Abstract: The present invention provides ceramic powder capable of being incorporated into rubber or a resin for the preparation of a composition, which shows excellent heat resistance and flame retardancy and which is used, for instance, as a semiconductor-sealing material. The ceramic powder has a multi-peak frequency distribution pattern having at least two peaks as a particle size distribution as determined using a laser diffraction-scattering type particle size-analyzer, wherein the maximum particle size for the first peak ranges from 40 to 80 ?m and that for the second peak ranges from 3 to 8 ?m and wherein the rate of the particles having a particle size of not less than 20 ?m and less than 40 ?m is not more than 20% by mass (inclusive of 0% by mass).

Abstract: The present invention provides ceramic powder capable of being incorporated into rubber or a resin for the preparation of a composition, which shows excellent heat resistance and flame retardancy and which is used, for instance, as a semiconductor-sealing material. The ceramic powder has a multi-peak frequency distribution pattern having at least two peaks as a particle size distribution as determined using a laser diffraction-scattering type particle size-analyzer, wherein the maximum particle size for the first peak ranges from 40 to 80 ?m and that for the second peak ranges from 3 to 8 ?m and wherein the rate of the particles having a particle size of not less than 20 ?m and less than 40 ?m is not more than 20% by mass (inclusive of 0% by mass).

Abstract: The present invention provides ceramic powder capable of being incorporated into rubber or a resin for the preparation of a composition, which shows excellent heat resistance and flame retardancy and which is used, for instance, as a semiconductor-sealing material. The ceramic powder has a multi-peak frequency distribution pattern having at least two peaks as a particle size distribution as determined using a laser diffraction-scattering type particle size-analyzer, wherein the maximum particle size for the first peak ranges from 40 to 80 ?m and that for the second peak ranges from 3 to 8 ?m and wherein the rate of the particles having a particle size of not less than 20 ?m and less than 40 ?m is not more than 20% by mass (inclusive of 0% by mass).

Abstract: The present invention herein provides fine inorganic hollow powder having a high hollowness rate, which can be incorporated into, for instance, a low dielectric rubber or resin composition. The inorganic hollow powder has an average hollowness rate of higher than 70% by volume and an average particle size ranging from 3 to 20 ?m and the powder preferably has an average hollowness rate ranging from 75 to 85% by volume, an average particle size ranging from 5 to 15 ?m, a maximum particle size of not more than 25 ?m, a specific surface area of not more than 10 m2/g, an average sphericity degree of not less than 0.90 and a purity of not less than 99% by mass.

Abstract: Inorganic hollow powder is provided having a high purity, an enhanced fineness and a high hollowness. Specifically, inorganic hollow powder is provided having an average particle diameter of 1 to 5 ?m, the maximum particle diameter of 20 ?m or less, a particle size distribution standard deviation of 3 ?m or less, and an average hollowness of 35 to 70 vol %. The inorganic hollow powder is obtained, for instance, by supplying, via an inorganic feed material powder supply pipe at a discharge rate of 80 m/s or more, inorganic raw material powder having a specific surface area of 500 m2/g or more and an average particle diameter of 7 ?m or less, into a flame formed by a burner comprising at least a triple pipe portion sequentially arranged with, in order from outside, a combustion supporting gas supply pipe, a combustible gas supply pipe and the inorganic feed material powder supply pipe.

Abstract: The present invention provides ceramic powder capable of being incorporated into rubber or a resin for the preparation of a composition, which shows excellent heat resistance and flame retardancy and which is used, for instance, as a semiconductor-sealing material. The ceramic powder has a multi-peak frequency distribution pattern having at least two peaks as a particle size distribution as determined using a laser diffraction-scattering type particle size-analyzer, wherein the maximum particle size for the first peak ranges from 40 to 80 ?m and that for the second peak ranges from 3 to 8 ?m and wherein the rate of the particles having a particle size of not less than 20 ?m and less than 40 ?m is not more than 20% by mass (inclusive of 0% by mass).

Abstract: The present invention herein provides fine inorganic hollow powder having a high hollowness rate, which can be incorporated into, for instance, a low dielectric rubber or resin composition. The inorganic hollow powder has an average hollowness rate of higher than 70% by volume and an average particle size ranging from 3 to 20 ?m and the powder preferably has an average hollowness rate ranging from 75 to 85% by volume, an average particle size ranging from 5 to 15 ?m, a maximum particle size of not more than 25 ?m, a specific surface area of not more than 10 m2/g, an average sphericity degree of not less than 0.90 and a purity of not less than 99% by mass.

Abstract: A silica filler containing from 30 to 90 wt % of particles having a particle size of at least 30 .mu.m, wherein the roundness of the particles having a particle size of at least 30 .mu.m, is from 0.83 to 0.94.