Conductive adhesive

Abstract

To provide a conductive adhesive which is cured by heating for a short time, and suppresses occurrence of droplets in a heated part after curing.SOLUTION: A conductive adhesive contains the following components (A) to (C): (A) one or more epoxy resins selected from biphenyl-type epoxy resins, fluorene-type epoxy resins, phenol novolac-type epoxy resins and bisphenol-type epoxy resins; (B) a microcapsule-type latent curing agent; and (C) 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, the present invention relates to a conductive adhesive that cures by short-time heating and suppresses the generation of droplets at the heated portion after curing.

Background Art

[0002] As conductive adhesives, those having various compositions are known. For example, in the production of circuits for electric and electronic devices, they are used for conductive connection (adhesion) of electric and electronic components instead 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, in the production of circuits for electric and electronic devices, the demand for conductive adhesives that cure by short-time heating has been increasing. In addition, induction heating (IH) that can be used for substrates with low heat resistance or high heat dissipation has been under consideration. Many of the conventional conductive adhesives have required long-term heating during heat curing, and there have been problems in using them for substrates with low heat resistance or high heat dissipation. In addition, when heat curing a conductive adhesive, droplets may occur at the heated portion after heat curing. The occurrence of droplets may deteriorate the working environment and cause product defects. Under such circumstances, there is a need for a conductive adhesive that can be cured by short-term heating and in which the generation of droplets at the heated portion after curing is suppressed. However, no conductive adhesive that satisfies these characteristics has been known so far.

[0005] The problem to be solved by the present invention is to provide a conductive adhesive that cures even with short-term heating and in which the generation of droplets at the heated portion after curing is suppressed.

Means for Solving the Problem

[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 (C); (A) One or more epoxy resins selected from biphenyl type epoxy resins, fluorene type epoxy resins, phenol novolac type epoxy resins, and bisphenol type epoxy resins, (B) Microcapsule type latent curing agent, and (C) One or more conductive powders selected from silver-coated copper powders, silver-based powders, nickel-based powders, conductive carbon powders, copper-based powders, and gold-based powders, A conductive adhesive containing [Item 2] The conductive adhesive according to Item 1, further containing (D) a thiol compound. [Item 3] The conductive adhesive according to Item 1 or 2, which is for induction heat curing.

Effect of the Invention

[0007] The present invention provides a conductive adhesive that cures even with short-time heating and suppresses the generation of droplets at the heated site after curing. Since the conductive adhesive of the present invention can cure even with short-time heating and suppress the generation of droplets at the heated site after curing, it is useful for applications in which the conductive adhesive is cured by induction heating (IH), a short-time heating method using a heating furnace (oven), laser, microwave, or the like to perform adhesion.

Mode for Carrying Out the Invention

[0008] The conductive adhesive of the present invention contains (A) one or more epoxy resins selected from biphenyl type epoxy resins, fluorene type epoxy resins, phenol novolak type epoxy resins, and bisphenol type epoxy resins, (B) a microcapsule type latent curing agent, and (C) one or more conductive powders selected from silver-coated copper powders, silver-based powders, nickel-based powders, conductive carbon powders, copper-based powders, and gold-based powders. By containing the components (A) to (C) or the components (A) to (D), it is possible to form a cured film that cures with short-time heating and has excellent bonding strength, and to obtain a conductive adhesive in which the generation of droplets at the heated site after curing is suppressed. Hereinafter, the conductive adhesive of the present invention will be described in detail.

[0009] <Component (A)> The component (A), which is a constituent component of the conductive adhesive of the present invention, is one or more epoxy resins selected from biphenyl type epoxy resins, fluorene type epoxy resins, phenol novolak type epoxy resins, and bisphenol type epoxy resins.

[0010] (Biphenyl type epoxy resin) The biphenyl type epoxy resin has the formula (a1) in the molecule;

Chemical formula

[0011] 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 s, they may be the same as 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, and the like. The substituent may be a single type or two or more types.

[0012] 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, and the like, but are not limited thereto. The biphenyl type epoxy resin may be used alone or in combination of two or more.

[0013] Examples of the biphenyl type epoxy resin 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; etc., but are not limited thereto.

[0014] (Fluorene type epoxy resin) The fluorene-type epoxy resin is not particularly limited as long as it is an epoxy resin having one or more 9,9-bisarylfluorene skeletons represented by the formula (a2) in the molecule; [Chemical formula] and one or more epoxy groups. The fluorene-type epoxy resin preferably has two or more epoxy groups.

