Process for preparation of paper-making hydrous silicic acid filler

摘要

An improved paper-making hydrous acid filler is prepared by classifying or pulverizing a slurry containing fine particles of hydrous silicic acid, which is obtained by neutralizing sodium silicate with sulfuric acid, by a wet classifier or a wet pulverizer, so that the proportion of particles having a particles size of 1 to 30 mu m is at least 80% and the proportion of particles having a particle size of at least 70 mu m is not more than 0.4%. The filler has a function of improving the ink receptivity of the paper of the internal additive type and is capable of improving the opacity of the paper after printing.