| 摘要 |
A composition for blocking ultraviolet radiation comprising multi-layeredly encapsulated titanium dioxide and silica sol as active ingredients and a manufacturing process thereof are provided to minimize whitening event when it is applied to the skin, improve UV-blocking effects and use feeling, and enhance safety and photostability by reducing photocatalyst activity. The composition for blocking ultraviolet radiation comprises (a) an inorganic UV blocking agent and (b) inorganic silica sol as active ingredients, wherein the inorganic UV blocking agent is multi-layeredly encapsulated by silica sol, and the inorganic UV blocking agent has average diameter of 20-40 nm and is titanium dioxide, zinc oxide or cerium oxide having spherical shape; the inorganic silica gol represented by the formula(1) is prepared by mixing silica alkoxide, alcohol and water in which M is silica, R is methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl or octyl, and n is an integer from 3 to 8; and the silica alkoxide is tetra ethyl ortho silicate or tetra methyl ortho silicate.
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