[0015] In the formula (a2), Ar 1 and Ar 2 are each independently an aromatic hydrocarbon ring which may have a substituent. Examples of the aromatic hydrocarbon ring 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, a terphenylen ring and the like. Among these aromatic hydrocarbon rings, a benzene ring, a naphthalene ring and a biphenyl ring are preferable, and a benzene ring is more preferable. Ar 1 and Ar 2 The substituents which may be possessed 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 substituents may be a single kind or two or more kinds. In the formula (a2), b1 is an integer from 0 to 8, R c is a substituent, and when there are a plurality of R c , 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 .

[0016] 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.

[0017] Examples of 9,9-bis(glycidyloxyphenyl)fluorenes include, but are not limited to, 9,9-bis(4-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.

[0018] 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.

[0019] 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, 9,9-bis(5-glycidyloxy-1-naphthyl)fluorene; etc.

[0020] Examples of 9,9-bis(glycidyloxy(poly)alkoxyphenyl)fluorenes include 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, 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; and the like, but are not limited thereto.

[0021] Examples of 9,9-bis(polyglycidyloxy(poly)alkoxyphenyl)fluorenes include 9,9-bis(di or triglycidyloxy(poly)C2-C4 alkoxy-phenyl)fluorenes such as 9,9-bis(3,4-di(2-glycidyloxyethoxy)phenyl)fluorene, 9,9-bis(3,5-di(2-glycidyloxyethoxy)phenyl)fluorene; and the like, but are not limited thereto.

[0022] Examples of 9,9-bis(glycidyloxy(poly)alkoxynaphthyl)fluorenes include 9,9-bis(glycidyloxy(poly)alkoxynaphthyl)fluorenes such as 9,9-bis[6-(2-glycidyloxyethoxy)-2-naphthyl]fluorene, 9,9-bis[5-(2-glycidyloxyethoxy)-1-naphthyl]fluorene; and the like, but are not limited thereto.

[0023] (Phenol novolac type epoxy resin) The phenol novolac type epoxy resin has the formula (a3) in the molecule; [Chemical formula] There is no particular limitation as long as it is an epoxy resin having one or more phenolic novolak-type skeletons represented by and one or more epoxy groups. The phenolic novolak-type epoxy resin preferably has two or more epoxy groups. In formula (a3), c1 is an integer from 0 to 3, and R c is a substituent, and when there are a plurality of R c , they may be the same as 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 substituents may be a single type or two or more types.

[0024] Examples of the phenolic novolak-type epoxy resin include 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 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; etc., but are not limited thereto. The phenolic novolak-type epoxy resin may be used alone or in combination of two or more.

[0025] (Bisphenol-type epoxy resin) The bisphenol type epoxy resin is an epoxy resin having at least one bisphenol type skeleton represented by the formula (a4) in the molecule; [Chemical formula] It is not particularly limited as long as it is an epoxy resin having at least one bisphenol type skeleton represented by the formula (a4) and at least one epoxy group.

[0026] 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 kind or two or more kinds. X is a group selected from -CR a41 R a42 -, -S(=O)2-, -O-, -C(=O)-, and R a41 and R a42 are hydrogen or an optionally substituted hydrocarbon group having 1 to 20 carbon atoms, which 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).

[0027] 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, 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.

[0028] Examples of bisphenol type epoxy resins 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, and the like. 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, and bisphenol Z type epoxy resin are preferable, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AD type epoxy resin are more preferable, and bisphenol A type epoxy resin is even more preferable.

[0029] 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.

[0030] (Content of component (A)) The content of component (A) "one or more epoxy resins selected from the group consisting of biphenyl type epoxy resins, fluorene type epoxy resins, phenol novolac type epoxy resins, and bisphenol type epoxy resins" in the conductive adhesive is not particularly limited. With respect to 100 parts by mass in total of components (A) to (C), it can be, for example, 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, 13.0 parts by mass or less, preferably 10.0 parts by mass or less, more preferably 7.0 parts by mass or less. When the content of component (A) is less than 0.5 parts by mass with respect to 100 parts by mass in total of components (A) to (C), 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 13.0 parts by mass, the curing may take time and the conductivity may decrease.

[0031] <Component (B)> Component (B), which is a constituent component of the conductive adhesive of the present invention, is a microcapsule type latent curing agent. Examples of the microcapsule type latent curing agent 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 broken 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.

[0032] The average particle size of the microcapsule-type latent curing agent is not particularly limited. From the viewpoint of dispersibility in the conductive adhesive, etc., it is, for example, 20 μm or less, preferably 12 μm or less. The average particle size means the average particle size 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 analyzer.

[0033] Examples of the microcapsule-type latent curing agent include 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.

