include, but are not limited to, 9,9-bis(glycidyloxy(poly)alkoxynaphthyl)fluorenes such as 9,9-bis[6-(2-glycidyloxyethoxy)-2-naphthyl]fluorene and 9,9-bis[5-(2-glycidyloxyethoxy)-1-naphthyl]fluorene; and the like.

[0025] (Phenolic novolak type epoxy resin) The phenolic novolak type epoxy resin is not particularly limited as long as it is an epoxy resin having at least one phenolic novolak type skeleton represented by the formula (a3) in the molecule; [Chemical formula] and having at least one epoxy group. The phenolic novolak type epoxy resin preferably has two or more epoxy groups. In the formula (a3), c1 is an integer from 0 to 3, and R c is a substituent. When there are a plurality of R c , they may be the same or different from each other. Examples of R c include, for example, a halogen atom, a hydrocarbon group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, a cycloalkylthio group, an arylthio group, an aralkylthio group, an acyl group, a nitro group, a cyano group, and the like. The substituent may be a single type or two or more types.

[0026] Examples of phenol novolak type epoxy resins include, for example, the jER series (152, 154, 157H65, etc.) manufactured by Mitsubishi Chemical Corporation; the EPICLON series (N-660, N-665, N-680, N-695, N-730A, N-740, N-770, N-775, N-500P-10, etc.) manufactured by DIC Corporation; the EPPN series (201, 202, etc.) manufactured by Nippon Kayaku Co., Ltd.; the EOCN series (102, 102S103, 103S, 104, 104S, 1012, 1020, 1025, 1027, etc.) manufactured by Nippon Kayaku Co., Ltd.; the RE series (305, 305S, 306, etc.) manufactured by Nippon Kayaku Co., Ltd.; the DEN series (431, 438, 485, etc.) manufactured by The Dow Chemical Company; the YDCN series (700, 700-10, 701, 702, 703, 704, etc.) manufactured by Nippon Steel Chemical & Material Co., Ltd.; the Araldite series (ECN1235, ECN1273, ECN1280) manufactured by Huntsman Corporation; and the like, but are not limited thereto. The phenol novolak type epoxy resin may be used alone or in combination of two or more.

[0027] (Bisphenol type epoxy resin) The bisphenol type epoxy resin is not particularly limited as long as it is an epoxy resin having one or more bisphenol type skeletons represented by the formula (a4) in the molecule; [Chemical formula] and one or more epoxy groups. In the formula (a4), d1 is an integer from 0 to 4, and d2 is an integer from 0 to 4. R c is a substituent, and when there are a plurality of R c , they may be the same or different from each other. Examples of R c include, for example, a halogen atom, a hydrocarbon group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, a cycloalkylthio group, an arylthio group, an aralkylthio group, an acyl group, a nitro group, a cyano group, etc. The substituent may be a single type or two or more types. X is -CR a41 R a42-、-S(=O)2-、-O-、-C(=O)-, a group selected from, R a41 and R a42 is hydrogen, a hydrocarbon group having 1 to 20 carbon atoms which may be substituted, may be the same or different from each other, and may be bonded to each other to form a ring. In the present invention, X in the formula (a4) is preferably a group selected from -C(CH3)2-, -CH2-, -C(CF3)2-, -S(=O)2-, -O-, -C(=O)-, -C(CH3)(Ph)-, -C(Ph)2-, -C(CH3)(C2H5)-, -CH(C2H5)-, =C(CH2)5 (Ph is a phenyl group).

[0028] The bisphenol type epoxy resin preferably has two or more epoxy groups. The epoxy equivalent of the bisphenol type epoxy resin is not particularly limited. For example, it can be 100 g / eq or more, preferably 150 g / eq or more, and for example, it can be 5,000 g / eq or less, preferably 2,000 g / eq or less. The epoxy equivalent is the number of grams (g / eq) of an epoxy resin containing 1 equivalent of epoxy groups.

[0029] Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, bisphenol B type epoxy resin, bisphenol BP type epoxy resin, bisphenol AP type epoxy resin, bisphenol E type epoxy resin, bisphenol Z type epoxy resin, etc. In the present invention, as the bisphenol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol BP type epoxy resin, bisphenol Z type epoxy resin are preferred, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin are more preferred, and bisphenol A type epoxy resin is even more preferred.

[0030] Examples of bisphenol type epoxy resins include the jER series manufactured by Mitsubishi Chemical Corporation (e.g., 806, 806H, 807, 825, 827, 828, 828EL, 828US, 828XA, 801N, 811, 813, 816, 819, 1001, 10010, 1002, 1002F, 1003, 1003F, 1004, 1004F, 1004AF, 1005, 1005F, 1007, 1055, 1256, 1256B40, 1255HX30, 1750, 4005P, 4007P, 4010P, YL6810, YL980, YL983U, etc.); the Epotote YD series manufactured by Nippon Steel Chemical & Material Co., Ltd. (011, 012, 013, 014, 017, 019, 020G, 115, 115CA, 127, 128, 128S, 128CA, 134, 825GS, 901, 902, 903N, 904, 907, 7910, 8125, etc.); the Epotote YDF series manufactured by Nippon Steel Chemical & Material Co., Ltd. (170, 170N, 2001, 2004, etc.); the DER series manufactured by Dow Chemical Company (301, 330, 361, etc.); the EPICLON series manufactured by DIC Corporation (830, 830-S, EXA830CRP, EXA830LVP, 835, EXA-835LV, 840, 840-S, 850, 850-S, EXA-850-CP, 850-LC, 855, 857, 860, 1050, 1055, 3050, 4050, 7050, N-865, N-885, N-890, etc.); the Adeka Resin series manufactured by ADEKA Corporation (EP-4100, EP-4100G, EP-4100E, EP-4100TX, EP-4100HF, EP-4300, EP-4300E, EP-4400, EP-4520S, EP-4530, EP-4504, EP-4700, EP-4901, EP-4901E, EP-4901HF, etc.), etc., but are not limited thereto. The bisphenol type epoxy resin may be used alone or in combination of two or more.

[0031] (Dicyclopentadiene phenol type epoxy resin) The dicyclopentadiene phenol type epoxy resin is not particularly limited as long as it is an epoxy resin having an optionally substituted phenyl ring and an optionally substituted dicyclopentadiene ring in the molecule. Examples of the dicyclopentadiene phenol type epoxy resin include those represented by the formula (a5); [ka] Examples of such compounds include the EPICLON series (HP-7200, HP-7200L, HP-7200H, HP-7200HHH, HP-7200H-75M, etc.) manufactured by DIC Corporation, TACTIX-556 manufactured by Huntsman Advanced Materials, and the XD series (1000, 1000-2L, 1000-H, etc.) manufactured by Nippon Kayaku Co., Ltd. The dicyclopentadiene phenol type epoxy resin may be used alone or in combination of two or more kinds.

[0032] (Naphthalene type epoxy resin) The naphthalene type epoxy resin is not particularly limited as long as it is a compound having one or more naphthalene rings and one or more epoxy groups which may be substituted in the molecule. Examples of the naphthalene type epoxy resin include dihydroxynaphthalene type epoxy resin, polyhydroxybinaphthalene type epoxy resin, and polyhydroxynaphthalene-aldehyde condensation reaction product epoxidized product.

[0033] Examples of dihydroxynaphthalene type epoxy resins include 1,3-diglycidyloxynaphthalene, 1,4-diglycidyloxynaphthalene, 1,5-diglycidyloxynaphthalene, 1,6-diglycidyloxynaphthalene, 2,3-diglycidyloxynaphthalene, 2,6-diglycidyloxynaphthalene, and 2,7-diglycidyloxynaphthalene. Examples of the polyhydroxybinaphthalene type epoxy resin include 1,1'-bi-(2-glycidyloxy) naphthyl, 1-(2,7-diglycidyloxy)-1'-(2'-glycidyloxy) binaphthyl, 1,1'-bi-(2,7-diglycidyloxy) naphthyl, and the like. Examples of the epoxy compound of the polyhydroxynaphthalene-aldehyde condensation reaction product include 1,1'-bis(2,7-diglycidyloxynaphthyl)methane, 1-(2,7-diglycidyloxynaphthyl)-1'-(2'-glycidyloxynaphthyl)methane, 1,1'-bis(2-glycidyloxynaphthyl)methane, and the like. The naphthalene type epoxy resin may be used alone or in combination of two or more.

[0034] (Aromatic glycidylamine type epoxy resin) The aromatic glycidylamine type epoxy resin is an epoxy resin having an aromatic ring in the molecule and an amino group in which the hydrogen of the amino group is substituted with a glycidyl group. Examples of the aromatic glycidylamine type epoxy resin include, but are not limited to, N,N-diglycidylaniline, N,N-diglycidyltoluidine, diamino diphenylmethane type glycidylamine, aminophenol type glycidylamine, and the like. The aromatic glycidylamine type epoxy resin may be used alone or in combination of two or more.

[0035] (Resorcinol diglycidyl ether) Resorcinol diglycidyl ether is a compound in which the phenolic hydroxyl group of resorcinol is a glycidyl ether group. Resorcinol diglycidyl ether has the formula (a6); [Chemical formula] It is a compound represented by.

