ELECTROCONDUCTIVE ADHESIVE

Abstract

Provided is an electroconductive adhesive which is less apt to suffer cracking, chipping, etc. upon sintering and gives sintered objects having excellent mechanical strength. The electroconductive adhesive comprises metallic microparticles which include a protective layer comprising one or more amines and have an average particle diameter of 30-300 nm, the amines comprising a C.sub.5-7 monoalkylamine and/or an alkoxyamine represented by the following general formula (1). NH.sub.2R.sup.2OR.sup.1 (1) In the protective layer, the ratio of the C.sub.5-7 monoalkylamine and/or alkoxyamine represented by the general formula (1) to one or more amines different therefrom is in the range of 100:0 to 10:90. [In formula (1), R.sup.1 represents a C.sub.1-4 alkyl group and R.sup.2 represents a C.sub.1-4 alkylene group.]

Claims

1. An electroconductive adhesive comprising metal fine particles A that include a protective layer containing an amine and have an average particle diameter of 30 nm to 300 nm, the amine including a monoalkylamine with 5 to 7 carbon atoms and/or an alkoxyamine represented by a following general formula (1):
NH.sub.2R.sup.2OR.sup.1(1), wherein R.sup.1 represents an alkyl group with 1 to 4 carbon atoms and R.sup.2 represents an alkylene group with 1 to 4 carbon atoms, and the protective layer having a ratio in a range of 100:0 to 10:90 between the monoalkylamine with 5 to 7 carbon atoms and/or the alkoxyamine represented by the general formula (1) and an amine different from these amines.

2. The electroconductive adhesive according to claim 1, wherein the protective layer further contains a fatty acid.

3. The electroconductive adhesive according to claim 1, further comprising a solvent.

4. A sintered object of the electroconductive adhesive according to claim 1.

5. A circuit or an apparatus comprising a part that bonds between members and is the sintered object according to claim 4.

6. A method of manufacturing an electroconductive adhesive, the method comprising a step of mixing metal fine particles A that include a protective layer containing an amine and have an average particle diameter of 30 nm to 300 nm, in the metal fine particles A used, the amine including a monoalkylamine with 5 to 7 carbon atoms and/or an alkoxyamine represented by a following general formula (1):
NH.sub.2R.sup.2OR.sup.1(1), wherein R.sup.1 represents an alkyl group with 1 to 4 carbon atoms and R.sup.2 represents an alkylene group with 1 to 4 carbon atoms, and the protective layer having a ratio in a range of 100:0 to 10:90 between the monoalkylamine with 5 to 7 carbon atoms and/or the alkoxyamine represented by the general formula (1) and an amine different from these amines.

7. The method of manufacturing an electroconductive adhesive according to claim 6, further comprising the steps of: arranging metal fine particles that include a protective layer containing an amine and have an average particle diameter of 30 nm to 300 nm; and substituting the amine contained in the protective layer of the metal fine particles by the monoalkylamine with 5 to 7 carbon atoms and the alkoxyamine represented by the general formula (1) and thus adjusting the ratio to within the range of 100:0 to 10:90 between the monoalkylamine with 5 to 7 carbon atoms and/or the alkoxyamine represented by the general formula (1) and an amine different from these amines to prepare the metal fine particles A.

8. A method of bonding members comprising the steps of: disposing the electroconductive adhesive according to claim 1 between members; and heating the electroconductive adhesive for sintering.

Description

EXAMPLES

[0095] The present invention is more specifically described by way of the following examples. The present invention, however, is not limited to these examples.

[0096] The detail of the components used in the examples and comparative examples is as follows. [0097] Silver oxalate ((COOAg).sub.2) synthesized by a method described in Patent Document 1 (U.S. Pat. No. 5,574,761) [0098] Oleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) [0099] N,N-Dimethyl-1,3-diaminopropane (manufactured by Wako Pure Chemical Industries, Ltd.) [0100] N,N-Diethyl-1,3-diaminopropane (manufactured by Wako Pure Chemical Industries, Ltd.) [0101] n-Hexylamine (6 carbon atoms, manufactured by Wako Pure Chemical Industries, Ltd.) [0102] n-Propylamine (3 carbon atoms, manufactured by Wako Pure Chemical Industries, Ltd.) [0103] n-Butylamine (4 carbon atoms, manufactured by Wako Pure Chemical Industries, Ltd.) [0104] 3-Methoxypropylamine (4 carbon atoms, manufactured by Wako Pure Chemical Industries, Ltd.) [0105] 2-(2-Ethylhexyloxy)ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) [0106] Butanol (manufactured by Wako Pure Chemical Industries, Ltd.) [0107] Pentanol (manufactured by Wako Pure Chemical Industries, Ltd.)