[0034] The content of the component (B) "microcapsule-type latent curing agent" in the conductive adhesive is not particularly limited. With respect to 100 parts by mass of the component (A) in the conductive adhesive and the epoxy component as other components, it can be, for example, 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 can be, 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. When the content of the component (B) is less than 0.1 part by mass with respect to 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 time to cure. When it exceeds 50.0 parts by mass, the conductive adhesive may not solidify and may not form a film.

[0035] <(C) component> The component (C) 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.

[0036] (C) 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 in shape. 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., spherical, substantially spherical, dendritic, flat, or flake-shaped (scaly) ones are preferred.

[0037] In the present invention, as the (C) 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", 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.

[0038] (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 silver-coating the copper powder, it has excellent oxidation resistance, can lower the volume resistivity, and can improve the storage stability of the conductive adhesive, etc. 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, silver-coated copper powder by the substitution reaction of copper and silver, etc. can be used.

[0039] 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 the screen printing method or the 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 a cumulative volume of 50% by volume measured by the laser diffraction scattering particle size distribution measurement method. This is because when the average particle diameter of the silver-coated copper powder is larger than 10 μm, the leveling property of the conductive paste deteriorates, and disconnection of the wiring pattern is likely to occur, making it difficult to form a narrow wiring pattern. Also, when the average particle diameter of the silver-coated copper powder is smaller than 0.5 μm, the core copper is exposed and copper oxidizes from this part, which may increase the specific resistance of the wiring pattern over time.

[0040] 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.

[0041] Specific examples of the silver-coated copper powder include 10% Ag-coated Cu-HWQ5μm, 10% Ag-coated FCC-2000, 10% Ag-coated FCC-115, 10% Ag-coated 2L3 (above, manufactured by Fukuda Metal Foil & Powder Co., Ltd.), 10% Ag / 1100Y, 10% Ag / 1100YP, 10% Ag / 05KP, ACFY-2, ACAX-225, ACBY-2 (above, manufactured by Mitsui Mining & Smelting Co., Ltd.), TFM-C02P, TFM-C05P, TFM-C05F, TFM-C15F (above, manufactured by Toyo Aluminium Co., Ltd.), etc. The silver-coated copper powder may be used alone or in combination of two or more.

[0042] 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 resistivity of the wiring pattern may increase over time. Also, if the silver content exceeds 30% by mass, there is a risk that ion migration may occur more easily.

[0043] (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. can be mentioned. The silver-based powder may be used alone or in combination of two or more.

[0044] 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.

[0045] 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 properties of the silver alloy powder. For example, it is 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 rate 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-based alloys, silver-platinum-based alloys, silver-palladium-based alloys, etc.

[0046] The silver-coated powder other than silver-coated copper powder is one 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 metallic particles (for example, palladium particles, aluminum particles, nickel particles, alloy particles, etc.), organic polymer particles, non-metallic inorganic particles (for example, silica particles, alumina particles, carbon particles, potassium titanate particles, glass particles, ceramic particles, mineral-based particles, etc.). As the means for coating with metallic silver, means such as plating and vapor deposition can be mentioned. The thickness of the metallic silver coating is not particularly limited, but it is preferably in the range of 0.01 μm or more and 5 μm or less.

[0047] The silver-based powder may further contain other atoms as long as the properties of the silver-based powder are not inhibited. Examples of 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 other atoms is, for example, 3 mass% or less, preferably 1 mass% or less in the silver-based powder.

[0048] 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 can be 100.0 μm or less, preferably 50.0 μm or less, more preferably 20.0 μm or less.

[0049] The specific surface area of the silver-based powder is not particularly limited. For example, it can be 0.30 m 2 / g or more, preferably 0.50 m 2 / g or more, more preferably 0.70 m 2 / g or more, and can be 2.5 m 2 / g or less, preferably 2.1 m 2 / g or less, more preferably 1.6 m 2 / g or less.

[0050] (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.

[0051] The nickel metal powder is obtained by pulverizing nickel metal. The nickel content in the nickel metal 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.

[0052] The nickel alloy powder is not particularly limited as long as it is an alloy powder containing nickel. The nickel content in the nickel alloy powder can be appropriately determined from viewpoints such as the melting point of the nickel alloy powder. 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) apparatus or the like. Examples of the nickel alloy powder include nickel-iron alloys (such as Ni-58Fe), nickel-copper alloys (such as Ni-75Cu), nickel-copper-zinc alloys (such as Ni-6Cu-20Zn), nickel-chromium alloys, nickel-chromium-silver alloys, and the like.

[0053] The nickel-coated powder is one in which at least a part of the particle surface is coated with nickel metal. Examples of the particles forming the nickel-coated powder include one or more of metal particles (such as palladium particles, aluminum particles, nickel particles, alloy particles, etc.), organic polymer particles, and non-metal inorganic particles (such as carbon particles, potassium titanate particles, glass particles, ceramic particles, mineral-based particles, etc.). Examples of the coating means of nickel metal include means such as plating and vapor deposition. The thickness of the nickel metal coating is not particularly limited, but it is preferably in the range of 0.01 μm or more and 5 μm or less.

