| 摘要 |
A water repellent silica sol and a process for preparing said silica sol are disclosed. The water repellent silica sol comprises the colloidal silica particles whose surfaces have been made water-repellent with an organic group-substituted silane, said colloidal silica particles having the water repellent surfaces being 100 nm or below in size. The water repellent silica sol is produced by a process (I) which comprises reacting a silica colloid dispersed in a non-polar organic solvent with an organic group-substituted silane so that the surfaces of the colloidal silica particles are made water-repellent with said organic group-substituted silane or a process (II) which comprises adding a non-polar organic solvent, a cationic surface active agent and an organic groupsubstituted silane to a water-dispersed silica colloid, forming an emulsion therefrom, removing water from the emulsion by azeotropic dehydration and then refluxing the emulsion under heating.
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