JP6541764B2 - Silver-coated copper powder and conductive paste, and method for producing them - Google Patents

Description

The present invention relates to a silver-coated copper powder used for a conductive paste applied to electrodes and circuits of electronic parts and the like, a conductive paste containing the silver-coated copper powder, and a method for producing them .

A conductive paste is applied to electrodes and circuits of electronic parts and the like, an electromagnetic wave shielding film, and a conductive adhesive sheet. And metal powder, such as copper powder and silver powder, is used for the said conductive paste.
Here, a silver paste using silver powder as metal powder is superior in oxidation resistance and conductivity as compared to a copper paste using copper powder as metal powder, but silver metal is expensive. It also has the problems that migration is likely to occur and that it is inferior in solder corrosion resistance.
In order to solve the subject of the said silver-based paste, an applicant is disclosing patent document 1, two. There is also a proposal of Patent Document 3.

JP, 2010-275638, A JP, 2012-167337, A Japanese Patent Application Laid-Open No. 63-81706

The shape of the metal powder used in the conductive paste may be spherical or flake.
Usually, spherical metal powder and flake metal powder are often used in combination.
At this time, the spherical metal powder exhibits effects such as reduction of viscosity of the conductive paste, and improvement of density when hardened or burned, and flake-like metal powder has an increase in viscosity of the conductive paste, and coatability. It is thought that the effect of improving the density of the metal powder and suppressing the increase of the bulk density of the metal powder is exhibited.
However, in the case of the conductive paste using the spherical and flake-like copper powder, particularly in the conductive paste with a low metal powder content, further improvement is desired from the viewpoint of conductivity.
The present invention has been accomplished under the above-described circumstances, and the problem to be solved is a metal powder that can be used for a conductive paste that exhibits sufficient conductivity even with a low metal powder content. To provide.

In order to solve the above-mentioned subject, the present inventors conducted earnest research.
And even a spherical shape such as a copper powder having dendrites, a copper powder in which a plurality of copper powders having the dendrites are entangled and aggregated to become inseparable, and a rod-like copper powder not having the dendrites The silver-coated copper powder which applied silver coating to the non-flake-like odd-shaped copper powder was discovered.
Here, when silver is coated on a mixture of these different-shaped copper powders, the coated state of silver such as silver-coated film thickness, silver coverage, etc. between respective copper powder particles or in copper powder particles. In some cases, the evenness of However, as a result of studies by the present inventors, significant effects of the silver coating could be obtained regardless of the uniformity. Although the reason is not clear, it is inferred that, in the case of silver coating on the odd-shaped copper powder, unlike the conventional silver-coated copper powder, a state in which uniformity is not required may be formed.
And, by using the silver-coated copper powder for the conductive paste, it is possible to form a large number of conductive paths with low electric resistance compared to the case where spherical or flake-like copper powder or silver-coated copper powder is used. As a result, the present invention has been completed in view of solving the above-mentioned problems.

In addition, for convenience of explanation, among the copper powders of a different shape used for the silver-coated copper powder according to the present invention, those having the above-mentioned dendritic projections are referred to as “dendritic copper powders”, copper powders having the dendritic projections. In some cases, those in which a plurality of entanglements aggregate and become inseparable may be referred to as “clad copper powder”, and a rod-like one having no dendrites as “rod-like copper powder”. Moreover, the silver-coated copper powder which gave silver coating to these copper powders may be described as "dendritic silver-coated copper powder", "棘 -like silver-coated copper powder", and "rod-like silver-coated copper powder".

That is, the first invention for solving the above-mentioned problems is:
A silver-coated copper powder comprising dendritic silver-coated copper powder, scale-like silver-coated copper powder, and rod-like silver-coated copper powder,
The amount of the silver coating is 0.1% by mass or more and 30% by mass or less,
1 type selected from palmitic acid, stearic acid and oleic acid on the surface of the silver-coated copper powder, and 1 type selected from adipic acid, malonic acid, succinic acid and azelaic acid Or a surface treatment agent comprising a mixture of these is provided, which is a silver-coated copper powder.
The second invention is
A silver-coated copper powder comprising dendritic silver-coated copper powder, scale-like silver-coated copper powder, and rod-like silver-coated copper powder,
The amount of the silver coating is 0.1% by mass or more and 30% by mass or less,
The surface treatment agent which consists of 1H-benzotriazole is provided in the surface of the said silver covering copper powder, It is a silver covering copper powder characterized by the above-mentioned.
The third invention is
A conductive paste comprising the silver-coated copper powder according to the first or second invention.
The fourth invention is
Silver coated copper powder, an emulsion comprising one or more selected from palmitic acid, stearic acid and oleic acid as a first surface treatment agent, or one or more selected from palmitic acid, stearic acid and oleic acid Adding a mixed solution with alcohol to form a mixed solution, and performing a first surface treatment on the silver-coated copper powder;
A second surface treatment agent containing one or more selected from adipic acid, malonic acid, succinic acid and azelaic acid is added to the first surface-treated silver-coated copper powder to perform surface treatment, Obtaining a silver-coated copper powder subjected to the first and second surface treatments, and a method of producing the silver-coated copper powder.
The fifth invention is
A method for producing a silver-coated copper powder comprising the steps of adding a surface treatment agent comprising 1H-benzotriazole to a silver-coated copper powder to perform surface treatment to obtain a silver-coated copper powder.
The sixth invention is
A method for producing a conductive paste, comprising the step of kneading the silver-coated copper powder produced by the method for producing a silver-coated copper powder according to the fourth or fifth invention, and an appropriate resin and solvent. It is.

The silver-coated copper powder according to the present invention can be used as a metal powder of a conductive paste that exhibits sufficient conductivity even with a low metal powder content.

