JP2022019452A - Conductive adhesive composition - Google Patents

Abstract

To provide a conductive adhesive composition capable of achieving good adhesive strength while achieving a good thickness between adherends when the blending amount of a conductive powder is relatively reduced.SOLUTION: The conductive adhesive composition contains (A) a conductive powder and (B) a curable component. The content of the curable component (B) is 20 pts.mass or more based on 100 pts.mass of the conductive powder (A). The conductive adhesive composition further contains (C) spacer particles having a larger average particle diameter (median diameter) than the conductive powder (A). The average particle diameter (median diameter) of the spacer particles (C) is within the range of 10-60 μm, and the CV value of the spacer particles (C) is 30% or less. The content of the spacer particles (C) is 0.01 pt.mass or more and 30 pts.mass or less based on 100 pts.mass of the total amount of the conductive powder (A) and the curable component (B).SELECTED DRAWING: None

Description

The present invention relates to a conductive adhesive composition, and more particularly to a conductive adhesive composition capable of maintaining a thickness between adherends to be adhered to each other.

In recent years, conductive adhesives (ECA) have been widely used in the fields of electrical equipment, electronic equipment, and the like. The conductive adhesive is basically composed of a conductive powder and a curable component, and various adherends can be conductively bonded by appropriately selecting the type or composition of the curable component. The conductivity can be adjusted by appropriately selecting the type of the conductive powder.

For example, Patent Document 1 describes a conductive adhesive using at least one kind of resin component (curable component) and micron-sized and submicron-sized conductive particles (conductive powder). Examples of the conductive particles include copper, silver, platinum, palladium, gold, tin, indium, aluminum, bismuth and the like, and as a particularly preferable example, conductive particles made of silver or conductive particles plated with silver are used. It is listed.

Special Table 2013-541611 Publication No.

As the conductive powder used for the conductive adhesive, as exemplified in Patent Document 1, a precious metal or a rare metal is often used. Therefore, it has been clarified that the viscosity characteristics of the conductive adhesive change when the content of the conductive powder is reduced in order to reduce the cost. If physical properties such as viscosity characteristics change, the thickness of the conductive adhesive formed between the adherends (thickness of the adhesive layer) may not be properly maintained.

If the thickness of the adhesive layer cannot be sufficiently maintained in a state where the adherends are conductively adhered to each other with a conductive adhesive, the distance between the adherends cannot be properly maintained. In such a case, there is a risk of affecting the long-term reliability of devices such as electric devices or electronic devices including adherends. In addition, changes in viscosity characteristics and the like may affect the adhesive strength of the conductive adhesive, and may not be able to achieve sufficient adhesive strength.

The present invention has been made to solve such a problem, and is good while achieving a good thickness between adherends when the blending amount of the conductive powder is relatively reduced. It is an object of the present invention to provide a conductive adhesive composition capable of achieving adhesive strength.

In order to solve the above-mentioned problems, the conductive adhesive composition according to the present invention contains (A) a conductive powder and (B) a curable component, and the (A) conductive powder is added to 100 parts by mass. The content of the (B) curable component is 20 parts by mass or more, and further contains (C) spacer particles having a larger average particle size (median diameter) than the (A) conductive powder. The average particle size (median diameter) of the (C) spacer particles is in the range of 10 to 60 μm, and the CV value (Coefficient of Variation) of the (C) spacer particles is 30% or less. When the total amount of the conductive powder and the (B) curable component is 100 parts by mass, the content of the (C) spacer particles is 0.01 part by mass or more and 30 parts by mass or less.

According to the above configuration, when the content of the (A) conductive powder in the conductive adhesive composition is relatively reduced, the content of the (A) conductive powder is higher than that of the (A) conductive powder separately from the (A) conductive powder. The spacer particles (C) having a large average particle size are contained within a predetermined range. As a result, even if (A) the viscosity characteristics of the conductive adhesive composition change due to the decrease in the conductive powder, (C) when the conductive adhesive composition is cured by the spacer particles. , The cured adhesive layer can achieve a good thickness. This makes it possible to realize good adhesive strength while ensuring good conductivity.

Moreover, according to the above configuration, when the conductive adhesive composition is applied, it is possible to realize a good thickness of the cured adhesive layer and to prevent the cured adhesive layer from spreading significantly. If the thickness of the hardened adhesive layer cannot be maintained and spreads significantly, the hardened adhesive layer protrudes from the adherend, resulting in poor appearance. Further, if the amount of the conductive adhesive is reduced in order to prevent the cured adhesive layer from sticking out, the cured adhesive layer may not have sufficient characteristics (adhesive strength, conductivity, reliability, etc.). According to the above configuration, not only a good thickness of the cured adhesive layer can be realized, but also protrusion can be suitably suppressed, so that the cured adhesive layer can realize good shape retention. Therefore, even if the blending amount of the conductive powder (A) is relatively reduced, good adhesive strength can be realized while achieving good shape retention, so that appearance defects can be suppressed and hardened adhesion can be achieved. It is also possible for the layer to achieve good properties.

In the conductive adhesive composition having the above structure, the conductive powder (A) may be at least one of silver powder, silver alloy powder, and silver coat powder.

Further, in the conductive adhesive composition having the above structure, the curable component (B) becomes any resin of acrylic resin, epoxy resin, silicone resin, or a curable composition obtained by curing. It may be a structure that is a thing.

Further, the conductive adhesive composition having the above-mentioned structure may be used by being applied onto a base material by a printing machine or a dispenser.

Further, in the conductive adhesive composition having the above-mentioned structure, the structure may be used for adhering the solar cell constituting the solar cell module.