[0108] In the following examples and comparative examples, an amine(s) in a protective layer of synthesized silver fine particles is measured by the following method.

(Method of Measuring Ratio of Amine(s) Contained in Protective Layer of Silver Fine Particles)

[0109] Methanol in an amount of 4 g was added to 1 g of silver fine particles and the mixture was stirred for 1 minute. Subsequently, 100 mg of concentrated hydrochloric acid was added to the mixture while the mixture was stirred, and the stirring was continued for another 10 minutes to free a protective layer. While the stirring was further continued, 150 mg of a 48% aqueous solution of sodium hydroxide was added to the mixture to give a solid-liquid mixture having a pH of more than 7. The solid-liquid mixture was filtrated to give a methanol solution containing an extracted amine(s) that had been contained in the protective layer, and the methanol solution was used as a sample for gas chromatography. The sample was analyzed by gas chromatography (GC-2010 manufactured by SHIMADZU CORPORATION, column: Rtx-5 Amine manufactured by Restek Corporation), and the ratio (GC %) of the amine(s) contained in the protective layer was quantitated by the obtained ratio of a peak area(s) of the amine(s). Tables 1 to 3 show the results.

[0110] In Tables 1 to 3, HA represents n-hexylamine, MP represents methoxypropylamine, DA represents N,N-diethyl-1,3-diaminopropane or N,N-dimethyl-1,3-diaminopropane, BuNH.sub.2 represents n-butylamine, and PrNH.sub.2 represents n-propylamine.

[0111] In the following examples and comparative examples, the mechanical strength and cracks and chips on a coating film were evaluated as follows. Tables 1 to 3 show the results.

(Evaluation of Mechanical Strength)

[0112] The shear strength of a coating film obtained in each of the examples and comparative examples was measured by performing a die shear test with use of a bond tester (SS30-WD manufactured by SEISHIN TRADING CO., LTD.).

Evaluation of Cracks and Chips on Coating Film

[0113] A surface of a coating film obtained in each of the examples and comparative examples was observed by visual inspection and evaluated for presence or absence of cracks and chips on the coating film.

<Synthesis Example 1> Synthesis Example of Metal Fine Particles Having Average Particle Diameter of 200 nm

[0114] Oleic acid (0.1 g), N,N-diethyl-1,3-diaminopropane (3.25 g), and pentanol (4.0 g) were charged into 50-mL glass-made centrifuge tubes each having a magnetic stirrer placed therein, the mixture was stirred for about 1 minute, and then, silver oxalate (4.0 g) was charged into each of the centrifuge tubes and stirred for about 10 minutes to give a silver fine particle preparation composition. Subsequently, these glass-made centrifuge tubes were set upright on a hot stirrer equipped with an aluminum block (HHE-19G-U manufactured by KOIKE PRECISION INSTRUMENTS), and the composition was stirred at 40 C. for 30 minutes and further stirred at 90 C. for 30 minutes. After the composition was allowed to cool, the magnetic stirrer was taken out, and 15 g of methanol was added to the composition and stirred with a vortex mixer. Then, the composition was subjected to centrifugal operation for 1 minute at 3000 rpm (about 1600G) by a centrifugal machine (CF7D2 manufactured by Hitachi Koki Co., Ltd.) and the centrifuge tube was inclined to remove a supernatant. The step of addition of 15 g of methanol, stirring, centrifugation, and removal of a supernatant was repeated two times, and silver fine particles 1 manufactured were recovered. The silver fine particles 1 obtained in Synthesis Example 1 were observed with a scanning electron microscope (S-4500 manufactured by Hitachi High-Technologies Corporation) and measurement was performed for the length of long sides of any 30 particles included in an image to determine an average value. The average particle diameter was 200 nm.