It is 1st visual field of the SEM photograph (1000 times of magnification) which captured the silver-coated copper powder which concerns on this invention by 11 visual fields. It is 2 visual fields of the SEM photograph (1000 times) which captured silver covering copper powder concerning the present invention with 11 visual fields. It is 3rd visual field of the SEM photograph (1000 times) which captured silver covering copper powder concerning the present invention with 11 fields of visual field. It is 4th visual field of the SEM photograph (1000 times) which captured the silver-coated copper powder which concerns on this invention by 11 sheets of visual field. It is the 5th visual field of the SEM photograph (1000 times of magnification) which caught silver covering copper powder concerning the present invention by 11 visual fields. It is the sixth visual field of a SEM photograph (1000 ×) of the silver-coated copper powder according to the present invention captured in eleven visual fields. It is the 7th visual field of the SEM photograph (1000 times of magnification) which caught silver covering copper powder concerning the present invention by 11 visual fields. It is the eighth view of the SEM photograph (1000 ×) of the silver-coated copper powder according to the present invention captured in 11 views. It is the 9th visual field of the SEM photograph (1000 times of magnification) which caught silver covering copper powder concerning the present invention with 11 sheets of visual field. It is the tenth visual field of the SEM photograph (1000 ×) of the silver-coated copper powder according to the present invention captured in eleven visual fields. It is the 11th visual field of the SEM photograph (1000 times of magnification) which caught silver covering copper powder concerning the present invention with 11 sheets of visual field. It is a manufacture flow figure of silver covering copper powder concerning the present invention.

The silver-coated copper powder for a conductive paste according to the present invention is a silver-coated copper powder in which a silver powder is coated on a modified copper powder, and further surface-treated with surface treatment agents 1 and 2 as desired.
The silver-coated copper powder for a conductive paste according to the present invention and the method for producing the same will be described below in this order.

1. Silver-coated copper powder for conductive paste according to the present invention In the silver-coated copper powder according to the present invention, a plurality of silver-coated copper powder having dendritic projections and a plurality of silver-coated copper powders having dendritic projections are entangled and aggregated to cause separation failure. There are silver-coated copper powders that have become possible, and rod-like silver-coated copper powders that do not have such dendrites. These silver-coated copper powders are described with reference to SEM photographs.
FIGS. 1-11 are 1000 which caught silver covering copper powder which concerns on Example 28 mentioned later in the visual field of 11 sheets.
It is a double SEM picture. In FIG. 1, typical examples of dendritic silver-coated copper powder, sickle-like silver-coated copper powder, and rod-like silver-coated copper powder are circled and marked.

As can be understood from FIG. 1, dendrite silver-coated copper powder has a trunk portion to be one main axis, and has a dendritic structure in which a plurality of branches are branched from the trunk portion. Protruding copper powder to 0.1
-30 mass% silver coating was made.
The cage-like silver-coated copper powder has a structure in which a plurality of dendritic silver-coated copper powders entangle and aggregate with each other to become inseparable, or a structure in which branches radially extend from a central portion serving as a core 0.1-30 mass% silver coating was made to the bowl-like copper powder which has these.
The rod-like silver-coated copper powder is 0.1 to 3 in dendrite copper powder having a trunk portion to be one main spindle.
A silver coating of 0% by mass was applied.

In the field of view 11 shown in FIGS. 1 to 11, 358 pieces of silver-coated copper powder according to the present invention were observed. Then, among the 358 silver-coated copper powders, 9 dendritic silver-coated copper powders, 254 scaly silver-coated copper powders, and 95 rod-shaped silver-coated copper powders were present. When the abundance ratio of the number was determined, the dendritic silver-coated copper powder was 2.5%, the scaly silver-coated copper powder was 71%, and the rod-like silver-coated copper powder was 26.5%. The results are shown in Table 1.

Furthermore, nine particles of dendrite-like silver-coated copper powder whose shapes are easy to understand are selected from the 11 fields of view mentioned above, and the major axis and minor axis are measured with respect to the dendrite-like silver-coated copper powder. The major diameter ratio was determined. The results are shown in Table 2.

The silver-coated copper powder according to the present invention preferably includes dendritic silver-coated copper powder, scaly silver-coated copper powder, and rod-shaped silver-coated copper powder. It is considered that the inclusion of the silver-coated copper powder having different shapes facilitates formation of a conductive path between the projections of each silver-coated copper powder.

In the silver-coated copper powder according to the present invention, the proportions of dendritic silver-coated copper powder, scale-like silver-coated copper powder, and rod-like silver-coated copper powder are the total number of these silver-coated copper powders. The percentage of the number occupied by the dendrite silver-coated copper powder is in the range of 0.10% or more and 80% or less, the number percentage of the scaly silver-coated copper powder is in the range of 0.10% or more and 75% or less, It is preferable from the viewpoint of securing sufficient conductivity that the number ratio occupied by the bar-silver-coated copper powder is in the range of 0.10% or more and 40% or less. This is because, in the conductive paste containing the silver-coated copper powder according to the present invention, when each silver-coated copper powder is present in the above-mentioned ratio range, the conductive path between the projections of each silver-coated copper powder Is considered to be easy to form.
Moreover, as a compounding ratio of these silver-coated copper powder, although there is also an influence of the addition chemical | medical agent in the case of electrically conductive paste-izing, etc., it is not necessary to be equivalent. For example, with respect to 1 part of dendritic silver coated copper powder,
What is necessary is just a compounding ratio of 0.1-1000 number part of bowl-like silver-coated copper powder and 0.1-1000 number part of rod-like silver-coated copper powder.

