Patent ID: 7192461

Claim:
A high concentration silica slurry, consisting of: a fumed silica powder dispersed in a solvent, said solvent consisting of at least one selected from the group consisting of water and alcohols, said silica slurry having a silica concentration of more than 50% by weight and a viscosity of less than 1000 mPa·s, wherein said silica powder has a ratio DL/DT of less than 1.3, wherein DL is an average particle size of the silica powder measured by a laser diffraction particle size distribution method and DT is an average primary particle size of the silica powder measured by a TEM photography observation, wherein a ratio B/A is less than 1.5, where A is the viscosity of the slurry measured at the time of preparing and B is the viscosity after one month, and wherein said silica powder has a uniform particle size and an average primary particle size of from 0.08 μm to 0.8 μm.