TW202204548A - Conductive adhesive composition - Google Patents

Abstract

An object of the present invention is to provide a conductive adhesive composition which is capable of realizing good adhesive strength while realizing good thickness between objects-to-be adhered when the blending amount of the conductive powder is relatively reduced. The conductive adhesive composition according to the present invention contains (A) a conductive powder and (B) a curable component, wherein the content of (B) the curable component is 20 parts by mass or more when (A) the conductive powder is taken as 100 parts by mass, and the conductive adhesive composition further contains (C) a spacer particle which has an average particle size (median diameter) larger than that of (A) the conductive powder. The average particle size (median diameter) of (C) the spacer particle is in the range of 10 to 60 [mu]m, and the CV value of (C) the spacer particle is 30% or less. When the total amount of (A) the conductive powder and (B) the curable component is taken as 100 parts by mass, the content of (C) the spacer particle is 0.01 part by mass or more and 30 parts by mass or less.

Description

Conductive Adhesive Composition

The present invention relates to a conductive adhesive composition, in particular, to a conductive adhesive composition capable of maintaining the thickness between adherends to be bonded.

In recent years, Electrically Conductive Adhesives (ECA) have been widely used in the field of electrical equipment, the field of electronic equipment, and the like. The conductive adhesive is basically composed of conductive powder and curable components, and various adherends can be conductively bonded by properly selecting the type or composition of the curable components, and by properly selecting the conductive powder type to adjust the conductivity.

For example, Patent Document 1 describes conductive bonding using at least one resin component (curable component) and conductive particles (conductive powder) of micron size and sub-micron size (conductive powder). agent. Examples of the conductive particles include copper, silver, platinum, palladium, gold, tin, indium, aluminum, or bismuth, and a particularly preferred example includes conductive particles composed of silver or conductive particles coated with silver.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2013-541611

The conductive powder used for the conductive adhesive is exemplified in Patent Document 1, and many noble metals or rare metals are used. Therefore, it turned out that if the content of the conductive powder is reduced for cost reduction, the viscosity characteristics of the conductive adhesive and the like are changed. When physical properties such as viscosity characteristics change, there is a possibility that the thickness of the conductive adhesive (the thickness of the adhesive layer) formed between the adherends cannot be properly maintained.

In a state where the adherends are conductively bonded by the conductive adhesive, if the thickness of the adhesive layer cannot be sufficiently maintained, the distance between the adherends cannot be properly maintained. In such a case, the long-term reliability may be affected in devices such as electrical equipment and electronic equipment including the adherend. Moreover, there exists a possibility that the change of a viscosity characteristic etc. may affect the adhesive strength of a conductive adhesive, and there exists a possibility that sufficient adhesive strength may not be achieved.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a conductive adhesive composition which can achieve a good thickness between adherends when the amount of the conductive powder to be blended is relatively reduced, and at the same time Good bond strength is achieved.

In order to solve the above-mentioned problems, the conductive adhesive composition according to the present invention has the following structure: (A) conductive powder and (B) curable component are contained, and when the above-mentioned (A) conductive powder is set to 100 mass When the content of the above-mentioned (B) curable component is 20 parts by mass or more, and the above-mentioned conductive adhesive composition further contains (C) spacers whose average particle size (median diameter) is larger than the above-mentioned (A) conductive powder Particles, the average particle diameter (median diameter) of the aforementioned (C) spacer particles is in the range of 10 to 60 μm, and the aforementioned (C) the CV value (Coefficient of Variation) of the spacer particles is 30% or less, when the aforementioned (A) Conductive powder and the above When the total amount of (B) curable components is 100 parts by mass, the content of the spacer particles (C) is 0.01 parts by mass or more and 30 parts by mass or less.

According to the above configuration, when the content of the conductive powder (A) in the conductive adhesive composition is relatively reduced, the conductive powder (A) is contained within a predetermined range and the average particle size is larger than the (A) conductive powder. (C) Spacer particles of A) conductive powder. Thereby, even if the viscosity characteristics of the conductive adhesive composition are changed due to the reduction of (A) the conductive powder, the conductive adhesive composition can be cured by the (C) spacer particles at the time of curing The layers then achieve a good thickness. Thereby, good electrical conductivity can be ensured and good adhesive strength can be achieved.

Furthermore, according to the above-mentioned configuration, when the conductive adhesive composition is applied, in addition to realizing a good thickness of the hardened adhesive layer, it is possible to suppress the hardened adhesive layer from spreading significantly. If the thickness of the hardened adhesive layer cannot be maintained and the thickness of the hardened adhesive layer is greatly expanded, the hardened adhesive layer will ooze out of the adherend, resulting in poor appearance. Furthermore, if the amount of the conductive adhesive is reduced in order to prevent bleeding of the cured adhesive layer, there is a possibility that the cured adhesive layer cannot obtain sufficient properties (adhesive strength, conductivity, reliability, etc.). According to the above-mentioned configuration, not only a good thickness of the hardened adhesive layer can be achieved, but also bleeding can be appropriately suppressed, so that the hardened adhesive layer can achieve good shape retention. Therefore, even if the compounding amount of the conductive powder (A) is relatively reduced, good shape retention and good adhesive strength can be achieved, so that poor appearance can be suppressed, and good properties can be achieved by hardening the adhesive layer.

In the conductive adhesive composition of the above-described configuration, the conductive powder (A) may be at least any one of silver powder, silver alloy powder, and silver-coated powder.

In addition, in the conductive adhesive composition of the above-mentioned structure, the curable component (B) may be any one of acrylic resin, epoxy resin, and polysiloxane resin, or may be cured by curing. Curable compositions of these resins.

Moreover, it may be a structure in which the conductive adhesive composition of the said structure is apply|coated to a base material by a printing machine or a dispenser (dispenser), and it may be used.

Moreover, it may be a structure in which the conductive adhesive composition of the said structure is used for the bonding of the solar cell which comprises a solar cell module.

In the present invention, according to the above configuration, it is possible to provide a conductive adhesive composition which exhibits "when the amount of the conductive powder to be blended is relatively reduced, a good thickness can be achieved between the adherends, and at the same time, the Achieving the effect of good bonding strength.