[0054] The nickel-based powder may further contain other atoms as long as the properties of the nickel-based powder are not inhibited. 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 mass% or less, preferably 1 mass% or less in the nickel-containing powder.

[0055] 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.

[0056] (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.

[0057] Examples of the carbon black include acetylene black, furnace black, ketjen black, channel black, lamp black, thermal black, etc.

[0058] The primary particle size of 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 size can be the arithmetic mean of the particle sizes of 100 particles observed and measured with an electron microscope (SEM or TEM).

[0059] Carbon nanotubes are cylindrical hollow fibrous substances composed of carbon, and can be either multi-walled carbon nanotubes or single-walled carbon nanotubes. From the perspective of conductivity, multi-walled carbon nanotubes are preferred. Carbon nanotubes include, for example, those produced by the arc discharge method, chemical vapor deposition method (CVD method), or laser ablation method. Commercially available products of carbon nanotubes may also be used.

[0060] The average diameter of carbon nanotubes 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 carbon nanotubes 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 carbon nanotubes are the arithmetic means of the average diameters and average lengths of 100 carbon nanotubes observed and measured with an electron microscope (SEM, TEM), respectively.

[0061] The BET specific surface area of carbon nanotubes, due to the relationship between viscosity and conductivity, can be, for example, 50 m 2 / g or more, preferably 100 m 2 / g or more, more preferably 150 m 2 / g or more, and can be 800 m 2 / g or less, preferably 600 m 2 / g or less, more preferably 500 m 2 / g or less.

[0062] Graphene is a material with a dense two-dimensional crystal structure having a carbon six-membered ring structure and has quantization conduction characteristics (ballistic conduction characteristics).

[0063] (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. For example, metallic copper powder, copper alloy powder, copper-coated powder, etc. can be mentioned. The copper-based powder may be used alone or in combination of two or more.

[0064] (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. For example, metallic gold powder, gold alloy powder, gold-coated powder, etc. can be mentioned. The gold-based powder may be used alone or in combination of two or more.

[0065] The content of the (C) 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” 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 can 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 (C) component is less than 75% by mass with 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 increases), and if it exceeds 97% by mass, the bonding strength of the conductive adhesive may be insufficient.

[0066] <(D) component> The conductive adhesive of the present invention may contain a thiol compound as the (D) component. 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.

[0067] 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.

[0068] Specifically, for example, multifunctional thiols manufactured by SC Organic Chemicals Co., Ltd. (TMMP-LV, PEMP-LV, DPMP, TEMPIC, PEMP, etc.), multifunctional thiols manufactured by Toray Fine Chemical Co., Ltd. (QE-340M, LP-2, LP-3, LP-55, LP-31, etc.), multifunctional thiols manufactured by Shikoku Kasei Kogyo Co., Ltd. (TS-G, C3TS-G, etc.), multifunctional thiols manufactured by Resonac Co., Ltd. (Karenz MT series (PE-1, BD-1, NR-1, TPMB, TEMB, etc.)), multifunctional thiols manufactured by Yodo Chemical Co., Ltd. (OTG, EGTG, TMTG, PETG, 3-MPA, TMTP, PETP, etc.), multifunctional 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.

[0069] The content of the (D) component "thiol compound" in the conductive adhesive is not particularly limited. When the (D) component "thiol compound" is contained in the conductive adhesive, the equivalent amount of the thiol group with respect to 1 equivalent of the epoxy group in the (A) component in the conductive adhesive and the epoxy component as other components can be, for example, 1.5 equivalents or less, preferably 1.2 equivalents or less, more preferably 1.1 equivalents or less, and even more preferably 1.0 equivalent or less. When it exceeds 1.5 equivalents, curing failure of the cured film may occur due to the influence of unreacted curing agent in excess, and the film hardness may decrease, and the reliability of the conductive connection may decrease.

[0070] When the conductive adhesive contains the (D) component "thiol compound", the lower limit value of the equivalent amount of the thiol group with respect to 1 equivalent of the epoxy group in the (A) component in the conductive adhesive and the epoxy component as other components can be, for example, 0.05 equivalent or more, preferably 0.2 equivalent or more. When it is less than 0.05 equivalent, the curability of the conductive adhesive may decrease, and it may take time for curing or curing failure of the cured film may occur.