In the silver-coated copper powder according to the present invention, sufficient conductivity can be ensured if the silver coating amount is 0.1% by mass or more. On the other hand, in terms of raw material cost, the silver coverage is preferably 30% by mass or less.

In the silver-coated copper powder according to the present invention, it is also preferable to provide one or more surface treatment agents on the surface of the silver-coated copper powder, if desired. By providing the surface treatment agent,
When the silver-coated copper powder is converted to a conductive paste, the dispersibility in the resin constituting the conductive paste is improved, and the chemical stability of the silver-coated copper powder in the resin is improved. It can.
And as a preferable example of the said surface treatment agent, stearic acid, palmitic acid, an oleic acid, 1H-benzotriazole, adipic acid, malonic acid, a succinic acid, azelaic acid etc. can be mentioned. One or more selected from these surface treatment agents can be provided on the surface of the silver-coated copper powder.
If the amount of the surface treatment agent provided on the surface of the silver-coated copper powder is 0.01% by mass or more, the above-described addition effect can be obtained. On the other hand, it is preferable that the quantity provided in the surface of silver covering copper powder is 2 mass% or less from the viewpoint of the influence which the said surface treating agent gives to electroconductivity, and raw material cost.

In the silver-coated copper powder according to the present invention, the BET value is preferably 0.1 m ² / g or more and 1.0 m ² / g or less. When the BET value is within the above range, when the silver-coated copper powder is made into a conductive paste, the dispersibility in the resin constituting the conductive paste is good, and the conductive path between the projections of each silver-coated copper powder is It is considered to be easy to form.

In the silver-coated copper powder according to the present invention, the TAP density value is 1 g / cm ³ or more, 5 g / cm ³
It is preferable to have the following. When the value of the TAP density is within the above range, when the silver-coated copper powder is made into a conductive paste, the dispersibility in the resin constituting the conductive paste is good, and the conductive between the projections of each silver-coated copper powder is It is thought that it is because it becomes easy to form a path.

The silver-coated copper powder which concerns on this invention can manufacture an electrically conductive paste by knead | mixing with appropriate resin and a solvent by a well-known method.

By using the silver-coated copper powder according to the present invention as described above for the conductive paste, the metal powder content is low even compared to when spherical or flake-like copper powder or silver-coated copper powder is used. It was possible to maintain the conductivity of the conductive paste.
This is because the silver-coated copper powder according to the present invention has a large number of projections, which makes it possible to form a large number of conductive paths between the projections in each other, which has a low metal powder content. It is considered that the conductivity of the conductive paste can be maintained.

2. Method for Producing Silver-Coated Copper Powder for Conductive Paste According to the Present Invention A method for producing silver-coated copper powder for conductive paste according to the present invention will be described with reference to the production flow shown in FIG.

Prepare pure water <1> and add ethylenediaminetetraacetic acid tetrasodium salt (EDTA · 4N)
a) 50% aqueous solution <2> and ammonium carbonate <3> were added <4>, dissolved <5>, and the solution temperature was adjusted to 10-45 ° C. to obtain <6> solution. In the solution, the concentration of tetrasodium ethylenediaminetetraacetate is 0.1 to 40% by mass, and the concentration of ammonium carbonate is 0.1 to 40% by mass. An aqueous solution of silver nitrate <7> is added to the solution <8> and mixed for 5 to 60 minutes <9> to prepare a silver complex salt solution. Silver concentration shall be 0.1-50 mass% in the said silver nitrate aqueous solution.

Prepare pure water <10> and add ethylenediaminetetraacetic acid tetrasodium salt (EDT)
A. 4Na) 50% aqueous solution <11>, ammonium carbonate <12> and optionally isopropyl alcohol <13> are added and dissolved <14><15>, and the solution temperature is adjusted to 10-45 ° C. The solution was obtained <16>. In the solution, the concentration of tetrasodium ethylenediaminetetraacetate is 0.1 to 40% by mass, the concentration of ammonium carbonate is 0.1 to 40% by mass, and the concentration of isopropyl alcohol is 0 to 40% by mass. Electrolytic copper powder <17> containing dendritic copper powder, cage-like copper powder and rod-like copper powder is added to the solution, <18>, stirring and holding for 5 to 60 minutes <19>, and copper powder dispersion Get In addition, as electrolytic copper powder <17>, a commercially available electrolytic copper powder containing dendritic copper powder, pot-like copper powder, and rod-like copper powder can be used.

The silver complex salt solution is added to the copper powder dispersion adjusted to 10 to 45 ° C. <20> to make a mixed solution, stirred for 5 to 60 minutes and aged <21>, and silver covering reaction to copper powder To produce a silver-coated copper powder.
The amount of silver added during the addition and mixing is 0.1 to 30% by mass with respect to the added electrolytic copper powder <17>
I assume.
At this time, the copper powder dispersion is placed in a dry nitrogen gas atmosphere, and the liquid temperature is 10 to 45.
After adjusting to ° C, addition and mixing can be performed while maintaining the liquid temperature at 10 to 45 ° C by adding the silver complex salt solution.

After the holding, if necessary, a solution of the surface treatment agent 1 (emulsion) <22> to the mixed solution.
<23>, and stirring is continued for 5 to 60 minutes to ripen <24>, and surface treatment of the produced silver-coated copper powder is performed.
Here, examples of the surface treatment agent 1 include palmitic acid, stearic acid, oleic acid and the like, and mixtures thereof. The addition amount of the surface treatment agent 1 in the solution of the surface treatment agent 1 (the emulsion of the surface treatment agent 1 or the mixed solution of the surface treatment agent 1 and alcohol) is 0.01 to 1.0 to the silver-coated copper powder. We assume mass%. In addition, the alcohol of the mixed solution of surface treatment agent 1 and alcohol is methanol, ethanol, isopropyl alcohol,
Various alcohols such as commercially available denatured alcohols can be used.

