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Alumina powder, process for production of the same, and resin compositions containing the same

A technology of alumina powder and resin composition, applied in the field of alumina powder, to achieve the effect of high flow characteristics and large average circularity

Active Publication Date: 2011-04-06
DENKA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among the spherical alumina particles obtained by this method, even particles with an average sphericity of 0.90 or more have surface irregularities derived from the aluminum hydroxide raw material, and there is room for improvement
In addition, even when Bayer process alumina powder is used as a raw material, unevenness originating from the raw material appears on the surface, and there is room for improvement

Method used

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  • Alumina powder, process for production of the same, and resin compositions containing the same
  • Alumina powder, process for production of the same, and resin compositions containing the same
  • Alumina powder, process for production of the same, and resin compositions containing the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～9 and comparative example 1～3

[0068] Examples 1-9 and Comparative Examples 1-3 (manufacture of alumina powder)

[0069] [Manufacture of pulverized fused alumina]

[0070] Bayer process calcined alumina powder "D" (Nippon Light Metal Co., Ltd. A11) was melted, cooled, and pulverized in an electric arc furnace to produce fused alumina pulverized products "A", "B" and "C". Separate production of "A", "B" and "C" was carried out by adjusting the pulverization time.

[0071] A ball mill (AXB-15 manufactured by SEIWA GIKEN Co., Ltd.) was used for pulverization during raw material preparation, and alumina balls (balls with a diameter of 30 mm) were used as pulverization media.

[0072] Table 1 shows the types and average particle diameters of the alumina powder raw materials "A", "B", "C" and "D" used in the present invention.

[0073] [Manufacture of alumina powder]

[0074] [heat treatment]

[0075] heat treatment use figure 1 shown in the fabrication setup. Fuel gas (LPG) and combustion-supporting gas (...

Embodiment 11～19 and comparative example 11～13

[0098] In Examples 11-18 and Comparative Examples 11-13 in Table 3, 30 parts by volume of the resin complex shown in Table 5 and 70 parts by volume of the alumina powder obtained in the above-mentioned Examples 1-8 or Comparative Examples 1-3 Parts were mixed to prepare an epoxy resin composition. About each resin composition of these Examples and a comparative example, fluidity|fluidity and thermal conductivity were evaluated as follows.

[0099] In addition, in Example 19, an epoxy resin composition was prepared by mixing 20 parts by volume of the resin complex shown in Table 5 with 80 parts by volume of the alumina powder of Example 9, and its fluidity and thermal conductivity were evaluated in the following manner Rate.

[0100] In addition, the heat dissipation member used for the measurement of thermal conductivity was produced as follows. The semiconductor sealing material prepared by heating and kneading with a twin-screw extrusion kneader was poured into a plate-sha...

Embodiment 21～29 and comparative example 21～23

[0104] [Viscosity evaluation]

[0105] In Examples 21 to 28 and Comparative Examples 21 to 23 in Table 4, 40 parts by volume of liquid silicone rubber was mixed with 70 parts by volume of alumina powder obtained in Examples 1 to 8 or Comparative Examples 1 to 3 above to prepare silicon rubber. rubber composition. About each silicone rubber composition of this Example and a comparative example, the viscosity and thermal conductivity were evaluated as follows.

[0106] In Example 29, 30 parts by volume of liquid silicone rubber and 70 parts by volume of alumina powder obtained in Example 9 were mixed to prepare a silicone rubber composition, and the viscosity and thermal conductivity were evaluated as follows. In addition, YE5822A (manufactured by Momentive Material Co., Ltd.) was used as the liquid silicone rubber.

[0107] The obtained results are shown in Table 4 together with the production conditions of the alumina powder (Examples 1-9 and Comparative Examples 1-3).

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Abstract

Provided are an alumina powder improved in fluidity, a process for the production of the same, and resin compositions containing the same. An alumina powder which has an a-phase content of 40% or below as determined by the following method, average circularities of 0.95 or above in the particle size region of particle diameter of 45 to 200[mu]m and in that of particle diameter of less than 45[mu]m respectively, and a mean particle diameter of 100[mu]m or below. [Method for determining alpha-phase content] Powders prepared by mixing a-phase alumina powder and alpha-phase alumina powder at mass ratios of 0:10, 5:5, and 10:0 respectively are subjected to powder X-ray diffraction, and the integrated intensity of an alpha-phase peak detected in the neighborhood of a diffraction angle (2theta) of 43 DEG is calculated. A working curve of integrated intensity plotted against mixing ratio is made. Then, a sample alumina powder is subjected to X-ray diffraction, and the integrated intensity of a peak appearing in the neighborhood of a diffraction angle (2theta) of 43 DEG is calculated. The alpha-phase content of the sample alumina powder is determined on the basis of the working curve.

Description

technical field [0001] The present invention relates to an alumina powder having a large average circularity and improved flow properties when filled at a high filling rate, a method for producing the same, and a resin composition using the alumina powder. Background technique [0002] In recent years, as heat-generating electronic components such as ICs have become more functional and high-speed, the amount of heat generated by electronic devices incorporating these components has increased, and semiconductor sealing materials are also required to have high heat dissipation characteristics. In order to improve the heat dissipation characteristics of semiconductor sealing materials, alumina powder with high thermal conductivity can be added to the rubber or resin. If the general alumina powder produced by the Bayer process is used, there will be a significant increase in the filling rate due to the high filling rate. The thickening phenomenon cannot make full use of the ther...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C08K7/16C08L63/00C08L83/00C08L101/00C01F7/027
CPCC01F7/027C08G59/688C08L63/00C01P2004/52C08G59/621C08G59/3218C01P2004/61C01F7/02C08L83/04C08K7/16C01P2004/32C08K3/22Y10T428/2982
Inventor 田中孝明国友修水本贵久江崎寿下川明范
Owner DENKA CO LTD