Method of Adjusting Ratio of Amine Contained in Protective Layer of Silver Fine Particles 1 (Substitution)

[0115] To a dispersion (methanol solution) containing the silver fine particles 1 obtained in Synthesis Example 1, each of n-hexylamine (used for preparing silver fine particles 1A) and methoxypropylamine (used for preparing silver fine particles 1B) was added in an amount of 3 times the mass of the silver fine particles 1 and stirred at room temperature for 4 hours to prepare a composition. After the stirring, the magnetic stirrer was taken out, and 15 g of methanol was added to each of the compositions and stirred with the vortex mixer. Then, the composition was subjected to centrifugal operation for 1 minute at 3000 rpm (about 1600G) by the centrifugal machine (CF7D2 manufactured by Hitachi Koki Co., Ltd.) and the centrifuge tube was inclined to remove a supernatant. The step of addition of 15 g of methanol, stirring, centrifugation, and removal of a supernatant was repeated two times to recover the silver fine particles 1A and 1B each having the ratio between the amines in the protective layer adjusted (substitution). The average particle diameter did not change.

Examples 1 and 2

[0116] In Examples 1 and 2, the silver fine particles 1A and 1B were used, respectively. Terpineol in an amount corresponding to 10% of the total mass was added to the silver fine particles to give a dispersion. This dispersion was mixed using MAZERUSTAR manufactured by KURABO INDUSTRIES LTD. with a two-time stirring priority mode, to prepare an electroconductive adhesive.

[0117] Next, a substrate was arranged that included a copper plate having non-electrolytic silver plating (0.5 m) performed thereon, the electroconductive adhesive was uniformly applied onto the substrate to form a coating film such that the thickness of the coating film became 50 m, and on the electroconductive adhesive was placed a silicon wafer (size 2 mm2 mm) having a rear surface (surface in contact with the electroconductive adhesive) thereof gold-plated or treated by gold sputtering. The layered product was heated by a drier (circulation type) at a predetermined temperature (150 C.) for 60 minutes to give a coating film that is the electroconductive adhesive sintered.

<Synthesis Example 2> Synthesis Example of Metal Fine Particles Having Average Particle Diameter of 75 nm

[0118] Oleic acid (0.1 g). N,N-diethyl-1,3-diaminopropane (3.25 g), and butanol (6.0 g) were charged into 50-mL glass-made centrifuge tubes each having a magnetic stirrer placed therein, the mixture was stirred for about 1 minute, and then, silver oxalate (4.0 g) was charged into each of the centrifuge tubes and stirred for about 10 minutes to give a silver fine particle preparation composition. Subsequently, these glass-made centrifuge tubes were set upright on a hot stirrer equipped with an aluminum block (HHE-19G-U manufactured by KOIKE PRECISION INSTRUMENTS), and the composition was stirred at 40 C. for 30 minutes and further stirred at 90 C. for 30 minutes. After the composition was allowed to cool, the magnetic stirrer was taken out, and 15 g of methanol was added to the composition and stirred with a vortex mixer. Then, the composition was subjected to centrifugal operation for 1 minute at 3000 rpm (about 1600G) by a centrifugal machine (CF7D2 manufactured by Hitachi Koki Co., Ltd.) and the centrifuge tube was inclined to remove a supernatant. The step of addition of 15 g of methanol, stirring, centrifugation, and removal of a supernatant was repeated two times, and silver fine particles 2 manufactured were recovered. The silver fine particles 2 obtained in Synthesis Example 2 were observed with the scanning electron microscope (S-4500 manufactured by Hitachi High-Technologies Corporation) and measurement was performed for the length of long sides of any 30 particles included in an image to determine an average value. The average particle diameter was 75 nm. The silver fine particles 2 obtained in Synthesis Example 2 were used in the examples as silver fine particles 2C.

Method of Adjusting Ratio of Amine Contained in Protective Layer of Silver Fine Particles 2 (Substitution)

[0119] To a dispersion (methanol solution) containing the silver fine particles 2 obtained in Synthesis Example 2, each of n-hexylamine (used for preparing silver fine particles 2A), methoxypropylamine (used for preparing silver fine particles 2B), n-butylamine (used for preparing silver fine particles 2D), and n-propylamine (used for preparing silver fine particles 2E) was added in an amount of 3 times the mass of the silver fine particles 2 and stirred at room temperature for 4 hours to prepare a composition. After the stirring, the magnetic stirrer was taken out, and 15 g of methanol was added to each of the compositions and stirred with the vortex mixer. Then, the composition was subjected to centrifugal operation for 1 minute at 3000 rpm (about 1600G) by the centrifugal machine (CF7D2 manufactured by Hitachi Koki Co., Ltd.) and the centrifuge tube was inclined to remove a supernatant. The step of addition of 15 g of methanol, stirring, centrifugation, and removal of a supernatant was repeated two times to recover the silver fine particles 2A to 2E each having the ratio between the amines in the protective layer adjusted (substitution). The average particle diameter did not change.