After the surface treatment, the mixture is filtered to obtain a filtrate, and the filtrate is washed with pure water.
25> Get a wet cake. The obtained wet cake is dried in a nitrogen atmosphere at 100 to 150 ° C. <26> to obtain a silver-coated copper powder. Use a vacuum dryer to dry 3
Drying may be performed at 0 to 100 ° C. From the obtained silver-coated copper powder, 25 to 50 μ openings
The coarse particles of <27> are removed by sieving operation m to obtain silver-coated copper powder <31> according to the present invention.
Here, the surface treatment agent 2 <28> is added to the silver-coated copper powder from which the coarse particles have been removed, if desired, to perform <29> surface treatment <30> to obtain the silver-coated copper powder <31> according to the present invention. It is good.
Here, as the surface treating agent 2, 1H-benzotriazole, adipic acid, malonic acid, succinic acid, azelaic acid and the like, and mixtures thereof can be mentioned. The addition amount of the surface treatment agent 2 shall be 0.01-1.0 mass% with respect to the said silver-coated copper powder.

Hereinafter, the present invention will be specifically described with reference to examples.
Example 1
197 g of ammonium carbonate and ethylenediaminetetraacetic acid tetrasodium salt (EDTA 4
Na) 50% aqueous solution (634 g) was dissolved in 729 g of pure water, and the solution temperature was adjusted to 25 ° C. to obtain a solution. The solution thus obtained was mixed with an aqueous solution of silver nitrate containing 27.8 g of silver to prepare a silver complex salt solution.
On the other hand, 178 g of ammonium carbonate and tetrasodium ethylenediaminetetraacetic acid salt (EDT
A. 4Na) 288 g of a 50% aqueous solution was dissolved in 2416 g of pure water to obtain a solution. To the resulting solution, 250 g of # 51-R (A) electrolytic copper powder manufactured by JX Nippon Mining & Metals Co., Ltd. was added and stirred to obtain a copper powder dispersion.
The copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C. Then, the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out to coat the silver Copper powder was produced. And the said liquid mixture was hold | maintained stirring for 30 minutes.
Thereafter, the mixed solution is filtered to obtain a filtrate, and the wet cake obtained by washing the filtrate with pure water is dried in a nitrogen atmosphere at 120 ° C. to obtain a silver-coated copper powder.
Coarse particles are removed from the obtained silver-coated copper powder using a sieve with an opening of 32 μm.
Silver-coated copper powder according to The preparation conditions of the said silver-coated copper powder are described in Table 3.

The BET value, TAP density, oxygen content, carbon content, and silver content of the silver-coated copper powder according to Example 1 were measured. The measurement results are described in Table 4. Next, the 10% cumulative particle size (D10), the 25% cumulative particle size (D25), the 50% cumulative particle size (D50), 75 of the silver-coated copper powder
% Cumulative particle size (D75), 90% cumulative particle size (D90), and further, color difference (L ^* ,
The a ^* and b ^* ) were measured. The measurement results are described in Table 4.

However, the BET value was determined by the BET method using a BET specific surface area measuring device (manufactured by Yua Sionix Inc .: 4 sorb US).
TAP density was measured based on Unexamined-Japanese-Patent No. 2007-263860.
Specifically, the sample was loaded into a mold (the height of the empty mold was h0 (μm), and the weight of the empty mold was w0 (mg)), and the sample was set to a micrometer. Next, the anvil of the micrometer was turned to compress the mold, the ratchet was clicked five times, the height of the mold at that time was read, and this height was set to h1 (μm). On the other hand, the weight of the mold containing the sample was measured, and the weight was defined as w1 (mg).
From the values of w0, w1, h0 and h1, the TAP density was determined by the following equation 1. Here, 36.6 is a coefficient.
TAP Density = 36.6 × (w1-w0) ÷ (h1-h0) (g / cm 3) ··· ( wherein 1
)
The oxygen content was measured by an oxygen / nitrogen analyzer (manufactured by LECO: model TC-436). The carbon content was measured by a carbon / sulfur analyzer (manufactured by Horiba, Ltd .: EMIA-220V).
The measuring method of Ag content is demonstrated.
2 g of a sample is weighed and transferred to a beaker while washing away with pure water, and then 10 ml of nitric acid is added and dissolved by heating. After allowing to cool, the solution is filtered to remove suspended organic components to obtain a filtrate. 100 ml of pure water is added to the filtrate, 6 ml of HCl is added, and the mixture is sufficiently stirred, and further HC
Add l. And after adding HCl until it can not precipitate new AgCl,
Heat and age until the solution becomes clear. Thereafter, it was filtered through a glass fiber filter (weight W1 (g)), and the recovered AgCl precipitate was dried by a drier at 110 ° C. for 3 hours. After cooling, the glass fiber filter and the recovered AgCl were combined and weighed, and the weight was set to W2 (g).
Ag content was calculated | required from following Formula 2 from the value of W1, W2.
Ag (mass%) = (W2-W1) / initial sample amount (g) × 0.7526 × 100.
(Formula 2)
The accumulated particle size was measured by a laser diffraction particle size distribution apparatus (manufactured by SYMPATEC, HEROS particle size distribution measuring apparatus, HELOS & RODOS).
Color difference is measured by a color difference meter (Nippon Denshoku Kogyo Co., Ltd. Spectro Color Meter
It measured by SQ2000).