[0036] (Content of component (A)) The content of component (A), "aromatic epoxy resin", in the conductive adhesive is not particularly limited. For example, it can be 0.5 parts by mass or more, preferably 1.0 parts by mass or more, more preferably 1.2 parts by mass or more, and for example, 15.0 parts by mass or less, preferably 13.0 parts by mass or less, more preferably 11.0 parts by mass or less, based on 100 parts by mass in total of components (A) to (D). When the content of component (A) is less than 0.5 parts by mass based on 100 parts by mass in total of components (A) to (D), the conductive adhesive may not form a film, the short-time heat bonding strength may decrease, and the heat resistance may decrease. When it exceeds 15.0 parts by mass, the curing may take a long time and the conductivity may decrease.

[0037] <(B) component> Component (B), which is a constituent component of the conductive adhesive of the present invention, is a microcapsule-type latent curing agent. Microcapsule-type latent curing agents include those obtained by encapsulating curing agents such as imidazole compounds, polyhydric phenol compounds, acid anhydrides, amine compounds, hydrazide compounds, mercapto compounds, Lewis acid-amine complexes, and latent curing agents with capsule materials that are destroyed by heating, such as vinyl compounds, urea compounds, phenol resins, urethane resins, epoxy resins, polyethylene, polypropylene, polystyrene, nylon, polyester, polyvinyl chloride, polyvinylidene chloride, and thermoplastic resins. Among them, a microcapsule-type latent curing agent obtained by treating an amine adduct-type latent curing agent with isocyanate is preferred. The microcapsule-type latent curing agent may be used alone or in combination of two or more.

[0038] The average particle diameter of the microcapsule-type latent curing agent is not particularly limited. From the viewpoint of dispersibility and the like in the conductive adhesive, for example, it is 20 μm or less, preferably 12 μm or less. The average particle diameter means the average particle diameter defined by the median diameter. More specifically, it refers to the Stokes diameter measured by the laser diffraction / light scattering method using a particle size distribution meter.

[0039] Examples of the microcapsule-type latent curing agent include, for example, the Novacure series manufactured by Asahi Kasei Corporation (for example, HX-3941HP, HXA-3792, HXA-3922HP, HXA-3932HP, HXA-3042HP, HX-3721, HX-3722, HX-3088, HX-3921HP, HX-3741, HX-3742, HX-3748, HX-3613, HX-3088, HX-3921HP, etc.); LC-80 manufactured by A&C Catalysts; and the like.

[0040] The content of the component (B), "microcapsule-type latent curing agent", in the conductive adhesive is not particularly limited. For example, it is 0.1 part by mass or more, preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and for example, 50.0 parts by mass or less, preferably 40.0 parts by mass or less, more preferably 30.0 parts by mass or less, based on 100 parts by mass of the component (A) in the conductive adhesive and the epoxy component as other components. When the content of the component (B) is less than 0.1 part by mass based on 100 parts by mass of the component (A) in the conductive adhesive and the epoxy component as other components, the curability of the conductive adhesive may decrease and it may take a long time to cure. When it exceeds 50.0 parts by mass, the conductive adhesive may not solidify and may not form a film.

[0041] <(C) component> The component (C) which is a constituent component of the conductive adhesive of the present invention is a thiol compound. Examples of the thiol compound include a thiol compound having one or more, preferably two or more thiol groups capable of reacting with an epoxy group in the molecular structure. As the thiol compound, a polyfunctional thiol compound having 2 to 6 (bifunctional to hexafunctional) thiol groups in the molecular structure is preferable, and a polyfunctional thiol compound having 3 to 6 (trifunctional to hexafunctional) thiol groups is more preferable. The thiol equivalent is not particularly limited. In the case of a low molecular weight thiol compound having a molecular weight of less than 500, it can be, for example, 50 g / eq or more, preferably 70 g / eq or more, and, for example, 200 g / eq or less, preferably 150 g / eq or less. In the case of a high molecular weight thiol compound having a weight average molecular weight of 500 or more, it can be, for example, 250 g / eq or more, preferably 400 g / eq or more, and, for example, 5,000 g / eq or less, preferably 3,000 g / eq or less.

[0042] Examples of the thiol compound include thiol compounds (polyfunctional thiol compounds) such as trimethylolpropane tris(3-mercaptopropionate) (abbreviation: TMTP), pentaerythritol tetrakis(3-mercaptopropionate) (abbreviation: PEMP), dipentaerythritol hexakis(3-mercaptopropionate) (abbreviation: DPMP), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (abbreviation: TEMPIC), tris(3-mercaptopropyl) isocyanurate (abbreviation: TMPIC), ethylene glycol bisthioglycolate (abbreviation: EGTG), trimethylolpropane tristthioglycolate (abbreviation: TMTG), pentaerythritol tetrakisthioglycolate (abbreviation: PETG), pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate) (abbreviation: TPMB), trimethylolethane tris(3-mercaptobutyrate) (abbreviation: TEMB), 1,3,4,6-tetrakis(2-mercaptoethyl) glycoluril, 1,3,4,6-tetrakis(2-mercaptopropyl) glycoluril, 4,4’-isopropylidene bis[(3-mercaptopropoxy)benzene], 1,3,5-triazine-2,4,6-trithiol, and polysulfide polymers having a thiol group.

[0043] Specifically, for example, polyfunctional thiols manufactured by SC Organic Chemical Co., Ltd. (TMMP-LV, PEMP-LV, DPMP, TEMPIC, PEMP, etc.), polyfunctional thiols manufactured by Toray Fine Chemical Co., Ltd. (QE-340M, LP-2, LP-3, LP-55, LP-31, etc.), polyfunctional thiols manufactured by Shikoku Kasei Kogyo Co., Ltd. (TS-G, C3TS-G, etc.), polyfunctional thiols manufactured by Resonac Co., Ltd. (Karenz MT series (PE-1, BD-1, NR-1, TPMB, TEMB, etc.)), polyfunctional thiols manufactured by Yodo Chemical Co., Ltd. (OTG, EGTG, TMTG, PETG, 3-MPA, TMTP, PETP, etc.), polyfunctional thiols manufactured by Asahi Chemical Industry Co., Ltd. (G-2S, PE-2S, PE-3S, PE-4S, TMP-3S, etc.) and the like can be mentioned. The thiol compound may be used alone or in combination of two or more.

[0044] The content of the (C) component "thiol compound" in the conductive adhesive is not particularly limited. With respect to 1 equivalent of epoxy groups in the (A) component and the epoxy component as other components in the conductive adhesive, the thiol groups are, for example, 0.05 equivalent or more, preferably 0.2 equivalent or more, and, for example, 1.5 equivalents or less, preferably 1.2 equivalents or less, more preferably 1.1 equivalents or less, still more preferably 1.0 equivalent or less. When the content of the (C) component is less than 0.05 equivalent with respect to 1 equivalent of epoxy groups, the curability of the conductive adhesive may decrease, it may take time to cure, or there may be a problem with incomplete curing of the cured film. When it exceeds 1.5 equivalents, there may be a problem with incomplete curing of the cured film due to the influence of excess uncured curing agent, and the film hardness may decrease, and the reliability of the conductive connection may decrease.

[0045] In addition, the content of component (C) "thiol compound" in the conductive adhesive is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, based on 100 parts by mass of the epoxy component in component (A) and the epoxy component as other components in the conductive adhesive, and can be, for example, 250 parts by mass or less, preferably 200 parts by mass or less, more preferably 180 parts by mass or less. When the content of component (C) is less than 5 parts by mass with respect to 100 parts by mass of component (A) and the epoxy component as other components in the conductive adhesive, the curability of the conductive adhesive may decrease and it may take a long time to cure. When it exceeds 250 parts by mass, the conductive adhesive may not solidify and may not form a film.

[0046] <(D) component> Component (D), which is a constituent component of the conductive adhesive of the present invention, is one or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, conductive carbon powder, copper-based powder, and gold-based powder.

[0047] (D) The shape of the component "one or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, conductive carbon powder, copper-based powder, and gold-based powder" is not particularly limited. True spherical, substantially spherical (for example, the aspect ratio of length to width is 1.5 or less), dendritic, flat, block-shaped, plate-shaped, polyhedral pyramid-shaped, polyhedral-shaped, flake-shaped (scaly), rod-shaped, fibrous, needle-shaped, irregular-shaped, etc. can be used according to the application, etc. In the present invention, from the viewpoints of oxidation resistance, volume resistivity, dispersibility, handleability, etc., true spherical, substantially spherical, dendritic, flat, or flake-shaped (scaly) ones are preferred.

[0048] In the present invention, as component (D) "one or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, conductive carbon powder, copper-based powder, and gold-based powder", from the viewpoints of cost, conductivity, migration characteristics, etc., it is preferable to use "one or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, and conductive carbon powder", and it is more preferable to use silver-coated copper powder.

[0049] (Silver-coated copper powder) The silver-coated copper powder is not particularly limited as long as the surface of the copper powder is coated with silver. By coating the copper powder with silver, it has excellent oxidation resistance, can reduce the volume resistivity, and can improve the storage stability of the conductive adhesive. The manufacturing method of the silver-coated copper powder is not particularly limited. For example, any silver-coated copper powder such as silver-coated copper powder by silver plating or silver-coated copper powder by the substitution reaction of copper and silver can be used.

