KR20150139414A - Conductive adhesive, and electronic component using the same - Google Patents

Abstract

The present invention provides a conductive adhesive which does not have an existing problem and has a low specific resistance value and high adhesive force. To this end, the conductive adhesive can be obtained by comprising: conductive powder containing flake-shaped conductive powder (A-1) and conductive powder (A-2) having the average particle diameter of less than or equal to one third of the average particle diameter of the flake-shaped conductive powder (A-1); a glycidylether compound (B); and a hardening agent (C). The conductive adhesive, however, does not contain a solvent.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a conductive adhesive,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive adhesive and an electronic component using the same, and more particularly to a conductive adhesive which is effective for electrical connection between members in an electronic product.

BACKGROUND ART [0002] Soldering has been used conventionally in mounting on a wiring board such as an electronic component, but in recent years, lead-free solder has become mainstream due to concerns about human body and natural environment.

On the other hand, in recent years, heat generation of electronic components is increasing due to the increase in the transfer speed accompanying the increase in the density of electronic components and the increase in the LSI operation speed accompanying miniaturization of electronic devices. Further, in recent years, electronic parts have been used under severe use conditions such as vehicle mounting.

As a result, in an electronic component mounted with solder, deformation is accumulated due to a cooling / heating cycle, and as a result, there is a problem that cracks easily occur in the solder joint.

On the other hand, development of a conductive adhesive replacing solder is progressing. As an example thereof, a conductive paste containing a mixture of silver and a predetermined thermosetting resin has been proposed (Patent Document 1).

Japanese Patent Publication No. 5-11365

Patent Document 1 proposes a technique of performing good adhesion at a fast curing rate by using a resin paste using two types of curing agents for a predetermined thermosetting resin for die bonding for a light emitting diode.

However, in the technique of Patent Document 1, curing at a high temperature is required to increase the curing rate. Therefore, there is a problem that it can not be applied to a substrate which can not withstand a high temperature such as a plastic substrate.

In addition, along with the increase in density of electronic components, the reduction of the bonding surface progresses, and further improvement of the adhesive strength and reduction of resistance of the conductive adhesive are required.

Accordingly, an object of the present invention is to provide a method of bonding a component having a small adhesive area including electronic components even with a relatively low temperature while maintaining the hardness originally required for the conductive adhesive, and further realizing lower resistance To provide a conductive adhesive.

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have completed the invention with the following content.

That is, the conductive adhesive of the present invention comprises a conductive powder (A-1) in the form of a flake, a conductive powder containing a conductive powder (A-2) having an average particle diameter of not more than 1/3 of the conductive powder in the flake, (B) a glycidyl ether compound, and (C) a curing agent, and does not contain a solvent.

In the conductive adhesive of the present invention, it is preferable that the conductive powder (A-2) is at least one conductive powder selected from flakes and spheres. In the conductive adhesive of the present invention, the glycidyl ether compound (B) is preferably a compound represented by the formula (I), particularly preferably a compound represented by the formula (II).

(Wherein R1 represents an alkyl group, an aryl group, an alkylaryl group or an arylalkyl group, and m + n = 0, 1 or 2)

The electronic component of the present invention is characterized in that the members are electrically connected to each other by using the above-described conductive adhesive of the present invention.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to strongly adhere a component having a small bonding area, including electronic components, even at a relatively low temperature while maintaining the hardness originally required for the conductive adhesive, A conductive adhesive can be provided.

Since the conductive adhesive agent of the present invention does not contain a solvent, hardening and shrinkage hardly occurs and the generation of bubbles in the cured product thereof is suppressed, so that strong conductive bonding becomes possible.

According to the conductive adhesive of the present invention, it is possible to provide an electronic part in which members are strongly electrically connected to each other.

The conductive adhesive of the present invention is a conductive adhesive containing a conductive powder (A-2) containing a conductive powder (A-1) in a flaky state and a conductive powder (A-2) having an average particle diameter of not more than one third of the conductive powder (B) a glycidyl ether compound, and (C) a curing agent, and does not contain a solvent.

In the conductive adhesive of the present invention, " no solvent " or " no solvent " means that the conductive adhesive does not substantially contain a solvent or diluent, and the adhesive has a reduced mass By mass is not more than 1% by mass as compared with the mass before heating.

