| 摘要 |
PROBLEM TO BE SOLVED: To obtain an ultraviolet absorbing layered double hydroxide that solves the problems that an inorganic substance formulated to a sunscreening cream tends to become a stained substance with poor appearance, when the cream is applied to the skin, because the inorganic substance is not clear, and an organic compound for absorbing ultraviolet rays tends to cause side-effects, for example, skin inflammation, and the like. SOLUTION: The objective composition comprises an ultraviolet ray-absorbing compound and a layered double hydroxide represented by the formula I [Zn(1-x) Alx(OH)2]x+[(CO3)x.yH2O]x- (I) (wherein (x) is in the range of 0.1<=x<0.4; y is a real number larger than zero). The layered double hydroxide including an ultraviolet rays-absorbing compound is produced by adding the layered double hydroxide represented by the formula I or a heat-treated product of the layered double hydroxide represented by the formula I to an aqueous solution containing the ultraviolet rays- absorbing compound, mixing them under stirring and collecting the precipitate followed by drying the precipitate. In another embodiment, the layered double hydroxide containing the ultraviolet rays-absorbing compound is produced by adding dropwise a mixed aqueous solution of Zn(NO3)2 and Al(NO3)3 to an aqueous solution containing the ultraviolet rays-absorbing compound, adjusting the pH of the reaction mixture to 5-9, separating the precipitate, followed by drying the precipitate.
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