[0050] The volume average particle diameter of the silver-coated copper powder is not particularly limited. For example, it can be 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, and can be 100 μm or less, preferably 50 μm or less, more preferably 20 μm or less. For example, in order to enable printing of the conductive adhesive, particularly coating by screen printing method or dispenser method, it is preferably 0.5 μm or more and 10 μm or less. Here, the average particle diameter of the silver-coated copper powder in the present invention is the value of the volume cumulative particle diameter D50 at 50% by volume of the cumulative volume measured by the laser diffraction scattering particle size distribution measurement method. If the average particle diameter of the silver-coated copper powder is larger than 10 μm, the leveling property of the conductive paste will deteriorate, or the disconnection of the wiring pattern will easily occur, making it difficult to form a narrow wiring pattern. Also, if the average particle diameter of the silver-coated copper powder is smaller than 0.5 μm, the core copper may be exposed and copper may oxidize from this part, increasing the specific resistance of the wiring pattern over time.

[0051] Also, in the case of flaky silver-coated copper powder, its thickness is not particularly limited. For example, it is 0.01 μm or more, preferably 0.05 μm or more, and is 20.0 μm or less, preferably 10.0 μm or less.

[0052] Specific examples of silver-coated copper powders include 10% Ag-coated Cu-HWQ5μm, 10% Ag-coated FCC-2000, 10% Ag-coated FCC-115, 10% Ag-coated 2L3 (all manufactured by Fukuda Metal Foil & Powder Co., Ltd.), 10% Ag / 1100Y, 10% Ag / 1100YP, 10% Ag / 05KP, ACFY-2, ACAX-225, ACBY-2 (all manufactured by Mitsui Mining & Smelting Co., Ltd.), TFM-C02P, TFM-C05P, TFM-C05F, TFM-C15F (all manufactured by Toyo Aluminum Co., Ltd.), etc. The silver-coated copper powder may be used alone or in combination of two or more kinds.

[0053] The silver content in the silver-coated copper powder is preferably 5% by mass or more and 30% by mass or less. If the silver content is less than 5% by mass, there is a risk that the core copper may be exposed, and the specific resistance of the wiring pattern may increase over time. Also, if the silver content exceeds 30% by mass, there is a high risk that ion migration may occur.

[0054] (Silver-based powder) The silver-based powder is a powder other than silver-coated copper and is not particularly limited as long as it is a powder containing metallic silver. For example, metallic silver powder, silver alloy powder, silver-coated powder other than silver-coated copper, etc. may be mentioned. The silver-based powder may be used alone or in combination of two or more kinds.

[0055] The metallic silver powder is obtained by pulverizing metallic silver. The silver content in the metallic silver powder is not particularly limited. For example, it is 97% by mass or more, preferably 98% by mass or more, and more preferably 99% by mass or more.

[0056] The silver alloy powder is not particularly limited as long as it is an alloy powder containing silver. The silver content in the silver alloy powder can be appropriately determined from viewpoints such as the melting point property of the silver alloy powder, and is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and for example, less than 97% by mass. The silver content in the silver-containing powder can be easily measured by using a fluorescent X-ray analysis (XRF) apparatus or the like. Examples of the silver alloy powder include silver-copper alloys, silver-platinum alloys, silver-palladium alloys, and the like.

[0057] Silver-coated powders other than silver-coated copper powders are those in which at least a part of the particle surface is coated with metallic silver. Examples of the particles forming the silver-coated powder include one or more of metal particles (for example, palladium particles, aluminum particles, nickel particles, alloy particles, etc.), organic polymer particles, and non-metallic inorganic particles (for example, silica particles, alumina particles, carbon particles, potassium titanate particles, glass particles, ceramic particles, mineral-based particles, etc.). Examples of the means for coating with metallic silver include means such as plating and vapor deposition. The thickness of the metallic silver coating is not particularly limited, but is preferably in the range of 0.01 μm or more and 5 μm or less.

[0058] The silver-based powder may further contain other atoms as long as the properties of the silver-based powder are not impaired. Examples of the other atoms include one or more of Ni, Mn, Sb, Si, K, Na, Li, Ba, Sr, Ca, Mg, Be, Zn, Pb, Cd, Tl, V, Al, Zr, W, Mo, Ti, Co, Sn, Au, Hf, Nb, Ta, Cr, Fe, Ru, Rh, Ir, Pd, Pt, Cu, Ga, In, Si, Ge, Bi, C, B, N, P, S, etc. The content rate of the other atoms is, for example, 3% by mass or less, preferably 1% by mass or less in the silver-based powder.

[0059] The volume average particle diameter of the silver-based powder is not particularly limited. It can be appropriately determined in consideration of dispersibility and handleability. For example, it can be 0.1 μm or more, preferably 0.4 μm or more, more preferably 0.7 μm or more, and for example, 100.0 μm or less, preferably 50.0 μm or less, more preferably 20.0 μm or less.

[0060] The specific surface area of the silver-based powder is not particularly limited. For example, 0.30 m 2 / g or more, preferably 0.50 m 2 / g or more, more preferably 0.70 m2 It can be 2.5 m / g or more, for example, 2.5 m 2 / g or less, preferably 2.1 m 2 / g or less, more preferably 1.6 m 2 / g or less.

[0061] (Nickel-based powder) The nickel-based powder is a powder containing metallic nickel and is not particularly limited as long as it is a powder other than the silver-based powder. For example, metallic nickel powder, nickel alloy powder, nickel-coated powder, etc. can be mentioned. The nickel-based powder may be used alone or in combination of two or more.

[0062] The metallic nickel powder is obtained by pulverizing metallic nickel. The content of nickel in the metallic nickel powder is not particularly limited. For example, it is 95% by mass or more, preferably 97% by mass or more, and more preferably 99% by mass or more.

[0063] The nickel alloy powder is not particularly limited as long as it is an alloy powder containing nickel. The content of nickel in the nickel alloy powder can be appropriately determined from the viewpoints of the melting point of the nickel alloy powder, etc. For example, it is 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and preferably less than 95% by mass. The nickel content rate in the nickel-containing powder can be easily measured by using a fluorescent X-ray analysis (XRF) device or the like. Examples of the nickel alloy powder include nickel-iron-based alloys (such as Ni-58Fe), nickel-copper-based alloys (such as Ni-75Cu), nickel-copper-zinc-based alloys (such as Ni-6Cu-20Zn), nickel-chromium-based alloys, nickel-chromium-silver-based alloys, etc.

[0064] The nickel-coated powder is one in which at least a part of the particle surface is coated with metallic nickel. Examples of the particles forming the nickel-coated powder include one or more of metal particles (e.g., palladium particles, aluminum particles, nickel particles, alloy particles, etc.), organic polymer particles, and non-metal inorganic particles (e.g., carbon particles, potassium titanate particles, glass particles, ceramic particles, mineral-based particles, etc.). Examples of the means for coating with metallic nickel include means such as plating and vapor deposition. The thickness of the metallic nickel coating is not particularly limited, but is preferably in the range of 0.01 μm or more and 5 μm or less.

[0065] The nickel-based powder may further contain other atoms as long as the properties of the nickel-based powder are not impaired. Examples of the other atoms include one or more of Ag, Mn, Sb, Si, K, Na, Li, Ba, Sr, Ca, Mg, Be, Zn, Pb, Cd, Tl, V, Al, Zr, W, Mo, Ti, Co, Sn, Au, Hf, Nb, Ta, Cr, Fe, Ru, Rh, Ir, Pd, Pt, Cu, Ga, In, Si, Ge, Bi, C, B, N, P, S, etc. The content rate of the other atoms is, for example, 3% by mass or less, preferably 1% by mass or less in the nickel-containing powder.

[0066] The volume average particle diameter of the nickel-based powder is not particularly limited and can be appropriately determined in consideration of dispersibility and handleability. For example, it can be 0.5 μm or more, preferably 1.0 μm or more, more preferably 3.0 μm or more, and can be 100.0 μm or less, preferably 50.0 μm or less, more preferably 20.0 μm or less.

[0067] (Conductive carbon powder) The conductive carbon powder is not particularly limited as long as it is a carbon powder composed of carbon atoms and is not coated with silver, nickel, copper, or gold. Examples thereof include carbon black, activated carbon, carbon fiber, carbon nanotube, graphene, etc. Preferably, carbon black, carbon nanotube, and graphene are included. The conductive carbon powder may be used alone or in combination of two or more.

[0068] Examples of the carbon black include acetylene black, furnace black, ketjen black, channel black, lamp black, thermal black, and the like.

[0069] The primary particle diameter of the carbon black is not particularly limited. For example, it can be 5 nm or more, preferably 10 nm or more, and can be 700 nm or less, preferably 500 nm or less. The primary particle diameter can be the arithmetic average of the particle diameters of 100 particles observed and measured by an electron microscope (SEM or TEM).

[0070] The carbon nanotube is a cylindrical hollow fibrous material composed of carbon, and may be either a multi-walled carbon nanotube or a single-walled carbon nanotube. From the viewpoint of conductivity, multi-walled carbon nanotubes are preferred. Examples of the carbon nanotubes include those produced by an arc discharge method, a chemical vapor deposition method (CVD method), or a laser ablation method. Commercially available carbon nanotubes may also be used.