Each component constituting the conductive adhesive of the present invention will be described below.

[(A) conductive powder]

The conductive powder of the present invention is preferably one-third or less, preferably one-fifth to one-twentieth, or more preferably one-half or less of the flaky conductive powder (A-1) and the flaky conductive powder (A- Is a conductive powder containing a conductive powder (A-2) having an average particle diameter D50 of 1/6 to 1/10.

This configuration of the conductive powder makes it possible to further reduce the resistance of the conductive adhesive. This is considered to be because the contact between the conductive powders becomes better by such a constitution, and the conductivity is further improved.

Further, by making the shape of the conductive powder (A-1) into a flake-like shape, the contact area between the conductive powders increases, and sufficient conductivity is obtained.

As the conductive powder (A-2), various materials such as spherical, flaky, dentrite and the like can be used, but at least one kind selected from flakes and spheres is preferable, and spherical conductive powder is more preferably used.

Examples of the conductive powders (A-1) and (A-2) used in the present invention include gold, silver, copper, nickel, aluminum, platinum, palladium, tin, bismuth, zinc, iron, indium, iridium (SnO ₂ ), indium oxide (In ₂ O ₃ ), ITO and the like, conductive carbon, and the like can be given as examples of the low-resistance metals such as tin oxide, tin oxide, . Among them, silver is preferable.

Hereinafter, the conductive powder (A-1) will be described.

The average particle diameter D50 of the conductive powder (A-1) is appropriately selected from the range of 2.0 占 퐉 to 20 占 퐉, preferably 5 占 퐉 to 15 占 퐉, and more preferably 7 占 퐉 to 13 占 퐉.

When the average particle diameter D50 of the conductive powder (A-1) is 2 m or more, the number of contact points between conductive powders becomes smaller, the contact resistance is suppressed, and sufficient conductivity is obtained. On the other hand, by setting the average particle diameter D50 of the conductive powder to 20 mu m or less, it becomes possible to apply the conductive adhesive to fine portions, and the adhesive strength becomes sufficient.

The tap density of the conductive powder (A-1) ranges from 4.0 g / cm3 to 7.0 g / cm3, preferably from 4.5 g / cm3 to 6.4 g / cm3, more preferably from 5.0 g / cm3 to 6.0 g / Is appropriately selected.

If the tap density of the conductive powder (A-1) is 4.0 g / cm3 or more, the density with respect to the capacity of the conductive powder (A-1) becomes sufficient and high filling becomes possible in a relatively compact state, . On the other hand, the conductive powder (A-1) having a tap density of 7.0 g / cm 3 or less is industrially easy to produce and has sufficient conductivity.

The conductive powder (A-1) has a BET specific surface area of 0.1 to 1.0 m 2 / g, preferably 0.2 to 0.6 m 2 / g, more preferably 0.2 to 0.3 m 2 / g .

When the BET specific surface area of the conductive powder (A-1) is 0.1 m 2 / g or more, the mutual contact area is increased, and sufficient conductivity is obtained. On the other hand, if the BET specific surface area is 1 m < 2 > / g or less, the viscosity can be easily adjusted even when the content of the conductive powder in the conductive adhesive is increased.

Such a conductive powder (A-1) is produced by a known method such as a wet reduction method, an electrolysis method, and an atomization method.

Particularly, in order to make the shape of the conductive powder into a flake-like shape, a physical force is applied to a machine having a crushing and rolling effect such as a vibrating mill or a stirring-type crushing machine by using a pulverizing medium.

Hereinafter, the conductive powder (A-2) will be described.

The average particle diameter D50 of the conductive powder (A-2) is suitably selected from the range of 0.1 탆 to 10 탆, preferably 0.5 탆 to 5.0 탆, and more preferably 1.0 탆 to 2.0 탆.

When the average particle diameter D50 of the conductive powder (A-2) is 0.1 m or more, the thickening of the conductive adhesive agent is suppressed, and sufficient application property can be obtained. On the other hand, by setting the average particle diameter D50 of the conductive powder (A-2) to 10 m or less, it becomes possible to apply the conductive adhesive to fine portions and the bonding strength becomes sufficient.