[0071] In addition, the content of the (D) component, "thiol compound", in the conductive adhesive can be, for example, 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, with respect to 100 parts by mass of the (A) component in the conductive adhesive and the epoxy component as other components, 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 the (D) component exceeds 250 parts by mass with respect to 100 parts by mass of the (A) component in the conductive adhesive and the epoxy component as other components, the conductive adhesive may not solidify and may not form a film. When the conductive adhesive contains the (D) component, "thiol compound", the lower limit of the content of the (D) component, "thiol compound", with respect to 100 parts by mass of the epoxy resin in the conductive adhesive can be, for example, 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more. If it is less than 5 parts by mass, the curability of the conductive adhesive may decrease, and it may take a long time to cure.

[0072] <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 (A) component, resins other than epoxy resins, coupling agents, wetting and dispersing agents, fillers, solvents, epoxy resin curing agents other than the (B) component and the (D) component, adhesion improvers, viscoelasticity modifiers, curing accelerators (curing catalysts), reactive diluents, conductive powders other than the (C) component, antioxidants, gap adjusters (spacers; interval control agents), organic acid compounds, pigments, corrosion inhibitors, surfactants, defoaming agents, dispersants, viscosity adjusters (thixotropy adjusters), adhesion imparting agents, anti-settling agents, etc., pH adjusters, leveling agents, ultraviolet absorbers, flame retardants, heavy metal inactivators, etc., as "other components". The other components may be used singly or in combination of two or more.

[0073] (Epoxy resins other than the (A) component) The conductive adhesive of the present invention may contain an epoxy resin other than the component (A). The epoxy resin other than the component (A) is not particularly limited as long as it is an epoxy resin other than "biphenyl type epoxy resin, fluorene type epoxy resin, phenol novolac type epoxy resin, bisphenol type epoxy resin".

[0074] (A) The epoxy resin other than the component may be any of a monomer, an oligomer, and a polymer having two or more glycidyl groups in one molecule, and the molecular weight is not particularly limited. For example, chelate-modified epoxy resin; hydroquinone type epoxy resin; stilbene type epoxy resin; resorcinol diglycidyl ether; triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, phenol aralkyl type epoxy resin having a phenylene skeleton; naphthol type epoxy resin such as dihydroxynaphthalene type epoxy resin, epoxy resin obtained by epoxidizing a dimer of dihydroxynaphthalene; triazine nucleus-containing epoxy resin such as triglycidyl isocyanurate, monoallyl diglycidyl isocyanurate; dicyclopentadiene type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated biphenol type epoxy resin, epoxy resin having an alicyclic structure such as glycidyl ether of polyol having an alicyclic structure such as cyclohexanediol, cyclohexanedimethanol, cyclohexanediethanol; aliphatic polyol glycidyl ether such as butanediol, hexanediol, octanediol, nonanediol, decanediol, trimethylolpropane, pentaerythritol, glycerin; aromatic glycidylamine type epoxy resin such as N,N-diglycidylaniline, N,N-diglycidyltoluidine, diaminodiphenylmethane type glycidylamine, aminophenol type glycidylamine; etc. (a) The epoxy resin other than the component and the component (b) may be used alone or in combination of two or more.

[0075] The conductive adhesive of the present invention preferably contains, as an epoxy resin other than the component (A), one or more epoxy resins selected from resorcinol diglycidyl ether, dicyclopentadiene type epoxy resin, and trimethylolpropane polyglycidyl ether.

[0076] {resorcinol diglycidyl ether} Resorcinol diglycidyl ether has the formula (d1);

Chemical formula

[0077] {dicyclopentadiene type epoxy resin} The dicyclopentadiene type epoxy resin is not particularly limited as long as it has one or more dicyclopentadiene type skeletons represented by the formula (d2) in the molecule and one or more epoxy groups. The dicyclopentadiene type epoxy resin preferably has two or more epoxy groups.

Chemical formula

[0078] The dicyclopentadiene type epoxy resin may be used alone or in combination of two or more.

[0079] ​Examples of the dicyclopentadiene type epoxy resin include EPICLON series (HP7200L, HP7200, HP7200H, HP7200HH, HP7200HHH, etc.) manufactured by DIC Corporation; Tactix series (558, etc.) manufactured by Huntsman Advanced Materials; XD series (1000, 1000-1L, 1000-2L, etc.) manufactured by Nippon Kayaku Co., Ltd.; Adeka Resin series (EP-4088S, EP-4088L, etc.) manufactured by ADEKA Corporation; and the like.