In the present invention, it is possible to realize good adhesive strength while achieving good thickness between adherends when the blending amount of the conductive powder is relatively reduced by the above configuration. It has the effect of being able to provide a conductive adhesive composition.

It is a top view schematically showing the structure of the conductor pattern for evaluation used for the evaluation of the conductivity and the adhesive strength after curing of the conductive adhesive composition in the Examples of this disclosure. FIG. 3 is a partial cross-sectional view schematically showing a state in which a rivet is adhered to a pad constituting the evaluation conductor pattern shown in FIG. 1. (A) is a schematic side view showing the structure of a solar cell module which is an example to which the conductive adhesive composition according to the present disclosure is applied, and (B) is a schematic side view of a conventional general solar cell module. It is a schematic side view which shows the structure.

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

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

(A) The specific material composition of the conductive powder is not particularly limited, and the powder is substantially composed of one kind of metal (or conductive material), the alloy powder is composed of a plurality of kinds of metals, and the metal. Examples thereof include composite material powder composed of non-metal. Examples of the composite material powder include a coated powder having a structure in which a metal having a relatively low resistance is coated on the surface of a non-metal powder or a metal powder having a relatively high resistance.

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

(A) The shape of the conductive powder is not particularly limited, and various shapes can be selected and used. Typical examples include a powder having a substantially spherical shape (spherical powder), a flake-like powder (flake-like powder), a dendritic powder, and the like. Although it depends on various conditions such as a specific composition, a specific use, and specific physical characteristics of the conductive adhesive composition, it is preferable to use a combination of a spherical powder and a flake-like powder. By using the powders having different shapes in combination as described above, (A) the conductive powder can be satisfactorily filled after the curing of the (B) curable component.

The flake-like powder in the present disclosure may be a powder having a shape similar to a flat plate or a thin rectangular parallelepiped when viewed as a whole, even if the powder is partially uneven and deformed. The flake shape can be rephrased as a flaky shape or a scale shape. Further, the spherical powder in the present disclosure may be a powder having a three-dimensional shape that is closer to a cube than a rectangular parallelepiped when viewed as a whole, even if the powder is partially uneven and deformed. In addition, spherical can be rephrased as granular.

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

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

(A) When the conductive powder is a coating powder, the coating amount of the conductive material (metal such as gold, silver, copper) to be coated is not particularly limited. When the mass of the original powder not coated with the conductive material is 100% by mass, the coating amount of the conductive material may be, for example, in the range of 5 to 30% by mass, and is 6 to 25% by mass. It may be in the range of 7.5 to 20% by mass. In the examples described later, the amount of silver coated in the silver-coated copper powder (silver powder 3, abbreviation A3) is 10% by mass (see Table 1).

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

In the conductive adhesive composition according to the present disclosure, "other conductive powder" composed of a material other than a metal material having a relatively low resistance such as gold, silver, and copper is (A) conductive. It may be used together as a powder. Examples of such "other conductive powders" include nickel powder, aluminum powder, lead powder, carbon powder and the like.

(A) The method for producing the conductive powder is not particularly limited, and a known method can be used. For example, as for the spherical powder, a powder produced by a wet reduction method, a spherical powder produced by another known method such as an electrolysis method or an atomizing method, and the like can be mentioned, but the present invention is not particularly limited. Alternatively, if it is a flake-like powder, the flake-like powder can be produced by using the spherical powder produced by a known method as the original powder and subjecting the original powder to a known mechanical treatment. The physical properties such as the particle size and the degree of cohesion of the original powder depend on the purpose of use of the conductive adhesive composition (types of electrodes and wiring, or types of electronic parts or devices equipped with these electrodes and wiring). It can be selected as appropriate.

[(B) Curable component]
The (B) curable component contained in the conductive adhesive composition according to the present disclosure functions as a curable binder that enables (A) electrical connection between conductive powders by curing and adheres to an adherend. Anything that does. 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, and polyimide resins. Among these, in particular, any resin such as acrylic resin, epoxy resin, and silicone resin can be mentioned. Depending on the type of resin, the curable component (B) before curing may be a monomer or a prepolymer instead of a polymer. Therefore, in the present disclosure, the curable component (B) 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 preferably used as the (B) curable component is not particularly limited. In the examples described later, three kinds of acrylic compounds are combined and used as (B) a curable component, but one kind or two kinds of acrylic compounds may be used, or four or more kinds of acrylic compounds may be used. Alternatively, another monomer or prepolymer that can be polymerized may be used in combination with the acrylic compound.

Typical acrylic compounds include, for example, (meth) acrylic rate (acrylate or methacrylate), ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate. , Heptyl (meth) acrylate, octyl (meth) acrylate, isoamyl (meth) acrylate (isopentyl (meth) acrylate), isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) Chain alkyl (meth) acrylates such as acrylates, dodecyl (meth) acrylates (lauryl (meth) acrylates) and stearyl (meth) acrylates (octadecyl (meth) acrylates); cyclohexyl (meth) acrylates, isobornyl (meth) acrylates and the like. Cyclic alkyl (meth) acrylate; alkoxy group-containing (meth) acrylate such as 1-methoxyethyl (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, methoxy-triethylene glycol (meth) acrylate; benzyl (meth) acrylate, phenyl Aryl (meth) acrylates such as (meth) acrylates, phenoxyethyl (meth) acrylates, phenoxydiethylene glycol (meth) acrylates, phenoxytetraethylene glycol (meth) acrylates, nonylphenoxyethyl (meth) acrylates, and nonylphenoxytetraethylene glycol (meth) acrylates. ) Acrylate; phenylglycidyl ether acrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluenediisocyanate urethane prepolymer, dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, etc. ) Acrylate-based urethane prepolymer; (meth) acrylate epoxy ester such as bisphenol A diglycidyl ether (meth) acrylic acid adduct, 2-hydroxy-3-phenoxypropyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, dimethyl Amino (meth) acrylates such as aminopropyl (meth) acrylates; polyethylene glyco Ludi (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tetra (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol Polyfunctional (meth) acrylates such as di (meth) acrylates; and the like. Only one kind of these acrylic compounds may be used, or two or more kinds may be appropriately combined and used.

