SPHERICAL PARTICLES OF SILICON DIOXIDE, COMPATIBLE WITH BIVALENT TIN COMPOUND, INTENDED FOR REDUCTION IN RDA VALUE Russian patent published in 2022 - IPC C01B33/12 C01B33/193 

FIELD: oral care.

SUBSTANCE: invention can be used in the manufacture of oral care products. Silicon dioxide particles are particles of amorphous precipitated silicon dioxide and are characterized by a median size d50 of 8-20 mcm; a sphericity coefficient (S₈₀) more than or equal to 0.9; a specific BET surface of 0.1-8 m²/g; a full pore volume determined using mercury porometry of 0.35-0.8 cm³/g; and losses on ignition (LOI) of 3-7 wt.%; Einlehner abrasion index of 7-25 mg of losses/100,000 revolutions; compatibility with a tin (II) compound of 70-99%; compatibility with SDAS of 70-99%; (d90-d10)/d50 from 1.1 to 2.2; amount of a residue on a sieve of 325 mesh, less than or equal to 1.2 wt.%; water absorption of 40-75 cm³/100 g; oil capacity of 20-75 cm³/100 g; CTAB surface area from 0 to 10 m²/g; losses on drying (LOD) of 1-15 wt.%; a value of relative abrasion degree (hereinafter – RDA) with content of 20 wt.% from 120 to about 200; and/or a value of the ratio of PCR/RDA with content of 20 wt.% from 0.4:1 to 0.8:1. The specified particles are obtained by a method including continuous loading of the first inorganic acid and the first alkali metal silicate to a loop reaction zone containing a fluid flow to form a basic silicon-oxide product in a liquid medium; continuous recirculation of the liquid medium through the loop reaction zone; continuous unloading from the loop reaction zone of part of the liquid medium, containing the basic silicon-oxide product; addition to the mixture of the second inorganic acid and the second alkali metal silicate in conditions of reduction in the surface area, stopping of addition to the mixture of the second alkali metal silicate, and continuation of addition of the second inorganic acid to provide a pH value of 5-8.5.

EFFECT: obtained particles have improved compatibility with a tin (II) compound, and oral care products containing them allow for reduction in dental plaque, gum inflammation, and tooth sensitivity.

18 cl, 10 dwg, 6 tbl, 11 ex