(Example 2)
A silver-coated copper powder according to Example 2 was obtained in the same manner as in Example 1 except that the silver content in the aqueous silver nitrate solution was changed to 20.3 g. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 3)
A silver-coated copper powder according to Example 3 was obtained in the same manner as in Example 1 except that the silver content in the aqueous silver nitrate solution was changed to 13.2 g. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 4)
197 g of ammonium carbonate and ethylenediaminetetraacetic acid tetrasodium salt (EDTA 4
Na) 50% aqueous solution (634 g) was dissolved in 729 g of pure water, and the solution temperature was adjusted to 25 ° C. to obtain a solution. The solution thus obtained was mixed with an aqueous solution of silver nitrate containing 27.8 g of silver to prepare a silver complex salt solution.
On the other hand, 178 g of ammonium carbonate and tetrasodium ethylenediaminetetraacetic acid salt (EDT
A. 4Na) 288 g of a 50% aqueous solution was dissolved in 2416 g of pure water to obtain a solution. 100 g of isopropyl alcohol was added to the solution obtained and stirred, and further 250 g of electrolytic copper powder FCC-115 manufactured by Fukuda Metal Foil & Powder Co., Ltd. was added and stirred to obtain a copper powder dispersion.
The copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C. Then, the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out to coat the silver Copper powder was produced. And the said liquid mixture was hold | maintained stirring for 30 minutes.
Thereafter, the mixed solution is filtered to obtain a filtrate, and the wet cake obtained by washing the filtrate with pure water is dried in a nitrogen atmosphere at 120 ° C. to obtain a silver-coated copper powder. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 5)
A silver-coated copper powder according to Example 5 was obtained in the same manner as in Example 4 except that the silver content in the aqueous silver nitrate solution was changed to 20.3 g. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 6)
A silver-coated copper powder according to Example 6 was obtained in the same manner as in Example 5 except that the silver content in the aqueous silver nitrate solution was changed to 13.2 g. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 7)
An emulsion was prepared containing a mixture of 75% by weight of stearic acid and 25% by weight of palmitic acid as the surface treatment agent 1. The concentration of surface treatment agent 1 in the emulsion is 15
. The concentration of the surface treatment agent 1 was adjusted to 1.34 wt% by adding 5 wt% and further adding pure water. Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is kept for 30 minutes while being stirred, 26.7 g of the surface treatment agent 1 emulsion is added to the mixed solution, and the stirring is continued for 30 minutes, and the surface to the generated silver-coated copper powder is generated. A silver-coated copper powder according to Example 7 was obtained in the same manner as in Example 1 except that the treatment was performed. The amount of the surface treatment agent for copper powder according to Example 7 obtained was 0.143% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 8)
An emulsion comprising a mixture of 75% by weight of stearic acid and 25% by weight of palmitic acid as a surface treatment agent 1 was prepared. The concentration of surface treatment agent 1 in the emulsion is 15
. The concentration of the surface treatment agent 1 was adjusted to 1.34 wt% by adding 5 wt% and further adding pure water.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is kept for 30 minutes while being stirred, 26.7 g of the surface treatment agent 1 emulsion is added to the mixed solution, and the stirring is continued for 30 minutes, and the surface to the generated silver-coated copper powder is generated. A silver-coated copper powder according to Example 8 was obtained in the same manner as in Example 2 except that the treatment was performed. The amount of the surface treatment agent for copper powder according to Example 8 obtained is 0.143% by mass
Met. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 9)
An emulsion was prepared containing a mixture of 75% by weight of stearic acid and 25% by weight of palmitic acid as the surface treatment agent 1. The concentration of surface treatment agent 1 in the emulsion is 15
. The concentration of the surface treatment agent 1 was adjusted to 1.34 wt% by adding 5 wt% and further adding pure water.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is kept for 30 minutes while being stirred, 26.7 g of the surface treatment agent 1 emulsion is added to the mixed solution, and the stirring is continued for 30 minutes, and the surface to the generated silver-coated copper powder is generated. A silver-coated copper powder according to Example 9 was obtained in the same manner as in Example 3 except that the treatment was performed. The amount of the surface treatment agent for copper powder according to Example 9 obtained is 0.143% by mass
Met. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 10)
An emulsion was prepared containing a mixture of 75% by weight of stearic acid and 25% by weight of palmitic acid as the surface treatment agent 1. The concentration of surface treatment agent 1 in the emulsion is 15
. The concentration of the surface treatment agent 1 was adjusted to 1.34 wt% by adding 5 wt% and further adding pure water.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, after the mixed solution is kept stirred for 30 minutes, 106.9 g of the surface treatment agent 1 emulsion is added to the mixed solution, and the stirring is continued for 30 minutes, and the surface to the generated silver-coated copper powder is generated. A silver-coated copper powder according to Example 10 was obtained in the same manner as in Example 1 except that the treatment was performed. The amount of the surface treatment agent for copper powder according to Example 10 obtained is 0.286.
It was mass%. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 11)
The surface treatment agent 1 was changed to palmitic acid, and a mixed solution with alcohol was prepared. The concentration of palmitic acid in the mixed solution was 3.0 wt%. As alcohol, Solmix AP-7 manufactured by Japan Alcohol Sales Co., Ltd. was used.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is held for 30 minutes with stirring, and then 11.9 g of the surface treatment agent 1 alcohol mixed solution is added to the mixed solution, and the stirring is continued for 30 minutes to generate the above-mentioned silver-coated copper powder. Example 11 was carried out in the same manner as Example 1, except that the surface treatment of
Silver-coated copper powder according to The amount of the surface treatment agent for copper powder according to Example 11 obtained is 0.1.
It was 43% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 12)
The surface treatment agent 1 was stearic acid, and a mixed solution with alcohol was prepared. The concentration of stearic acid in the mixed solution was 3.0 wt%. As alcohol, Solmix AP-7 manufactured by Japan Alcohol Sales Co., Ltd. was used.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is held for 30 minutes with stirring, and then 11.9 g of the surface treatment agent 1 alcohol mixed solution is added to the mixed solution, and the stirring is continued for 30 minutes to generate the above-mentioned silver-coated copper powder. Example 12 was carried out in the same manner as Example 1, except that the surface treatment of
Silver-coated copper powder according to The amount of the surface treatment agent for copper powder according to Example 12 obtained is 0.1.
It was 43% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 13)
The surface treatment agent 1 was made into industrial stearic acid, and the mixed solution with alcohol was prepared. The concentration of industrial stearic acid in the alcohol mixture solution was 3.0 wt%. As alcohol, Solmix AP-7 manufactured by Japan Alcohol Sales Co., Ltd. was used.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is held for 30 minutes with stirring, and then 11.9 g of the surface treatment agent 1 alcohol mixed solution is added to the mixed solution, and the stirring is continued for 30 minutes to generate the above-mentioned silver-coated copper powder. Example 13 was carried out in the same manner as Example 1, except that the surface treatment of
Silver-coated copper powder according to The amount of the surface treatment agent for copper powder according to Example 13 obtained is 0.1.
It was 43% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 14)
The surface treatment agent 1 was oleic acid, and a mixed solution with alcohol was prepared. The concentration of oleic acid in the alcohol mixture solution was 10.0 wt%. As alcohol, Solmix AP-7 manufactured by Japan Alcohol Sales Co., Ltd. was used.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is held for 30 minutes with stirring, and then 1.7 g of the surface treatment agent 1 alcohol mixed solution is added to the mixed solution, and the stirring is continued for 30 minutes to generate the above-mentioned silver-coated copper powder. The silver coated copper powder which concerns on Example 14 was obtained by performing the same operation as Example 1 except having performed surface treatment of this. The amount of the surface treatment agent for copper powder according to Example 14 obtained is 0.14.
It was 3% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 15)
An emulsion was prepared containing a mixture of 75% by weight of stearic acid and 25% by weight of palmitic acid as the surface treatment agent 1. The concentration of surface treatment agent 1 in the emulsion is 15
. The concentration of the surface treatment agent 1 was adjusted to 1.34 wt% by adding 5 wt% and further adding pure water.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is held for 30 minutes with stirring, and then 22.8 g of the surface treatment agent 1 emulsion is added to the mixed solution, and the stirring is continued for 30 minutes, and the surface to the generated silver-coated copper powder is generated. A silver-coated copper powder according to Example 15 was obtained in the same manner as in Example 4 except that the treatment was performed. The amount of the surface treatment agent for copper powder according to Example 15 obtained was 0.122% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 16)
An emulsion was prepared containing a mixture of 75% by weight of stearic acid and 25% by weight of palmitic acid as the surface treatment agent 1. The concentration of the surface treatment agent 1 in the emulsion is 15.
The concentration of the surface treatment agent 1 was adjusted to 1.34 wt% by adding 5 wt% and further adding pure water.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is held for 30 minutes with stirring, and then 22.8 g of the surface treatment agent 1 emulsion is added to the mixed solution, and the stirring is continued for 30 minutes, and the surface to the generated silver-coated copper powder is generated. A silver-coated copper powder according to Example 16 was obtained by performing the same operation as Example 5 except that the treatment was performed. The amount of the surface treatment agent for copper powder according to Example 16 obtained was 0.122% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 17)
An emulsion was prepared containing a mixture of 75% by weight of stearic acid and 25% by weight of palmitic acid as the surface treatment agent 1. The concentration of the surface treatment agent 1 in the emulsion is 15.
The concentration of the surface treatment agent 1 was adjusted to 1.34 wt% by adding 5 wt% and further adding pure water.
Then, after the copper powder dispersion is placed in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., the silver complex salt solution is added to form a mixed solution, and the silver coating reaction on copper powder is carried out. Silver coated copper powder was produced. Then, the mixed solution is held for 30 minutes with stirring, and then 22.8 g of the surface treatment agent 1 emulsion is added to the mixed solution, and the stirring is continued for 30 minutes, and the surface to the generated silver-coated copper powder is generated. A silver-coated copper powder according to Example 17 was obtained in the same manner as in Example 6, except that the treatment was performed. The amount of the surface treatment agent for copper powder according to Example 17 obtained was 0.122% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 18)
220 g of silver-coated copper powder from which coarse particles have been removed using a sieve with an opening of 32 μm obtained by performing the same operation as in Example 1, 1H-benzotriazole as a surface treatment agent 2 (Wako Pure Chemical Industries, Ltd. A silver-coated copper powder according to Example 18 was obtained in the same manner as in Example 1 except that 0.32 g of special grade was added. The amount of the surface treatment agent for copper powder according to Example 18 was 0.143% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 19)
220 g of a silver-coated copper powder from which coarse particles were removed using a sieve with an opening of 32 μm obtained by performing the same operation as in Example 7 and a coffee mill as a surface treatment agent 2 (Select Blind MJ manufactured by Merita Japan Co., Ltd. The silver coating according to Example 19 is carried out in the same manner as in Example 7, except that 0.32 g of adipic acid (Wako Pure Chemical Industries, Ltd. Wako special grade) pulverized for a total of 40 seconds at -518) is mixed. I got a copper powder. The amount of the surface treatment agent for copper powder according to Example 19 was 0.143% by mass, and the amount of the surface treatment agent 2 was 0.143% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