The tap density of the conductive powder (A-2) is appropriately selected from the range of 4.0 g / cm3 to 7.0 g / cm3, preferably 4.5 g / cm3 to 6.5 g / cm3, more preferably 5.0 to 6.0 g / cm3 .

When the tap density of the conductive powder (A-2) is 4.0 g / cm3 or more, the conductive powder (A-2) can be highly filled in a relatively compact state, and sufficient conductivity is obtained. On the other hand, the conductive powder (A-2) having a tap density of 7.0 g / cm 3 or less is industrially easy to produce and has sufficient conductivity.

The BET specific surface area of the conductive powder (A-2) is in the range of 0.5 to 1.5 m 2 / g, preferably 0.7 to 1.3 m 2 / g, more preferably 0.9 to 1.1 m 2 / g .

When the BET specific surface area of the conductive powder (A-2) is 0.5 m 2 / g or more, the mutual contact area is increased, and sufficient conductivity is obtained. On the other hand, by setting the BET specific surface area to 1.5 m < 2 > / g or less, viscosity can be easily adjusted even when the content of the conductive powder in the conductive adhesive is increased.

The conductive powder (A-2) may be a commercially available spherical silver powder produced by a known method such as a wet reduction method, electrolytic method or atomization method.

In the present embodiment, the average particle diameter D50 of the conductive powder is a value measured by a particle size distribution measuring apparatus using a laser diffraction scattering type particle size distribution measuring apparatus or a laser Doppler method.

The tap density of the conductive powder was determined by putting a specified amount of powder in a container according to JIS Z 2512 and tapping to the point where the volume of the powder was not further reduced by using a tapping device and changing the mass of the powder to the powder volume after tap Divided.

The BET specific surface area of the conductive powder is a value obtained by adsorbing nitrogen (N ₂ ) to the conductive powder by the BET method (gas adsorption method) and determining the adsorption amount thereof.

(Conductive powder (A-1): conductive powder (A-2) (mass ratio)) of the conductive powder (A-1) to the conductive powder (A- 5 to 40:60, preferably 90:10 to 50:50, and more preferably 82:18 to 58:42.

The blending ratio of the conductive powder (A) in the conductive adhesive agent is appropriately selected in the range of 80% by mass to 95% by mass, preferably 85% by mass to 93% by mass, and more preferably 89% by mass to 91% by mass .

[(B) glycidyl ether compound]

The conductive adhesive of the present invention comprises (B) a glycidyl ether compound.

As the glycidyl ether compound, for example, a known epoxy resin can be used. In the present invention, in order to maintain the fluidity of the conductive adhesive, the viscosity at a liquid phase, particularly at room temperature, is 0.5 to 100 dPa · s, preferably 1 To 10 dPa · s, more preferably 1.5 to 5 dPa · s, and a polyfunctional epoxy resin having two or more epoxy groups in one molecule is preferably used.

Examples of the polyfunctional epoxy resin include bisphenol A type epoxy resins, brominated epoxy resins, novolak type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, glycidylamine type epoxy resins, Alicyclic epoxy resin, trihydroxyphenylmethane type epoxy resin, biquileneol type or biphenol type epoxy resin or a mixture thereof, bisphenol S type epoxy resin, bisphenol A novolak type epoxy resin, tetraphenylol ethane type epoxy resin, A cyclic epoxy resin, a diglycidyl phthalate resin, a tetraglycidyl silyloyl ethane resin, a naphthalene group-containing epoxy resin, an epoxy resin having a dicyclopentadiene skeleton, a glycidyl methacrylate copolymer epoxy resin, A copolymerized epoxy resin of mid and glycidyl methacrylate, a CTBN-modified epoxy resin It can be given.

Of the glycidyl ether compounds (B), glycidyl ether compounds represented by the formula (I) are preferably used in the present invention.

According to this compound, good results can be obtained in any case of the adhesive strength and hardness of the cured product. Further, the influence on the conductivity of the adhesive can be minimized.

In the formula (I), R 1 represents an alkyl group, an aryl group, an alkylaryl group or an arylalkyl group, and m + n = 0, 1 or 2. In the case of m + n ≠ 0, 1, 2, there is a fear that an excellent balance between low carbon and low absorbability is not obtained.