[0080] {Trimethylolpropane polyglycidyl ether} Trimethylolpropane polyglycidyl ether has the formula (d3); [Chemical formula] It is not particularly limited as long as it is mainly composed of trimethylolpropane triglycidyl ether represented by the formula. For example, it may contain trimethylolpropane triglycidyl ether and by-products contained during the production of trimethylolpropane triglycidyl ether. Further, for example, it may be a mixture mainly composed of trimethylolpropane triglycidyl ether and containing any one or more of trimethylolpropane monoglycidyl ether, trimethylolpropane diglycidyl ether, and the condensation product of trimethylolpropane and epihalohydrin.

[0081] When the conductive adhesive contains an epoxy resin other than the component (A), particularly one or more epoxy resins selected from resorcinol diglycidyl ether, dicyclopentadiene type epoxy resin, and trimethylolpropane polyglycidyl ether, the content of the epoxy resin other than the component (A) (particularly one or more epoxy resins selected from resorcinol diglycidyl ether, dicyclopentadiene type epoxy resin, and trimethylolpropane polyglycidyl ether) is not particularly limited. It can be, for example, 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, 13.0 parts by mass or less, preferably 10.0 parts by mass or less, more preferably 7.0 parts by mass or less with respect to a total of 100 parts by mass of the components (A) to (D).

[0082] (Resin other than epoxy resin) The conductive adhesive of the present invention may contain a resin other than the epoxy resin. The resin other than the 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, etc. 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, etc. In the present invention, as resins other than epoxy resins, blocked urethane resins, polyurethane resins, polyvinyl acetal resins, resol-type phenolic 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 a base material, etc., blocked urethane resins, polyurethane resins, polyester resins, polyvinyl acetal resins, and acrylic resins are more preferable. As the resin other than the epoxy resin, one kind may be used alone, or two or more kinds may be used.

[0083] (Wetting dispersant) The conductive adhesive of the present invention may contain a wetting dispersant as necessary in order to prevent aggregation of the constituent components of the conductive adhesive. Specific examples of the wetting dispersant include, for example, the Solsperse series (9000, 12000, 17000, 20000, 21000, 24000, 26000, 27000, 28000, 32000, 35100, 54000, etc.) manufactured by Lubrizol Japan, the 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, the Ajisper series (PA111, PB711, PB821, PB822, PN411, etc.) manufactured by Ajinomoto Fine-Techno Co., Ltd., the 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 Japan, etc. As the wetting dispersant, one kind may be used alone, or two or more kinds may be used.

[0084] (Coupling agent) The conductive adhesive of the present invention may contain a coupling agent. Thereby, the short-time heating 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; and the like. 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, and the like. Examples of the aluminum coupling agent include aluminate compounds having an alkoxide group such as alkyl acetoacetate aluminum diisopropylate, and aluminate compounds having an acetylacetonate group such as aluminum trisacetylacetonate.Examples of zirconium coupling agents 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.

[0085] (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, silas 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.

[0086] (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 improve workability, coatability, handleability, etc. 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 or printed on a substrate and / or a viscosity that can appropriately impregnate an impregnated material such as a nonwoven fabric or a porous body.

[0087] 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 of these are mentioned.; The solvent may be used alone or in combination of two or more kinds.;

[0088] (Epoxy resin curing agent other than component (B) and component (D)) The conductive adhesive of the present invention may contain an epoxy resin curing agent other than component (B) (microcapsule type latent curing agent) and component (D) (thiol compound). Examples of such an epoxy resin curing agent include acid anhydride curing agents, phenol curing agents, amine curing agents, amide curing agents, and thermal cationic polymerization initiators, etc.; The epoxy resin curing agent other than component (B) and component (D) may be used alone or in combination of two or more kinds.;

[0089] The acid anhydride curing agent 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 above-mentioned 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.

[0090] 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 polyanhydride, 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 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.

[0091] 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; phenolic resins; phenol novolak resins; biphenyl aralkyl type phenolic 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 Industries Co., Ltd. The phenolic curing agent may be used alone or in combination of two or more.

[0092] 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 its molecular structure. For example, diethylenetriamine, triethylenetetramine, diethylaminopropylamine, menthanediamine, 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 mentioned. The amine curing agent may be used alone or in combination of two or more kinds.

[0093] The thermal cationic polymerization initiator is not particularly limited as long as it is a compound that generates cations 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. are mentioned. For example, TA-100, TA-100FG, IK-1, IK-1FG, etc. manufactured by San-Apro 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, etc. are mentioned. The thermal cationic polymerization initiator may be used alone or in combination of two or more kinds.

[0094] (Adhesion promoter) The conductive adhesive of the present invention may contain an adhesion promoter. Thereby, when the conductive adhesive is applied to a substrate, the adhesion to the substrate and the like can be improved. Examples of the adhesion promoter include triazole compounds, thiazole compounds, triazine compounds, polymers having functional groups (such as carboxylic acid groups, amino groups, hydroxyl groups) and salts thereof. Examples of the adhesion promoter include BYK series (4509, 4510, 4512, etc.) manufactured by BYK-Chemie Japan Co., Ltd. The adhesion promoter may be used alone or in combination of two or more.