11: Printing Graphics

11a: Wiring pattern

11b: Terminal

11c: Wiring Department

11d: Pad Pattern

12: Alumina substrate

13: Rivets

20: Solar cell module

21: Solar cell unit

22: Hardening the adhesive layer

30: Solar cell module

31: Solar cell unit

32: Internal connection line

FIG. 1 is a plan view schematically showing the configuration of a conductor pattern for evaluation used in evaluation of the electrical conductivity and adhesive strength of the conductive adhesive composition after curing in the examples and the like of the present disclosure.

FIG. 2 is a partial cross-sectional view schematically showing a state in which a rivet is attached to the pad constituting the conductor pattern for evaluation shown in FIG. 1 .

Part (A) of FIG. 3 is a schematic side view showing the configuration of a solar cell module to which an example of the conductive adhesive composition of the present disclosure is applied, and part (B) of FIG. 3 is a conventional conventional solar cell module Schematic side view of the composition of the group.

Hereinafter, an example of a preferred embodiment of the present disclosure will be specifically described. The conductive adhesive composition of the present disclosure contains (A) conductive powder and (B) curable component, and when (A) conductive powder is mixed When it is 100 parts by mass, the content of the (A) conductive powder is relatively reduced so that the content of the (B) curable component is 20 parts by mass or more. Furthermore, the conductive adhesive composition of the present disclosure contains (C) spacer particles having an average particle diameter (median diameter) larger than that of the conductive powder (A). The (C) spacer particles have an average particle diameter (median diameter) in the range of 10 to 60 μm, and a CV value (Coefficient of Variation) of 30% or less. Furthermore, when the (A) conductive powder is added When the total amount of (B) curable components is 100 parts by mass, the content of the (C) spacer particles is in the range of 0.01 parts by mass or more and 30 parts by mass or less.

[(A) Conductive powder]

The (A) conductive powder contained in the conductive adhesive composition of the present disclosure is not particularly limited as long as it is a powder (particle) having conductivity. The material is also not particularly limited, but from the viewpoint of achieving good conductivity, a relatively low-resistance conductive material is exemplified. Specifically, for example, gold, silver, copper, and alloys of these can be preferably used. Among these, a powder containing silver can be suitably used in particular.

(A) The specific material composition of the conductive powder is not particularly limited, and examples include powders substantially composed of one metal (or conductive material), alloy powder composed of a plurality of metals, and powders composed of metals and nonmetals. The formed composite powder, etc. The composite material powder includes, for example, a coating powder formed by coating a surface of a non-metallic powder or a metal powder with a relatively high electrical resistance and a metal having a relatively low electrical resistance.

When silver is used as the material of the (A) conductive powder, for example, silver powder, silver alloy powder, silver-coated copper powder, silver-coated nickel powder, silver-coated aluminum powder, or silver-coated glass powder, etc. are mentioned. That is, in the present disclosure, as a preferable example of the (A) conductive powder, at least any one of silver powder, silver alloy powder, and silver coating powder can be mentioned.

(A) The shape of the conductive powder is also not particularly limited, and various shapes can be selected and used. Typical examples include powders having a substantially spherical shape (spherical powders) and powders (flakes) in the shape of flakes. powder), tree-like powder, etc. Although the specific composition of the conductive adhesive composition varies depending on various conditions such as specific applications and specific physical properties, it is preferable to use a combination of spherical powder and flake powder. By combining and using the powders of different shapes in this way, the (A) conductive powder can be well filled after the hardening of the (B) curable component.

In the present disclosure, the so-called flake powder refers to a powder having a shape close to a flat plate or a thin rectangular parallelepiped when viewed as a whole even if there are local irregularities and deformation is seen. In addition, the so-called flaky shape may be changed to a flake shape or a scaly shape. In addition, the spherical powder in the present disclosure may be a powder having a three-dimensional shape closer to a rectangular parallelepiped than a cube when viewed as a whole even if there are local irregularities and deformation is seen. In addition, the so-called spherical shape may be changed to a granular shape.

(A) The specific physical properties of the conductive powder are also not particularly limited, and the average particle diameter, specific surface area, tap density and the like may be within a known range. Among them, the average particle diameter (median diameter) is, for example, in the range of 0.1 to 10 μm. (A) When the conductive powder is flake powder, the average particle size may be in the range of 2 to 20 μm.

The conductive adhesive composition of the present disclosure contains (C) spacer particles in addition to (A) conductive powder and (B) curable component which are basic components. The average particle diameter of the (A) conductive powder may be relatively smaller than the average particle diameter of the (C) spacer particles. In addition, the method for measuring the average particle diameter of the conductive powder (A4) is not particularly limited, but in the present disclosure, a method of measuring using a particle size distribution measuring apparatus is employed as described in the examples described later.

(A) When the conductive powder is a coating powder, the coating amount of the conductive material to be coated (metals such as gold, silver, copper, etc.) is not particularly limited. When the mass of the raw powder uncoated with the conductive material is set to 100% by mass, the coating amount of the conductive material can be, for example, in the range of 5 to 30% by mass, or 6% by mass. Within the range of 25 mass %, it may be within the range of 7.5 to 20 mass %. In the examples described later, the coating amount of silver in the silver-coated copper powder (silver powder 3, abbreviated as A3) was 10 mass % (refer to Table 1).

In the conductive adhesive composition of the present disclosure, only one type of the conductive powder (A) may be used, or two or more types of powders may be appropriately combined and used. The type of (A) conductive powder referred to here includes not only difference in material, difference in shape (spherical or flake), but also difference in average particle size and the like. In the examples to be described later, (A) the conductive powder may be an example in which a spherical silver powder (silver powder 1, abbreviated as A1) and a flake silver powder (silver powder 2, abbreviated as A2) are combined, or This is an example in which spherical silver powder (silver powder 1, abbreviated as A1) and spherical silver-coated copper powder (silver powder 3, abbreviated as A3) are combined (see Table 1).

In addition, in the conductive adhesive composition of the present disclosure, "other conductive powder" can be used in combination as (A) conductive powder, and the "other conductive powder" is relatively low in gold, silver, copper, etc. Resistors made of materials other than metal materials. Such "other conductive powders" include, for example, nickel powder, aluminum powder, lead powder, carbon powder, and the like.