In the examples described later, three kinds of acrylic compounds are used in combination as the (B) curable component. Of these, compound 1 (abbreviation B1) is isoamyl acrylate, compound 2 (abbreviation B2) is phenoxyethyl acrylate, and compound 3 (abbreviation B3) is phenylglycidyl ether acrylate hexamethylene disosocyanate urethane prepolymer (. See Table 2). Therefore, in the present disclosure, when (B) the curable component is an acrylic resin (or a curable composition that becomes an acrylic resin by curing), an alkyl (meth) acrylate, an aryl (meth) acrylate, ( A suitable combination of acrylate-based urethane prepolymers can be mentioned as a suitable example. (B) When a plurality of types of acrylic compounds are used in combination as the curable component, the mixing ratio (blending ratio) of each acrylic compound is not particularly limited.

(B) When the curable component is an acrylic resin (or a curable composition that becomes an acrylic resin by curing), a polymerization initiator is used. The specific polymerization initiator is not particularly limited, but typical examples thereof include organic peroxides and azo-based initiators.

Typical organic peroxides include t-butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxybenzoate, t-butylperoxyneodecanoate, t. -Peroxyesters such as butylperoxylaurate, t-butylcumyl peroxide, t-butylperoxyacetate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate; methylethylketone peroxide Ketone peroxides such as; 1,1,3,3-tetramethylbutylhydroperoxide, cumenehydroperoxide, hydroperoxides such as p-menthanehydroperoxide; Oxide; etc. can be mentioned.

Typical azo-based initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), and 2,2'-azobis (2,4-azobis). Dimethylvaleronitrile), 1,1'-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2'-azobisisobutyrate, 2- (carbamoylazo) isobutyronitrile, 2-phenylazo-4-methoxy- Examples thereof include 2,4-dimethylvaleronitrile, azodi-t-octane, and azodi-t-butane.

Only one kind of these polymerization initiators may be used, or two or more kinds thereof may be used in combination as appropriate. Further, the amount or conditions of use of the polymerization initiator are not particularly limited, and the polymerization initiator may be used in a known amount or conditions. In the examples described later, t-butylperoxy-2-ethylhexanoate is used as the polymerization initiator (see Table 2).

In the present disclosure, an epoxy resin can be preferably used as the (B) curable component in addition to the acrylic resin described above. As a specific epoxy resin, a polyvalent epoxy resin having two or more oxylan rings (epoxy groups) in one molecule can be mentioned.

For example, epichlorohydrin and polyvalent phenols such as phenol novolac, novolak such as cresol novolak, bisphenol A, hydrogenated bisphenol A, bisphenol F, bisphenol AD, resorcin, ethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol. , A glycidyl ether type obtained by reacting with a polyhydric alcohol such as triethylene glycol or polypropylene glycol; a glycidylamine type obtained by reacting with a polyamino compound such as ethylenediamine, triethylenetetramine or aniline; , A glycidyl ester type obtained by reacting with a polyvalent carboxyl compound such as phthalic acid and isophthalic acid, an alicyclic type synthesized from oxidation of an olefin, and the like. These epoxy resins may be used alone or in combination.

(B) If the curable component is an epoxy resin, a curing agent is used for curing. The curing agent used in the present disclosure is not particularly limited, and may be any one that cures the above-mentioned epoxy resin.

Specific curing agents include, for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic acid anhydride. , Acid anhydrides such as succinic anhydride; imidazole, 2-methylimidazole, 2-ethyl-4methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl Imidazoles such as -4 methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-aminoethyl-2-methylimidazole, 1-methylimidazole, 2-ethylimidazole; dimethyloctylamine, dimethyldecylamine, dimethyllaurylamine, etc. Dimethylmyristylamine, dimethylpalmitylamine, dimethylstearylamine, dimethylbehenylamine, dilaurylmonoethylamine, methyldidecylamine, methyldiorailamine, triallylamine, triisopropanolamine, triethylamine, 3- (dibutylamino) propylamine, tri Tertiary amines such as -n-octylamine, 2,4,6-trisdimethylaminomethylphenol, triethanolamine, methyldiethanolamine, diazabicycloundecene; boron trifluoride ethyl ether, boron trifluoride phenol Lewis acid or a compound thereof containing boron fluoride such as boron trifluoride piperidine, boron trifluoride acetate, boron trifluoride monoethylamine, boron trifluoride triethanolamine, boron trifluoride monoethanolamine; Ajinomoto Fine Amine Adducts such as Amicure Series PN-23 or MY-24 commercially available from Techno Co., Ltd., Fuji Cure Series FXR-1020 or FXR-1030 commercially available from Fuji Kasei Kogyo Co., Ltd .; dicyandiamide; etc. Can be mentioned.

Only one kind of these curing agents may be used, or two or more kinds of these curing agents may be used in combination as appropriate. Further, the amount or conditions of use of the curing agent are not particularly limited, and the curing agent may be used in a known amount or conditions.

In the present disclosure, a silicone resin can be preferably used as the (B) curable component in addition to the acrylic resin or epoxy resin described above. Specific examples of the silicone resin include known thermosetting silicone resins.

As a typical thermosetting silicone resin, for example, it has a skeleton structure such as silane, silicone oligomer, silicone resin, organosiloxane, diorganosiloxane, organopolysiloxane, diorganopolysiloxane, and the skeleton structure is one. Examples of the structure having the above reactive functional groups can be mentioned. The skeleton structure may be a linear structure or may have a branched chain.