Among the glycidyl ether compounds represented by the above general formula (I), the compound in which m + n = 1 or 2 is, for example, dicyclopentadienedimethanol, alkyl monoglycidyl ether, aryl monoglycidyl ether , Alkylaryl monoglycidyl ether or arylalkyl monoglycidyl ether is reacted with a Lewis acid catalyst to deactivate the catalyst with an alkali and then epichlorohydrin is added to the hydroxyl moiety in the presence of an alkali and phase transfer catalyst Followed by reaction.

Examples of the alkyl group represented by R 1 in the general formula (I) include alkyl having 1 to 18 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec- Butyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1- ethylpropyl, 1,1- dimethylpropyl, 1,2- dimethylpropyl, 2,2-dimethylpropyl, hexyl, cyclohexyl, For example, heptyl, cyclohexylmethyl, octyl, isoheptyl, 2-ethylhexyl, tert-octyl, nonyl, decyl, isodecyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl Branched or cyclic groups such as methyl, ethyl, n-propyl, and the like, which may contain an unsaturated group.

Examples of the aryl group represented by R 1 include groups such as phenyl and naphthyl.

As the alkylaryl group represented by R 1, there may be mentioned a group such as phenyl or naphthyl substituted by the above-mentioned alkyl group.

Examples of the arylalkyl group represented by R < 1 > include groups such as benzyl, alpha -methylbenzyl, alpha, alpha -dimethylbenzyl and the like.

Among them, it is preferable that R1 has an alkyl group having 4 to 18 carbon atoms, whereby a balance of low absorptivity and low elasticity can be obtained.

In the present invention, among the glycidyl ether compounds of the formula (I), a compound wherein m + n = 0, that is, a compound represented by the formula (II) is preferably used.

The glycidyl ether compound of formula (II) can be prepared, for example, by reacting epichlorohydrin with the hydroxyl group portion of dicyclopentadiene dimethanol in the presence of an alkali catalyst and an phase transfer catalyst.

Among the glycidyl ether compounds of the formula (I), the compound of the formula (II) has a low viscosity and improves the handling properties of the conductive adhesive, and good results are obtained in any of the surface properties, the adhesive strength and the hardness of the cured product . Further, by using the glycidyl ether compound of the formula (II), deterioration of the conductivity of the conductive adhesive can be minimized.

The blending ratio of the glycidyl ether compound (B) in the conductive adhesive is appropriately selected in the range of 1% by mass or more to 30% by mass, preferably 5% by mass to 15% by mass, and more preferably 8% to 12% .

[(C) Curing Agent]

The conductive adhesive agent of the present invention includes (C) a curing agent.

As the curing agent, for example,

Chain aliphatic polyamine-based curing agents such as diethylenetriamine, triethylenetriamine, tetraethylenepentamine,

Alicyclic polyamine curing agents such as 1,2-diaminocyclohexane, 1,4-diamino-3,6-diethylcyclohexane and isophoronediamine,

aromatic polyamine curing agents such as m-xylylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone,

A secondary amine-based curing agent such as piperidine,

(Tertiary) amine such as N, N-dimethylpiperazine, triethylenediamine, 2,4,6-tris (dimethylaminomethyl) phenol, benzyldimethylamine (BDMA) An amine-based curing agent and a curing agent such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, Methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1- Isocyanuric acid adduct of 2,4-diamino-6- [2'-methylimidazolyl- (1 ')] - ethyl-s-triazine, An imidazole-based curing agent such as isocyanuric acid is added to N at the 1-position of the compound

Acid anhydrides such as methyl tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride and methylhexahydrophthalic anhydride can be used.

In addition, it is also possible to use a latent curing agent such as boron trifluoride-amine complex, dicyandiamide, organic acid hydrazide, photo-ultraviolet curing agent and the like.

Of these curing agents, an imidazole-based curing agent and a tertiary amine-based curing agent are preferably used, and an imidazole-based curing agent is particularly preferably used. When these curing agents are used, a firm cured state can be obtained at a relatively mild reaction rate.

Examples of commercially available imidazole-based curing agents used in the present invention include 2MZ, 2MZ-P, 2PZ, 2PZ-PW, 2P4MZ, C11Z-CNS, 2PZ-CNS, 2PZCNS- OK, 2MZ-OK, 2PHZ, 2PHZ-PW, 2P4MHZ, 2P4MHZ-PW, 2E4MZ BIS, VT, VT-OK, MAVT, MAVT-OK Manufactured by Shikoku Kasei Kogyo Co., Ltd.).