(A) The manufacturing method of the electroconductive powder is not specifically limited, A well-known method can be used. For example, in the case of spherical powder, powder produced by a wet reduction method, spherical powder produced by other known methods such as electrolysis or atomization method, etc. There is no particular limitation. Alternatively, in the case of flake powder, the spherical powder produced by a known method can be used as the raw powder, and the raw powder can be subjected to a known mechanical treatment to produce flake powder. The physical properties such as particle size and degree of aggregation of the original powder can be determined according to the purpose of use of the conductive adhesive composition (the type of electrodes, wiring, etc., or the type of electronic parts or electronic devices equipped with such electrodes or wirings). Choose appropriately.

[(B) sclerosing component]

As long as the (B) curable component contained in the conductive adhesive composition of the present disclosure can electrically connect the (A) conductive powders to each other by hardening, and can exert the function of the curable adhesive bonded to the adherend function can be. Typical examples include thermosetting resins. Examples of general thermosetting resins include acrylic resins, epoxy resins, silicone resins, phenol resins, polyester resins, polyurethane resins, melamine resins, polyimide resins, and the like. Among these, in particular, any resin of acrylic resin, epoxy resin, and polysiloxane can be mentioned. In addition, depending on the type of resin, the (B) curable component before curing may be a monomer or a prepolymer instead of a polymer. Therefore, in the present disclosure, the (B) curable component includes not only a curable resin but also a curable composition that becomes a resin by curing.

In the present disclosure, the specific type of the acrylic resin suitable for use as the (B) curable component is not particularly limited. In the examples to be described later, three acrylic compounds are used in combination as the curable component (B), but one or two kinds of acrylic compounds may be used, four or more kinds of acrylic compounds may be used, or a combination of acrylic compounds capable of Other monomers or prepolymers of compound polymerization.

Typical acrylic compounds include, for example, (meth)acrylate (acrylate or methacrylate), ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, Amyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isoamyl methacrylate (meth)acrylate [(meth)acrylate isopentyl methacrylate], isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, (meth)acrylate ) Chain alkyl esters of (meth)acrylates such as dodecyl acrylate [lauryl (meth)acrylate], stearyl (meth)acrylate [octadecyl (meth)acrylate], etc.; (meth) Cyclic alkyl esters of (meth)acrylic acid such as cyclohexyl acrylate, isocamphenyl (meth)acrylate; 1-methoxyethyl (meth)acrylate, ethoxy-diethylene glycol (meth)acrylic acid (meth)acrylates containing alkoxy groups such as methoxy-triethylene glycol (meth)acrylate; benzyl (meth)acrylate, phenyl (meth)acrylate, (meth)acrylate Phenoxyethyl acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, nonyl Phenoxytetraethylene glycol (meth)acrylate and other (meth)propane Aryl alkenoates; phenyl glycidyl ether acrylate, hexamethylene diisocyanate amine ester prepolymer, neotaerythritol triacrylate hexamethylene diisocyanate amine ester prepolymer, neotaerythritol triacrylate (Meth)acrylate-based urethane prepolymers, such as ester toluene diisocyanate amine ester prepolymer, dipivalerythritol pentaacrylate hexamethylene diisocyanate amine ester prepolymer; bisphenol A diglycidyl group Ether (meth)acrylic acid adduct, 2-hydroxy-3-phenoxypropyl (meth)acrylate and other (meth)acrylate epoxy esters; (meth)acrylate dimethylaminoethyl ester , (meth) dimethylaminopropyl (meth) acrylate and other (meth) acrylic acid amino esters; polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate (Meth)acrylate, trimethylolpropane tri(meth)acrylate, di(trimethylolpropane)tetra(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene diethylene glycol Polyfunctional (meth)acrylates such as alcohol di(meth)acrylates; etc. Only one type of these acrylic compounds may be used, or two or more types may be appropriately used in combination.

In the examples to be described later, three acrylic compounds were used in combination as the (B) curable component. Among them, compound 1 (abbreviated as B1) is isoamyl acrylate, compound 2 (abbreviated as B2) is phenoxyethyl acrylate, and compound 3 (abbreviated as B3) is phenyl glycidyl ether acrylate hexamethylene Diisocyanate urethane prepolymer (refer to Table 2). Therefore, in the present disclosure, when the (B) curable component is an acrylic resin (or a curable composition that becomes an acrylic resin by curing), (meth)acrylic acid alkyl ester, (meth)acrylic acid aromatic A combination of ester and (meth)acrylate-based urethane prepolymer is a preferable example. When a plurality of acrylic compounds are used in combination as the (B) curable component, the mixing ratio (mixing ratio) of each acrylic compound is not particularly limited.

(B) When the curable component is an acrylic resin (or a curable composition which becomes an acrylic resin by curing), a polymerization initiator can be used. The specific polymerization initiator is not particularly limited, and representative examples thereof include organic peroxides and azo initiators.

Representative organic peroxides include tert-butyl-2-ethylhexanoate peroxide, tert-hexyl-isopropyl-peroxide, tert-butyl-benzoate peroxide, tert-butyl peroxide Tert-butyl neodecanoate, tert-butyl laurate peroxide, tert-butyl cumyl peroxide, tert-butyl peroxy acetate, peroxy-2-ethylhexanoic acid Peroxyesters such as 1,1,3,3-tetramethylbutyl ester; ketone peroxides such as methyl ethyl ketone peroxide; 1,1,3,3-tetramethylbutyl hydroperoxide , cumene hydroperoxide, hydrogen peroxide, p-menthane and other hydroperoxides; dialkyl peroxides such as di-tert-butyl peroxide; etc.

In addition, typical azo-based initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis Azobis(2,4-dimethylvaleronitrile), 1,1'-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2'-azobisisobutyrate, 2- (Aminocarboxyazo)isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, azobis-tertiary octane, azobis-tertiary Butane etc.

Only one type of these polymerization initiators may be used, or two or more types may be appropriately used in combination. Moreover, the usage-amount and usage conditions etc. of a polymerization initiator are not specifically limited either, What is necessary is just to use a well-known usage-amount or usage condition. In the examples described later, tert-butyl-2-ethylhexanoate peroxide was used as a polymerization initiator (refer to Table 2).

In the present disclosure, as the curable component (B), epoxy resins can be suitably used in addition to the aforementioned acrylic resins. As a specific epoxy resin, the polyvalent epoxy resin which has two or more oxirane rings (epoxy groups) in 1 molecule is mentioned.