The reactive functional group includes a hydroxy group, an alkenyl group, a hydrogensilyl group, a (meth) acryloyl group, an epoxy group, an amino group, a carbinol group and a mercapto group, which are bonded to a silicon atom contained in the skeleton structure. , Carboxy group, phenol group and the like, but are not particularly limited. In addition to the reactive functional group, the skeletal structure may have a functional group such as an alkyl group, an alkenyl group, or an aromatic group.

The thermosetting silicone resin used as the (B) curable component in the present disclosure may have a single type of skeletal structure and a single type of reactive functional group, or may have a plurality of types of skeletal structures and a plurality of types. It may have the reactive functional group of. Further, as described above, one or more reactive functional groups may be contained in one skeletal structure, in other words, one molecule of silicone resin (having an arbitrary skeletal structure) has at least one reactivity. It suffices to have a functional group. The reactive functional group may be at the end of the skeletal structure, at the side chain, or at either the end or the side chain.

In the present disclosure, an acrylic resin, an epoxy resin, and a silicone resin may be appropriately combined and used as the (B) curable component, or a thermosetting resin other than these (curing to become a resin by curing). Sex composition) may be used in combination. The mixing ratio (blending 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 a larger average particle size (median diameter) than the (A) conductive powder.

(C) The average particle size (median diameter) of the spacer particles is not particularly limited, but as described above, (A) the preferable average particle size when the conductive powder is a spherical powder is within the range of 0.1 to 10 μm. Therefore, (C) the average particle size of the spacer particles may be in the range of 10 to 60 μm (or may be more than 10 μm and 60 μm or less). Further, since (A) the preferable average particle size when the conductive powder is a flake-like powder is in the range of 2 to 20 μm, (C) the average particle size of the spacer particles is in the range of 20 to 60 μm. It may be (or may be more than 20 μm and 6 μm or less).

When the conductive adhesive composition is cured to form a cured adhesive layer that conductively adheres the adherends to each other, the specific thickness required for the cured adhesive layer depends on (C). The lower limit of the average particle size of the spacer particles may be 30 μm or more. Therefore, the lower limit of the average particle size of the (C) spacer particles can be appropriately set according to the average particle size of the (A) conductive powder used in combination.

On the other hand, the upper limit of the average particle size of the (C) spacer particles is preferably 60 μm or less. (C) When the average particle size of the 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. The method for measuring the average particle size of (C) spacer particles is not particularly limited, and in the present disclosure, the particle size distribution is as described in Examples described later, similarly to (A) the average particle size of the conductive powder. A method of measuring using a measuring device is adopted.

(C) The material of the spacer particles is not particularly limited, and any material may be used as long as it has shape stability so that the cured adhesive layer can achieve a sufficient thickness even after the conductive adhesive composition is cured. Typical materials include glass; ceramics such as zirconia (ZrO ₂ ), alumina (Al ₂ O ₃ ), silica (SiO ₂ ), silicon carbide (SiC), and silicon nitride (Si ₃ N ₄ ); acrylic resin. , Nylon resin, phenol resin, silicone resin and other resins; and the like.

Although metal can be used as the (C) spacer particles, if the (C) spacer particles are made of metal, they can function as (A) conductive powder. In the present disclosure, since it is necessary to realize a composition that relatively reduces the content of the conductive powder (A), the spacer particles (C) are not metal particles but the above-mentioned glass and ceramics. , It is preferable to use a non-conductive material such as resins.

However, in order to improve the conductivity of the cured adhesive layer according to the above-mentioned conditions in the conductive adhesive composition, the surface of the spacer particles (C) may be coated with a metal material. good. Examples of such a metal material include gold, silver, copper, or alloys thereof, which are the same as those exemplified for the material of (A) conductive powder. (C) The coating amount (coating amount) of the metal material coated on the surface of the spacer particles is not particularly limited, and the conductivity required for the cured adhesive layer (cured product), the cost associated with the coating, and (C) the spacer particles. It can be appropriately set according to various conditions such as the influence on shape stability.

In the examples described later, a total of 10 types of particles are used as the (C) spacer particles. Of these, spacer 1 (abbreviation C01), spacer 7 (abbreviation C07) and spacer 10 (abbreviation C10) are acrylic resin particles (abbreviation C04), and spacer 4 (abbreviation C04), spacer 6 (abbreviation C06), Spacer 8 (abbreviation C08) and spacer 9 (abbreviation C09) are glass particles (glass particles), and spacer 5 (abbreviation C05) is zirconia particles (zirconia particles). Further, the spacer 2 (abbreviation C02) and the spacer 3 (abbreviation C03) are both silver-coated particles, and the core particles are glass particles in the spacer 2 and acrylic particles in the spacer 3.

(C) The shape of the spacer particles may be spherical. Although it is possible to adopt a shape other than the spherical shape, the spherical shape is preferable from the viewpoint of achieving a more stable thickness of the cured adhesive layer. If the shape is other than the spherical shape, the (C) spacer particles have a longitudinal direction, and the thickness of the layer may vary depending on the direction of the (C) spacer particles in the cured adhesive layer.

The other physical properties of the spacer particles (C) are not particularly limited, but the CV value (Coefficient of Variation) of the spacer particles is preferably 30% or less. The CV value is an index showing the variation in the particle size distribution of the particles, and it can be judged that the smaller the value, the smaller the variation in the particle size distribution and the higher the uniformity. If the CV value of the (C) spacer particles exceeds 30%, the variation in the particle size distribution of the (C) spacer particles becomes large, and the shape retention of the conductive adhesive composition may decrease. In this case, the cured adhesive layer may spread more than expected, or the thickness of the cured adhesive layer may not be sufficiently secured. The method for evaluating the CV value is not particularly limited, and in the present disclosure, the evaluation is performed by the method described in Examples described later.