Example 20
220 g of a silver-coated copper powder from which coarse particles have been removed using a sieve with an opening of 32 μm obtained by performing the same operation as in Example 19, and a coffee mill as a surface treatment agent 2 (Select Blind MJ manufactured by Merita Japan Co., Ltd. The silver coating according to Example 20 is carried out in the same manner as in Example 19, except that 0.32 g of adipic acid (Wako Pure Chemical Industries, Ltd. Wako special grade) pulverized in a total of 80 seconds by -518) is mixed. I got a copper powder. The amount of the surface treatment agent of the copper powder according to Example 20 was 0.143% by mass, and the amount of the surface treatment agent 2 was 0.143% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 21)
220 g of a silver-coated copper powder from which coarse particles have been removed using a sieve with an opening of 32 μm obtained by performing the same operation as in Example 19, and a coffee mill as a surface treatment agent 2 (Select Blind MJ manufactured by Merita Japan Co., Ltd. The silver coating according to Example 21 is carried out in the same manner as in Example 19, except that 0.32 g of adipic acid (Wako Pure Chemical Industries, Ltd. Wako special grade) pulverized for a total of 400 seconds at -518) is mixed. I got a copper powder. The amount of the surface treatment agent for copper powder according to Example 21 was 0.143% by mass, and the amount of the surface treatment agent 2 was 0.143% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 22)
A silver-coated copper powder according to Example 22 was obtained in the same manner as in Example 19, except that the silver content in the aqueous silver nitrate solution was changed to 20.3 g. The amount of the surface treatment agent of the copper powder according to Example 22 was 0.122% by mass, and the amount of the surface treatment agent 2 was 0.143% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 23)
A silver-coated copper powder according to Example 22 was obtained in the same manner as in Example 19, except that the silver content in the aqueous silver nitrate solution was changed to 13.2 g. The amount of the surface treatment agent for the copper powder according to Example 23 was 0.143% by mass, and the amount of the surface treatment agent 2 was 0.143% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 24)
Surface treatment agent 2 from adipic acid (Wako Pure Chemical Industries, Ltd. Wako special grade) to coffee mill (
Example 24 is carried out in the same manner as Example 19, except that malonic acid (Wako Pure Chemical Industries, Ltd. Wako special grade) pulverized for a total of 240 seconds is substituted by Merita Japan Ltd. select blind MJ-518). Silver-coated copper powder according to The amount of the surface treatment agent of the copper powder according to Example 24 was 0.143% by mass, and the amount of the surface treatment agent 2 was 0.143% by mass.
The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 25)
Surface treatment agent 2 from adipic acid (Wako Pure Chemical Industries, Ltd. Wako special grade) to coffee mill (
Example 25 is carried out in the same manner as Example 19, except that a succinic acid (Wako Pure Chemical Industries, Ltd. Wako special grade) pulverized for a total of 240 seconds with Merita Japan Ltd. Select Blind MJ-518) is substituted. Silver-coated copper powder according to The amount of the surface treatment agent for copper powder according to Example 25 was 0.143% by mass, and the amount of the surface treatment agent 2 was 0.143% by mass.
The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 26)
Example 19 except that a surface treating agent 2 was substituted from adipic acid to azelaic acid (for Wako Pure Chemical Industries, Ltd., chemical) crushed for a total of 240 seconds with a coffee mill (Select Blind MJ-518, manufactured by Melita Japan, Inc.) The same procedure as in the above was performed to obtain a silver-coated copper powder according to Example 26. The amount of the surface treatment agent for the copper powder according to Example 26 was 0.143% by mass, and the amount of the surface treatment agent 2 was 0.143% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 27)
220 g of a silver-coated copper powder from which coarse particles were removed using a sieve with an aperture of 32 μm obtained by performing the same operation as in Example 15, and adipic acid as a surface treatment agent 2 (manufactured by Wako Pure Chemical Industries, Ltd. Wako A silver-coated copper powder according to Example 27 was obtained in the same manner as in Example 15, except that special grade 0.27 g was mixed. The amount of the surface treatment agent for copper powder according to Example 27 was 0.122% by mass, and the amount of the surface treatment agent 2 was 0.122% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 28)
220 g of a silver-coated copper powder from which coarse particles were removed using a sieve with an aperture of 32 μm obtained by performing the same operation as in Example 15, and a coffee mill as a surface treatment agent 2 (Select Blind MJ manufactured by Merita Japan Co., Ltd. Silver coated according to Example 28 by the same operation as Example 15 except that adipic acid (manufactured by Wako Pure Chemical Industries, Ltd., Wako special grade) 0.27 g pulverized in a total of 40 seconds by -518) was mixed. I got a copper powder. The amount of the surface treatment agent for copper powder according to Example 28 was 0.122% by mass, and the amount of the surface treatment agent 2 was 0.122% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 29)
220 g of a silver-coated copper powder from which coarse particles were removed using a sieve with an aperture of 32 μm obtained by performing the same operation as in Example 15, and a coffee mill as a surface treatment agent 2 (Select Blind MJ manufactured by Merita Japan Co., Ltd. The silver coating according to Example 29 is carried out in the same manner as in Example 15, except that 0.44 g of adipic acid (Wako Pure Chemical Industries, Ltd., Wako special grade) pulverized in a total of 40 seconds in -518) is mixed. I got a copper powder. The amount of the surface treatment agent for the copper powder according to Example 29 was 0.122% by mass, and the amount of the surface treatment agent 2 was 0.2% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 30)
220 g of a silver-coated copper powder from which coarse particles have been removed using a sieve with an opening of 32 μm obtained by performing the same operation as in Example 17 and a coffee mill as a surface treatment agent 2 (Select Blind MJ manufactured by Merita Japan Co., Ltd. Silver coated copper according to Example 30 by the same operation as Example 17 except that adipic acid (manufactured by Wako Pure Chemical Industries, Ltd., Wako special grade) 0.27 g pulverized in a total of 40 seconds by -518) was mixed. I got a powder. The amount of the surface treatment agent for copper powder according to Example 30 was 0.122% by mass, and the amount of the surface treatment agent 2 was 0.122% by mass. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Example 31)
An emulsion comprising a mixture of 75% by weight of stearic acid and 25% by weight of palmitic acid as a surface treatment agent 1 was prepared. The concentration of the surface treatment agent 1 in the emulsion is 15.
The concentration of the surface treatment agent 1 was adjusted to 1.34 wt% by adding 5 wt% and further adding pure water.
Then, 25 g of isopropyl alcohol is added to the solution before adding the copper powder to the copper powder dispersion and stirred, and the copper powder dispersion is set in a dry nitrogen gas atmosphere to adjust the liquid temperature to 25 ° C., The silver complex solution was added to form a mixture, and a silver coating reaction on copper powder was carried out to form silver-coated copper powder. Then, the mixed solution is held for 30 minutes with stirring, and then 56.0 g of the surface treatment agent 1 emulsion is added to the mixed solution, and the stirring is continued for 30 minutes, and the surface to the generated silver-coated copper powder is generated. A silver-coated copper powder according to Example 31 was obtained in the same manner as in Example 15, except that the treatment was performed. The amount of the surface treatment agent for copper powder according to Example 31 obtained was 0.3 mass%. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Comparative example 1)
JX Nippon Mining & Metals Co., Ltd. # 51-R (A) electrolytic copper powder, wet spherical copper powder (D50 6
. A silver-coated copper powder according to Comparative Example 1 was obtained in the same manner as in Example 7 except that the thickness was changed to 4 μm. The amount of the surface treatment agent for the silver-coated copper powder according to Comparative Example 1 obtained is 0.143% by mass
Met. The preparation conditions of the said silver-coated copper powder are described in Table 3. In addition, the same measurement as in Example 1 is performed on the silver-coated copper powder, and the measurement result is described in Table 4.