Examples 3 and 4 and Comparative Examples 1 to 3

[0120] Terpineol in an amount corresponding to 10% of the total mass was added to each of the silver fine particles 2A to 2E obtained above to give a dispersion. The silver fine particles 2A was used in Example 3, the silver fine particles 2B in Example 4, the silver fine particles 2C in Comparative Example 1, the silver fine particles 2D in Comparative Example 2, and the silver fine particles 2E in Comparative Example 3. Each of these dispersions was mixed using MAZERUSTAR manufactured by KURABO INDUSTRIES LTD. with a two-time stirring priority mode, to prepare an electroconductive adhesive.

[0121] Next, a substrate was arranged that included a copper plate having non-electrolytic silver plating (0.5 m) performed thereon, the electroconductive adhesive was uniformly applied onto the substrate to form a coating film such that the thickness of the coating film became 50 m, and on the electroconductive adhesive was placed a silicon wafer (size 2 mm2 mm) having a rear surface (surface in contact with the electroconductive adhesive) thereof gold-plated or treated by gold sputtering. The layered product was heated by a drier (circulation type) at a predetermined temperature (150 C.) for 60 minutes to give a coating film that is the electroconductive adhesive sintered.

<Synthesis Example 3> Synthesis Example of Metal Fine Particles Having Average Particle Diameter of 20 nm

[0122] Oleic acid (0.06 g), hexylamine (1.4 g), N,N-dimethyl-1,3-diaminopropane (0.3 g), butylamine (0.6 g), and 2-(2-ethylhexyloxy)ethanol (4.0 g) were charged into 50-mL glass-made centrifuge tubes each having a magnetic stirrer placed therein, the mixture was stirred for about 1 minute, and then, silver oxalate (4.0 g) was charged into each of the centrifuge tubes and stirred for about 10 minutes to give a silver fine particle preparation composition. Subsequently, these glass-made centrifuge tubes were set upright on a hot stirrer equipped with an aluminum block (HHE-19G-U manufactured by KOIKE PRECISION INSTRUMENTS), and the composition was stirred at 40 C. for 30 minutes and further stirred at 90 C. for 30 minutes. After the composition was allowed to cool, the magnetic stirrer was taken out, and 15 g of methanol was added to the composition and stirred with a vortex mixer. Then, the composition was subjected to centrifugal operation for 1 minute at 3000 rpm (about 1600G) by a centrifugal machine (CF7D2 manufactured by Hitachi Koki Co., Ltd.) and the centrifuge tube was inclined to remove a supernatant. The step of addition of 15 g of methanol, stirring, centrifugation, and removal of a supernatant was repeated two times, and silver fine particles 6 manufactured were recovered. The silver fine particles 3 obtained in Synthesis Example 3 were observed with the scanning electron microscope (S-4500 manufactured by Hitachi High-Technologies Corporation) and measurement was performed for the length of long sides of any 30 particles included in an image to determine an average value. The average particle diameter was 20 nm.

Method of Adjusting Ratio of Amines Contained in Protective Layer of Silver Fine Particles 3 (Substitution)

[0123] n-Hexylamine was added to a dispersion (methanol solution) containing the silver fine particles 3 obtained in Synthesis Example 3 in an amount of 3 times the mass of the silver fine particles and stirred at room temperature for 4 hours to prepare a composition. After the stirring, the magnetic stirrer was taken out, and 15 g of methanol was added to each of the compositions and stirred with the vortex mixer. Then, the composition was subjected to centrifugal operation for 1 minute at 3000 rpm (about 1600G) by the centrifugal machine (CF7D2 manufactured by Hitachi Koki Co., Ltd.) and the centrifuge tube was inclined to remove a supernatant. The step of addition of 15 g of methanol, stirring, centrifugation, and removal of a supernatant was repeated two times to recover silver fine particles 3A having the ratio between the amines contained in the protective layer adjusted (substitution). The average particle diameter did not change.