[0071] The average diameter of the carbon nanotube can be, for example, 1 nm or more, preferably 3 nm or more, more preferably 5 nm or more, and can be 30 nm or less, preferably 25 nm or less, more preferably 20 nm or less. The average length of the carbon nanotube can be, for example, 0.1 μm or more, preferably 0.5 μm or more, and can be 100 μm or less, preferably 70 μm or less. The average diameter and average length of the carbon nanotube are the arithmetic averages of the average diameter and average length of 100 carbon nanotubes observed and measured by an electron microscope (SEM, TEM), respectively.

[0072] The BET specific surface area of the carbon nanotube is, for example, 50 m 2 / g or more, preferably 100 m 2150 m / g or more, more preferably 150 m / g or more 2 and may be, for example, 800 m / g or less 2 preferably 600 m / g or less 2 more preferably 500 m / g or less 2 and may be, for example, 800 m / g or less

[0073] Graphene is a material having a dense two-dimensional crystal structure with a carbon six-membered ring structure and has quantized conduction characteristics (ballistic conduction characteristics).

[0074] (Copper-based powder) The copper-based powder is a powder containing metallic copper and is not particularly limited as long as it is a powder other than silver-coated copper powder, silver-based powder, and nickel-based powder. Examples include metallic copper powder, copper alloy powder, copper-coated powder, and the like. The copper-based powder may be used alone or in combination of two or more.

[0075] (Gold-based powder) The gold-based powder is a powder containing metallic gold and is not particularly limited as long as it is a powder other than silver-coated copper powder, silver-based powder, nickel-based powder, and copper-based powder. Examples include metallic gold powder, gold alloy powder, gold-coated powder, and the like. The gold-based powder may be used alone or in combination of two or more.

[0076] The content of the component (D) "one or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, conductive carbon powder, copper-based powder, and gold-based powder" in the conductive adhesive is not particularly limited. Taking the total amount of the cured product of the conductive adhesive as 100% by mass, for example, it may be 75% by mass or more, preferably 80% by mass or more, more preferably 82% by mass or more, and, for example, 97% by mass or less, preferably 95% by mass or less, more preferably 93% by mass or less. If the content of the component (D) is less than 75% by mass based on the total amount of the cured product of the conductive adhesive being 100% by mass, the conductivity of the obtained cured product of the conductive adhesive (conductive film) may be insufficient (the volume resistivity may increase). If it exceeds 97% by mass, the bonding strength of the conductive adhesive may be insufficient.

[0077] <Other components> The conductive adhesive of the present invention may contain, as necessary and within a range where the performance does not deteriorate, epoxy resins other than the component (A), resins other than epoxy resins, coupling agents, wetting and dispersing agents, fillers, solvents, epoxy resin curing agents other than the component (B) and the component (C), adhesion improvers, viscoelasticity modifiers, curing accelerators (curing catalysts), reactive diluents, conductive powders other than the component (D), antioxidants, gap adjusters (spacers; interval control agents), organic acid compounds, pigments, corrosion inhibitors, surfactants, defoamers, dispersants, viscosity adjusters (thixotropy adjusters), adhesion imparting agents, anti-settling agents, etc., pH adjusters, leveling agents, ultraviolet absorbers, flame retardants, heavy metal inactivators, etc., "other components". The other components may be used singly or in combination of two or more.

[0078] (Epoxy resins other than the component (A)) The conductive adhesive of the present invention may contain an epoxy resin other than the component (A). Examples of the epoxy resin other than the component (A) include epoxy resins having no aromatic ring in the molecule, such as alicyclic epoxy resins and / or aliphatic epoxy resins. The epoxy resin other than the component (A) may be any of monomers, oligomers, and polymers having two or more glycidyl groups in one molecule, and the molecular weight is not particularly limited. For example, dicyclopentadiene type epoxy resins having no aromatic ring in the molecule, condensed alicyclic epoxy resins (vinylcyclohexene dioxide, dicyclopentadiene oxide, etc.), hydrogenated aromatic epoxy resins (hydrogenated bisphenol type epoxy resins, hydrogenated biphenol type epoxy resins, etc.), glycidyl ethers of alicyclic polyols (glycidyl ethers of cyclohexanediol, cyclohexanedimethanol, cyclohexanediethanol, etc.), glycidyl ethers of aliphatic polyols (butanediol, hexanediol, octanediol, nonanediol, decanediol, trimethylolpropane, pentaerythritol, etc.), triazine nucleus-containing epoxy resins (triglycidyl isocyanurate, monoallyl diglycidyl isocyanurate, etc.) and the like.

[0079] As the epoxy resin other than the component (A), the conductive adhesive of the present invention preferably contains one or more epoxy resins selected from dicyclopentadiene type epoxy resins having no aromatic ring and trimethylolpropane polyglycidyl ether.

[0080] {Dicyclopentadiene type epoxy resin having no aromatic ring} The dicyclopentadiene type epoxy resin having no aromatic ring has, in the molecule, the formula (d1);

Chemical formula

[0081] Examples of the dicyclopentadiene type epoxy resin having no aromatic ring include those obtained by epoxidizing dicyclopentadiene polyol. For example, ADEKA Resin series (EP-4088S, EP-4088L, etc.) manufactured by ADEKA Corporation; etc. can be mentioned.

[0082] {Trimethylolpropane polyglycidyl ether} The trimethylolpropane polyglycidyl ether has the formula (d2);

Chemical formula

[0083] When the conductive adhesive contains an epoxy resin other than component (A), particularly a dicyclopentadiene type epoxy resin and / or trimethylolpropane polyglycidyl ether having no aromatic ring, the content of the epoxy resin other than component (A) (particularly, a dicyclopentadiene type epoxy resin and / or trimethylolpropane polyglycidyl ether having no aromatic ring) is not particularly limited. For example, it is 0.5 part by mass or more, preferably 1.0 part by mass or more, more preferably 1.2 part by mass or more, and for example, 13.0 part by mass or less, preferably 10.0 part by mass or less, more preferably 7.0 part by mass or less with respect to 100 parts by mass in total of components (A) to (D).

[0084] (Resin other than epoxy resin) The conductive adhesive of the present invention may contain a resin other than an epoxy resin. The resin other than an epoxy resin may be either a thermoplastic resin or a thermosetting resin. Examples of the thermoplastic resin include polyvinyl acetal resins, acrylic resins, polyester resins, phenoxy resins, polyimide resins, polyolefin resins, polyurethane resins, polyamide resins, polycarbonate resins, polyphenylene ether resins, polyvinyl ether resins, polyvinyl alcohol resins, polyvinyl acetate resins, ionomer resins, polyvinyl pyrrolidone resins, terpene resins, and the like. Examples of the thermosetting resin include resol type phenol resins, polyimide resins, xylene resins, polyurethane resins, melamine resins, urea resins, furan resins, isocyanate resins, urea resins, blocked urethane resins, and the like. In the present invention, as the resin other than the epoxy resin, blocked urethane resins, polyurethane resins, polyvinyl acetal resins, resol type phenol resins, acrylic resins, polyester resins, phenoxy resins, polyimide resins, and xylene resins are preferable. Among these, from the viewpoints of film-forming state, connection reliability, adhesion to the base material, etc., blocked urethane resins, polyurethane resins, polyester resins, polyvinyl acetal resins, and acrylic resins are more preferable. The resin other than the epoxy resin may be used alone or in combination of two or more.

[0085] (Coupling agent) The conductive adhesive of the present invention may contain a coupling agent. Thereby, the short-time heat bonding strength of the conductive adhesive can be improved. Examples of the coupling agent include silane coupling agents, titanium coupling agents, aluminum coupling agents, and zirconium coupling agents. Examples of the silane coupling agent include amino group-containing silane compounds such as aminoethylaminopropyltrimethoxysilane, aminoethylaminopropylmethyldimethoxysilane, and aminoethylaminopropylmethylmethoxysilane; vinyl group-containing silane compounds such as vinyltrimethoxysilane; epoxy group-containing silane compounds such as 3-glycidoxypropyltrimethoxysilane; (meth)acryloyl group-containing silane compounds such as γ-methacryloxypropyltrimethoxysilane; mercaptosilanes such as γ-mercaptopropyltrimethoxysilane; isocyanate group-containing silane compounds such as γ-isocyanatopropyltrimethoxysilane; etc. Examples of the titanium coupling agent include tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate, tetraoctyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate, titanium dodecylbenzenesulfonate compound, titanium octylene glycolate, titanium ethylacetoacetate, titanium lactate ammonium salt, titanium lactate, titanium triethanolamineate, tetraisopropyl titanate, tetra-t-butyl titanate, tetrastearyl titanate, titanium acetylacetonate, titanium octylene glycolate, titanium isostearate, titanium diethanolamineate, titanium aminoethylaminoethanolate, titanium oligomer, etc. Examples of the aluminum coupling agent include aluminate compounds having an alkoxide group such as alkylacetoacetate aluminum diisopropylate, and aluminate compounds having an acetylacetonate group such as aluminum trisacetylacetonate.Examples of the zirconium coupling agent include tetra-n-propoxyzirconium, tetra-butoxyzirconium, zirconium tetraacetylacetonate, zirconium dibutoxybis(acetylacetonate), zirconium tributoxyethyl acetoacetate, zirconium butoxyacetylacetonate bis(ethyl acetoacetate), tetrakis(2,4-pentanedionate)zirconium, and the like. The coupling agent may be used alone or in combination of two or more.