[0095] (Rheology modifier) The conductive adhesive of the present invention may contain a rheology modifier (rheology control agent). Thereby, the rheology of the conductive adhesive can be adjusted, which can contribute to the improvement of workability and the like. Examples of the rheology modifier (rheology control agent) include rheology modifiers (rheology control agents) such as polyamide-based, aminoplast-based, polycarboxylic acid-based, urethane-based, cellulose-based, and inorganic layered compound-based. For example, RHEOBYK series (H370, H400, H600, H600VF, 100, 405, 410, 411, 415, 430, 431, 440, 7410ET, etc.) manufactured by BYK-Chemie Japan Co., Ltd.; DISPARON series (AQ-600, AQH-800, 3600N, 3900EF, etc.) manufactured by Kusumoto Chemicals, Ltd.; SN thickener series (613, 617, 618, 630, 634, 636, 621N, 623N, etc.) manufactured by San Nopco Ltd.; ADEKA NOL 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. The rheology modifier may be used alone or in combination of two or more.

[0096] (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).

[0097] 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. The curing accelerator (curing catalyst) may be used alone or in combination of two or more.

[0098] (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 Glycerol ED-502, Adeka Glycerol ED-502S, Adeka Glycerol ED-509E, Adeka Glycerol ED-509S, Adeka Glycerol 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.

[0099] (Conductive powder other than component (C)) The conductive adhesive of the present invention may contain a conductive powder other than the component (C) "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 powder other than the component (C) 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 a metal other than silver, nickel, copper, and gold.

[0100] (C) The shape of the conductive powder other than the component 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. (C) The conductive powder other than the component may be used alone or in combination of two or more.

[0101] (Antioxidant) The conductive adhesive of the present invention may contain an antioxidant. This can contribute to improving the 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.

[0102] Examples of the antioxidant include 2,2-methylenebis(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 side chain 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-phenylbenzenamine 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, 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; phosphite antioxidants such as 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; and the like. 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., and the like can be mentioned. The antioxidant may be used alone or in combination of two or more.

[0103] (Gap Adjuster (Spacer; Spacing Controller)) The conductive adhesive of the present invention may contain a gap adjuster (spacer; spacing controller). The gap adjuster (spacer; spacing controller) is used to control the thickness between adherends (the thickness of the adhesive layer). The gap adjuster (spacer; spacing 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 fibers, resin beads, and the like 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 High Presica series manufactured by Ube Eximer Co., Ltd., the Micro Pearl series manufactured by Sekisui Chemical Co., Ltd., the Tech Polymer series manufactured by Sekisui Chemical Products Co., Ltd., the Uni Beads series manufactured by Unitika Glass Beads Co., Ltd., etc. can be mentioned. The gap adjuster (spacer; interval controller) may be used alone or in combination of two or more.

[0104] <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 to 100 μm, and measuring with a resistivity meter (for example, "Loresta GP-MCP T610" (manufactured by Nitto Seiko Analytic Co., Ltd.), etc.).

[0105] <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 of (A) to (C) and other components used as required 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.

[0106] 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 it can also be carried out under an inert atmosphere.

[0107] <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 of the conductive adhesive is 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 mixture obtained by stirring and mixing the constituent components of the conductive adhesive used as the conductive adhesive as it is, 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, and if necessary, mixing a solvent such as an organic solvent to obtain a liquid conductive adhesive, casting and coating it 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, the film-like conductive adhesive can be obtained by impregnating a nonwoven fabric or the like, forming it on a release substrate, drying to remove the solvent, and then peeling it off from the release substrate.

[0108] 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 as 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-like conductive adhesive, etc. 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 bonding to form a conductive connection can be mentioned.

[0109] The conductive adhesive of the present invention can also be used substantially as an anisotropic conductive material. In addition, the conductive adhesive of the present invention can be used in a method of connecting electrodes in which it is formed between opposing electrodes on a substrate, and contact between the two electrodes and adhesion between the substrates are obtained by heating and pressurizing as 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, for example, even at a low temperature of 200°C or lower, it can enable conductive connection.

[0110] 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.

[0111] 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 then 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.

[0112] The conductive adhesive of the present invention can also be used, for example, as a conductive material for printing for forming a coating film such as wiring by printing on a substrate. 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 at the time of 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.

[0113] <Inductive heating curing of conductive adhesive> The conductive adhesive of the present invention can form a cured film with excellent 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. Further, in the conductive adhesive of the present invention, generation of droplets at the heated portion is suppressed after heat curing. Therefore, it is useful as a conductive adhesive for induction heating curing that is cured by induction heating (IH). 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.

