Process for preparation of paper-making hydrous silicic acid filler
AssigneeOji Paper Co., Ltd.
InventorsShigeru Eimaeda, Kunihiko Aida, Shinji Seto, Takao Suzuki
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Abstract
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.
Claims11
A process for preparing a wet hydrous silicic acid filler used in the wet state for papermaking, consisting essentially of obtaining a slurry containing fine particles of hydrous silicic acid by neutralizing sodium silicate with sulfuric acid, and then pulverizing said slurry by use of a wet pulverizer so that the proportion of particles of hydrous silicic acid having a particle size of 1-30 .mu.m is at least 80% and the proportion of particles of hydrous silicic acid having a particle size of at least 70 .mu.m is not more than 0.4%.
A process for preparing a wet hydrous silicic acid filler used in the wet state for papermaking, consisting essentially of obtaining a slurry containing fine particles of hydrous silicic acid by neutralizing sodium silicate with sulfuric acid, and then classifying said slurry by the use of a wet classifier so that the proportion of particles of hydrous silicic acid having a particle size of 1-30 .mu.m is at least 80% and the proportion of particles of hydrous silicic acid having a particle size of at least 70 .mu.m is not more than 0.4%.
A process for preparing a wet hydrous silicic acid filler used in the wet state for papermaking, consisting essentially of obtaining a slurry containing fine particles of hydrous silicic acid by neutralizing sodium silicate with sulfuric acid, and then classifying and pulverizing said slurry by the combined use of a wet classifier and a wet pulverizer so that the proportion of particles of hydrous silicic acid having a particle size of 1-30 .mu.m is at least 80% and the proportion of particles of hydrous silicic acid having a particle size of at least 70 .mu.m is not more than 0.4%.
Dependencies are inferred from the claim text.