For example, combining epichlorohydrin with novolaks such as novolac and cresol novolak, polyhydric phenols such as bisphenol A, hydrogenated bisphenol A, bisphenol F, bisphenol AD, resorcinol, ethylene glycol, The glycidyl ether type obtained by the reaction of polyols such as neopentyl glycol, glycerol, trimethylolpropane, neopentylerythritol, triethylene glycol, polypropylene glycol, etc.; Glycidylamine type obtained by the reaction of polyamine compounds such as ethylenetetramine and aniline; Glycidyl ester type obtained by compound reaction; alicyclic type synthesized by oxidation of olefin, etc. These epoxy resins may be used alone or in combination.

If the (B) curable component is an epoxy resin, a curing agent can be used when curing. The hardener used in the present disclosure is not particularly limited as long as it hardens the aforementioned epoxy resin.

Specific curing agent systems include, for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl Anhydrides such as hexahydrophthalic anhydride and succinic anhydride; imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1-benzyl 2-methylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-aminoethyl-2-methylimidazole, 1-methylimidazole, Imidazoles such as 2-ethylimidazole; dimethyloctylamine, dimethyldecylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylpalmitylamine, dimethylstearin amine, dimethyl behenyl amine, dilauryl monoethyl amine, methyl didecyl amine, methyl dioleyl amine, triallyl amine, triisopropanolamine, triethylamine, 3-(Dibutylamino)propylamine, tri-n-octylamine, 2,4,6-paradimethylaminomethylphenol, triethanolamine, methyldiethanolamine, diazabicyclodeca Tertiary amines such as monoene; boron trifluoride ethyl ether, boron trifluoride phenol, boron trifluoride hexahydropyridine, boron trifluoride acetate, boron trifluoride monoethylamine, boron trifluoride Triethanolamine, boron trifluoride monoethanolamine, etc. Lewis acid containing boron fluoride or its compounds; AMICURE series PN-23 or MY-24 sold by Ajinomoto FINE TECHNO Co., Ltd. Amine adducts such as FUJICURE series FXR-1020 or FXR-1030 sold by Co., Ltd. in the market; dicyandiamide; etc.

Only one type of these curing agents may be used, or two or more types may be appropriately used in combination. Moreover, the usage-amount and usage conditions etc. of a hardener are also not specifically limited, What is necessary is just to use a well-known usage-amount or usage condition.

In the present disclosure, as the curable component (B), in addition to the aforementioned acrylic resin or epoxy resin, a polysiloxane resin can be suitably used. Specific polysiloxane resins include known thermosetting polysiloxane resins.

Typical thermosetting polysiloxanes include, for example, silanes, polysiloxane oligomers, polysiloxanes, organosiloxanes, diorganosiloxanes, organopolysiloxanes, and diorganopolymers. A skeleton structure such as siloxane, which has one or more reactive functional groups. The aforementioned skeleton structure may be a straight chain structure or may have a branched chain.

In addition, the reactive functional group includes a hydroxyl group, an alkenyl group, a hydrosilyl group, a (meth)acryloyl group, an epoxy group, an amino group, and a carbitol group bonded to a silicon atom contained in the aforementioned skeleton structure. , mercapto group, carboxyl group, phenol group, etc., but are not particularly limited. Moreover, in addition to the said reactive functional group, the said skeleton structure may have functional groups, such as an alkyl group, an alkenyl group, and an aromatic group.

In the present disclosure, the thermosetting silicone resin used as the (B) curable component may have a single skeleton structure and a single reactive functional group, or may have a plurality of skeleton structures and a plurality of Reactive functional groups. In addition, the reactive functional group is only required to contain one or more reactive functional groups in one skeleton structure as described above, in other words, one molecule of polysiloxane resin (having any skeleton structure) only needs to have at least one reactive functional group. In addition, the reactive functional group may be at the terminal of the skeleton structure, or may be at the side chain, and may be attached to any of the terminal and the side chain.

In addition, in the present disclosure, the (B) curable component may be used in combination with an appropriate combination of acrylic resin, epoxy resin, and polysiloxane resin, or may be used in combination with a thermosetting resin other than these ( It can be used as a curable composition of resin by hardening. The mixing ratio (mixing ratio) at the time of combination is also not particularly limited.

[(C) Spacer particles]

The conductive adhesive composition according to the present disclosure contains the above-mentioned (A) conductive powder and (B) curable component as basic components, and further contains (C) spacer particles. The (C) spacer particles have an average particle diameter (median diameter) larger than that of the (A) conductive powder.

(C) The average particle diameter (median diameter) of the spacer particles is not particularly limited, but as described above, when the conductive powder (A) is spherical powder, the preferred average particle diameter is in the range of 0.1 to 10 μm, Therefore, (C) the average particle diameter of the spacer particles may be in the range of 10 to 60 μm (or may exceed 10 μm and be 60 μm or less). In addition, (A) when the conductive powder is a flake powder, the preferred average particle size is in the range of 2 to 20 μm, so (C) the average particle size of the spacer particles can be in the range of 20 to 60 μm ( Or it may be over 20 μm and below 60 μm).

When the conductive adhesive composition is hardened to form a hardened adhesive layer that enables the adherends to be conductively bonded to each other, although the average particle size of the (C) spacer particles depends on the specific thickness required for the hardened adhesive layer Although different, (C) the lower limit of the average particle diameter of the spacer particles may be 30 μm or more. Therefore, the lower limit of the average particle diameter of the (C) spacer particles can be appropriately set according to the average particle diameter of the (A) conductive powder to be used together.

On the other hand, the upper limit of the average particle diameter of the (C) spacer particles is preferably 60 μm or less.

When the average particle diameter of the (C) spacer particles exceeds 60 μm, the adhesive strength tends to decrease in the cured adhesive layer which is a cured product of the conductive adhesive composition. In addition, the method for measuring the average particle size of the (C) spacer particles is not particularly limited, but in the present disclosure, the same as the average particle size of the (A) conductive powder is used as described in the examples described later. A method for measuring by a particle size distribution measuring device.

