Copper flake powder, method for producing copper flake powder, and conductive paste using copper flake powder

Inactive Publication Date: 2006-06-29
MITSUI MINING & SMELTING CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0036] Further, it is preferable to use media beads, wherein the gravity of each of the media beads is from 3.0 g/cm3 to 6.5 g/cm3. In case of a specific gravity of the media beads is smaller than 3.0 g/cm3, so that it takes a long time for compressive deformation because the gravity of media beads is too light. Considering productivity of flake copper powder, this is not a reasonable condition for production. On the contrary, in a case of specific gravity of the media exceeds 6.5 g/cm3, the gravity of media beads becomes heavier, so that compressive deformation force of each of particles of copper powder becomes large and it becomes easy to condensate each powder particle. Additionally, it is unable to have uniformed thickness of flake copper powder after the deformation. By obtaining flake copper powder using the above-mentioned method, products can be produced effectively providing powder properties relating to flake copper powder of the present invention. In addition, the producing conductive paste for which this flake copper powder is used has excelle

Problems solved by technology

Further, the thickness of each of the powder particles is uneven and the particle distribution is uneven.
As apparent from the FIG. 2, thickness of co

Method used

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  • Copper flake powder, method for producing copper flake powder, and conductive paste using copper flake powder
  • Copper flake powder, method for producing copper flake powder, and conductive paste using copper flake powder
  • Copper flake powder, method for producing copper flake powder, and conductive paste using copper flake powder

Examples

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Example

EXAMPLE 1

[0040] In this example, copper powder obtained from raw material powder by a below-mentioned method is used, as starting powder for the production process of the present invention to produce flake copper powder.

[0041] The powder properties of the original powder utilized in this example are defined in that, the cumulative particle diameter; D50 was 0.35 μm, which was obtained using a laser diffraction scattering particle size distribution measurement method and average particle diameter; DIA was 0.20 μm obtained by an image analysis. Accordingly, an agglomerate value calculated on D50 / DIA was 1.75.

[0042] The above-mentioned original powder under agglomerate condition was circulated at 6500 rpm, with a Turbo classifier manufactured by Nissei Engineering Limited, which is a commercial pneumatic classification device to perform an operation by which agglomerate particles were made to be singular by colliding the powder particles against each other.

[0043] As a result, the c...

Example

EXAMPLE 2

[0049] In this example, copper powder obtained from raw material powder with the below-mentioned method was used, as starting powder in a production process of the present invention to produce flake copper powder.

[0050] Powder properties of the original powder utilized in this example are defined in that, the cumulative particle diameter, i.e., D50 value was 0.85 μm, in which the value was obtained using the laser diffraction scattering particle size distribution measurement method, and an average particle diameter, i.e., DIA value was 0.48 μm, which was obtained by image analysis. Accordingly, an agglomerate value calculated based on D50 / DIA value was 1.77.

[0051] With respect to the above-mentioned original particles powder under agglomerate condition, the powder was used in purified water as a copper powder slurry, and then circulated at 3000 rpm, with a fine flow mill manufactured by Pacific Machinery & Engineering Co., Ltd. which is a commercial fluid mill using a ce...

Example

EXAMPLE 3

[0056] In this example, copper powder obtained from raw material powder with a below-mentioned method was used, as starting in a production process of the present invention to produce flake copper powder. The raw material and starting powder utilized in this example were produced in the same way as in Example 2. Therefore, to avoid duplicate explanation about the properties of powder particle and similarly the properties after finishing the treatment, the explanation is omitted.

[0057] Next, 500 g of starting powder constituted by single particles in the same way as in Example 1 were used to compress powder particles of the starting powder and deform them by plastic deformation, so as to obtain from substantially spherical starting powder particles and the flake copper powder. However, in the media dispersion mill called the DISPERMAT D-5226 manufactured by VMG-GETAMANN used the processing time was only changed from Example 1 to 7 hours in this treatment. Then the powder p...

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Abstract

The present invention is mainly for providing a flake copper powder for a conductive paste with particle properties which are defined by that the particle thickness is thinner being possible for use to form an electrode or a circuit, and a production process thereof. To achieve the object of producing the following particles, each powder particles shape is plastically processed into a flake-shape, wherein the flake copper powder has a cumulative particle diameter D50 of 10 μm or smaller measured with laser diffraction scattering particle size distribution method. The D10, D50 and D90 measured with the laser diffraction scattering particle size distribution method are illustrative and the SD/D50 value measured by the standard deviation of particle distribution with the laser diffraction scattering particle size distribution, is 0.55 or larger and/or a D90/D10 of 4.5 or smaller. The flake copper powder is compressed with a high energy ball mill whose media beads having fine particle diameter which plastically deforms the copper particles into flake-shaped particles, so that stable flake copper powder is produced.

Description

TECHNICAL FIELD [0001] The present invention relates to flake copper powder, a method of producing flake copper powder and a conductive paste using the flake copper powder. BACKGROUND ART [0002] Conventionally flake copper powder has widely been used as raw material for a conductive paste. Also, conductive pastes have been typically applied to various electrical contacts in order to form a circuit of a printed-wiring board and an external electrode of a ceramic capacitor in order to ensure electrical conduction. [0003] Normal shape of flake copper powder is substantially spherical. When flake copper powder is processed to a conductive paste, some properties are required for such flake copper powder, in which viscosity of a conductive paste can be controlled to form a thinner electrode of chip material and enhance filling capability for a via-hole. When a conductive circuit is formed using a method of sintering and solidifying the circuit by drawing a conductive pattern with the cond...

Claims

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Application Information

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IPC IPC(8): B22F1/00B22F1/05B22F1/06B22F1/068B22F1/12C22C1/04H01B1/00H01B1/22H01L23/498H05K1/09
CPCB22F1/0007B22F1/0011H01L2924/0002H05K1/095H01L2924/09701H01L23/49883B22F2999/00B22F2998/00B22F1/0055B22F9/04H01L2924/00B22F1/05B22F1/068B22F1/12B22F1/06
Inventor SAKAUE, TAKAHIKOYASUNARI, KUNIHIKOYOSHIMARU, KATSUHIKO
Owner MITSUI MINING & SMELTING CO LTD
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