[Manufacturing and use of conductive adhesive composition]
The method for producing the conductive adhesive composition according to the present disclosure is not particularly limited, and a method known in the field of the conductive adhesive composition can be preferably used. As a typical example, there is a method of blending each of the above-mentioned components at a predetermined blending ratio (based on mass) and forming a paste using a known kneading device. Examples of the kneading device include a three-roll mill and the like.

In the conductive adhesive composition according to the present disclosure, as described above, it is preferable that the blending amount (content) of the conductive powder (A) is relatively small. Specifically, the conductive adhesive composition according to the present disclosure contains (A) a conductive powder and (B) a curable component as basic components, and of the two components which are the basic components, (A) conductivity. When the powder is taken as a reference of 100 parts by mass, (B) the lower limit of the content of the curable component may be 20 parts by mass or more, 25 parts by mass or more, or 30 parts by mass or more. It may be 35 parts by mass or more.

When the content of the (B) curable component is less than 20 parts by mass, the content of the (A) conductive powder is relatively large in the conductive adhesive composition, in other words, the content of the (A) conductive powder is relatively high. It cannot be said that the content was relatively reduced. On the other hand, the upper limit of the content of (B) the curable component is not particularly limited, and (B) curing to the extent that the required conductivity can be realized according to the above-mentioned conditions in the conductive adhesive composition. The content of the sex component can be set to be large.

In the conductive adhesive composition according to the present disclosure, the content (blending amount) of (C) spacer particles with respect to the basic component is the total amount of the basic component ((A) the conductive powder and (B) the total amount of the curable component). ) Is 100 parts by mass, it may be within the range of 0.01 parts by mass or more and 30 parts by mass or less (0.01 to 30 parts by mass).

When the content of (C) spacer particles is less than 0.01 parts by mass, the action and effect (realization of good shape retention and good adhesive strength in the cured adhesive layer) by blending (C) spacer particles can be obtained. It may not be enough. Further, if the content of the (C) spacer particles exceeds 30 parts by mass, not only the action and effect commensurate with the blending amount cannot be obtained, but also the (C) spacer particles become too large and the adhesive strength of the cured adhesive layer is increased. May decrease.

In the conductive adhesive composition according to the present disclosure, if necessary, in addition to the above-mentioned components ((A) conductive powder, (B) curable component, and (C) spacer particles, conductive adhesion is performed. Various additives known in the field of the agent composition may be contained. The additive is not particularly limited, but specifically, for example, a solvent, a leveling agent, an antioxidant, an ultraviolet absorber, and a silane cup. Examples thereof include a ring agent, a defoaming agent, a viscosity modifier, and the like. These additives can be added within a range that does not interfere with the effects of the present disclosure.

Further, the method for forming a pattern to be a cured adhesive layer by the conductive adhesive composition according to the present disclosure is not particularly limited, and various known forming methods can be preferably used. Typically, as shown in Examples described later, a screen printing method is mentioned, and a printing method such as a gravure printing method, an offset printing method, an inkjet method, a dispenser method, and a dip method can also be applied. Therefore, the conductive adhesive composition according to the present disclosure may be any one that can be applied and used on a substrate by a printing machine or a dispenser.

The conductive adhesive composition according to the present disclosure can be widely used for forming high-definition electrodes, wiring, and the like, or for adhering electronic components. Specifically, for example, the current collecting electrode of a solar cell; the internal electrode or the external electrode of a chip-type electronic component; RFID (Radio Frequency IDentification), electromagnetic wave shield, vibrator adhesion, membrane switch, touch panel, electroluminescence, etc. It can be suitably used for applications such as electrodes or wiring or adhesion of parts used in the above.

The conductive adhesive composition according to the present disclosure can be suitably applied to the field of solar cells, among the above-mentioned applications. Specifically, the conductive adhesive composition according to the present disclosure can be suitably used for, for example, adhering a solar cell module.

As shown in FIG. 3B, conventionally, the solar cell module 30 is generally configured to connect a plurality of solar cell 31s with a ribbon-shaped wiring member called an interconnector 32. On the other hand, in recent years, as shown in FIG. 3A, a plurality of solar cells 21 so that the lower surface of the long side of any solar cell 21 overlaps the upper surface of the long side of another solar cell 21. A solar cell module 20 having a configuration in which the solar cells are partially sequentially stacked and tilted is also proposed. In such a solar cell module 20, a conductive adhesive is used instead of the interconnector 32 to connect the solar cell 21 to each other.

Here, when the long sides of the solar cell 21 are bonded to each other, if the conductive adhesive spreads out from the bonded region, a problem such as a short circuit may occur in the solar cell module 20. Further, if the thickness of the cured product (cured adhesive layer 22) of the conductive adhesive is not sufficiently secured, the inclination angle thereof may not be appropriately adjusted when the solar cell 21 is bonded.

As described above, the conductive adhesive composition according to the present disclosure contains (C) spacer particles in addition to (A) the conductive powder and (B) the curable component. As a result, not only a good thickness can be ensured in the cured adhesive layer after curing, but also the possibility that the cured adhesive layer 22 spreads out from the adhesive region can be effectively suppressed.