[0114] 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 by causing the conductive substance to self-heat, it is possible to heat-cure the conductive adhesive at an arbitrary location in a short time. 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 by induction heating and bond non-conductive materials.

[0115] 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 the base material in the space portion of the coil, and an adjustment mechanism for independently adjusting the interval 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, and a method of performing induction heating (IH) using a device or the like are exemplified.

[0116] Since the conductive adhesive of the present invention can be cured by heating in a short time, 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 use a material with not very high heat resistance as the adherend. In addition, for example, by using a substrate provided with a conductive pad on a surface different from the surface provided with the conductive layer of the substrate such that at least a part of the conductive pad overlaps with the conductive layer, it is possible to more reliably bond (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 substrate 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 the conductive adhesive can be effectively heat-cured. At that time, since it is possible to suppress the temperature rise of the substrate, the conductive adhesive of the present invention can also be used to bond a substrate having low heat resistance by using heat curing of the conductive adhesive.

Example

[0117] 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”. In addition, all numerical values related to the blending amounts of the respective components in Tables 1 and 2 are “parts” (parts by mass).

[0118] [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 are values that result in a predetermined epoxy equivalent. Also, 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.

[0119] <Component (A)> ·BPA-EP1: Bisphenol A type epoxy resin (epoxy equivalent 948, glass transition temperature 100 ° C, solid at 25 ° C)

Chemical formula

Chem.

Chem.

Chem.

Chem.

[0120] <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)

[0121] <Component (C)> ·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%)

[0122] <Component (D)> ·PEMP: Pentaerythritol tetrakis(3-mercaptopropionate) ·MPGU: 1,3,4,6-Tetrakis(3-mercaptopropyl) glycoluril

[0123] <Other components> ·DCPD-EP: Dicyclopentadiene dimethanol diglycidyl ether (epoxy equivalent 165 g / eq, boiling point 426 °C, liquid at 25 °C)

Chem.

Chem.

Chem.

[0124] [Measurement and Evaluation of the Properties of the Conductive Adhesive] In the examples, the measurement and evaluation of the properties of the conductive adhesive ("droplets at the heated part after curing") were carried out as follows.

[0125] <Droplets at the Heated Part after Curing> A metal mask with a pattern of 2.3 mm × 1.1 mm and a thickness of 100 μm was used to apply a conductive adhesive onto a glass substrate. Next, a surface mount connector HH-1-G (manufactured by Mac Etch Co., Ltd.) was placed thereon, and induction heating (working distance (WD) 6.0 mm, gap 14.0 mm, output 15%, 3 seconds) was performed using an electromagnetic induction heating reflow (IH reflow) apparatus manufactured by Wonder Future Corporation to cure the conductive adhesive. After curing, the induction heating sites around the connector were visually observed, the generation of droplets at the induction heating sites was confirmed, and evaluation was carried out according to the following criteria. An A evaluation where no droplet generation is visually observed is considered qualified, and a D evaluation where droplet generation is visually observed is considered unqualified.

[0126] (Evaluation Criteria) A evaluation: No droplet generation is visually observed. D evaluation: Droplet generation is visually observed.

[0127] [Example 1] 4.9 parts of BPA-EP1, 1.6 parts of MCLCA, 5.2 parts of PEMP, 85.0 parts of SCC, and 3.3 parts of TMP-EP were added to a container, stirred and mixed to prepare a conductive adhesive. The properties of the obtained conductive adhesive ("droplets at the heated site after curing") were evaluated. The results are shown together with Table 1.

[0128] [Examples 2 to 19] A conductive adhesive was prepared in the same manner as in Example 1, except that the constituent components and their amounts used of the conductive adhesive were those shown in Table 1 and Table 2. The properties of the obtained conductive adhesive ("droplets at the heated site after curing") were evaluated. The results are shown together with Table 1 and Table 2.

[0129] [Table 1]

[0130] [Table 2]

[0131] From Table 1 and Table 2, it can be seen that the conductive adhesive according to the present invention cures by short-time heating and is excellent in the "droplet after curing heating part" evaluation. Therefore, it is possible to suppress the occurrence of product defects and the deterioration of the working environment caused by the generation of droplets at the heating part after curing.

Claims

1. The following (A) to (C); (A) One or more epoxy resins selected from biphenyl type epoxy resins, fluorene type epoxy resins, phenol novolak type epoxy resins, and bisphenol type epoxy resins, (B) Microcapsule type latent curing agent, and (C) 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. (D) Thiol compound, The conductive adhesive according to claim 1, further containing the same.

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

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