(C) The material of the spacer particles is not particularly limited, and it is sufficient if it is a material having shape stability, and the shape stability is that after the conductive adhesive composition is cured, the cured adhesive layer can still achieve a sufficient thickness. Typical materials include glass; ceramics such as zirconia (ZrO ₂ ), alumina (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), silicon carbide (SiC), and silicon nitride (Si ₃ N ₄ ). ; Acrylic resin, nylon resin, phenol resin, polysiloxane and other resins; etc.

In addition, a metal may be used as the (C) spacer particles, but when the (C) spacer particles are made of a metal, they can function as the (A) conductive powder. In the present disclosure, since it is necessary to achieve a composition in which the content of the conductive powder (A) is relatively reduced, it is preferable that the spacer particles (C) are not metal particles, but glass, ceramics, and resins as described above are used. Such non-conductive materials.

However, in accordance with the aforementioned conditions for the conductive adhesive composition, in order to make the conductivity of the cured adhesive layer more favorable, the surface of the (C) spacer particles may be coated with a metal material. As such a metal material, gold, silver, copper, or alloys of these, which are the same as those exemplified as the material of the conductive powder (A), can be exemplified. The coating amount (coating amount) of the metal material to coat the surface of the spacer particles (C) is not particularly limited, and can be determined according to the conductivity required for the hardened adhesive layer (hardened product), the cost associated with the coating, (C) Various conditions such as the influence of the spacer particles on the shape stability are appropriately set.

In the Examples to be described later, a total of ten kinds of particles were used as (C) spacer particles. Among them, spacer 1 (abbreviated as C01), spacer 7 (abbreviated as C07) and spacer 10 (abbreviated as C10) are particles made of acrylic resin (acrylic particles), spacer 4 (abbreviated as C04), spacer 6 (C06 for short), spacer 8 (C08 for short) and spacer 9 (C09 for short) are particles made of glass (glass particles), and spacer 5 (C05 for short) is particles made of zirconia (zirconia particles). In addition, the spacer 2 (abbreviated as C02) and the spacer 3 (abbreviated as C03) are both silver-coated particles, the particle-based spacer 2 serving as the core is a glass particle, and the spacer 3 is an acrylic particle.

(C) The shape of the spacer particles may be spherical. A shape other than a spherical shape can also be used, but a spherical shape is preferable from the viewpoint of realizing the thickness of the hardened adhesive layer more stably. If it is a shape other than spherical, the (C) spacer particles will have a long direction, and the direction of the (C) spacer particles in the hardened adhesive layer may cause unevenness in the thickness of the layer. .

The other physical properties of the (C) spacer particles are not particularly limited, but the CV value (Coefficient of Variation) of the (C) spacer particles is preferably 30% or less. The CV value is an index indicating the unevenness of the particle size distribution of the particles, and it can be judged that the smaller the value is, the less the unevenness of the particle size distribution is, and the higher the uniformity is. When the CV value of the (C) spacer particles exceeds 30%, the unevenness of the particle size distribution of the (C) spacer particles becomes large, and the shape retention of the conductive adhesive composition may decrease. In such a case, there is a possibility that the hardened adhesive layer may expand beyond expectations, or the thickness of the hardened adhesive layer may not be sufficiently secured. In addition, the evaluation method of a CV value is also not specifically limited, In this disclosure, evaluation is performed according to the method demonstrated in the Example mentioned later.

[Manufacture and use of conductive adhesive composition]

The method for producing the conductive adhesive composition of the present disclosure is not particularly limited, and a method known in the field of the conductive adhesive composition can be suitably used. A typical example is a method of mixing the above-mentioned components at a predetermined mixing ratio (quality basis), and using a known kneading apparatus to form a paste. As a kneading apparatus system, a three-roll mill etc. are mentioned, for example.

In the conductive adhesive composition of the present disclosure, as described above, it is preferable that the compounding amount (content) of the (A) conductive powder is relatively small. Specifically, although the conductive adhesive composition of the present disclosure has (A) conductive powder and (B) curable component as basic components, (A) conductive The lower limit of the content of the (B) curable component may be 20 parts by mass or more, 25 parts by mass or more, 30 parts by mass or more, when the powder is set to 100 parts by mass or more as a standard. 35 parts by mass or more.

If the content of the (B) curable component is less than 20 parts by mass, the content of the (A) conductive powder in the conductive adhesive composition will relatively increase, in other words, the content of the (A) conductive powder cannot be Said to be relatively reduced. On the other hand, the upper limit of the content of the (B) curable component is not particularly limited, and may be determined according to The content of the (B) curable component is set to be slightly larger to the extent that the required conductivity can be achieved under the aforementioned conditions of the conductive adhesive composition.

In the conductive adhesive composition of the present disclosure, when the total amount of the basic components [(A) the total amount of the conductive powder and (B) the curable component] is set to 100 parts by mass, the amount of ( C) The content (mixing amount) of the spacer particles may be in the range of not less than 0.01 parts by mass and not more than 30 parts by mass (0.01 to 30 parts by mass).

If the content of the (C) spacer particles is less than 0.01 part by mass, there is a possibility that the effects (good shape retention and good shape retention in the hardened adhesive layer) by blending the (C) spacer particles may not be sufficiently obtained. the realization of the subsequent strength). In addition, when the content of the (C) spacer particles exceeds 30 parts by mass, not only the effect corresponding to the compounding amount cannot be obtained, but there may be too many (C) spacer particles and the adhesive strength of the hardened adhesive layer may decrease.

Moreover, in the conductive adhesive composition of the present disclosure, the conductive adhesive may be contained in the conductive adhesive other than the above-mentioned components (A) conductive powder, (B) curable component, and (C) spacer particles as required. Various additives well known in the field of formulations. Although this additive is not specifically limited, Specifically, a solvent, a leveling agent, an antioxidant, an ultraviolet absorber, a silane coupling agent, a defoaming agent, a viscosity modifier, etc. are mentioned, for example. These additives can be added within a range that does not inhibit the effects of the present disclosure.

Moreover, the method of forming the pattern which becomes a hardened adhesive layer by the electroconductive adhesive composition of this disclosure is not specifically limited, Various well-known formation methods can be used suitably. A typical forming method is shown in the examples described later, and a screen printing method can be used, and printing methods such as a gravure printing method, an offset printing method, an inkjet method, a dispenser method, and a dipping method can also be applied. Therefore, the conductive adhesive composition of the present disclosure can be used as long as it can be coated on a substrate by a printer or a dispenser.