[0086] (Wetting and dispersing agent) The conductive adhesive of the present invention may contain a wetting and dispersing agent as needed to prevent aggregation of the components of the conductive adhesive. Specific examples of the wetting and dispersing agent include, for example, Solsperse series (9000, 12000, 17000, 20000, 21000, 24000, 26000, 27000, 28000, 32000, 35100, 54000, etc.) manufactured by Lubrizol Japan Co., Ltd., EFKA series (4008, 4009, 4010, 4015, 4046, 4047, 4060, 4080, 7462, 4020, 4050, 4055, 4400, 4401, 4402, 4403, 4300, 4330, 4340, 6220, 6225, 6700, 6780, 6782, 8503, etc.) manufactured by BASF, Ajisper series (PA111, PB711, PB821, PB822, PN411, etc.) manufactured by Ajinomoto Fine-Techno Co., Inc., DISPERBYK series (101, 106, 108, 116, 130, 140, 145, 161, 163, 166, 168, 171, 180, 192, 2000, 2001, 2020, 2025, 2070, 2152, 2155, 2164, 220S, 300, 320, 340, 378, 380N, 410, 425, 430, etc.) manufactured by BYK-Chemie Japan Co., Ltd., and the like. The wetting and dispersing agent may be used alone or in combination of two or more.

[0087] (Filler) The conductive adhesive of the present invention may contain a filler. Examples of the filler include fused silica, fumed silica, precipitated silica, crystalline silica, carbon black, dolomite, anhydrous silicic acid, hydrous silicic acid, heavy calcium carbonate, colloidal calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, glass powder, zinc oxide, shirasu balloon, glass balloon, phenol resin microballoon, vinylidene chloride resin microballoon, vinyl chloride resin, acrylic resin powder, styrene resin powder, urethane resin powder, polyamide resin powder, glass fiber, potassium titanate fiber, and the like. The filler may be used alone or in combination of two or more.

[0088] (Solvent) The conductive adhesive of the present invention may contain a solvent. Thereby, it is possible to adjust the fluidity of the conductive adhesive, and workability, coatability, handleability, etc. can be improved. When using a solvent, the content is not particularly limited, and it may be appropriately adjusted so that the viscosity of the conductive adhesive becomes a viscosity that can be appropriately applied, printed, etc. on a substrate and / or a viscosity that can be appropriately impregnated into an impregnated material such as a non-woven fabric or a porous body.

[0089] As the solvent, any one or more selected from the group consisting of water and various organic solvents can be used. Examples of the organic solvent include alcohols such as ethyl alcohol, propyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, ethyl carbitol, butyl carbitol, 2-ethyl-1,3-hexanediol, methyl methoxybutanol, α-terpineol, β-terpineol, hexylene glycol, benzyl alcohol, 2-phenylethyl alcohol, isopalmitoyl alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), 2-octanone, isophorone (3,5,5-trimethyl-2-cyclohexen-1-one), diisobutyl ketone (2,6-dimethyl-4-heptanone); ester solvents such as ethyl acetate, butyl acetate, diethyl phthalate, dibutyl phthalate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octanoate, methyl decanoate, methyl cellosolve acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, ethyl diglycol acetate, 1,2-diacetoxyethane;Ether solvents such as tetrahydrofuran, dimethyl ether, diethyl ether, dipropyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, ethoxyethyl ether, 1,2-bis(2-diethoxy)ethane, 1,2-bis(2-methoxyethoxy)ethane; ether ester solvents such as 2-(2-butoxyethoxy)ethyl acetate, methyl cellosolve acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate; ether alcohol solvents such as 2-(2-methoxyethoxy)ethanol; hydrocarbon solvents such as benzene, toluene, xylene, n-paraffin, isoparaffin, dodecylbenzene, turpentine oil, kerosene, light oil; nitrile solvents such as acetonitrile, propionitrile; nitrogen-containing polar solvents such as dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone; silicone oil solvents, etc., and one or more selected from the group consisting thereof are mentioned.; The solvent may be used alone or in combination of two or more kinds.;

[0090] (Epoxy resin hardener other than component (B) and component (C)) The conductive adhesive of the present invention may contain an epoxy resin hardener other than component (B) (microcapsule type latent hardener) and component (C) (thiol compound). Examples of such an epoxy resin hardener include acid anhydride type hardeners, phenol type hardeners, amine type hardeners, amide type hardeners, and thermal cationic polymerization initiators, etc.; The epoxy resin hardener other than component (B) and component (C) may be used alone or in combination of two or more kinds.;

[0091] The acid anhydride type hardener is not particularly limited as long as it is a compound having one or more carboxylic acid anhydride groups (-C(=O)-O-C(=O)-) in its molecular structure.; The acid anhydride-based curing agent is obtained by dehydration between two molecules of an organic carboxylic acid and / or dehydration in the molecular structure of one molecule of an organic carboxylic acid. In the present invention, for example, among the organic carboxylic acids, one or more selected from the group consisting of those obtained by intermolecular dehydration of an organic monocarboxylic acid and those obtained by intramolecular dehydration and / or intermolecular dehydration of an organic polycarboxylic acid can be mentioned. For example, aliphatic monocarboxylic acid anhydrides, aliphatic polycarboxylic acid anhydrides, alicyclic polycarboxylic acid anhydrides, aromatic polycarboxylic acid anhydrides, etc. can be mentioned.

[0092] Examples of the acid anhydride-based curing agent include acetic anhydride, propionic anhydride, oxalic anhydride, maleic anhydride, phthalic anhydride, benzoic anhydride, succinic anhydride, 2-methylsuccinic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, (poly)adipic anhydride, (poly)azelaic anhydride, (poly)sebacic anhydride, norbornene-2,3-dicarboxylic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride, polyacid polyanhydrides, etc. Here, the polyacid polyanhydride is obtained by the intermolecular dehydration condensation reaction of a long-chain aliphatic dicarboxylic acid. For example, SL-12AH, SL-20AH, SB-20AH, IPU-22AH, ST-2PAH, etc. manufactured by Okamura Yushosha Co., Ltd. can be mentioned, and in particular, SB-20AH, IPU-22AH, and ST-2PAH can be mentioned. The acid anhydride-based curing agent may be used alone or in combination of two or more.

[0093] The phenolic curing agent is not particularly limited as long as it is a compound having one or more, preferably two or more phenolic hydroxyl groups capable of reacting with epoxy groups in the molecular structure. For example, bisphenols such as bisphenol A, bisphenol B, bisphenol F, bisphenol AD, and bisphenol S; biphenyls such as biphenyl and tetramethylbiphenyl; phenols such as hydroxyphenol and bis(4-hydroxyphenyl) ether; alkylphenols; phenol novolacs such as 2,6-bis[(2-hydroxyphenyl)methyl]-phenol and phenol biphenylene novolak (biphenyl aralkylphenol); cresol novolacs such as o-cresol novolak, m-cresol novolak, and p-cresol novolak; triphenylmethanes; tetrakisphenols; phenol resins; phenol novolak resins; biphenyl aralkyl type phenol resins; 4,4’,4’’-trihydroxytriphenylmethane, 4,4’,4’’,4’’’-methanetetrayltetraphenol, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, MEH-8005 manufactured by Meiwa Kasei Co., Ltd., KAYAHARD GPH-65, KAYAHARD GPH-103 manufactured by Nippon Kayaku Co., Ltd., TEP-DF, PAPS series (BPAN, PN2, etc.) manufactured by Asahi Organic Materials Industry Co., Ltd., BRG-555, BRG-556, BRG-557, BRG-558, CRG-951, TAM-005, etc. manufactured by Aica Kogyo Co., Ltd. The phenolic curing agent may be used alone or in combination of two or more kinds.

[0094] The amine curing agent is not particularly limited as long as it is a compound having one or more amino groups capable of reacting with an epoxy group in the molecular structure. For example, diethylenetriamine, triethylenetetramine, diethylaminopropylamine, methanediamine, isophoronediamine, bis[4-amino-3-methyldicyclohexyl]methane, diaminodicyclohexylmethane, bis(aminomethyl)cyclohexane, m-xylylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiethyldiphenylmethane, and modified polyamines, polyamideamines, etc. obtained by modifying these by epoxy adduct, Michael addition, Mannich reaction, etc. are included. The amine curing agent may be used alone or in combination of two or more kinds.

[0095] The thermal cationic polymerization initiator is not particularly limited as long as it is a compound that generates a cation by heat. For example, at least one cation selected from aromatic sulfonium, aromatic iodonium, aromatic diazonium, pyridinium, etc., and BF4 - , PF6 - , SbF6 - , AsF6 - , CF3SO3 - , (CF3SO2)2N - and at least one anion selected from B(C6F5)4 - etc., and onium salts composed of these; aluminum complexes; etc. are included. For example, TA-100, TA-100FG, IK-1, IK-1FG, etc. manufactured by San-Apro Co., Ltd.; SI-60, SI-80, SI-100, SI-150, etc. manufactured by Sanshin Chemical Industry Co., Ltd.; K-PURE TAG series, K-PURE CXC series, etc. manufactured by KING INDUSTRIES Co., Ltd.; etc. are included. The thermal cationic polymerization initiator may be used alone or in combination of two or more kinds.