If the thickness of the hardened adhesive layer 22 cannot be maintained and is greatly expanded, the hardened adhesive layer 22 protrudes from the adherend, resulting in poor appearance. Further, if the amount of the conductive adhesive is reduced in order to prevent the cured adhesive layer 22 from sticking out, sufficient characteristics (adhesive strength, conductivity, reliability, etc.) may not be obtained for the cured adhesive layer 22. According to the present disclosure, by blending the spacer particles (C) in an appropriate amount, the cured adhesive layer 22 not only realizes a good thickness but also can suppress protrusion, and realizes good shape retention. be able to. Therefore, it is possible to suppress poor appearance and realize good characteristics of the cured adhesive layer.

Moreover, in the conductive adhesive composition according to the present disclosure, by appropriately containing (C) spacer particles, the cured adhesive layer 22 can realize good adhesive strength while ensuring good conductivity. can. Therefore, the conductive adhesive composition according to the present disclosure can be particularly well applied to the production of the solar cell module 20 as shown in FIG. 3A.

The present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited thereto. One of ordinary skill in the art can make various changes, modifications, and modifications without departing from the scope of the present invention. The measurement and evaluation of physical properties, etc. in the following Examples and Comparative Examples were carried out as shown below.

[Evaluation method for conductive powder and spacer particles]
(1) Medium diameter (A) The median diameter of the conductive powder or (C) spacer particles was evaluated by a laser diffraction method. Weigh 0.3 g of a sample of (A) conductive powder or (C) spacer particles in a 50 ml beaker, add 30 ml of isopropyl alcohol, and then treat with an ultrasonic washer (USM-1 manufactured by AS ONE Co., Ltd.) for 5 minutes. The particles were dispersed, and the median diameter was measured and evaluated using a particle size distribution measuring device (Microtrac MT3300EXII manufactured by Nikkiso Co., Ltd.).

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

[Shape evaluation after pasting of conductive adhesive composition]
The conductive adhesive composition of the example or the comparative example was applied onto an alumina substrate using a dispenser so as to have a diameter of 60 μm and a height of 200 μm, and a glass substrate weighing 5 g was laminated from above. This substrate laminate was heated at 150 ° C. for 30 seconds using a hot plate to cure the conductive adhesive composition (formation of a cured adhesive layer). As a result, a test piece for shape evaluation after pasting was obtained.

The spread of the cured adhesive layer from the surface of the test piece on the glass substrate side was measured with an optical measuring microscope. When the diameter of the cured adhesive layer was less than 900 μm, it was evaluated as “◯”, and when it was 900 μm or more, it was evaluated as “x”. In addition, the thickness of the cured adhesive layer was measured with an optical measuring microscope. When the thickness of the cured 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 “Δ”, and when it was less than 30 μm, it was evaluated as “x”.

[Evaluation of Conductivity and Adhesive Strength of Conductive Adhesive Composition]
The conductive adhesive composition of the example or the comparative example was printed with the printing pattern 11 on the alumina substrate 12 using a printing machine as shown in FIG. The print 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, and the wiring portion 11c is zigzag-shaped, and the aspect ratio of the wiring portion 11c is 75. The five pad patterns 11d are arranged side by side in a row adjacent to the wiring pattern 11a, and each has a square shape of 2 mm × 2 mm.

Next, as shown in FIG. 2, an aluminum rivet 13 having a circular fixing surface having a diameter of 4 mm was placed on the pad pattern 11d (2 mm × 2 mm) on the alumina substrate 12. The alumina substrate 12 on which the rivet 13 was placed was heated at 150 ° C. for 30 seconds using a hot plate to cure the conductive adhesive composition (printing pattern 11) (formation of a cured adhesive layer). Specimens for evaluating properties and adhesive strength were obtained.

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

The adhesive strength of the cured adhesive layer was evaluated by the adhesiveness of the rivet 13 to the pad pattern 11d. Specifically, a shearing force was applied in the horizontal direction to the rivet 13 mounted on the pad pattern 11d, and the strength when the rivet 13 was detached from the pad pattern 11d was measured. The adhesive strength of the cured adhesive layer was evaluated as "◯" when the strength was 15 MPa, "Δ" when the strength was 5 MPa or more and less than 15 MPa, and "×" 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 of the three powders shown in Table 1 below were used as the (A) conductive powder. The abbreviations in Table 1, Table 2 and Table 3 below are used to show the components of Examples or Comparative Examples in Tables 4 to 8.

また、以下の実施例または比較例では、（Ｂ）硬化性成分として、下記表２に示す３種類のアクリル系化合物を組み合わせて用いた。なお、（Ｂ）硬化性成分の重合開始剤としては、下記表３に示すものを用いた。

Further, in the following Examples or Comparative Examples, three kinds of acrylic compounds shown in Table 2 below were used in combination as the (B) curable component. As the polymerization initiator of the (B) curable component, those shown in Table 3 below were used.

また、以下の実施例または比較例では、（Ｃ）スペーサー粒子として、下記表３に示す１０種類のいずれかを用いた。

Further, in the following Examples or Comparative Examples, any one of the 10 types shown in Table 3 below was used as the (C) spacer particles.

（実施例１）
表４に示すように、（Ａ）導電性粉末として、表１に示す球状の銀粉１（略号Ａ１）およびフレーク状の銀粉２（略号Ａ２）を用い、（Ｂ）硬化性成分として、表２に示す樹脂１（略号Ｂ１）、樹脂２（略号Ｂ２）および樹脂３（略号Ｂ３）を用い、これらを表４に示す配合量（質量部）となるよう配合し、これら各成分を３本ロールミルで混練した。混練後、（Ｃ）スペーサー粒子として、表３に示すスペーサー１（略号Ｃ０１）を用い、このスペーサー１を表４に示す配合量（質量部）で配合し、自転公転式撹拌機で混合した。これにより、実施例１の導電性接着剤組成物を調製（製造）した。

(Example 1)
As shown in Table 4, (A) spherical silver powder 1 (abbreviation A1) and flake-shaped silver powder 2 (abbreviation A2) shown in Table 1 were used as the conductive powder, and (B) curable component was used in Table 2. Resin 1 (abbreviation B1), resin 2 (abbreviation B2) and resin 3 (abbreviation B3) shown in the above are used, and these are blended so as to have the blending amount (parts by mass) shown in Table 4, and each of these components is blended in a three-roll mill. Kneaded with. After kneading, spacer 1 (abbreviation C01) shown in Table 3 was used as the spacer particles (C), and the spacer 1 was blended in the blending amount (part by mass) shown in Table 4 and mixed with a rotation / revolution type stirrer. As a result, the conductive adhesive composition of Example 1 was prepared (manufactured).