Comparative Example 4

[0124] Terpineol in an amount corresponding to 10% of the total mass was added to the silver fine particles 3A to give a dispersion. This dispersion was mixed using MAZERUSTAR manufactured by KURABO INDUSTRIES LTD. with a two-time stirring priority mode, to prepare an electroconductive adhesive.

[0125] Next, a substrate was arranged that included a copper plate having non-electrolytic silver plating (0.5 m) performed thereon, the electroconductive adhesive was uniformly applied onto the substrate to form a coating film such that the thickness of the coating film became 50 m, and on the electroconductive adhesive was placed a silicon wafer (size 2 mm2 mm) having a rear surface (surface in contact with the electroconductive adhesive) thereof gold-plated or treated by gold sputtering. The layered product was heated by a drier (circulation type) at a predetermined temperature (150 C.) for 60 minutes to give a coating film that is the electroconductive adhesive sintered.

TABLE-US-00001 TABLE 1 Compar- Compar- Compar- Compar- ative ative ative ative Silver fine particles Exam- Exam- Exam- Exam Exam- Exam- Exam- Exam- (amine in protective layer) ple 1 ple 2 ple 3 ple 4 ple 1 ple 2 ple 3 ple 4 Mixing 1A 200 nm (n-Hexylamine) 100 ratio 1B 200 nm (3-Methoxypropylamine) 100 (part by 2A 75 nm (n-Hexylamine) 100 mass) 2B 75 nm (3-Methoxypropylamine) 100 2C 75 nm (Diethyl diminopropane) 100 2D 75 nm (n-Butylamine) 100 2E 75 nm (n-Propylamine) 100 3A 20 am (n-Hexylamine) 100 Average particle diameter (m) 200 200 75 75 75 20 Ratio between amines (GC %) HA MP HA:DA MP:DA DA BuNH.sub.2 PrNH.sub.2 HA 100 100 99:1 98:2 100 100 100 100 Cracks on coating film None None None None None None None Found Shear strength [kgf] 25.8 12.9 13.5 11.2 3.2 1.2 1.7 0.6

[0126] As is clear from the results shown in Table 1, the electroconductive adhesives of Examples 1 to 4 were high in shear strength of the coating film and had neither cracks nor chips on the coating film. In the electroconductive adhesives, the metal fine particles had an average particle diameter in a range of 30 nm to 300 nm, the amine in the protective layer included a monoalkylamine with 5 to 7 carbon atoms and/or an alkoxyamine represented by the general formula (1), and the ratio between the monoalkylamine with 5 to 7 carbon atoms and/or the alkoxyamine represented by the general formula (1) and an amine different from these amines was in a range of 100:0 to 10:90. On the other hand, the electroconductive adhesives of Comparative Examples 1 to 3 were low in shear strength of the coating film. In the electroconductive adhesives, the protective layer contained, as the amine, N,N-diethyl-1,3-diaminopropane, n-butylamine, and n-propylamine at a ratio of 100% in Comparative Examples 1 to 3, respectively. The electroconductive adhesive of Comparative Example 4 where the metal fine particles had an average particle diameter of 20 nm was also low in shear strength of the coating film.

Examples 5 to 11

[0127] The silver fine particles 1A, 1B, 2A, 2B, and 2C obtained above were mixed at a ratio shown in Table 2, and terpineol in an amount corresponding to 10% of the total mass was added to give a dispersion. This dispersion was mixed using MAZERUSTAR manufactured by KURABO INDUSTRIES LTD. with a two-time stirring priority mode, to prepare an electroconductive adhesive. The average particle diameter after the mixing was obtained by the method described above.

[0128] Next, a substrate was arranged that included a copper plate having non-electrolytic silver plating (0.5 m) performed thereon, the electroconductive adhesive was uniformly applied onto the substrate to form a coating film such that the thickness of the coating film became 50 m, and on the electroconductive adhesive was placed a silicon wafer (size 2 mm2 mm) having a rear surface (surface in contact with the electroconductive adhesive) thereof gold-plated or treated by gold sputtering. The layered product was heated by a drier (circulation type) at a predetermined temperature (150 C.) for 60 minutes to give a coating film that is the electroconductive adhesive sintered.