[0096] (Adhesion promoter) The conductive adhesive of the present invention may contain an adhesion imparting agent. This can improve the adhesion between the conductive adhesive and the substrate when the adhesive is applied to the substrate. Examples of the adhesion imparting agent include triazole compounds, thiazole compounds, triazine compounds, polymers having functional groups (such as carboxylic acid groups, amino groups, and hydroxyl groups) and salts thereof. Examples of the adhesion promoter include the BYK series (4509, 4510, 4512, etc.) manufactured by BYK Japan. The adhesion imparting agent may be used alone or in combination of two or more kinds.

[0097] (Viscoelasticity modifier) The conductive adhesive of the present invention may contain a viscoelasticity adjuster (rheology control agent), which can adjust the viscoelasticity (rheology) of the conductive adhesive and contribute to improving workability, etc. Examples of the viscoelasticity adjusting agent (rheology control agent) include polyamide-based, aminoplast-based, polycarboxylic acid-based, urethane-based, cellulose-based, and inorganic layered compound-based viscoelasticity adjusting agents (rheology control agents). For example, RHEOBYK series (H370, H400, H600, H600VF, 100, 405, 410, 411, 415, 430, 431, 440, 7410ET, etc.) manufactured by BYK Japan; Disparlon series (AQ-600, AQH-800, 3600N, 3900EF, etc.) manufactured by Kusumoto Chemical Industries, Ltd.; SN Thickener series (613, 617, 618, 630, 634, 636, 621N, 623N, etc.) manufactured by San Nopco; Adekanol series (UH-814N, UH-752, UH-750, UH-462, etc.) manufactured by ADEKA Corporation, HEC Daicel series (SP600N, etc.) manufactured by Daicel Corporation; BENTONE HD manufactured by Elementis Japan Co., Ltd., etc. The viscoelasticity modifier may be used alone or in combination of two or more kinds.

[0098] (Curing accelerator (curing catalyst)) The conductive adhesive of the present invention may contain a curing accelerator (curing catalyst) for accelerating the curing of an epoxy resin and a curing agent. The curing accelerator is not particularly limited, and examples thereof include one or more selected from the group consisting of amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, phosphonium-based curing accelerators, transition metal-based curing accelerators, and the like. In the conductive adhesive of the present invention, from the viewpoints of workability, handleability, and manufacturing suitability, etc., it is preferable to contain a curing accelerator (curing catalyst) that is liquid at room temperature (25 °C ± 5 °C).

[0099] Examples of the curing accelerator (curing catalyst) include amine-based curing accelerators such as triethylamine, tripropylamine, tributylamine, dimethylbutylamine, dimethylpentylamine, dimethylcyclohexylamine, triethylenediamine, dimethylbenzylamine, 2-(dimethylaminomethyl)phenol, dimethylamino-p-cresol, piperidine, N,N-dimethylpiperazine, α-picoline, pyridine, 4-dimethylaminopyridine, 2,4,6-tris(dimethylaminomethyl)phenol, 3,4,5-tris(dimethylaminomethyl)phenol, N-aminoethylpiperazine, 1,3,6-trisaminomethylhexane, m-xylenediamine, p-xylenediamine, N-(2-aminoethyl)piperazine, m-phenylenediamine, p-phenylenediamine, diaminodiphenylmethane, methylenedianiline, 2,4-toluenediamine, 2,4-diaminoanisole, 2,4-toluenediamine, 2,4-diaminodiphenylamine, 4,4'-methylenedianiline, 1,3-diaminocyclohexane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraazapentacyclo[5,5]undecane, 1,8-diazabicyclo[5,4,0]undecene-7, 1,5-diazabicyclo[4,3,0]-nonene, polyamine, polyamideamine, polyamide, modified polyamine, modified polyamideamine, modified polyamide; imidazole-based curing accelerators such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, modified imidazole;Guanidine-based curing accelerators such as dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, di(o-tolyl)guanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4,4,0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide; Phosphonium-based curing accelerators such as tetraphenylphosphonium bromide, tetrabutylphosphonium bromide, butyltriphenylphosphonium bromide, tetraphenylphosphonium iodide, tetrabutylphosphonium iodide, butyltriphenylphosphonium iodide, tetraphenylphosphonium tetraphenylborate, tetrabutylphosphonium tetraphenylborate, butyltriphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetrabutylborate, tetrabutylphosphonium tetrabutylborate, butyltriphenylphosphonium tetrabutylborate, tetraphenylphosphonium acetate, tetrabutylphosphonium acetate, butyltriphenylphosphonium acetate, tetrabutylphosphonium tetrafluoroborate, tetrabutylphosphonium hexafluorophosphate, methyltributylphosphonium dimethylphosphate, tetrabutylphosphonium acetate, tetrabutylphosphonium hydroxide; Transition metal-based curing accelerators containing transition metals such as titanium and cobalt; etc. can be mentioned.; The curing accelerator (curing catalyst) may be used alone or in combination of two or more kinds.

[0100] (Reactive diluent) The conductive adhesive of the present invention may contain a reactive diluent for viscosity adjustment, curability adjustment, etc. The reactive diluent is not particularly limited, and examples thereof include one or more compounds having one epoxy group in the molecular structure, compounds having one or more oxetane groups in the molecular structure, and the like. For example, glycidyl phenyl ether, glycidyl lauryl ether, 2-phenylphenol glycidyl ether, tolyl glycidyl ether, allyl glycidyl ether, 4-tert-butylphenyl glycidyl ether, N-glycidyl phthalimide, 2-ethylhexyl glycidyl ether, 2-ethylhexyl glycidyl ether, YED111N, YED111AN, YED188 manufactured by Mitsubishi Chemical Corporation, Adeka Glycilol ED-502, Adeka Glycilol ED-502S, Adeka Glycilol ED-509E, Adeka Glycilol ED-509S, Adeka Glycilol ED-529 manufactured by Adeka Corporation, Denacol EX-145, Denacol EX-171, Denacol EX-192 manufactured by Nagase ChemteX Corporation, Epolite M-1230, Epolite 100MF manufactured by Kyoeisha Chemical Co., Ltd., Aron Oxetane OXT-101, Aron Oxetane OXT-212, Aron Oxetane OXT-121, Aron Oxetane OXT-221 manufactured by Toagosei Co., Ltd., ETERNACOLL EHO, ETERNACOLL HBOX, ETERNACOLL OXMA, ETERNACOLL OXBP manufactured by UBE Corporation, and the like. In the present invention, the boiling point of the reactive diluent is, for example, 150°C or higher, preferably 200°C or higher, more preferably 250°C or higher. The reactive diluent may be used alone or in combination of two or more.

[0101] (Conductive powder other than component (D)) The conductive adhesive of the present invention may contain conductive powders other than the component (D) "one or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, conductive carbon powder, copper-based powder, and gold-based powder). Examples of the conductive powders other than the component (D) include lead-free solder powder, tin-based powder, zinc-based powder, aluminum-based powder, iron-based powder, metal alloy powders other than silver-based, nickel-based, copper-based, and gold-based, and resin particles coated with metals other than silver, nickel, copper, and gold.

[0102] The shape of the conductive powder other than the component (D) is not particularly limited. It can be in the shape of a true sphere, substantially spherical (for example, the aspect ratio of length to width is 1.5 or less), flat, block-shaped, plate-shaped, polyhedral pyramid-shaped, polyhedral-shaped, flaky, rod-shaped, fibrous, needle-shaped, irregular-shaped, etc. From the viewpoints of oxidation resistance, volume resistivity, dispersibility, handleability, etc., those in the shape of a true sphere, substantially spherical, flat, or flaky are preferable. The conductive powder other than the component (D) may be used alone or in combination of two or more.

[0103] (Antioxidant) The conductive adhesive of the present invention may contain an antioxidant. This can contribute to the improvement of heat resistance, yellowing resistance, etc. of the cured product of the conductive adhesive. The antioxidant is not particularly limited as long as it is a compound having an antioxidant function, and known or commonly used antioxidants can be used. For example, phenolic antioxidants such as hindered phenol compounds, quinone antioxidants such as hydroquinone, phosphorus antioxidants, sulfur antioxidants, hindered amine antioxidants such as hindered amine compounds, etc. can be mentioned.