With respect to the obtained conductive adhesive composition, as described above, a test piece for shape evaluation after attachment and a test piece for evaluation of conductivity and adhesive strength were prepared, and a cured adhesive layer (cured adhesive layer) was prepared from these test pieces. The spread, thickness, adhesive strength, and volumetric resistance of the conductive adhesive composition) were evaluated. The results are shown in Table 4. In Table 4 (and Tables 5 to 8), the spread of the cured adhesive layer is described as "adhesive layer spread", the thickness of the cured adhesive layer is described as "adhesive layer thickness", and the volume resistivity is described as "resistance". Value ".

(Examples 2 to 4)
As shown in Table 4, the conductive adhesive compositions of Examples 2 to 4 were prepared in the same manner as in Example 1 except that (C) the type of spacer particles (see Table 3) or the blending amount was changed. (Manufactured).

As described above, two types of test pieces were prepared for each of the obtained conductive adhesive compositions, and the spread, thickness, adhesive strength, and adhesive strength of the cured adhesive layer (conductive adhesive composition) were produced by these test pieces. The volume resistivity was evaluated. The results are shown in Table 4.

（実施例５～８）
表５に示すように、（Ｃ）スペーサー粒子の種類（表３参照）または配合量を変更した以外は、実施例１と同様にして、実施例５～８の導電性接着剤組成物を調製（製造）した。

(Examples 5 to 8)
As shown in Table 5, the conductive adhesive compositions of Examples 5 to 8 were prepared in the same manner as in Example 1 except that (C) the type of spacer particles (see Table 3) or the blending amount was changed. (Manufactured).

As described above, two types of test pieces were prepared for each of the obtained conductive adhesive compositions, and the spread, thickness, adhesive strength, and adhesive strength of the cured adhesive layer (conductive adhesive composition) were produced by these test pieces. The volume resistivity was evaluated. The results are shown in Table 5.

（実施例９～１３）
表６に示すように、（Ａ）導電性粉末の種類（表１参照）または配合量、（Ｂ）硬化性成分の配合量、並びに（Ｃ）スペーサー粒子の種類（表３参照）または配合量を変更した以外は、実施例１と同様にして、実施例９～１３の導電性接着剤組成物を調製（製造）した。

(Examples 9 to 13)
As shown in Table 6, (A) the type (see Table 1) or blending amount of the conductive powder, (B) the blending amount of the curable component, and (C) the type (see Table 3) or blending amount of the spacer particles. The conductive adhesive compositions of Examples 9 to 13 were prepared (manufactured) in the same manner as in Example 1 except that the above was changed.

As described above, two types of test pieces were prepared for each of the obtained conductive adhesive compositions, and the spread, thickness, adhesive strength, and adhesive strength of the cured adhesive layer (conductive adhesive composition) were produced by these test pieces. The volume resistivity was evaluated. The results are shown in Table 6.

（比較例１，２）
表７に示すように、（Ｃ）スペーサー粒子の配合量を過剰（比較例１）または過少（比較例２）となるように変更した以外は、実施例２（（Ｃ）スペーサー粒子がスペーサー２（略号Ｃ０２）の実施例）と同様にして、比較例１または比較例２の導電性接着剤組成物を調製（製造）した。

(Comparative Examples 1 and 2)
As shown in Table 7, Example 2 ((C) spacer particles are spacers 2 except that the blending amount of (C) spacer particles is changed to be excessive (Comparative Example 1) or too small (Comparative Example 2). The conductive adhesive composition of Comparative Example 1 or Comparative Example 2 was prepared (manufactured) in the same manner as in Example) of (Abbreviation C02).

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

(Comparative Examples 3 and 4)
As shown in Table 7, as the spacer particles (C), the spacer 7 (abbreviation C07) shown in Table 3 is used and blended in the blending amount shown in Table 7 (Comparative Example 3), or the spacer 8 shown in Table 3 (Comparative Example 3). A conductive adhesive composition of Comparative Example 3 or Comparative Example 4 was prepared (manufactured) in the same manner as in Example 1 except for the compounding amount shown in Table 7 using the abbreviation C08) (Comparative Example 4). did.

As described above, two types of test pieces were prepared for each of the obtained conductive adhesive compositions, and the spread, thickness, adhesive strength, and adhesive strength of the cured adhesive layer (conductive adhesive composition) were produced by these test pieces. The volume resistivity was evaluated. The results are shown in Table 4.

（比較例５，６）
表８に示すように、（Ｃ）スペーサー粒子として、表３に示すスペーサー９（略号Ｃ０９）を用いて表８に示す配合量で配合するか（比較例５）、表３に示すスペーサー１０（略号Ｃ１０）を用いて表８に示す配合量で配合した（比較例６）以外は、実施例１と同様にして、比較例５または比較例６の導電性接着剤組成物を調製（製造）した。

(Comparative Examples 5 and 6)
As shown in Table 8, as the spacer particles (C), the spacer 9 (abbreviation C09) shown in Table 3 is used and blended in the blending amount shown in Table 8 (Comparative Example 5), or the spacer 10 shown in Table 3 (Comparative Example 5). A conductive adhesive composition of Comparative Example 5 or Comparative Example 6 was prepared (manufactured) in the same manner as in Example 1 except for the compounding amount shown in Table 8 using the abbreviation C10) (Comparative Example 6). did.