The conductive adhesive composition of the present disclosure can be widely used in the formation of high-precision electrodes, wiring, etc., and the bonding of electronic parts. Specifically, for example, it can be suitably used for collector electrodes of solar cells; internal electrodes or external electrodes of chip-type electronic parts; RFID (Radio Frequency IDentification), electromagnetic wave shielding, oscillator bonding, membrane switches, touch panels, or Electrode, wiring or bonding of parts used in electroluminescence, etc.

Among the aforementioned uses, the conductive adhesive composition of the present disclosure is particularly suitable for use in the field of solar cells. Specifically, the conductive adhesive composition of the present disclosure can be suitably used for bonding of solar cell modules, for example.

As shown in part (B) of FIG. 3 , conventionally, the solar cell module 30 has a configuration in which a plurality of solar cells 31 are connected by a strip-shaped wiring member called an internal connection wire 32 . On the other hand, in recent years, as shown in part (A) of FIG. 3 , a plurality of solar cells have been proposed such that the lower surface of the long side of any solar cell 21 overlaps the upper surface of the long side of the other solar cell 21 . The solar cell module 20 of the configuration in which the battery cells 21 are partially overlapped in order and arranged obliquely. In such a solar cell module 20 , a conductive adhesive is used to connect the solar cells 21 to each other instead of the internal connection wires 32 .

Here, when the long sides of the solar battery cells 21 are bonded to each other, if the conductive adhesive spreads from the bonding region and oozes out, there is a possibility that a short-circuit or the like may occur in the solar battery module 20 . Furthermore, if the thickness of the cured product of the conductive adhesive (the cured adhesive layer 22 ) cannot be sufficiently secured, there is a possibility that the inclination angle cannot be properly adjusted when bonding the solar cell 21 .

As described above, the conductive adhesive composition of the present disclosure contains (C) spacer particles in addition to (A) conductive powder and (B) curable component. In this way, not only the hardening after hardening is followed by The layer can ensure a good thickness, and can also effectively suppress the possibility of the hardened adhesive layer 22 spreading out from the adhesive area and oozing out.

If the thickness of the hardened adhesive layer 22 cannot be maintained and the thickness is greatly expanded, the hardened adhesive layer 22 may bleed from the adherend, resulting in poor appearance. Furthermore, if the amount of the conductive adhesive is reduced in order to prevent the exudation of the cured adhesive layer 22 , sufficient properties (adhesion strength, conductivity, reliability, etc.) may not be obtained in the cured adhesive layer 22 . According to the present disclosure, by blending the (C) spacer particles in an appropriate amount, the hardened adhesive layer 22 can achieve not only a good thickness but also good shape retention so-called bleed-out suppression. Therefore, appearance defects can be suppressed, and the hardened adhesive layer can achieve good characteristics.

Furthermore, by appropriately containing (C) spacer particles in the conductive adhesive composition of the present disclosure, the hardened adhesive layer 22 can achieve good electrical conductivity while achieving good adhesive strength. Therefore, the conductive adhesive composition of the present disclosure can be particularly favorably applied to the manufacture of the solar cell module 20 shown in part (A) of FIG. 3 .

[Example]

The present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Those having ordinary knowledge in the technical field to which the present invention pertains can make various changes, corrections, and changes without departing from the scope of the present invention. In addition, the measurement/evaluation of physical properties etc. in the following Examples and Comparative Examples was carried out as follows.

[Evaluation method of conductive powder and spacer particles]

(1) Median diameter

The median diameter of (A) conductive powder or (C) spacer particles was evaluated by a laser diffraction method. Weigh 0.3 g of (A) conductive powder or (C) sample of spacer particles into a 50 ml beaker, add 30 ml of isopropyl alcohol, and process with an ultrasonic cleaner (USM-1, manufactured by AS ONE Co., Ltd.) 5 minutes to make it The particle size distribution analyzer (MICROTRACK MT3300EXII manufactured by Nikkiso Co., Ltd.) was used to measure and evaluate the median diameter.

(2) CV value

The CV value (Coefficient of Variation) was calculated by dividing the standard deviation of the particle diameter of the (C) spacer particles by the median diameter of the (C) spacer particles obtained by the method described above.

[Evaluation of Shape after Attachment of Conductive Adhesive Composition]

Using a dispenser, the conductive adhesive compositions of Examples or Comparative Examples were coated on an alumina substrate so as to have a diameter of 60 μm and a height of 200 μm, and a glass substrate with a weight of 5 g was laminated thereon. The substrate laminate was heated at 150° C. for 30 seconds using a hot plate to harden the conductive adhesive composition (formation of a hardened adhesive layer). Thereby, the test piece for shape evaluation after sticking was obtained.

The spread of the cured adhesive layer was measured from the surface of the test piece on the glass substrate side with an optical measuring microscope. When the diameter of the hardened adhesive layer was less than 900 μm, it was evaluated as “○”, and when it was 900 μm or more, it was evaluated as “×”. Furthermore, the thickness of the hardened adhesive layer was measured with an optical measuring microscope. When the thickness of the hardened adhesive layer was 50 μm or more, it was evaluated as “○”, when it was 30 μm or more and less than 50 μm, it was evaluated as “△”, and when it was less than 30 μm, it was evaluated as “×”.

[Evaluation of Conductivity and Adhesion Strength of Conductive Adhesive Composition]

As shown in FIG. 1 , the conductive adhesive composition of the example or the comparative example was printed on an alumina substrate 12 into a printed pattern 11 using a printer. The printed pattern 11 is composed of one wiring pattern 11a and five pad patterns 11d. The wiring pattern 11a has rectangular terminals 11b at both ends, the wiring portion 11c is bent, and the aspect ratio of the wiring portion 11c is 75. The five pad patterns 11d are arranged adjacent to the wiring pattern The shapes 11a are arranged in a row, each in a square shape of 2mm x 2mm.

Next, as shown in FIG. 2 , an aluminum rivet 13 is placed on the pad pattern 11d (2 mm×2 mm) on the alumina substrate 12 , and the aluminum rivet 13 has a circular fixing surface with a diameter of 4 mm. The alumina substrate 12 on which the rivets 13 were placed was heated at 150° C. for 30 seconds using a hot plate to harden the conductive adhesive composition (print pattern 11 ) (form a hardened adhesive layer) to obtain electrical conductivity and Next, test pieces for strength evaluation.