[0104] Examples of antioxidants include 2,2 - methylene - bis(4 - methyl - 6 - tert - butylphenol), catechol, tert - butylcatechol, 2 - butyl - 4 - hydroxyanisole, 2,6 - di - tert - butyl - p - cresol, 2,4 - di - tert - butyl - 6 - methylphenol, 2 - tert - butyl - 4 - methylphenol, 2,4 - di - tert - butylphenol, 2,4 - di - tert - pentylphenol, bis - [3,3 - bis - (4’ - hydroxy - 3’ - tert - butylphenyl) - butanoic acid] - glycol ester, 2 - tert - butyl - 6 - (3 - tert - butyl - 2 - hydroxy - 5 - methylbenzyl) - 4 - methylphenyl acrylate, 2 - [1 - (2 - hydroxy - 3,5 - di - tert - pentylphenyl)ethyl] - 4,6 - di - tert - pentylphenyl acrylate, 4,4’ - butylidenebis(6 - tert - butyl - 3 - methylphenol), 2,2’ - butylidenebis(4,6 - di - tert - butylphenol), 4,4’ - thiobis(6 - tert - butyl - 3 - methylphenol), 3,9 - bis[2 - [3 - (3 - tert - butyl - 4 - hydroxy - 5 - methylphenyl)propionyloxy] - 1,1 - dimethylethyl] - 2,4,8,10 - tetraoxaspiro[5,5]undecane, pentaerythritol tetrakis[3 - (3,5 - di - tert - butyl - 4 - hydroxyphenyl)propionate], thiodiethylene bis[3 - (3,5 - di - tert - butyl - 4 - hydroxyphenyl)propionate], octadecyl - 3 - (3,5 - di - tert - butyl - 4 - hydroxyphenyl)propionate, N,N’ - hexane - 1,6 - diylbis[3 - (3,5 - di - tert - butyl - 4 - hydroxyphenyl)propionamide], benzenepropanoic acid - 3,5 - bis(1,1 - dimethylethyl) - 4 - hydroxy - C7 - C9 branched alkyl ester, 2,4 - dimethyl - 6 - (1 - methylpentadecyl)phenol, diethyl[[3,5 - bis(1,1 - dimethylethyl) - 4 - hydroxyphenyl]methyl]phosphonate, 3,3’,3’’,5,5’,5’’ - hexa - tert - butyl - a,a’,a’’ - (mesitylene - 2,4,6-Tril) tri-p-cresol, calcium diethyl bis[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, reaction product of N-phenylbenzeneamine and 2,4,6-trimethylpentene, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, phenolic antioxidants such as picric acid and citric acid; quinone antioxidants such as β-naphthoquinone, 2-methoxy-1,4-naphthoquinone, methylhydroquinone, hydroquinone, hydroquinone monomethyl ether, mono-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, p-benzoquinone, 2,5-diphenyl-p-benzoquinone, 2,5-di-tert-butyl-p-benzoquinone; tris(2,4-di-tert-butylphenyl) phosphite, tris[2-[[2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphefin-6-yl]oxy]ethyl]amine, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphorous acid, tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,Phosphorus-based antioxidants such as 4'-diylbisphosphonite and 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenz[d,f][1,3,2]dioxaphosphepine; sulfur-based antioxidants such as dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, pentaerythrityl tetrakis(3-laurylthiopropionate), and 2-mercaptobenzimidazole; amine-based antioxidants such as phenothiazine; lactone-based antioxidants; vitamin E-based antioxidants; etc. can be mentioned., Commercially available products may be used as the antioxidant. For example, IRGANOX series manufactured by BASF, ADEKA STAB series manufactured by ADEKA, NONFLEX series manufactured by Seiko Chemical Co., Ltd., Sumilizer series manufactured by Sumitomo Chemical Co., Ltd., etc. can be mentioned., The antioxidant may be used alone or in combination of two or more.,

[0105] (Gap adjuster (spacer; interval controller)) The conductive adhesive of the present invention may contain a gap adjuster (spacer; interval controller). The gap adjuster (spacer; interval controller) is used to control the thickness between adherends (the thickness of the adhesive layer). The gap adjuster (spacer; interval controller) is not particularly limited as long as it has a hardness that can withstand use and a desired particle size and aspect ratio. For example, silica fine particles (spherical silica), glass beads, pulverized glass fiber, resin beads, etc. can be mentioned., The resin beads are not particularly limited. For example, various (meth)acrylates such as polyethylene, polypropylene, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polycarbonate, polymethyl methacrylate, polyimide, polyamide, polyester, polyvinyl chloride, polyvinylidene chloride, polydivinylbenzene, fluororesin, polyphenylene oxide, polyphenylene sulfide, polymethylpentene, urea resin, melamine resin, phenol resin, epoxy resin, benzoguanamine resin, polyacetal resin, xylene resin, furan resin, polyisocyanate resin, phenoxy resin, silicone resin, etc. can be mentioned. The resin beads may have their surfaces coated with a conductive metal such as Ag, Cu, Au, Pt, Ni, Al, Sn, Zn or its oxide, alloy, etc. As the gap adjuster (spacer; interval controller), commercially available products may be used. For example, the Highprecca series manufactured by Ube Eximer, the Micropearl series manufactured by Sekisui Chemical Co., Ltd., the Techpolymer series manufactured by Sekisui Chemical Products Co., Ltd., the Unibeads series manufactured by Unitika Glass Beads Co., Ltd., etc. can be mentioned. As the gap adjuster (spacer; interval controller), one kind may be used alone, or two or more kinds may be used.

[0106] <Conductivity of the cured film of the conductive adhesive> The conductive adhesive of the present invention has a cured film with a low volume resistivity and excellent conductivity. As the volume resistivity of the cured film of the conductive adhesive, for example, it is less than 1.0×10 -2 Ω·cm, preferably less than 8.0×10 -3 Ω·cm, more preferably less than 5.0×10 -3 Ω·cm. The volume resistivity of the cured film can be determined, for example, by casting or coating the conductive adhesive on a peelable substrate, heating and curing at 150°C for 30 minutes to form a cured film with a thickness of 80 - 100 μm, and measuring it with a resistivity meter (for example, "Loresta GP-MCP T610" (manufactured by Nitto Seiko Analytic Co., Ltd.), etc.).

[0107] <Method for preparing the conductive adhesive> The method for preparing the conductive adhesive of the present invention is not particularly limited. For example, there is a method of preparing by adding the essential components (A) to (D) and other components used as necessary to a mixing container in any order and mixing and stirring them. When mixing and stirring, for example, a ball mill, a roll mill, a bead mill, a planetary mixer, a tumbler, a stirrer, a stirrer, a mechanical homogenizer, an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a V-type blender, a Nauta mixer, a Banbury mixer, a rotating and revolving mixer, a kneading roll, a single-screw or twin-screw extruder, etc. can be used for mixing and stirring.

[0108] The temperature when preparing the conductive adhesive (the temperature when mixing each component) is not particularly limited. If necessary, heating or the like can be performed, and for example, it can be set to 10 to 40°C. The atmosphere when preparing the conductive adhesive is not particularly limited. It can be carried out in the air, or can also be carried out under an inert atmosphere.

[0109] <Uses of the Conductive Adhesive> The conductive adhesive of the present invention can be used for conductive connection between various electronic components and a circuit board, connection (adhesion) between electrical and electronic circuits, and assembly of the electronic components themselves. The shape and the like of the conductive adhesive are not particularly limited, but it is preferably liquid (paste-like or varnish-like), film-like or powder-like at room temperature (25°C ± 5°C). The liquid conductive adhesive can be, for example, a product obtained by simply stirring and mixing the constituent components of the conductive adhesive as the conductive adhesive, and if necessary, a solvent such as an organic solvent can be mixed. The film-like conductive adhesive can be obtained, for example, by stirring and mixing the constituent components of the conductive adhesive, mixing a solvent such as an organic solvent as necessary to obtain a liquid conductive adhesive, casting and coating the liquid conductive adhesive on a release substrate to form a film, drying to remove the solvent to form a film, and peeling it from the release substrate. A film-shaped conductive adhesive can be obtained, for example, by stirring and mixing the constituent components of the conductive adhesive, and if necessary, mixing a solvent such as an organic solvent to obtain a liquid conductive adhesive, casting and coating the liquid conductive adhesive on a release substrate to form a film, drying to remove the solvent to form a film, and peeling it from the release substrate. Alternatively, a film-shaped conductive adhesive can be obtained by impregnating a non-woven fabric or the like and then forming it on a release substrate, drying to remove the solvent, and then peeling it from the release substrate.

[0110] The electrical connection method and the like using the conductive adhesive of the present invention are not particularly limited. For example, a method of providing a conductive adhesive between an electrode of an electronic component or a circuit and an electrode on a substrate facing it, and heating and / or pressurizing if necessary to perform electrical connection between the two electrodes and adhesion between the two electrodes can be mentioned. The method of providing a conductive adhesive between opposing electrodes is not particularly limited. For example, a method of applying a liquid conductive adhesive, a method of sandwiching a film-shaped conductive adhesive, and the like can be mentioned. In addition, when making a conductive connection between a pin of an electronic component or the like and a circuit, a method of providing a conductive adhesive at the base of the pin and performing butt joint to form a conductive connection can be mentioned.

[0111] The conductive adhesive of the present invention can also be used substantially as an anisotropic conductive material. Further, the conductive adhesive of the present invention can be used in an electrode connection method of forming the conductive adhesive between opposing electrodes on a substrate and obtaining contact between the two electrodes and adhesion between the substrates by heating and pressurizing if necessary. The substrate for forming the electrodes is not particularly limited. Examples include inorganic substances such as semiconductors, glass, and ceramics, organic substances such as polyimide and polycarbonate, composites such as glass / epoxy, and combinations thereof. Furthermore, since the conductive adhesive of the present invention can form a film at a low temperature, it can enable conductive connection even at a low temperature of, for example, 200°C or lower.