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

(Comparative Examples 7 and 8)
As shown in Table 8, comparisons were made in the same manner as in Example 1 except that (C) the amount of the conductive powder and (B) the amount of the curable component were changed without using the spacer particles. The conductive adhesive composition of Example 7 or Comparative Example 8 was prepared (manufactured).

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

（実施例および比較例の対比）
実施例１～１３の結果と比較例７，８の結果の対比から明らかなように、本開示に係る導電性接着剤組成物であれば、（Ｃ）スペーサー粒子を適切に含有することにより、導電性を良好に保持しつつ良好な形状保持性（広がりにくく良好な厚みを実現できる）と良好な接着強度を実現することができる。

(Comparison between Examples and Comparative Examples)
As is clear from the comparison between the results of Examples 1 to 13 and the results of Comparative Examples 7 and 8, the conductive adhesive composition according to the present disclosure can be appropriately contained with (C) spacer particles. It is possible to realize good shape retention (hard to spread and good thickness can be realized) and good adhesive strength while maintaining good conductivity.

When the content of (A) the conductive powder is significantly increased as in Comparative Example 7, the spread of the cured adhesive layer can be satisfactorily suppressed in the shape retention, but the thickness of the cured adhesive layer is (1). C) It may be insufficient when compared with the case where the spacer particles are appropriately contained. Further, as in Comparative Example 8, if the content of the conductive powder (A) is reduced as much as possible, good adhesive strength can be achieved, but the shape retention is significantly improved (both the spread and the thickness of the cured adhesive layer). Decreases to. In the conductive adhesive composition according to the present disclosure, the shape is as good as (Comparative Example 7) when (A) the conductive powder is increased by appropriately containing the spacer particles (C). Retention can be achieved.

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

Further, as is clear from the results of Comparative Examples 3 to 6, when (C) the CV value of the spacer particles is too large, and (C) the average particle size of the spacer particles is too small or too large, the shape retention property is maintained. And it becomes impossible to achieve both adhesive strength.

As described above, the conductive adhesive composition according to the present disclosure contains (A) a conductive powder and (B) a curable component, and (A) when the conductive powder is 100 parts by mass, (B). It contains (C) spacer particles having a curable component content of 20 parts by mass or more and (A) a larger average particle size (median diameter) than the conductive powder, and (C) average particles of the spacer particles. The diameter (median diameter) is in the range of 10 to 60 μm, the CV value of (C) spacer particles is 30% or less, and the total amount of (A) conductive powder and (B) curable component is 100 mass. When the portion is taken as a portion, the content of the spacer particles (C) is 0.01 parts 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 (A) conductive powder is separated from the (A) conductive powder. The spacer particles (C) having a larger average particle size than the above are contained within a predetermined range. As a result, even if (A) the viscosity characteristics of the conductive adhesive composition change due to the decrease in the conductive powder, (C) when the conductive adhesive composition is cured by the spacer particles. The cured adhesive layer can achieve a good thickness.

Moreover, according to such a configuration, when the conductive adhesive composition is applied, it is possible to realize a good thickness of the cured adhesive layer and to prevent the cured adhesive layer from spreading significantly. As a result, the cured adhesive layer can realize good shape retention. Therefore, even if the blending amount of the conductive powder (A) is relatively reduced, good adhesive strength can be realized while achieving good shape retention, so that appearance defects can be suppressed and hardened adhesion can be achieved. It is also possible for the layer to achieve good properties.

It should be noted that the present invention is not limited to the description of the above-described embodiment, and various modifications can be made within the scope of the claims, and the present invention is disclosed in different embodiments and a plurality of modifications. Embodiments obtained by appropriately combining the above technical means are also included in the technical scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be widely and suitably used in the field of electrical equipment or the field of electronic equipment, in the field of conductively adhering an adherend. Typically, it can be particularly suitably used in the field of manufacturing a solar cell module or the like.

11: Print pattern 11a: Wiring pattern 11b: Terminal 11c: Wiring part 11d: Pad pattern 12: Alumina substrate 13: Rivet 20: Solar cell module 21: Solar cell 22: Curing adhesive layer 30: Solar cell module 31: Solar cell Cell 32: interconnector

Claims (5)

It contains (A) a conductive powder and (B) a curable component, and when the (A) conductive powder is 100 parts by mass, the content of the (B) curable component is 20 parts by mass or more.
Further, it contains (C) spacer particles having a larger average particle size (median diameter) than the (A) conductive powder.
The average particle size (median diameter) of the (C) spacer particles is in the range of 10 to 60 μm, and the CV value (Coefficient of Variation) of the (C) spacer particles is 30% or less.
When the total amount of the (A) conductive powder and the (B) curable component is 100 parts by mass, the content of the (C) spacer particles is 0.01 parts by mass or more and 30 parts by mass or less. Characterized by,
Conductive adhesive composition. The conductive powder (A) is at least one of a silver powder, a silver alloy powder, and a silver-coated powder.
The conductive adhesive composition according to claim 1. The curable component (B) is a resin of any of acrylic resin, epoxy resin, and silicone resin, or a curable composition that becomes these resins when cured.
The conductive adhesive composition according to claim 1 or 2. It is characterized in that it is used by being applied on a substrate by a printing machine or a dispenser.
The conductive adhesive composition according to any one of claims 1 to 3. It is characterized in that it is used for adhering solar cells constituting a solar cell module.
The conductive adhesive composition according to claim 4.

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