The conductivity of the hardened adhesive layer was evaluated by the volume resistivity of the wiring pattern 11a. Specifically, the film thickness of the wiring pattern 11a was measured with a surface roughness meter (SURFCOM 480A manufactured by Tokyo Seiki Co., Ltd.), and the electrical resistance was measured with a digital multimeter (R6551 manufactured by ADVANTEST Co., Ltd.). The volume resistivity (Ω·cm) of the wiring pattern 11a was calculated by equalizing the film thickness, electrical resistance and the aspect ratio of the wiring portion 11c, and the volume resistivity was evaluated as the resistance value of the cured adhesive layer.

The adhesion strength of the hardened adhesion layer is evaluated according to the adhesion of the rivet 13 to the pad pattern 11d. Specifically, a shear force was applied in the horizontal direction to the rivet 13 assembled to the pad pattern 11d, and the strength of the rivet 13 when separated from the pad pattern 11d was measured. The adhesive strength of the hardened adhesive layer was evaluated by assigning "○" when the strength was 15 MPa, "△" when the strength was 5 MPa or more and less than 15 MPa, and "x" when the strength was less than 5 MPa.

[(A) Conductive Powder, (B) Curable Component, and (C) Spacer Particles]

In the following Examples or Comparative Examples, two powders among the three powders shown in Table 1 below were used as the (A) conductive powder. In addition, the abbreviations of the following Table 1, Table 2, and Table 3 are used to show the components of Examples or Comparative Examples in Tables 4 to 8.

[Table 1]

In addition, in the following Examples or Comparative Examples, three acrylic compounds shown in the following Table 2 were used in combination as the (B) curable component. In addition, the polymerization initiator of (B) curable component used what was shown in following Table 3.

[Table 2]

In addition, in the following Examples or Comparative Examples, any one of ten types shown in the following Table 3 was used as the (C) spacer particle.

[table 3]

(Example 1)

As shown in Table 4, spherical silver powder 1 (abbreviated as A1) and flake silver powder 2 (abbreviated as A2) shown in Table 1 were used as (A) conductive powder, and resin 1 (abbreviated as B1), Resin 2 (abbreviated as B2) and resin 3 (abbreviated as B3) were used as (B) conductive powders, and these were prepared in the amounts (parts by mass) shown in Table 4. These components are kneaded in a three-roll mill. After kneading, use the spacer 1 (abbreviated as C01) shown in Table 3 as (C) the spacer particles, and prepare the spacer 1 with the preparation amount (parts by mass) shown in Table 4, and mix with an autorotating revolution mixer. . Thereby, the conductive adhesive composition of Example 1 was prepared (manufactured).

For the obtained conductive adhesive composition, a test piece for shape evaluation after sticking and a test piece for electrical conductivity and adhesive strength evaluation were prepared as described above, and the cured adhesive layer ( Conductive adhesive composition) expansion, thickness, bonding strength and volume resistivity. The results are shown in Table 4. In addition, in Table 4 (and Tables 5 to 8), the expansion of the cured adhesive layer is described as "adhesive layer expansion", the thickness of the cured adhesive layer is described as "adhesive layer thickness", and the volume resistivity is described as "resistance".

(Examples 2 to 4)

The conductive adhesives of Examples 2 to 4 were prepared (produced) in the same manner as in Example 1, except that the type of (C) spacer particles (refer to Table 3) or the amount to be compounded were changed as shown in Table 4. agent composition.

For each of the obtained conductive adhesive compositions, two kinds of test pieces were prepared as described above, and the spread, thickness, adhesive strength, and volume resistivity. The results are shown in Table 4.

[Table 4]

(Examples 5 to 8)

The conductive adhesives of Examples 5 to 8 were prepared (produced) in the same manner as in Example 1, except that the type of (C) spacer particles (refer to Table 3) or the amount to be compounded were changed as shown in Table 5. agent composition.

For each of the obtained conductive adhesive compositions, two types of test pieces were prepared as described above, and the spread, thickness, adhesive strength and volume resistivity. The results are shown in Table 5.

[table 5]

(Examples 9 to 13)

Except for changing (A) the type of conductive powder (refer to Table 1) or the compounding amount, (B) the compounding amount of the curable component, and (C) the type of spacer particles (refer to Table 3) as shown in Table 6 Or the conductive adhesive compositions of Examples 9 to 13 were prepared (produced) in the same manner as in Example 1 except for the amount to be added.

For each of the obtained conductive adhesive compositions, two types of test pieces were prepared as described above, and the spread, thickness, adhesive strength, and volume resistivity. The results are shown in Table 6.

[Table 6]

(Comparative Examples 1 and 2)

As shown in Table 7, except that the compounding amount of (C) spacer particles was changed to excess (Comparative Example 1) or too little (Comparative Example 2), the rest were the same as in Example 2 [(C) Spacer particles and spacers The conductive adhesive composition of Comparative Example 1 or Comparative Example 2 was prepared (manufactured) in the same manner as Example 2 (abbreviated as C02)].

For each of the obtained conductive adhesive compositions, two kinds of test pieces were prepared as described above, and the spread, thickness, adhesive strength, and volume of the cured adhesive layer (conductive adhesive composition) were evaluated from these test pieces. resistivity. The results are shown in Table 7.

(Comparative Examples 3 and 4)

Except using the spacer 7 (abbreviated as C07) shown in Table 3 as the (C) spacer particles as shown in Table 7, and mixing with the mixing amount shown in Table 7 (Comparative Example 3), or using Table 3 Except that the spacer 8 (abbreviated as C08) shown in Table 7 was prepared with the preparation amount shown in Table 7 (Comparative Example 4), the rest were prepared (manufactured) in the same manner as in Example 1 to prepare (manufacture) the conductive materials of Comparative Example 3 or Comparative Example 4. Adhesive composition.

For each of the obtained conductive adhesive compositions, two types of test pieces were prepared as described above, and the spread, thickness, adhesive strength, and volume of the cured adhesive layer (conductive adhesive composition) were evaluated from these test pieces. resistivity. The results are shown in Table 7.