[0112] The conductive adhesive of the present invention can be used for applications as a conductive material. Examples of the conductive material include conductive ink, circuit connection material, conductive paste, conductive film, conductive fiber, conductive paint, conductive material for semiconductor packages, conductive material for microelectronic devices, antistatic material, electromagnetic wave shielding material, die attach paste, actuator, sensor, conductive resin molded body, and the like.

[0113] For example, the conductive adhesive can be applied to various substrates by any printing or coating method such as casting method, dipping method, bar coating method, dispenser method, roll coating method, gravure coating method, screen printing method, metal mask printing method, flexographic printing method, spray coating method, spin coating method, inkjet method, etc., and heated and dried at a temperature of 300 °C or lower to form a conductive film. The atmosphere during drying includes one or more selected from the group consisting of air, inert gas, vacuum, reduced pressure, etc. In particular, from the viewpoint of suppressing deterioration of the conductive film (preventing oxidation of conductive powder, etc.), an inert gas atmosphere such as nitrogen or argon is preferable.

[0114] The conductive adhesive of the present invention can also be used as a conductive material for printing, for example, to form a coating film such as wiring on a substrate by printing. Examples of the printing and coating methods include screen printing method, metal mask printing method, inkjet printing method, flexographic printing method, gravure printing method, etc. In the present invention, since it has excellent printability and shape retention, it is preferable to use one or more printing methods selected from the group consisting of screen printing method, inkjet printing method, etc. The mesh during screen printing can be appropriately selected, and it is preferable to adopt a mesh that does not excessively remove the conductive powder. The film thickness of the coating film formed by printing can be set to an appropriate thickness according to various applications. For example, it is 1 μm or more, preferably 2 μm or more, more preferably 5 μm or more, and for example, 100 μm or less.

[0115] <Inductive heating and curing of the conductive adhesive> The conductive adhesive of the present invention can form a cured film excellent in bonding strength even with short-time heating. The heating time is 120 seconds or less, preferably 60 seconds or less, more preferably 30 seconds or less, and even more preferably 15 seconds or less. Therefore, it is useful as a conductive adhesive for induction heating curing that is cured by induction heating (IH; Induction Heating). Further, it is possible to complete the heat curing in a short time using a heating furnace (oven), and it is also possible to cure by a short-time heating method using a laser, microwaves, or the like.

[0116] Examples of induction heating curing include a method in which a conductive adhesive is interposed between a conductive layer and a member, and the conductive adhesive is heat-cured by induction heating such as electromagnetic induction heating. Thereby, a conductive connection by the conductive adhesive can be formed. Induction heating curing uses the phenomenon that Joule heat is generated by passing an eddy current through a conductive substance, and it is possible to heat-cure the conductive adhesive at an arbitrary location in a short time by self-heating the conductive substance. Note that it is also possible to perform induction heating curing of the conductive adhesive by utilizing the self-heating of the conductive substance in the conductive adhesive and perform adhesion between non-conductive materials.

[0117] The induction heating method is not particularly limited. For example, in a plan view, a coil having a space portion inside, a plurality of ferrites arranged along the conveyance direction of a base material in the space portion of the coil, and an adjustment mechanism for independently adjusting the distance between each ferrite and a conductive layer formed on the base material, and a power source for applying an alternating voltage to the coil to induction-heat the conductive layer and / or the conductive adhesive formed on the base material. Examples thereof include a method of performing induction heating (IH) using a device provided with the above.

[0118] Since the conductive adhesive of the present invention can be cured by short-time heating and can form a joint excellent in strength, it is useful as an adhesive for induction heating (IH) curing. Since it is possible to cure the conductive adhesive in a short time by induction heating to form a joint (conductive connection), it is possible to apply a material with not so high heat resistance as an adherend. Further, for example, by using a base material provided with a conductive pad on a surface different from the surface provided with the conductive layer of the base material such that at least a part of the conductive pad overlaps with the conductive layer, it is possible to more reliably join (electrically connect) the conductive layer and the member by induction heating. Since the conductive pad provided on a surface different from the surface provided with the conductive layer of the base material has a larger volume compared to the conductive layer or the conductive adhesive, the amount of heat generated by induction heating is large. Therefore, the heat generated in the conductive pad by induction heating is transferred to the conductive adhesive, and thus the conductive adhesive can be effectively heat-cured. At that time, since it is possible to suppress the temperature rise of the base material, the conductive adhesive of the present invention can also be used to perform the adhesion of a base material having low heat resistance by using the heat-curing of the conductive adhesive.

Examples

[0119] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these examples. Unless otherwise specified, “%” means “mass %” and “part” means “part by mass”. Further, all numerical values related to the blending amounts of the respective components in Tables 1 and 2 are all “parts” (parts by mass).

[0120] [Components Used] The components used in the examples are as follows. In each structural formula, n and m are the number of repeating units, and each has a value that gives a predetermined epoxy equivalent. Further, R 1 ~R 4 are each independently hydrogen or a substituent, R 5 and R 6 are each independently hydrogen or a methyl group, and p to s are each independently an integer of 0 or more and 4 or less.

[0121] <Component (A)> ·BPA-EP1: Bisphenol A type epoxy resin (epoxy equivalent 948 g / eq, glass transition temperature 100 ° C, solid at 25 ° C)

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[0122] <Component (B)> ·MCLCA1: Novacure HXA-3792 (manufactured by Asahi Kasei Corporation, microcapsule type latent curing agent)) ·MCLCA2: Novacure HX-3722 (manufactured by Asahi Kasei Corporation, microcapsule type latent curing agent)

[0123] <Component (C)> ·PEMP: Pentaerythritol tetrakis(3-mercaptopropionate) ·MPGU: 1,3,4,6-Tetrakis(3-mercaptopropyl) glycoluril

[0124] <Component (D)> ·SCC: ACFY-2 (manufactured by Mitsui Mining & Smelting Co., Ltd., silver-coated copper powder, volume average particle diameter 5.4 μm, silver content 10 mass%)

[0125] <Other components> ·DCPD-EP: Dicyclopentadiene dimethanol diglycidyl ether (epoxy equivalent 165 g / eq, boiling point 426 °C, liquid at 25 °C)

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[0126] [Measurement and Evaluation of Characteristics of Conductive Adhesive] In the examples, the measurement and evaluation of the characteristics ("short-time heating bonding strength") of the conductive adhesive were carried out as follows.

[0127] <Short-time heating bonding strength> Using a metal mask with a pattern of 2.3 mm × 1.1 mm and a thickness of 100 μm, the conductive adhesive was applied onto a glass substrate. Then, a surface-mount connector HH-1-G (manufactured by Macatech Co., Ltd.) was placed thereon, and induction heating (working distance (WD) 6.0 mm, output 15%, gap 14.0 mm, 3 seconds) was performed using an electromagnetic induction heating soldering reflow (IH reflow) apparatus manufactured by Wonder Future Corporation. After induction heating, it was left standing at room temperature (25°C ± 5°C) for 1 hour, and then the die shear bonding strength was measured as the short-time heating bonding strength using a bonding tester PTR1102 (manufactured by Resca Co., Ltd.), and the short-time heating bonding strength was evaluated according to the following criteria. An A evaluation with a die shear bonding strength of 4,000 gf or more is considered qualified, and a D evaluation with a die shear bonding strength of less than 4,000 gf is considered unqualified.

[0128] (Evaluation Criteria) A evaluation: Die shear bonding strength is 4,000 gf or more. D evaluation: Die shear bonding strength is less than 4,000 gf.

[0129] [Example 1] 4.9 parts by mass of BPA-EP1, 1.6 parts by mass of MCLCA1, 5.2 parts by mass of PEMP, 85.0 parts by mass of SCC, and 3.3 parts by mass of TMP-EP were added to a container and stirred and mixed to prepare a conductive adhesive. The characteristics ("short-time heating bonding strength") of the obtained conductive adhesive were evaluated. The results are shown together with Table 1.

[0130] [Examples 2 to 21] Conductive adhesives were prepared in the same manner as in Example 1, except that the constituent components and their amounts used of the conductive adhesives were as shown in Table 1 and Table 2. The properties of the obtained conductive adhesive ("short-time heating bonding strength") were evaluated. The results are shown together in Tables 1 and 2.

[0131]

Table 1

[0132]

Table 2

[0133] From Tables 1 and 2, it can be seen that the conductive adhesive according to the present invention is excellent in the "short-time heating bonding strength" evaluation, so it is possible to firmly bond the adherend even with short-time heating. Also, since it is possible to form a cured film with excellent bonding strength even with short-time heating, it is useful for applications where the conductive adhesive is cured and bonded using an induction heating method, a short-time heating method using a heating furnace (oven), laser, microwave, etc., for example, for forming conductive connections.

Claims

1. The following (A) to (D); (A) an aromatic epoxy resin, (B) a microcapsule-type latent curing agent, (C) a thiol compound, and (D) one or more conductive powders selected from silver-coated copper powder, silver-based powder, nickel-based powder, conductive carbon powder, copper-based powder, and gold-based powder, A conductive adhesive containing the same.

2. The conductive adhesive according to claim 1, which is for induction heating curing.

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