(Summary)
As mentioned above, silver covering copper powder was prepared over Examples 1-31 changing the kind of surface treating agents 1 and 2, and the amount of addition. With respect to the silver-coated copper powder samples according to Examples 1 to 31, the SEM photograph of 1000 magnifications captured in 11 fields of view is taken, dendrite silver-coated copper powder, scale-like silver-coated copper powder, and rod-like silver The state of presence of the coated copper powder was measured.
Then, in the silver-coated copper powder samples according to Examples 1 to 31, it was found that dendritic silver-coated copper powder, cage-like silver-coated copper powder, and rod-like silver-coated copper powder are contained.
And, in any silver-coated copper powder sample, the dendritic silver-coated copper powder and the scaly silver-coated copper powder,
In the total number of rod-shaped silver-coated copper powder, the proportion of the number of dendritic-type silver-coated copper powder is 0. 0.
10% or more and 80% or less, or 0.10% or so of the number ratio of the bowl-like silver-coated copper powder
The percentage of the number occupied by the bar-silver-coated copper powder is 0.10% or more, or 75% or less.
It was less than 40%.
Furthermore, the silver coating amount was 0.1 mass% or more and 30 mass% or less in any silver-coated copper powder sample.
Also, BET value either silver-coated copper powder sample 0.1 m ² / g or more, was 1.0 m ² / g or less.
Moreover, as for any silver-coated copper powder sample, the value of TAP density was 1 g / cm ³ or more and 5 g / cm ³ or less.
From the above results, it is considered that any silver-coated copper powder sample is also a metal powder that can be used as a conductive paste that exhibits sufficient conductivity even with a low metal powder content.