[Table 7]

(Comparative Examples 5 and 6)

Except using the spacer 9 (abbreviated as C09) shown in Table 3 as the (C) spacer particles as shown in Table 8, the compounding amount shown in Table 8 was prepared (Comparative Example 5), or the spacer 9 shown in Table 3 was used. Except that the spacer 10 (abbreviated as C10) shown in Table 8 was prepared in the amount shown in Table 8 (Comparative Example 6), the rest were prepared (manufactured) in the same manner as in Example 1 to prepare (manufacture) the conductive materials of Comparative Example 5 or Comparative Example 6. Adhesive composition.

For each of the obtained conductive adhesive compositions, two types of test pieces were prepared as described above, and the spread, thickness, adhesive strength, and volume of the cured adhesive layer (conductive adhesive composition) were evaluated from these test pieces. resistivity. The results are shown in Table 8.

(Comparative Examples 7 and 8)

As shown in Table 8, the preparation was carried out in the same manner as in Example 1, except that the (C) spacer particles were not used, and the amount of the (A) conductive powder and the amount of the (B) curable component were changed. (Production) The conductive adhesive composition of Comparative Example 7 or Comparative Example 8.

For each of the obtained conductive adhesive compositions, two types of test pieces were prepared as described above, and the spread, thickness, adhesive strength and volume resistivity. The results are shown in Table 8.

[Table 8]

(Comparison of Examples and Comparative Examples)

From the comparison between the results of Examples 1 to 13 and the results of Comparative Examples 7 and 8, it is clear that the conductive adhesive composition of the present disclosure can be well maintained by appropriately containing (C) spacer particles Electrical conductivity, while achieving good shape retention (difficult to spread and good thickness achievable) and good bond strength.

As in Comparative Example 7, if the content of the conductive powder (A) is greatly increased, although the expansion of the hardened adhesive layer in the shape retention can be suppressed well, the thickness of the hardened adhesive layer is relatively In the case where (C) spacer particles are contained, there may be insufficient cases. Furthermore, when the content of the conductive powder (A) is slightly reduced as in Comparative Example 8, good adhesive strength can be achieved, but the shape retention (either the expansion and the thickness of the hardened adhesive layer) is large. drastically reduced. In the conductive adhesive composition of the present disclosure, by appropriately containing (C) spacer particles, it is possible to achieve the same level or even more than the case where (A) conductive powder is added (Comparative Example 7). Good shape retention.

On the other hand, as is clear from the results of Comparative Examples 1 and 2, when the content of the (C) spacer particles is too large, although shape retention can be achieved, appropriate adhesive strength cannot be achieved. When the content of the (C) spacer particles is too small, although good adhesive strength can be achieved, suitable shape retention properties cannot be achieved.

In addition, it is clear from the results of Comparative Examples 3 to 6 that when (C) the CV value of the spacer particles is too large, and when (C) the average particle diameter of the spacer particles is too small or too large, the shape cannot be obtained. Both retention and adhesion strength.

As described above, the composition of the conductive adhesive composition of the present disclosure contains (A) conductive powder and (B) curable component, and when (A) conductive powder is 100 parts by mass, (B) The content of the curable component is 20 parts by mass or more, and the conductive adhesive composition further contains (C) spacer particles and (C) spacer particles having an average particle diameter (median diameter) larger than (A) the conductive powder The average particle size (median diameter) is in the range of 10 to In the range of 60 μm, and the CV value of (C) spacer particles is 30% or less, when the total amount of (A) conductive powder and (B) curable component is 100 parts by mass, (C) spacer The content of the particles is 0.01 part by mass or more and 30 parts by mass or less.

According to such a configuration, when the content of the (A) conductive powder in the conductive adhesive composition is relatively reduced, the conductive powder (A) is contained within a predetermined range and the average particle size is larger than that of the (A) conductive powder. (A) Spacer particles of (C) conductive powder. Thereby, even if the viscosity characteristics of the conductive adhesive composition are changed due to the reduction of (A) the conductive powder, the conductive adhesive composition can be cured by the (C) spacer particles when the conductive adhesive composition is cured. The layers then achieve a good thickness.

Furthermore, according to such a configuration, when the conductive adhesive composition is applied, the cured adhesive layer can have a good thickness, and the cured adhesive layer can be suppressed from spreading significantly. Thereby, the hardened adhesive layer can achieve good shape retention. Therefore, even if the compounding amount of the (A) conductive powder is relatively reduced, good shape retention and good adhesive strength can be achieved, so that poor appearance can be suppressed and good properties can be achieved by hardening the adhesive layer.

In addition, the present invention is not limited to the description of the aforementioned embodiments, and various modifications can be made within the scope indicated in the scope of the patent application, and the technical scope of the present invention also includes different embodiments or a plurality of modifications. The implementation forms obtained by appropriately combining the disclosed technical means are included in this document.

[Industrial Availability]

The present invention can be widely used in the field of electrically conductively adhering adherends in the field of electrical equipment or the field of electronic equipment. Typically, it is particularly suitable for use in the field of manufacturing solar cell modules.

Claims (5)

A conductive adhesive composition containing (A) a conductive powder and (B) a curable component, when the (A) conductive powder is taken as 100 parts by mass, the content of the (B) curable component is: 20 parts by mass or more, and The above-mentioned conductive adhesive composition further contains (C) spacer particles having an average particle diameter (median diameter) larger than the above-mentioned (A) conductive powder, The average particle diameter (median diameter) of the aforementioned (C) spacer particles is in the range of 10 to 60 μm, and the aforementioned (C) the CV value (Coefficient of Variation) of the spacer particles is 30% or less, The content of the (C) spacer particles is 0.01 part by mass or more and 30 parts by mass or less, when the total amount of the conductive powder (A) and the curable component (B) is 100 parts by mass. The conductive adhesive composition according to claim 1, wherein the (A) conductive powder is at least one of silver powder, silver alloy powder, and silver coating powder. The conductive adhesive composition according to claim 1 or 2, wherein the curable component (B) is any one of acrylic resin, epoxy resin, and polysiloxane resin, or is formed by curing Curable compositions such as resins. The conductive adhesive composition according to claim 1 or 2, which is applied to a substrate by a printing machine or a dispenser and used. The conductive adhesive composition according to claim 4, which is used for bonding of solar cells constituting a solar cell module.

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