In particular, 1-cyanoethyl-2-phenylimidazole (2PZ-CN: manufactured by Shikoku Chemicals Corporation) and 2,4-diamino-6- [2'-methylimidazolyl- Ethyl-s-triazine and isocyanuric acid adducts (2MA-OK: manufactured by Shikoku Chemical Industry Co., Ltd.) is preferably used from the viewpoint of the curing state and storage stability. The curing agent may be one type, but it is also possible to use two or more types of curing agents.

The blending ratio of such a curing agent is 1% by mass to 12% by mass, preferably 3% by mass to 9% by mass, and more preferably 5% by mass to 7% by mass, based on the glycidyl ether compound.

The conductive adhesive of the present invention as described above can be mixed with an additive such as a defoaming agent and a leveling agent as necessary.

The conductive adhesive of the present invention as described above preferably has a mass reduction by heating at 150 DEG C for 30 minutes of 0.7 mass% or less, more preferably 0.5 mass% or less, more preferably 0.5 mass% or less, 0.3 mass% or less. As a result, bubbles can be reliably suppressed, and as a result, it is possible to provide a conductive adhesive having a stable bonding strength at the time of mass production.

The conductive adhesive according to the present invention is excellent in handleability because it can be produced mainly as a one-pack type adhesive by mixing the above-mentioned respective components. The conductive adhesive of the present invention is also excellent in storage stability.

Adhesion of members by the conductive adhesive agent of the present invention is performed, for example, as follows.

An adhesive is applied to a bonding portion of an adhesive member such as a printed circuit board by pattern printing with a screen mesh or a metal mask or by application using a dispenser such as a dispenser.

(Part) is placed on the bonding portion of the bonding member (substrate), and the bonding member is bonded to the bonding portion at a temperature of 100 占 폚 to 180 占 폚, preferably 120 占 폚 to 160 占 폚 for 15 minutes 50 minutes, preferably 20 minutes to 40 minutes.

As a result, the glycidyl ether compound in the adhesive reacts with the curing agent to be cured, and the adhesive member (substrate) and the member to be adhered (component) mounted thereon are firmly adhered to each other.

The conductive adhesive agent of the present invention is preferably used for bonding electronic components and exhibits excellent adhesiveness regardless of the bonding area.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto. In the following description, " part " and "% " are based on mass unless otherwise specified.

<Examples>

I. Preparation of Conductive Adhesive

Examples 1 to 4, Comparative Examples 1 and 2

Each component was compounded at the compounding ratio (mass ratio) shown in Table 1 below, stirred and mixed, and then dispersed by a three-roll mill. Thus, the conductive adhesive agent of the present invention and the comparative conductive adhesive agent were obtained.

II. Measurement of resistivity value

The glass substrate was masked by a cellophane tape with a gap of 2 mm in width, and the conductive adhesive obtained in Examples 1 to 4 and Comparative Examples 1 and 2 was applied by a scraper.

After the application, the cellophane tape was peeled off and heated and cured at 150 占 폚 for 30 minutes using a hot air circulation type drying furnace to obtain a test piece for measurement.

The obtained test piece was measured for the pattern film thickness of the conductive adhesive agent using Surfcoda (Kosaka Gensen Co., SE-30H), and the pattern width was measured using a MEASURING MICROSCOPE (STM-MJS manufactured by OLYMPUS Co., ). Further, the resistance value R of the pattern length 5 cm was measured using a tester (Milliohm HiTester 3540, manufactured by Hioki Denka Co., Ltd.).

The resistivity value (? 占) m) was calculated from the film thickness, the pattern width, the pattern length (5 cm), and the resistance value measured in the above by the following formula.

ρ (Ω · cm) = R (Ω) · A (cm 2) / L (cm)

ρ: specific resistance value

R: resistance value

A: Cross-sectional area

L: Length

The obtained results are shown in Table 1.

III. Measurement of adhesion strength

A gap of about 10 mm in width was provided on a glass epoxy copper substrate (base material FR4, copper thickness 35 mu m), and masking was performed by cellophane tape. The electroconductivity obtained by Examples 1 to 4 and Comparative Examples 1 and 2 The adhesive was applied.