Claims (6)

A silver-coated copper powder comprising dendritic silver-coated copper powder, scale-like silver-coated copper powder, and rod-like silver-coated copper powder,
The amount of the silver coating is 0.1% by mass or more and 30% by mass or less,
1 type selected from palmitic acid, stearic acid and oleic acid on the surface of the silver-coated copper powder, and 1 type selected from adipic acid, malonic acid, succinic acid and azelaic acid And a silver-coated copper powder provided with a surface treatment agent comprising a mixture thereof. A silver-coated copper powder comprising dendritic silver-coated copper powder, scale-like silver-coated copper powder, and rod-like silver-coated copper powder,
The amount of the silver coating is 0.1% by mass or more and 30% by mass or less,
1. A silver-coated copper powder, wherein a surface treatment agent comprising 1H-benzotriazole is provided on the surface of the silver-coated copper powder. A conductive paste comprising the silver-coated copper powder according to claim 1 or 2 . Silver coated copper powder, an emulsion comprising one or more selected from palmitic acid, stearic acid and oleic acid as a first surface treatment agent , or one or more selected from palmitic acid, stearic acid and oleic acid Adding a mixed solution with alcohol to form a mixed solution, and performing a first surface treatment on the silver-coated copper powder;
A second surface treatment agent containing one or more selected from adipic acid, malonic acid, succinic acid and azelaic acid is added to the first surface-treated silver-coated copper powder to perform surface treatment, 1) and a step of obtaining a silver-coated copper powder subjected to the second surface treatment, and a method of producing the silver-coated copper powder. A method for producing a silver-coated copper powder, comprising the step of adding a surface treatment agent comprising 1H-benzotriazole to silver-coated copper powder to perform surface treatment to obtain a silver-coated copper powder. A method for producing a conductive paste, comprising the step of kneading the silver-coated copper powder produced by the method for producing a silver-coated copper powder according to claim 4 or 5 with an appropriate resin and a solvent.