AMORPHOUS SILICON DIOXIDES, METHOD OF PREPARING AMORPHOUS SILICON DIOXIDES AND COMPOSITION FOR MOUTH CAVITY BASED THEREON Russian patent published in 2001 - IPC

FIELD: abrasives in oral compositions. SUBSTANCE: described are abrasives in oral composition and method of preparing thereof, amorphous silicon dioxide has dentine abrasion radioactive index of 30-70; oil absorbing capacity of 100-155 cubic m/100 g, surface area BET of 50-200 sq.m/g. Method comprises adding sodium silicate solution to water at concentration. Sodium silicate concentration of 17.0-21.5 wt % and SiO₂:Na₂O molar ratio from 2.1 to 2.5; adding 15-20% aqueous sulfuric acid solution and sodium silicate at the same concentration and SiO₂:Na₂O ratio for period of more than 40 minutes and pH from 8 to 9.0; aging the resulting mixture at 90-100 C for 30 minutes; adding 15-20 % aqueous sulfuric acid solution to reduce pH to 3-5; aging mixture to 20 minutes at 90-100 C; adjusting pH to 3.5-5.0, filtering, washing and drying final liquid pasty compound. EFFECT: good cleaning properties of precipitated amorphous silicon dioxides having low abrasive characteristics. 11 cl, 5 ex, 2 tbl