After the application, the cellophane tape was peeled off, and the surface of the gold-plated M3 nut (pendulum distance: 5.5 mm, diagonal distance: 6.4 mm, height: 2.4 mm, type 1) And heated at 150 캜 for 30 minutes using a hot-air circulation type drying furnace to be adhered. Thus, a test piece for measurement was obtained.

A shearing force of 5 mm / min in shear rate was applied parallel to the surface of the substrate on the side of the gold-plated M3 nut of the obtained test piece, and a digital force gauge (FGP-50 manufactured by Nippon Densan Co., -TV) was used to measure the shear strength of the bonding surface between the gold-plated M3 nut and the substrate. The measured shear strength was divided by the area of adhesion of gold-plated M3 nuts to calculate the adhesive strength.

The obtained results are shown together in Table 1.

IV. Confirmation of application status

As to the coating state, the coating film coated with the conductive adhesive was checked visually for scratches and bleeding, and it was confirmed that there was no problem in all cases.

V. Pencil hardness test

The pencil hardness (according to the test method of JIS K 5600) was measured for the cured adhesive portion of each sample. It was confirmed that any sample had pencil hardness of 8H or more.

VI. Mass reduction

The conductive adhesives obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were each taken on an aluminum plate having a diameter of 5 cm and 2 g respectively and heated in a hot air circulating type drying furnace at 150 DEG C for 30 minutes to measure the mass after heating did. When the masses of the respective adhesives before and after the heating were compared, all of them showed a mass reduction of 0.3 mass% or less.

The materials in Table 1 are as follows.

Glycidyl ether compound: EP-4088L (dicyclopentadienedimethanol type epoxy resin, epoxy equivalent: 165 g / eq, viscosity: 2.3 dPa.s, total chlorine: 0.09 mass%) manufactured by ADEKA

Conductive powder 1: EA-0101 (specific surface area: 0.32 m 2 / g, tap density: 5.5 g / cm 3, average particle diameter: 5.5 μm)

Conductive powder 2: FA-D-6 (specific surface area: 0.24 m 2 / g, tap density: 5.3 g / cm 3, average particle diameter: 9.6 탆, manufactured by DOWA ELECTRONICS CO., LTD.

(FA-S-12 manufactured by DOWA ELECTRONICS, specific surface area: 0.96 m2 / g, tap density: 5.2 g / cm3, average particle diameter: 2.1 mu m)

Conductive powder 4: AA-4703 (specific surface area: 1.01 m 2 / g, tap density: 3.5 g / cm 3, average particle size: 4 μm, manufactured by DOWA ELECTRONICS CO.

Conductive powder 5: spherical silver powder (K-0082P manufactured by Metalo K., specific surface area: 0.99 m 2 / g, tap density: 5.4 g / cm 3,

Hardener: 2,4-diamino-6- [2'-methylimidazolyl- (1 ')] -ethyl-s-triazine isocyanuric acid adduct (2MAOK-PW manufactured by Shikoku Chemicals Corporation)

Conductive Powder (A-1): In each of the examples / comparative examples,

Conductive powder (A-2): Silver powder having a small particle size mixed in each of the examples and comparative examples

Not measurable: means that the resistance value was too large to be measured.

As is clear from Table 1, the cured products of the conductive adhesives of Examples 1 to 4 had small specific resistances and excellent adhesive strength. On the other hand, it was confirmed that the conductive adhesives of Comparative Examples 1 and 2 had a very high resistance value.

In addition, the conductive adhesive of the present invention can be said to have excellent quality because the composition of the comparative example is excellent in the application state, hardness and mass reduction.

Claims (3)

A conductive powder comprising a conductive powder (A-1) on a flake, a conductive powder (A-2) having an average particle diameter of not more than one-third of the flaky conductive powder (A-
(B) a glycidyl ether compound,
(C) a curing agent, and does not contain a solvent. 2. The conductive adhesive according to claim 1, wherein the conductive powder (A-2) is at least one kind of conductive powder selected from a flake and spheres. An electronic part in which members are electrically connected to each other by using the conductive adhesive according to any one of claims 1 to 3.