Patent ID: 7820750

Claim:
A silica powder at least having, in a volume-based frequency distribution of particle size as determined by a laser diffraction-scattering technique, a maximum frequency value for a mode peak 1 present in a particle size range extending from 1.5 to 3.5 μm and a maximum frequency value for a mode peak 2 present in a particle size range extending from 25 to 40 μm, wherein the maximum frequency value for the mode peak 2 is greater than that for the mode peak 1 ; the mode peak 2 has a shoulder; the content of particles whose particle size ranges from 15 to 55 μm is larger than that of particles whose particle size ranges from 1 to 4 μm; the silica powder comprises: 35 to 55% by volume of particles having a particle size ranging from 15 to 55 μm; 10 to 30% by volume of particles having a particle size ranging from 1 to 4 μm; 0 to 5% by volume of particles having a particle size of greater than 55 μm; 0 to 10% by volume of particles having a particle size of smaller than 1 μm; and the balance of particles having a particle size of greater than 4 μm and less than 15 μm; and the shoulder for the mode peak 2 is present in the particle size range of from 4 to 20 μm and the content of the particles constituting the shoulder is 10 to 20% by volume of the total particles of the silica powder.