TABLE-US-00002 TABLE 2 Silver fine particles Exam- Exam- Exam- Exam- Exam- Exam- Exam- (amine in protective layer) ple 5 ple 6 ple 7 ple 8 ple 9 ple 10 ple 11 Mixing 1A 200 nm (n-Hexylamine) 50 25 10 50 ratio 1B 200 nm (3-Methoxypropylamine) 50 50 (part by 2A 75 nm (n-Hexylamine) 50 50 75 90 50 mass) 2B 75 nm (3-Methoxypropylamine) 2C 75 nm (Diethyl diaminopropane) 50 50 50 Average particle diameter (m) 81 81 77 76 75 81 81 Ratio between amines (GC %) HA MP:HA HA HA HA:DA HA:DA MP:DA 100 29:71 100 100 55:45 47:53 31:69 Cracks on coating film None None None None None None None Shear strength [kgf] 21.2 21.6 28.7 19.6 13.8 12.6 13.6

[0129] As is clear from the results shown in Table 2, the electroconductive adhesives of Examples 5 to 11 were high in shear strength of the coating film and had neither cracks nor chips on the coating film at a sintering temperature of 150 C., because while each of the electroconductive adhesives was obtained by mixing types of metal fine particles that had different average particle diameters and/or included the protective layers containing different amines, the mixed types of metal fine particles had an average particle diameter in a range of 30 nm to 300 nm, the amines in the protective layers included a monoalkylamine with 5 to 7 carbon atoms and/or an alkoxyamine represented by the general formula (1), and the ratio between the monoalkylamine with 5 to 7 carbon atoms and/or the alkoxyamine represented by the general formula (1) and an amine different from these amines was in a range of 100:0 to 10:90.

Examples 12 and Comparative Examples 5 and 6

[0130] The silver fine particles 1A, 1B, 2A, 2B, 2C, and 3A obtained above were mixed at a ratio shown in Table 3, and terpineol in an amount corresponding to 10% of the total mass was added to give a dispersion. This dispersion was mixed using MAZERUSTAR manufactured by KURABO INDUSTRIES LTD. with a two-time stirring priority mode, to prepare an electroconductive adhesive. The average particle diameter after the mixing was obtained by the method described above.

[0131] Next, a substrate was arranged that included a copper plate having non-electrolytic silver plating (0.5 m) performed thereon, the electroconductive adhesive was uniformly applied onto the substrate to form a coating film such that the thickness of the coating film became 50 m, and on the electroconductive adhesive was placed a silicon wafer (size 2 mm2 mm) having a rear surface (surface in contact with the electroconductive adhesive) thereof gold-plated or treated by gold sputtering. The layered product was heated by a drier (circulation type) at a predetermined temperature (150 C.) for 60 minutes to give a coating film that is the electroconductive adhesive sintered.

TABLE-US-00003 TABLE 3 Comparative Comparative Silver fine particles (amine in protective layer) Example 12 Example 5 Example 6 Mixing ratio 1A 200 nm (n-Hexylamine) 24 30 (part by mass) 1B 200 nm (3-Methoxypropylamine) 30 2A 75 nm (n-Hexylamine) 72 2B 75 nm (3-Methoxypropylamine) 2C 75 nm (Diethyl diaminopropane) 60 60 3A 20 nm (n-Hexylamine) 4 10 10 Average particle diameter (m) 35 26 26 Ratio between amines (GC %) HA HA:DA MP:HA:DA 100 68:32 3:51:46 Cracks on coating film None None None Shear strength [kgf] 31.3 6.7 5.5

[0132] As is clear from the results shown in Table 3, the electroconductive adhesive of Example 12 was high in shear strength of the coating film and had neither cracks nor chips on the coating film at a sintering temperature of 150 C., because while the electroconductive adhesive was obtained by mixing three types of metal fine particles that had different average particle diameters and included the protective layers containing different amines, the mixed types of metal fine particles had an average particle diameter in a range of 30 nm to 300 nm, the amines in the protective layers included a monoalkylamine with 5 to 7 carbon atoms and/or an alkoxyamine represented by the general formula (1), and the ratio between the monoalkylamine with 5 to 7 carbon atoms and/or the alkoxyamine represented by the general formula (1) and an amine different from these amines was in a range of 100:0 to 10:90. On the other hand, the electroconductive adhesives of Comparative Examples 5 and 6 where the average particle diameter was under 30 m were low in shear strength of the coating film.